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Sample records for monoclinic crystal system

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

    Science.gov (United States)

    Schubert, Mathias

    2016-11-18

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

  2. Synthesis of monoclinic zinc diphosphide single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Mowles, T.A.

    1978-05-01

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

  3. Monoclinic deformation of calcite crystals at ambient conditions

    Science.gov (United States)

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

    2016-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-07

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

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

    Science.gov (United States)

    Isaak, D. G.; Ohno, I.

    2001-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Aina Mardia Akhmad Aznan

    2014-08-01

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

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

    Science.gov (United States)

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

    2015-12-10

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

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Science.gov (United States)

    Ghosh, Krishnendu; Singisetti, Uttam

    2016-08-01

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

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

    KAUST Repository

    Harb, Moussab

    2015-08-26

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

  11. Molecular replacement study on form-B monoclinic crystal of insulin

    Institute of Scientific and Technical Information of China (English)

    定瑾晖; 万柱礼; 常文瑞; 梁栋材

    1996-01-01

    The form-B monodinic insulin crystal was obtained from the sodium citrate buffer with 1% zinc chloride, keeping phenolic content between 0.76% and 1.25%. Its space group is P21, cell constants are: a = 4.924nm, b=6.094nm, c=4.818nm, β=95.8°. There are 6 insulin molecules which form a hexamer. The initial phase was obtained by using rotation function program of X-PLOR program package and molecular packing program of our laboratory. The molecular model was chosen from 4 zinc bovine insulin hexamer. After the preliminary refinement by using the rnacromolecular rigid body refinement technique, the molecular model was further refined and adjusted by using the energy-minimizing stereochemically restrained least-squared refinement on the difference Fourier maps. The finial R-factor is 214% at 0.3nm resolution, the r.m.s. deviations from standard bond length and bond angle are 0.0022nm and 4.7°, respectively.

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-15

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    NARCIS (Netherlands)

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

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

  17. A Process for Modelling Diffuse Scattering from Disordered Molecular Crystals, Illustrated by Application to Monoclinic 9-Chloro-10-methylanthracene

    Directory of Open Access Journals (Sweden)

    D. J. Goossens

    2015-01-01

    Full Text Available Diffuse scattering from a crystal contains valuable information about the two-body correlations (related to the nanoscale order in the material. Despite years of development, the detailed analysis of single crystal diffuse scattering (SCDS has yet to become part of the everyday toolbox of the structural scientist. Recent decades have seen the pair distribution function approach to diffuse scattering (in fact, total scattering from powders become a relatively routine tool. However, analysing the detailed, complex, and often highly anisotropic three-dimensional distribution of SCDS remains valuable yet rare because there is no routine method for undertaking the analysis. At present, analysis requires significant investment of time to develop specialist expertise, which means that the analysis of diffuse scattering, which has much to offer, is not incorporated thorough studies of many compounds even though it has the potential to be a very useful adjunct to existing techniques. This article endeavours to outline in some detail how the diffuse scattering from a molecular crystal can be modelled relatively quickly and largely using existing software tools. It is hoped this will provide a template for other studies. To enable this, the entire simulation is included as deposited material.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-09-03

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

  20. Phase Relationship in Phenol-Insulin Crystal Growth System

    Institute of Scientific and Technical Information of China (English)

    梁栋材; 宋浪舟; 万柱礼; 常文瑞

    1994-01-01

    Based on the crystal growth system of rhombohedral 2Zn-insulin,the phase transition ofinsulin crystals has been investigated with the phenol concentration as an independent component.The dia-gram of the phase relationship in this crystal growth system was established,and two points of phase transi-tion were found.The transition point Ⅰ indicates the phase transition between rhombohedral 2Zn-insulin crys-tal and rhombohedral 4Zn-insulin crystal,and these two phases coexist within a narrow region of phenol con-centration (0.028%-0.029% (g/ml)).Point Ⅱ at 0.76%-0.77% (g/ml) of phenol concentration showsthe phase transition between rhombohcdral crystal and monoclinic crystals,and a new phase of monocliniccrystal (B-form monoclinic insulin crystal) has been observed.This paper reports the diagram of phase rela-tionship obtained from our experiments,and analyses and discusses the dependence of phase transition of in-sulin crystals on phenol concentration in crystal growth system.

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

    Science.gov (United States)

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

    2000-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Chien Ing Yeo

    2016-08-01

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

  3. Dielectric frame, Sellmeier equations, and phase-matching properties of the monoclinic acentric crystal GdCasub>4sub>O(BOsub>3sub>)sub>3sub>.

    Science.gov (United States)

    Guo, Feng; Segonds, Patricia; Ménaert, Bertrand; Debray, Jerôme; Aka, Gerard; Loiseau, Pascal; Boulanger, Benoît

    2016-11-15

    We directly measured the phase-matching properties of the biaxial GdCasub>4sub>O(BOsub>3sub>)sub>3sub> (GdCOB) crystal using the sphere method. We studied second-harmonic generation and difference frequency generation in two principal planes of the crystal. All these data allowed us to refine the Sellmeier equations of the three principal refractive indices. These equations are valid over the entire transparency range of GdCOB and then could be used to calculate the tuning curves of infrared optical parametric generation.

  4. Polarized IR reflectance spectra of the monoclinic single crystal K2Ni(SO4)2.6H2O: dispersion analysis, dielectric and optical properties.

    Science.gov (United States)

    Ivanovski, Vladimir; Mayerhöfer, Thomas G; Popp, Jürgen; Petrusevski, Vladimir M

    2008-02-01

    Polarized IR reflectance spectra of K2Ni(SO4)2.6H2O single crystal (belonging to the group of Tutton salts) were recorded at near-normal incidence. From the dispersion analysis performed on the spectra recorded from the ac crystal plane, mode parameters: transversal frequency, oscillator strength, attenuation constant and the orientation of the transition moment were determined. The polarized spectrum along the b crystallographic axis was also recorded and a dispersion analysis performed. Comparison between the spectroscopically obtained transition moment directions with those obtained from the structure data for various modes is discussed. All dielectric tensor component values were obtained for the whole mid-IR frequency range. Also, the real and the imaginary parts of the complex indexes of refraction for the waves with wave vector in the direction of the b crystallographic axis and in the ac plane (when the direction of the electric vector is oriented along the b axis) were found as functions of frequency.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-10-15

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

  6. 2-(4-Fluorobenzylidenepropanedinitrile: monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Ahmed M. El-Agrody

    2013-04-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  8. Expression, Purification, Crystallization and Molecular Replacement Studies of TorI, an Inhibition Protein of Tor System

    Institute of Scientific and Technical Information of China (English)

    HUANG Wei; YUAN Cai; Ansaldi Mireille; Morelli Xavier; Edward J. Meehan; CHEN Li-Qing; HUANG Ming-Dong

    2007-01-01

    TorI, a Tor system inhibitor acting through protein-protein interaction with the TorR response regulator, is an excisionase that interacts with the integrase and DNA during prophage excision. It has been crystallized by the vapor-diffusion method using polyethylene glycol 3350 as a precipitant at pH 8.5. The X-ray diffraction data sets from the TorI crystal was collected at a resolution of 2.1 (A), using a synchrotron source. The crystal belongs to primitive monoclinic lattice with cell parameters of 46.210(A) × 53.992(A) × 73.561(A)

  9. 2,3-Dibromo-3-phenylpropanoic acid: a monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Trent R. Howard

    2016-11-01

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

  10. Crystal collimator systems for high energy frontier

    CERN Document Server

    AUTHOR|(CDS)2100516; Tikhomirov, Viktor; Lobko, Alexander

    2017-01-01

    Crystalline collimators can potentially considerably improve the cleaning performance of the presently used collimator systems using amorphous collimators. A crystal-based collimation scheme which relies on the channeling particle deflection in bent crystals has been proposed and extensively studied both theoretically and experimentally. However, since the efficiency of particle capture into the channeling regime does not exceed ninety percent, this collimation scheme partly suffers from the same leakage problems as the schemes using amorphous collimators. To improve further the cleaning efficiency of the crystal-based collimation system to meet the requirements of the FCC, we suggest here a double crystal-based collimation scheme, to which the second crystal is introduced to enhance the deflection of the particles escaping the capture to the channeling regime in its first crystal. The application of the effect of multiple volume reflection in one bent crystal and of the same in a sequence of crystals is simu...

  11. What causes the Besnus transition in monoclinic pyrrhotite?

    Science.gov (United States)

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

    2016-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Ahmed M. Orlando

    2010-08-01

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

  13. 1-Nitro-4-(4-nitrophenoxybenzene: a second monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Arif Nadeem

    2013-12-01

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

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

    Science.gov (United States)

    Mamivand, Mahmood

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

  15. Crystal collimator systems for high energy frontier

    Science.gov (United States)

    Sytov, A. I.; Tikhomirov, V. V.; Lobko, A. S.

    2017-07-01

    Crystalline collimators can potentially considerably improve the cleaning performance of the presently used collimator systems using amorphous collimators. A crystal-based collimation scheme which relies on the channeling particle deflection in bent crystals has been proposed and extensively studied both theoretically and experimentally. However, since the efficiency of particle capture into the channeling regime does not exceed ninety percent, this collimation scheme partly suffers from the same leakage problems as the schemes using amorphous collimators. To improve further the cleaning efficiency of the crystal-based collimation system to meet the requirements of the FCC, we suggest here a double crystal-based collimation scheme, to which the second crystal is introduced to enhance the deflection of the particles escaping the capture to the channeling regime in its first crystal. The application of the effect of multiple volume reflection in one bent crystal and of the same in a sequence of crystals is simulated and compared for different crystal numbers and materials at the energy of 50 TeV. To enhance also the efficiency of use of the first crystal of the suggested double crystal-based scheme, we propose: the method of increase of the probability of particle capture into the channeling regime at the first crystal passage by means of fabrication of a crystal cut and the method of the amplification of nonchanneled particle deflection through the multiple volume reflection in one bent crystal, accompanying the particle channeling by a skew plane. We simulate both of these methods for the 50 TeV FCC energy.

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Bonell Schmitt

    2011-08-01

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

  19. S-SAD phasing of monoclinic histidine kinase from Brucella abortus combining data from multiple crystals and orientations: an example of data-collection strategy and a posteriori analysis of different data combinations.

    Science.gov (United States)

    Klinke, Sebastián; Foos, Nicolas; Rinaldi, Jimena J; Paris, Gastón; Goldbaum, Fernando A; Legrand, Pierre; Guimarães, Beatriz G; Thompson, Andrew

    2015-07-01

    The histidine kinase (HK) domain belonging to the light-oxygen-voltage histidine kinase (LOV-HK) from Brucella abortus is a member of the HWE family, for which no structural information is available, and has low sequence identity (20%) to the closest HK present in the PDB. The `off-edge' S-SAD method in macromolecular X-ray crystallography was used to solve the structure of the HK domain from LOV-HK at low resolution from crystals in a low-symmetry space group (P21) and with four copies in the asymmetric unit (∼108 kDa). Data were collected both from multiple crystals (diffraction limit varying from 2.90 to 3.25 Å) and from multiple orientations of the same crystal, using the κ-geometry goniostat on SOLEIL beamline PROXIMA 1, to obtain `true redundancy'. Data from three different crystals were combined for structure determination. An optimized HK construct bearing a shorter cloning artifact yielded crystals that diffracted X-rays to 2.51 Å resolution and that were used for final refinement of the model. Moreover, a thorough a posteriori analysis using several different combinations of data sets allowed us to investigate the impact of the data-collection strategy on the success of the structure determination.

  20. Poloxamer thermogel systems as medium for crystallization.

    Science.gov (United States)

    Cespi, Marco; Bonacucina, Giulia; Casettari, Luca; Mencarelli, Giovanna; Palmieri, Giovanni Filippo

    2012-03-01

    To prepare a thermoreversible gel system able to work as a medium for crystallization at around 20°C, allowing easy retrieval of crystals by simply decreasing the gel temperature. Lactose was selected has model substance for crystallization. Water solutions with different% of poloxamer 407, α-Lactose monohydrate, and ethanol were prepared and analysed by rheology to understand how the different components alter the gelling temperature. The systems with the required characteristics for lactose crystallization were prepared and the crystals recovered by cooling and then filtering the dispersion. Rheological analysis showed interaction between the poloxamer and lactose. Increasing the quantity of poloxamer or lactose lowered the gelation temperature while the addition of small amounts of ethanol had a modest effect on the same property. These data were used to identify the ideal concentration of the components in order to prepare a system matching the features of our purpose. Such system yielded high quality crystals, with well-defined geometry and narrow particle size distribution. Poloxamer is a very interesting polymer in that it is able to generate a reversible gelling medium from which crystals can be harvested by filtering, without the addition of any chemicals to promote the sol-gel transition.

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

    DEFF Research Database (Denmark)

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

    1994-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Mohammad T. M. Al-Dajani

    2010-02-01

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

  3. Coulomb crystallization in classical and quantum systems

    Science.gov (United States)

    Bonitz, Michael

    2007-11-01

    Coulomb crystallization occurs in one-component plasmas when the average interaction energy exceeds the kinetic energy by about two orders of magnitude. A simple road to reach such strong coupling consists in using external confinement potentials the strength of which controls the density. This has been succsessfully realized with ions in traps and storage rings and also in dusty plasma. Recently a three-dimensional spherical confinement could be created [1] which allows to produce spherical dust crystals containing concentric shells. I will give an overview on our recent results for these ``Yukawa balls'' and compare them to experiments. The shell structure of these systems can be very well explained by using an isotropic statically screened pair interaction. Further, the thermodynamic properties of these systems, such as the radial density distribution are discussed based on an analytical theory [3]. I then will discuss Coulomb crystallization in trapped quantum systems, such as mesoscopic electron and electron hole plasmas in coupled layers [4,5]. These systems show a very rich correlation behavior, including liquid and solid like states and bound states (excitons, biexcitons) and their crystals. On the other hand, also collective quantum and spin effects are observed, including Bose-Einstein condensation and superfluidity of bound electron-hole pairs [4]. Finally, I consider Coulomb crystallization in two-component neutral plasmas in three dimensions. I discuss the necessary conditions for crystals of heavy charges to exist in the presence of a light component which typically is in the Fermi gas or liquid state. It can be shown that their exists a critical ratio of the masses of the species of the order of 80 [5] which is confirmed by Quantum Monte Carlo simulations [6]. Familiar examples are crystals of nuclei in the core of White dwarf stars, but the results also suggest the existence of other crystals, including proton or α-particle crystals in dense matter

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-02-25

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

  5. Data Acquisition System for Quartz Crystal Microbalances

    Directory of Open Access Journals (Sweden)

    Kleber Romero Felizardo

    2006-02-01

    Full Text Available This work presents a data acquisition system used in a mass sensor: quartz crystal microbalance. This system reads the frequency of this sensor along the time and sends the collected data to the computer through a serial interface.

  6. Single crystal growth and anisotropic crystal-fluid interface tension in soft colloidal systems

    NARCIS (Netherlands)

    Nguyen, V.D.; Hu, Z.; Schall, P.

    2011-01-01

    We measure the anisotropy of the crystal-fluid interfacial free energy in soft colloidal systems. A temperature gradient is used to direct crystal nucleation and control the growth of large single crystals in order to achieve well-equilibrated crystal-fluid interfaces. Confocal microscopy is used to

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

    Science.gov (United States)

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

    2014-08-15

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

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

    Directory of Open Access Journals (Sweden)

    Julia A. Rusanova

    2011-02-01

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

  9. Proton ordering in tetragonal and monoclinic H2O ice

    CERN Document Server

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  11. Curvature properties of the slowness surface of the system of crystal acoustics for cubic crystals

    OpenAIRE

    LIESS, Otto

    2008-01-01

    In this paper we study geometric properties of the slowness surface of the system of crystal acoustics for cubic crystals. In particular we shall study curvature properties of the surface and the behaviour of the surface near singular points. The main result is that in the generic nearly isotropic case there are no planes which are tangent to the surface along entire curves. This is in contrast with what happens for the slowness surface of the system of crystal optics for...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-01

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

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

    Science.gov (United States)

    Ochi, Masayuki; Akashi, Ryosuke; Kuroki, Kazuhiko

    2016-09-01

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

  14. Electrochemical system including lamella settler crystallizer

    Science.gov (United States)

    Maimoni, Arturo

    1988-01-01

    A crystallizer which incorporates a lamella settler and which is particularly applicable for use in batteries and power cells for electric vehicles or stationary applications. The lamella settler can be utilized for coarse particle separation or for agglomeration, and is particularly applicable to aluminum-air batteries or power cells for solving the hydrargillite (aluminum-hydroxide) removal problems from such batteries. This invention provides the advantages of very low energy consumption, turbulence, shear, cost and maintenance. Thus, due to the low shear and low turbulence of this invention, it is particularly effective in the control of aluminum hydroxide particle size distribution in the various sections of an aluminum-air system, as will as in other elecrochemical systems requiring separation for phases of different densities.

  15. Studies on synthesis, growth, structural, optical properties of organic 8-hydroxyquinolinium succinate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Thirumurugan, R., E-mail: singlecrystalxrd@gmail.com; Anitha, K., E-mail: singlecrystalxrd@gmail.com [School of Physics, Madurai Kamaraj University, Madurai-625021 (India)

    2014-04-24

    8-hydroxyquinolinium succinate (8HQSU), an organic material has been synthesized and single crystals were grown by employing the technique of slow evaporation. The structure of the grown crystal was elucidated by using single crystal X-ray diffraction analysis. 8HQSU crystal belongs to the monoclinic crystallographic system with non-centro symmetric space group of P2{sub 1}. FT-IR spectral investigation has been carried out to identify the various functional groups present in the grown crystal. UV–vis spectral studies reveal that 8HQSU crystals are transparent in the entire visible region and the cut-off wavelength has been found to be 220nm.

  16. Growth, Structural and Microhardness Studies on New Semiorganic Single Crystals of Calcium Para Nitrophenolate Dihydrate

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Good quality crystals of calcium p-nitrophenolate (NPCa) were grown from saturated solution by slow evaporation method. The crystal structure analysis and the molecular arrangement of these crystals were determined using X-ray diffraction (XRD). From single crystal XRD studies, NPCa is found to be crystallized in the monoclinic system with a space group P21/n. The functional groups of the material were confirmed qualitatively by FTIR (Fourier transform infrared spectroscopy) spectral analysis. Optical absorption studies reveal the absorption region and microhardness studies were carried out to confirm the mechanical behaviour of the crystals.

  17. Studies on growth, crystal structure and characterization of novel organic nicotinium trifluoroacetate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Dhanaraj, P.V. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Rajesh, N.P., E-mail: rajeshnp@hotmail.com [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Sundar, J. Kalyana; Natarajan, S. [Department of Physics, Madurai Kamaraj University, Madurai 625 021 (India); Vinitha, G. [Department of Physics, Crescent Engineering College, Chennai 600 048 (India)

    2011-09-15

    Highlights: {yields} Good quality crystals of nicotinium trifluoroacetate in monoclinic system were grown for first time. {yields} Nicotinium trifluoroacetate crystal exhibits third order nonlinear optical properties. {yields} The optical spectrum of nicotinium trifluoroacetate crystal reveals the wide transmission in the entire range with cutoff wavelength at 286 nm. {yields} Nicotinium trifluoroacetate is a low dielectric constant material. - Abstract: An organic material, nicotinium trifluoroacetate (NTF) was synthesized and single crystals in monoclinic system were grown from aqueous solution for the first time. Its solubility and metastable zone width were estimated. The crystal structure of NTF was analyzed to reveal the molecular arrangements and the formation of hydrogen bonds in the crystal. High-resolution X-ray diffraction rocking curve measurements were performed to analyze the structural perfection of the grown crystals. Functional groups in NTF were identified by Fourier transform infrared spectral analysis. Thermal behaviour and stability of NTF were studied by thermogravimetric and differential thermal analysis and differential scanning calorimetry. Mechanical and dielectric properties of NTF crystals were analyzed. Optical studies reveal that NTF crystals are transparent in the wavelength range 286-1100 nm. The third order nonlinear optical parameters of NTF were derived by the Z-scan technique.

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

    Science.gov (United States)

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

    2017-02-01

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

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

    Science.gov (United States)

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

    2011-11-01

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

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

    Science.gov (United States)

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

    2017-07-01

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

  1. Light scattering from macromolecular systems: Molecular crystals and polymers

    Science.gov (United States)

    Bernstein, E. R.

    1981-11-01

    The research objectives were to: (1) characterize phase transitions theoretically and experimentally in molecular crystal systems; (2) use the above understanding gained by light scattering studies and theoretical interpretation to apply to the more complex system of lyotropic liquid crystals; and (3) then apply knowledge gained on the model systems of increasing complexity to polymer liquid crystals and solid polymers as observed by laser light scattering techniques. Systems experimentally and theoretically discussed are: trioxane, triazine, benzil, and chloranil. Studies of lyotropic liquid crystals (sodium decyl sulfate, sodium sulfate, decanol, water) have progressed. The major findings are: a number of phase transitions occur between 20 and 60 C; these transitions evidence strong critical behavior and long correlation times for fluctuations; and liquid crystals can be studied by light scattering. Spectra of solid powders, ribbons, and liquid crystals of PBT and solid PBO were obtained.

  2. Growth and Characterization of Organic NLO Crystal: β-Naphthol

    Institute of Scientific and Technical Information of China (English)

    S.Janarthanan; R.Sugaraj Samuel; S.Selvakumar; Y.C.Rajan; D.Jayaraman; S.Pandi

    2011-01-01

    Single crystals ofβ-Naphthol (βN), an organic nonlinear optical (NLO) material was successfully grown by temperature lowering method using chloroform as solvent. The initial compound was purified by repeated recrystallization process. As-grown crystals were characterized by single crystal X-ray diffraction (XRD) studies to ascertain that βN crystal crystallized in the monoclinic system with a noncemtrosymmetric space group. Vibrational frequencies of various functional groups in the crystals were derived from Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (NMR) spectrum. Optical characterization was done using UV-Visible near-infrared (NIR) spectroscopy. The thermal behaviour of the material was studied by thermo gravimetric and differential thermal plots. Scanning electron microscopy (SEM) study was carried out on the surface of the grown crystals to investigate the nature of defects in the crystal surface and the NLO property of the crystal was tested by Nd:YAG laser as a source.

  3. CRYSTAL GROWTH OF RARE EARTH COMPOUNDS IN CLOSED SYSTEM

    OpenAIRE

    1991-01-01

    Remarkable improvements have been made on the crystal growth of rare earth pnictides and chalchogenides by the development of new growth technique and the construction of several new equipments for the crystal growth such as electron beam welding system of tungsten crucible provided with large glove box and vacuum HF furnace. This system has really worked on obtaining excellent quality of single crystals and made easier to explore unknown materials of rare earth compounds. Interesting and att...

  4. Mimer: an automated spreadsheet-based crystallization screening system.

    Science.gov (United States)

    Brodersen, Ditlev Egeskov; Andersen, Gregers Rom; Andersen, Christian Brix Folsted

    2013-07-01

    In this paper, a simple low-cost alternative to large commercial systems for preparing macromolecular crystallization conditions is described. Using an intuitive spreadsheet-based approach, the system allows the rapid calculation of relevant pipetting volumes given known stock-solution concentrations and incorporates the automatic design of custom crystallization screens via the incomplete-factorial and grid-screen approaches. Automated dispensing of the resulting crystallization screens is achieved using a generic and relatively inexpensive liquid handler.

  5. 1-Nitro-4-(4-nitro-phen-oxy)benzene: a second monoclinic polymorph.

    Science.gov (United States)

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

    2013-11-01

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

  6. Crystallization Methods for Preparation of Nanocrystals for Drug Delivery System.

    Science.gov (United States)

    Gao, Yuan; Wang, Jingkang; Wang, Yongli; Yin, Qiuxiang; Glennon, Brian; Zhong, Jian; Ouyang, Jinbo; Huang, Xin; Hao, Hongxun

    2015-01-01

    Low water solubility of drug products causes delivery problems such as low bioavailability. The reduced particle size and increased surface area of nanocrystals lead to the increasing of the dissolution rate. The formulation of drug nanocrystals is a robust approach and has been widely applied to drug delivery system (DDS) due to the significant development of nanoscience and nanotechnology. It can be used to improve drug efficacy, provide targeted delivery and minimize side-effects. Crystallization is the main and efficient unit operation to produce nanocrystals. Both traditional crystallization methods such as reactive crystallization, anti-solvent crystallization and new crystallization methods such as supercritical fluid crystallization, high-gravity controlled precipitation can be used to produce nanocrystals. The current mini-review outlines the main crystallization methods addressed in literature. The advantages and disadvantages of each method were summarized and compared.

  7. An automatic system for crystal growth studies at constant supersaturation

    Science.gov (United States)

    March, J. G.; Costa-Bauzá, A.; Grases, F.; Söhnel, O.

    1992-01-01

    An automatic system for growing crystals from seeded supersaturated solutions at constant supersaturation is described. Control of burettes and data acquisition are controlled by computer. The system was tested with a study of the calcium oxalate kinetics of crystal growth. PMID:18924950

  8. Crystallization dynamics in glass-forming systems

    Energy Technology Data Exchange (ETDEWEB)

    Cullinan, Timothy Edward [Iowa State Univ., Ames, IA (United States)

    2016-02-19

    Crystallization under far-from-equilibrium conditions is investigated for two different scenarios: crystallization of the metallic glass alloy Cu50Zr50 and solidification of a transparent organic compound, o-terphenyl. For Cu50Zr50, crystallization kinetics are quanti ed through a new procedure that directly fits thermal analysis data to the commonly utilized JMAK model. The phase evolution during crystallization is quantified through in-situ measurements (HEXRD, DSC) and ex-situ microstructural analysis (TEM, HRTEM). The influence of chemical partitioning, diffusion, and crystallographic orientation on this sequence are examined. For o-terphenyl, the relationship between crystal growth velocity and interface undercooling is systematically studied via directional solidification.

  9. Designing Robust Process Analytical Technology (PAT) Systems for Crystallization Processes: A Potassium Dichromate Crystallization Case Study

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan

    2013-01-01

    The objective of this study is to test and validate a Process Analytical Technology (PAT) system design on a potassium dichromate crystallization process in the presence of input uncertainties using uncertainty and sensitivity analysis. To this end a systematic framework for managing uncertainties...... in the nucleation and crystal growth parameters affect the product-process performances (e.g. crystal size distribution (CSD)). Analysis of the proposed PAT system design (closedloop), on the other hand, shows that the effect of the input uncertainties on the outputs (product quality) is minimized, and the target...

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

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

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

    CERN Document Server

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

    2003-01-01

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

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

    Science.gov (United States)

    Ghosh, Krishnendu; Singisetti, Uttam

    2017-07-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

    2008-11-01

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

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

    Science.gov (United States)

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

    2013-07-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

  17. Physicochemical properties of dimethylammonium p-nitrophenolate– p-nitrophenol: A nonlinear optical crystal

    Energy Technology Data Exchange (ETDEWEB)

    Rathika, A. [Department of Physics, Noorul Islam Centre for Higher Education, Noorul Islam University, Kumaracoil 629 180 (India); Prasad, L. Guru [Departemnt of Science & Humanities, M. Kumarasamy College of Engineering, Karur (India); Raman, R. Ganapathi, E-mail: ganapathiraman83@gmail.com [Department of Physics, Noorul Islam Centre for Higher Education, Noorul Islam University, Kumaracoil 629 180 (India)

    2016-03-15

    Single crystals of Dimethylammonium p-nitrophenolate–p-nitrophenol have been grown from aqueous solution by slow evaporation solution growth technique. Unit cell parameters of the grown crystal were confirmed by single crystal X-ray diffraction analysis and the synthesized compound is crystallized in monoclinic system. Various functional groups and their vibrational frequencies were recognized from the FT-IR and FT-Raman spectrum. Thermal stability of the crystal was examined by recording the TGA/DTA curve. The grown crystal has wider transparency nature in the visible region and the lower cut-off wavelength is found at 465 nm. Mechanical property of the crystal was studied by analyzing the Vicker's microhardness measurements. The fluorescence emission from the crystal is observed at 350 nm which arise due to the presence of aromatic ring. Relative SHG conversion efficiency of the grown crystal is about 0.59 times that of KDP.

  18. Physicochemical properties of dimethylammonium p-nitrophenolate- p-nitrophenol: A nonlinear optical crystal

    Science.gov (United States)

    Rathika, A.; Prasad, L. Guru; Raman, R. Ganapathi

    2016-03-01

    Single crystals of Dimethylammonium p-nitrophenolate-p-nitrophenol have been grown from aqueous solution by slow evaporation solution growth technique. Unit cell parameters of the grown crystal were confirmed by single crystal X-ray diffraction analysis and the synthesized compound is crystallized in monoclinic system. Various functional groups and their vibrational frequencies were recognized from the FT-IR and FT-Raman spectrum. Thermal stability of the crystal was examined by recording the TGA/DTA curve. The grown crystal has wider transparency nature in the visible region and the lower cut-off wavelength is found at 465 nm. Mechanical property of the crystal was studied by analyzing the Vicker's microhardness measurements. The fluorescence emission from the crystal is observed at 350 nm which arise due to the presence of aromatic ring. Relative SHG conversion efficiency of the grown crystal is about 0.59 times that of KDP.

  19. Synthesis and crystal structure determination of Br2SeIBr polyhalogen–chalcogen

    Indian Academy of Sciences (India)

    A A Alemi; E Solaimani

    2004-06-01

    In this paper polyhalogen–chalcogen Br2SeIBr was synthesized and the crystal structure was determined by single crystal X-ray diffraction method. This compound was prepared in the temperature range 150–50°C which was brownish-red in colour and crystallized in monoclinic crystal system and space group 21/c with four molecules per unit cell. Lattice parameters were: = 6.3711(1), = 6.7522(2), = 16.8850(5) Å, = = 90°, = 95·96°, = 722·45 Å3.

  20. Crystallization inhibition of an amorphous sucrose system using raffinose

    Institute of Scientific and Technical Information of China (English)

    LEINEN K.M.; LABUZA T.P.

    2006-01-01

    The shelf life of pure amorphous sucrose systems, such as cotton candy, can be very short. Previous studies have shown that amorphous sucrose systems held above the glass transition temperature will collapse and crystallize. One study,however, showed that adding a small percent of another type of sugar, such as trehalose, to sucrose can extend the shelf life of the amorphous system by slowing crystallization. This study explores the hypothesis that raffinose increases the stability of an amorphous sucrose system. Cotton candy at 5 wt% raffinose and 95 wt% sucrose was made and stored at room temperature and three different relative humidities (%RH) 11%RH, 33%RH, and 43%RH. XRD patterns, and glass transition temperatures were obtained to determine the stability as a function of %RH. The data collected showed that raffinose slows sucrose crystallization in a low moisture amorphous state above the glass transition temperature and therefore improves the stability of amorphous sucrose systems.

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

    Science.gov (United States)

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

    2011-01-01

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

  2. Non-laminate Microstructures in Monoclinic-I Martensite

    CERN Document Server

    Chenchiah, Isaac Vikram

    2012-01-01

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

  3. Non-Laminate Microstructures in Monoclinic-I Martensite

    Science.gov (United States)

    Chenchiah, Isaac Vikram; Schlömerkemper, Anja

    2013-01-01

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

  4. Temperature-induced reversible first-order single crystal to single crystal phase transition in Boc-γ(4)(R)Val-Val-OH: interplay of enthalpy and entropy.

    Science.gov (United States)

    Pal, Rumpa; Reddy, M B Madhusudana; Dinesh, Bhimareddy; Balaram, Padmanabhan; Guru Row, Tayur N

    2014-10-01

    Crystals of Boc-γ(4)(R)Val-Val-OH undergo a reversible first-order single crystal to single crystal phase transition at Tc ≈ 205 K from the orthorhombic space group P22121 (Z' = 1) to the monoclinic space group P21 (Z' = 2) with a hysteresis of ∼2.1 K. The low-temperature monoclinic form is best described as a nonmerohedral twin with ∼50% contributions from its two components. The thermal behavior of the dipeptide crystals was characterized by differential scanning calorimetry experiments. Visual changes in birefringence of the sample during heating and cooling cycles on a hot-stage microscope with polarized light supported the phase transition. Variable-temperature unit cell check measurements from 300 to 100 K showed discontinuity in the volume and cell parameters near the transition temperature, supporting the first-order behavior. A detailed comparison of the room-temperature orthorhombic form with the low-temperature (100 K) monoclinic form revealed that the strong hydrogen-bonding motif is retained in both crystal systems, whereas the non-covalent interactions involving side chains of the dipeptide differ significantly, leading to a small change in molecular conformation in the monoclinic form as well as a small reorientation of the molecules along the ac plane. A rigid-body thermal motion analysis (translation, libration, screw; correlation of translation and libration) was performed to study the crystal entropy. The reversible nature of the phase transition is probably the result of an interplay between enthalpy and entropy: the low-temperature monoclinic form is enthalpically favored, whereas the room-temperature orthorhombic form is entropically favored.

  5. Designing Robust Process Analytical Technology (PAT) Systems for Crystallization Processes: A Potassium Dichromate Crystallization Case Study

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan

    2013-01-01

    The objective of this study is to test and validate a Process Analytical Technology (PAT) system design on a potassium dichromate crystallization process in the presence of input uncertainties using uncertainty and sensitivity analysis. To this end a systematic framework for managing uncertaintie...

  6. Solid State Synthesis and Properties of Monoclinic Celsian

    Science.gov (United States)

    Bansal, Narottam P.

    1996-01-01

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

  7. Curvature properties of the slowness surface of the system of crystal acoustics for cubic crystals II

    OpenAIRE

    LIESS, Otto; Sonobe, Tetsuya

    2012-01-01

    In this paper we study geometric properties of the slowness surface of the system of crystal acoustics for cubic crystals in the special case when the stiffness constants satisfy the condition $a = -2b$. The paper is a natural continuation of the paper [9] in which related properties were studied for general constants $a$ and $b$, but assuming that we were in the nearly isotropic case, in which case $a - b$ has to be small. We also take this opportunity to correct a state...

  8. Neutron imaging systems utilizing lithium-containing semiconductor crystals

    Energy Technology Data Exchange (ETDEWEB)

    Stowe, Ashley C.; Burger, Arnold

    2017-04-25

    A neutron imaging system, including: a plurality of Li-III-VI.sub.2 semiconductor crystals arranged in an array, wherein III represents a Group III element and VI represents a Group VI element; and electronics operable for detecting and a charge in each of the plurality of crystals in the presence of neutrons and for imaging the neutrons. Each of the crystals is formed by: melting the Group III element; adding the Li to the melted Group III element at a rate that allows the Li and Group III element to react, thereby providing a single phase Li-III compound; and adding the Group VI element to the single phase Li-III compound and heating. Optionally, each of the crystals is also formed by doping with a Group IV element activator.

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

    Science.gov (United States)

    Zhao, Zongyan; Li, Zhaosheng; Zou, Zhigang

    2011-03-14

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

  10. Bcc crystal-fluid interfacial free energy in Yukawa systems.

    Science.gov (United States)

    Heinonen, V; Mijailović, A; Achim, C V; Ala-Nissila, T; Rozas, R E; Horbach, J; Löwen, H

    2013-01-28

    We determine the orientation-resolved interfacial free energy between a body-centered-cubic (bcc) crystal and the coexisting fluid for a many-particle system interacting via a Yukawa pair potential. For two different screening strengths, we compare results from molecular dynamics computer simulations, density functional theory, and a phase-field-crystal approach. Simulations predict an almost orientationally isotropic interfacial free energy of 0.12k(B)T/a(2) (with k(B)T denoting the thermal energy and a the mean interparticle spacing), which is independent of the screening strength. This value is in reasonable agreement with our Ramakrishnan-Yussouff density functional calculations, while a high-order fitted phase-field-crystal approach gives about 2-3 times higher interfacial free energies for the Yukawa system. Both field theory approaches also give a considerable anisotropy of the interfacial free energy. Our result implies that, in the Yukawa system, bcc crystal-fluid free energies are a factor of about 3 smaller than face-centered-cubic crystal-fluid free energies.

  11. A nondestructive characterization system of periodically poled crystals

    Science.gov (United States)

    Chen, Huaixi; Zhou, Huang; Chen, Liyuan; Zou, Xiaolin; Miao, Long; Feng, Xinkai; Li, Guangwei; Liang, Wanguo

    2015-08-01

    Periodically poled crystals are widely used as SHG, DFG, SFG, OPO and THz generation, and there is a broad application prospect in some areas such as the laser display, optical fiber communication, atmospheric exploration and military confrontation. At present, to get the parameters of periodically poled crystals, like duty ratio, the main method is chemical etching of the samples. In this paper, we present a nondestructive characterization system of periodically poled crystals. When we apply a proper high voltage on both sides of the periodically poled crystal, the refractive index difference of positive and negative domain will be increased and we can observe a clear domain pattern by the a microscope so as to obtain general information. Then a single frequency laser is prepared to radiate on +z surface of the periodically poled crystal, we can get some orders of diffraction according to diffraction optics principle. Finally, we can measure the parameters such as period, duty ratio by use of numerical analysis. The testing sample size of this system can be up to 60mm, The accuracy of the testing period can be 0.1μm, and the measurement range of duty ratio is 20%-50%.

  12. Epsilon Systems on Geometric Crystals of type $A_n$

    CERN Document Server

    Nakashima, Toshiki

    2009-01-01

    We introduce an epsilon system on a geometric crystal of type $A_n$, which is a certain set of rational functions with some conditions. We shall show that there is a product structure and that it is invariant under the action of tropical R maps.

  13. Epsilon Systems on Geometric Crystals of type A_n

    Directory of Open Access Journals (Sweden)

    Toshiki Nakashima

    2010-03-01

    Full Text Available We introduce an epsilon system on a geometric crystal of type A_n, which is a certain set of rational functions with some nice properties. We shall show that it is equipped with a product structure and that it is invariant under the action of tropical R maps.

  14. Critical Time Crystals in Dipolar Systems

    Science.gov (United States)

    Ho, Wen Wei; Choi, Soonwon; Lukin, Mikhail D.; Abanin, Dmitry A.

    2017-07-01

    We analyze the quantum dynamics of periodically driven, disordered systems in the presence of long-range interactions. Focusing on the stability of discrete time crystalline (DTC) order in such systems, we use a perturbative procedure to evaluate its lifetime. For 3D systems with dipolar interactions, we show that the corresponding decay is parametrically slow, implying that robust, long-lived DTC order can be obtained. We further predict a sharp crossover from the stable DTC regime into a regime where DTC order is lost, reminiscent of a phase transition. These results are in good agreement with the recent experiments utilizing a dense, dipolar spin ensemble in diamond [Nature (London) 543, 221 (2017), 10.1038/nature21426]. They demonstrate the existence of a novel, critical DTC regime that is stabilized not by many-body localization but rather by slow, critical dynamics. Our analysis shows that the DTC response can be used as a sensitive probe of nonequilibrium quantum matter.

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

    Directory of Open Access Journals (Sweden)

    Saray Argibay-Otero

    2017-10-01

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

  16. Critical Time Crystals in Dipolar Systems.

    Science.gov (United States)

    Ho, Wen Wei; Choi, Soonwon; Lukin, Mikhail D; Abanin, Dmitry A

    2017-07-07

    We analyze the quantum dynamics of periodically driven, disordered systems in the presence of long-range interactions. Focusing on the stability of discrete time crystalline (DTC) order in such systems, we use a perturbative procedure to evaluate its lifetime. For 3D systems with dipolar interactions, we show that the corresponding decay is parametrically slow, implying that robust, long-lived DTC order can be obtained. We further predict a sharp crossover from the stable DTC regime into a regime where DTC order is lost, reminiscent of a phase transition. These results are in good agreement with the recent experiments utilizing a dense, dipolar spin ensemble in diamond [Nature (London) 543, 221 (2017)NATUAS0028-083610.1038/nature21426]. They demonstrate the existence of a novel, critical DTC regime that is stabilized not by many-body localization but rather by slow, critical dynamics. Our analysis shows that the DTC response can be used as a sensitive probe of nonequilibrium quantum matter.

  17. Synthesis and Crystal Structure of Metronidazole-derived Compound

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A MET-OH derivative, MET-OTs 1, was designed, prepared and structurally charac- terized by single-crystal X-ray diffraction. X-ray structure analysis reveals that 1 crystallizes in the monoclinic system, space group P21/c, with a = 16.1178(14), b = 7.5473(6), c = 13.4161(11) (A), V = 1520.3(2) (A)3, β = 111.3210(10)o, Z = 4, Dc = 1.421 g/cm3 and F(000) = 680.

  18. Synthesis and characterization of monoclinic TiO2 nanosheets

    Institute of Scientific and Technical Information of China (English)

    WU Yu; XU Boqing

    2005-01-01

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

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

    CERN Document Server

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

    2016-01-01

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

  20. Liquid crystal devices especially for use in liquid crystal point diffraction interferometer systems

    Science.gov (United States)

    Marshall, Kenneth L [Rochester, NY

    2009-02-17

    Liquid crystal point diffraction interferometer (LCPDI) systems that can provide real-time, phase-shifting interferograms that are useful in the characterization of static optical properties (wavefront aberrations, lensing, or wedge) in optical elements or dynamic, time-resolved events (temperature fluctuations and gradients, motion) in physical systems use improved LCPDI cells that employ a "structured" substrate or substrates in which the structural features are produced by thin film deposition or photo resist processing to provide a diffractive element that is an integral part of the cell substrate(s). The LC material used in the device may be doped with a "contrast-compensated" mixture of positive and negative dichroic dyes.

  1. Growth and structure of a new photonic crystal: Chlorine substituted chalcone

    Science.gov (United States)

    Sarveshwara, H. P.; Raghavendra, S.; A, Jayarama; Menezes, Anthoni Praveen; Dharmaprakash, S. M.

    2015-06-01

    A new organic photonic material 3-(2, 4-dichlorophenyl)-1-(2,5-dimethylthiophen-3-yl)propan-1-one(DMTP) has been synthesized and crystallised in acetone solution. The functional groups present in the new material were identified by FTIR spectroscopy. The material is optically transparent in the wavelength range of 400-1100 nm. The crystal structure of DMTP was determined by single crystal X-ray diffraction. The title compound crystallizes in monoclinic system with a centrosymmetric space group P21/c. The Z-scan study revealed that the optical limiting property exhibited by the DMTP molecule is based on the reverse saturable absorption phenomena.

  2. Quantum evolution from spin-gap to AF state in a low-dimensional spin system

    Energy Technology Data Exchange (ETDEWEB)

    Gnezdilov, Vladimir [ILTP, Kharkov (Ukraine); Lemmens, Peter; Wulferding, Dirk [IPKM, TU-BS, Braunschweig (Germany); Kremer, Reinhard [MPI-FKF, Stuttgart (Germany); Broholm, Collin [DPA, Johns Hopkins Univ., Baltimore (United States); Berger, Helmuth [EPFL Lausanne (Switzerland)

    2010-07-01

    The low-dimensional spin systems {alpha}- and {beta}-TeVO{sub 4} share the same monoclinic crystal symmetry while having a different connectivity of VO{sub 4} octahedra and long range order vs. a quantum disordered ground state, respectively. We report a rich magnetic Raman spectrum and phonon anomalies that evidence strong spin-lattice coupling in both systems.

  3. Growth of strontium oxalate crystals in agar–agar gel

    Indian Academy of Sciences (India)

    P V Dalal; K B Saraf

    2011-04-01

    Single crystals of strontium oxalate have been grown by using strontium chloride and oxalic acid in agar–agar gel media at ambient temperature. Different methods for growing crystals were adopted. The optimum conditions were employed in each method by varying concentration of gel and reactants, and gel setting time etc. Transparent prismatic bi-pyramidal platy-shaped and spherulite crystals were obtained in various methods. The grown crystals were characterized with the help of FT–IR studies and monoclinic system of crystals were supported with lattice parameters = 9.67628 Å, = 6.7175 Å, = 8.6812 Å, = 113.566°, and = 521.84 Å3 calculated from X-ray diffractogram.

  4. Growth, crystalline perfection and characterization of benzophenone oxime crystal

    Science.gov (United States)

    Rajasekar, M.; Muthu, K.; Meenatchi, V.; Bhagavannarayana, G.; Mahadevan, C. K.; Meenakshisundaram, SP.

    Single crystals of benzophenone oxime (BPO) have been grown by slow evaporation solution growth technique from ethanol at room temperature. The single crystal X-ray diffraction study reveals that the crystal belongs to monoclinic system and cell parameters are, a = 9.459 Å, b = 8.383 Å, c = 26.690 Å, v = 2115 Å3 and β = 92.807°. The structure and the crystallinity of the materials were further confirmed by powder X-ray diffraction analysis. The various functional groups present in the molecule are confirmed by FT-IR analysis. The TG/DSC studies reveal the purity of the material and the crystals are transparent in the entire visible region having a lower optical cut-off at ˜300 nm. The crystalline perfection was evaluated by high-resolution X-ray diffraction (HRXRD). The crystal is further characterized by Kurtz powder technique, dielectric studies and microhardness analysis.

  5. Crystal growth, defects, and mechanical and spectral properties of a novel mixed laser crystal Nd:GdYNbO4

    Science.gov (United States)

    Ding, Shoujun; Liu, Wenpeng; Zhang, Qingli; Peng, Fang; Luo, Jianqiao; Dou, Renqin; Sun, Guihua; Sun, Dunlu

    2017-01-01

    A mixed laser crystal of Nd-doped GYNO crystal was grown successfully by Czochralski method. The crystal belongs to monoclinic system with space group I2/a, the structural parameters are obtained by the X-ray Rietveld refinement method. The defects and dislocations along three crystallographic orientations were studied by using the chemical etching method with the phosphoric acid etchant. The mechanical properties (including hardness, yield strength, fracture toughness, and brittle index) of the crystal were estimated by Vickers hardness test. The transmission spectrum was measured at room temperature, and the absorption peaks were assigned. Spectral properties of the as-grown crystal were investigated by Judd-Ofelt theory, and the Judd-Ofelt intense parameters Ω2,4,6 were obtained to be 9.674 × 10-20, 2.092 × 10-20, and 4.061 × 10-20 cm2, respectively.

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

    Science.gov (United States)

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

    2017-06-01

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

  7. FRACTIONAL CRYSTALLIZATION LABORATORY TESTING WITH INTERIM PRETREATMENT SYSTEM FEEDS

    Energy Technology Data Exchange (ETDEWEB)

    HERTING DL

    2008-09-17

    The fractional crystallization process was developed as a pretreatment method for saltcake waste retrieved from Hanford single-shell tanks (SST). The process separates the retrieved SST waste into a high-level waste stream containing the bulk of the radionuclides and a low-activity waste stream containing the bulk of the nonradioactive sodium salts. The Interim Pretreatment System project shifted the focus on pretreatment planning from SST waste to double-shell tank waste.

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

    Directory of Open Access Journals (Sweden)

    Alan R. Kennedy

    2016-12-01

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

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

    Science.gov (United States)

    Börzsönyi, Tamás; Akamatsu, Silvère; Faivre, Gabriel

    2009-11-01

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

  10. Synthesis, Characterization, Crystal Structure and Quantum Chemical Calculation of Novel Compound 1,3-Dimethyl-2-ferrocenylmethylbenzimidazolium Iodide

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing; YANG Bing-Qin; ZHU Hai-Yan; LI Tao; WEN Zhen-Yi

    2006-01-01

    A novel benzimidazole derivative, 1,3-dimethyl-2-ferrocenylmethylbenzimidazolium iodide (1) was synthesized and characterized by elemental analysis, MS, 1H NMR and IR spectra. Its crystal structure was determined by X-ray single crystal diffraction, and the title compound belongs to monoclinic system with space group P2(1)/c.According to the crystal structure, the quantum chemistry calculation was performed by Gaussian 03 program, and full geometry optimizations of the title compound were carried out with DFT method at B3LYP/6-31G level. Its structure, stability, frontier molecular orbital components and net charge distribution were discussed.

  11. Growth of L-Valinium Aluminium Chloride single crystal for OLED and super-capacitor applications

    Science.gov (United States)

    Kalaivani, D.; Vijayalakshmi, S.; Theras, J. Elberin Mary; Jayaraman, D.; Joseph, V.

    2015-12-01

    L-Valinium Aluminium Chloride (LVAC), a novel semi-organic material, was grown using slow evaporation under isothermal condition. The single crystal data reveal that the grown crystal belongs to monoclinic system. The SEM micrographs give clear picture about the surface morphology. Further, they confirm the inclusion of aluminium chloride into atomic sites of L-Valine. The compositional elements present in the crystal were identified through EDAX analysis. The mass spectral analysis was carried out to determine the molecular weight of the grown crystal. The optical transparency of the grown crystal was investigated by UV-vis-NIR spectrum. FTIR spectral study was used to identify the functional groups present in the grown material. The luminescence characteristics of grown material were analysed to confirm the effect of metal ion on the ligand. This property makes the material suitable for OLED application. The supercapacitive performance of the grown crystal was finally studied using cyclic voltammetry.

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

    NARCIS (Netherlands)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Sukumar Saha

    2011-01-01

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

  14. Electromagnetically induced grating in a crystal of molecular magnets system

    Science.gov (United States)

    Liu, Jibing; Liu, Na; Shan, Chuanjia; Liu, Tangkun; Li, Hong; Zheng, Anshou; Xie, Xiao-Tao

    2016-07-01

    We investigate the response of the molecular system to the magnetic field modulation. Molecular magnets are subjected to a strong standing ac magnetic field and a weak probe magnetic field. The transmission and absorption of the weak probe magnetic field can be changed due to quantum coherence and the spatially modulating of the standing field. And a electromagnetically induced grating is formed in the crystal of molecular magnets via electromagnetically induced transparency (EIT). The diffraction efficiency of the grating can be adjusted efficiently by tuning the intensity of the standing wave field and the single photon detuning.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-08-01

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

  16. Studies on 2-amino-5-nitropyridinium nitrate (2A5NPN): A semi-organic third order nonlinear optical single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Sivasubramani, V.; Pandian, Muthu Senthil, E-mail: senthilpandianm@ssn.edu.in; Ramasamy, P. [SSN Research Centre, SSN College of Engineering, Kalavakkam-603 110, Chennai, Tamilnadu (India)

    2016-05-23

    2-amino-5-nitropyridinium nitrate (2A5NPN) is a semi-organic nonlinear optical crystal and optically good quality 2A5NPN single crystals were successfully grown by slow evaporation solution growth technique (SEST) at ambient temperature. The crystallographic structure of the grown crystal was determined by single crystal X-Ray diffraction analysis and it belongs to Monoclinic crystal system with centro symmetric crystalline nature. The crystallinity of the grown crystal was confirmed by powder X-ray diffraction analysis. The other physical properties of grown crystals are also characterized using TG-DTA, UV-Visible NIR, chemical etching, photoconductivity and Z-scan measurements. The Z-scan method reveals that the 2A5NPN crystal possesses multi photon absorption behaviour and the significantly higher third order susceptibility and it is a promising potential NLO material.

  17. Phase equilibria and crystal structures of the compounds in the Pr-Ni-Sb system at 870 K

    Energy Technology Data Exchange (ETDEWEB)

    Chykhrij, S.I. [Department of Analytical Chemistry, Ivan Franko National University of Lviv, Kyryla and Mefodiya Str. 6, L' viv 79005 (Ukraine)]. E-mail: chykhrij@yahoo.com; Smetana, V.B. [Department of Analytical Chemistry, Ivan Franko National University of Lviv, Kyryla and Mefodiya Str. 6, L' viv 79005 (Ukraine)

    2005-09-01

    The isothermal section of the Pr-Ni-Sb system at 870 K over the whole concentration region has been built using X-ray analysis. At the temperature of the investigation three already known ternary antimonides PrNiSb, {approx}PrNiSb{sub 2} and {approx}PrNi{sub 2}Sb{sub 2} have been confirmed and three compounds {approx}Pr{sub 5}NiSb{sub 2}, PrNiSb{sub 3}, and PrNi{sub 2+x}Sb{sub 2-y} have been synthesized for the first time. The crystal structures of the obtained compounds belong to the following structure types: PrNiSb-ZrBeSi type, space group P6{sub 3}/mmc, a = 0.43838(2) nm, c = 0.81068(6) nm; PrNiSb{sub 3}-CeNiSb{sub 3} type, space group Pbcm, a = 1.2579(2) nm, b = 0.62051(8) nm, c = 1.8371(2) nm; {approx}Pr{sub 5}NiSb{sub 2}-structure related to Y{sub 5}Ni {sub x}Sb{sub 3-x}-type, space group Pnma, a = 1.2457(1) nm, b = 0.9159(1) nm, c = 0.8118(1) nm. The PrNi{sub 2}Sb{sub 2} compound crystallizes with an orthorhombic or monoclinic unit cell and a structure related to the tetragonal CaBe{sub 2}Ge{sub 2} type. The PrNi{sub 2+x}Sb{sub 2-y} antimonide has a small homogeneity region and crystallizes with a tetragonal unit cell (space group P4/nmm) and lattice parameters a = 0.431256(9) - 0.4319(1) nm, c = 0.99830(2) - 1.0092(3) nm. The existence of a considerable homogeneity region of the PrNi{sub 0.62-1.35}Sb{sub 2} compound is caused by a deficiency of Ni atoms or their excess compared to the initial structure of stoichiometric composition and a corresponding transition from the HfCuSi{sub 2} type to the CaBe{sub 2}Ge{sub 2} type with preservation of the unit cell symmetry (a 0.43539(4) - 0.44130(2) nm, c = 0.9653(1) - 0.97643(5) nm)

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

    Science.gov (United States)

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

    2011-01-15

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

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

    Science.gov (United States)

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

    2016-12-01

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

  20. Properties of the Sodium Naproxen-Lactose-Tetrahydrate Co-Crystal upon Processing and Storage

    DEFF Research Database (Denmark)

    Sovago, Ioana; Wang, Wenbo; Qiu, Danwen

    2016-01-01

    naproxen-lactose-tetrahydrate co-crystal and the co-amorphous mixture of sodium, naproxen, and lactose was investigated. The structure of the co-crystal is described using single-crystal X-ray diffraction. The structural analysis revealed a monoclinic lattice, space group P21, with the asymmetric unit...... containing one molecule of lactose, one of naproxen, sodium, and four water molecules. Upon heating, it was observed that the co-crystal transforms into a co-amorphous system due to the loss of its crystalline bound water. Dehydration and co-amorphization were studied using synchrotron X-ray radiation......Co-crystals and co-amorphous systems are two strategies to improve the physical properties of an active pharmaceutical ingredient and, thus, have recently gained considerable interest both in academia and the pharmaceutical industry. In this study, the behavior of the recently identified sodium...

  1. Crystal growth, defects, and mechanical and spectral properties of a novel mixed laser crystal Nd:GdYNbO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Shoujun; Dou, Renqin [Chinese Academy of Sciences, Anhui Institute of Optics and Fine Mechanics, Hefei, Anhui Province (China); University of Science and Technology of China, Hefei (China); Liu, Wenpeng; Zhang, Qingli; Peng, Fang; Luo, Jianqiao; Sun, Guihua; Sun, Dunlu [Chinese Academy of Sciences, Anhui Institute of Optics and Fine Mechanics, Hefei, Anhui Province (China)

    2017-01-15

    A mixed laser crystal of Nd-doped GYNO crystal was grown successfully by Czochralski method. The crystal belongs to monoclinic system with space group I2/a, the structural parameters are obtained by the X-ray Rietveld refinement method. The defects and dislocations along three crystallographic orientations were studied by using the chemical etching method with the phosphoric acid etchant. The mechanical properties (including hardness, yield strength, fracture toughness, and brittle index) of the crystal were estimated by Vickers hardness test. The transmission spectrum was measured at room temperature, and the absorption peaks were assigned. Spectral properties of the as-grown crystal were investigated by Judd-Ofelt theory, and the Judd-Ofelt intense parameters Ω{sub 2,4,6} were obtained to be 9.674 x 10{sup -20}, 2.092 x 10{sup -20}, and 4.061 x 10{sup -20} cm{sup 2}, respectively. (orig.)

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

    Institute of Scientific and Technical Information of China (English)

    Hua Huang

    2000-01-01

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

  3. Synthesis, Crystal Growth and Characterization of bis Dl-Valine Picrate Single Crystal for Second-Order Nonlinear Optical Applications

    Science.gov (United States)

    Silambarasan, A.; Krishna Kumar, M.; Sudhahar, S.; Thirunavukkarasu, A.; Mohan Kumar, R.; Umarani, P. R.

    2013-08-01

    An organic compound Bis DL-Valine picrate (BDLVP) was synthesized successfully and single crystal was grown by slow evaporation solution growth method. The presence of functional groups in the compound was identified by FTIR spectral analysis. Single crystal X-ray diffraction study revealed that the grown crystal belongs to P21/n space group of monoclinic crystal system. Powder X-ray diffraction pattern was recorded to know the crystalline perfection of the grown crystal. The reaction mechanism, thermal decomposition stages and thermal stability of the grown crystal were studied by using TG/DTA analysis. From the UV-visible spectral study, the electronic band gap energy (Eg) of the grown crystal was found to be 2.43 eV. The second harmonic generation (SHG) efficiency of grown crystal was found to be 1.3 times higher than KDP crystal by using Kurtz powder SHG technique. The microhardness property of the grown crystal was examined by Vicker's microhardness test.

  4. Crystallization of molecular systems from solution: phase diagrams, supersaturation and other basic concepts.

    Science.gov (United States)

    Coquerel, Gérard

    2014-04-07

    The aim of the tutorial review is to show that any crystallization from solution is guided by stable or metastable equilibria and thus can be rationalized by using phase diagrams. Crystallization conducted by cooling, by evaporation and by anti-solvent addition is mainly considered. The driving force of crystallization is quantified and the occurrence of transient metastable states is logically explained by looking at the pathways of crystallization and the progressive segregation which might occur in a heterogeneous system.

  5. Crystal front shape control by use of an additional heater in a Czochralski sapphire single crystal growth system

    Science.gov (United States)

    Hur, Min-Jae; Han, Xue-Feng; Choi, Ho-Gil; Yi, Kyung-Woo

    2017-09-01

    The quality of sapphire single crystals used as substrates for LED production is largely influenced by two defects: dislocation density and bubbles trapped in the crystal. In particular, the dislocation density has a higher value in sapphire grown by the Czochralski (CZ) method than by other methods. In the present study, we predict a decreased value for the convexity and thermal gradient at the crystal front (CF) through the use of an additional heater in an induction-heated CZ system. In addition, we develop a solute concentration model by which the location of bubble formation in CZ growth is calculated, and the results are compared with experimental results. We further calculate the location of bubble entrapment corresponding with the use of an additional heater. We find that sapphire crystal growth with an additional heater yields a decreased thermal gradient at the CF, together with decreased CF convexity, improved energy efficiency, and improvements in terms of bubble formation location.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-05-15

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

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

    Directory of Open Access Journals (Sweden)

    Xiaoyan Lu

    2016-10-01

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

  8. A Robust Process Analytical Technology (PAT) System Design for Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan; Gernaey, Krist

    2013-01-01

    for generation of the supersaturation setpoint for a supersaturation controller, a tool for design of a process monitoring and control system (also called Process Analytical Technology (PAT) system) as well as a tool for performing uncertainty and sensitivity analysis of the PAT system design. The uncertainty......A generic computer-aided framework for systematic design of a process monitoring and control system for crystallization processes has been developed to study various aspects of crystallization operations. The design framework contains a generic multidimensional modelling framework, a tool...... crystallization process to achieve the target crystal size distribution (CSD) in the presence of parametric uncertainties....

  9. Nitrogen-rich 6-(3,5-Dimethylpyrazol-1-yl)-3-(2,4,6-trinitroanilino)-1,2,4,5-tetrazin: Synthesis, Crystal Structure and Thermal Property

    Institute of Scientific and Technical Information of China (English)

    PAN, Wan-Long; HUANG, Kun-Lin; TANG, Wang; XU, Yan-Qing; HU, Chang-Wen

    2007-01-01

    6-(3,5-Dimethylpyrazol-1-yl)-3-(2,4,6-trinitroanilino)-1,2,4,5-tetrazin (1) has been synthesized and characterized by 1H NMR, MS, elemental analysis, infrared spectra and thermal analyses. The crystal structure was determined by X-ray diffraction method. 1 is crystallized in P21/c space group of monoclinic crystal system, and exhibits good physical properties, such as high densities (> 1.55 g·cm-3) and good thermal stabilities (Td>220 ℃). The intrermolecular hydrogen bonds construct the P- and M-helices from organic molecules and may contribute to the high melting points.

  10. Introducing uncertainty analysis of nucleation and crystal growth models in Process Analytical Technology (PAT) system design of crystallization processes.

    Science.gov (United States)

    Samad, Noor Asma Fazli Abdul; Sin, Gürkan; Gernaey, Krist V; Gani, Rafiqul

    2013-11-01

    This paper presents the application of uncertainty and sensitivity analysis as part of a systematic model-based process monitoring and control (PAT) system design framework for crystallization processes. For the uncertainty analysis, the Monte Carlo procedure is used to propagate input uncertainty, while for sensitivity analysis, global methods including the standardized regression coefficients (SRC) and Morris screening are used to identify the most significant parameters. The potassium dihydrogen phosphate (KDP) crystallization process is used as a case study, both in open-loop and closed-loop operation. In the uncertainty analysis, the impact on the predicted output of uncertain parameters related to the nucleation and the crystal growth model has been investigated for both a one- and two-dimensional crystal size distribution (CSD). The open-loop results show that the input uncertainties lead to significant uncertainties on the CSD, with appearance of a secondary peak due to secondary nucleation for both cases. The sensitivity analysis indicated that the most important parameters affecting the CSDs are nucleation order and growth order constants. In the proposed PAT system design (closed-loop), the target CSD variability was successfully reduced compared to the open-loop case, also when considering uncertainty in nucleation and crystal growth model parameters. The latter forms a strong indication of the robustness of the proposed PAT system design in achieving the target CSD and encourages its transfer to full-scale implementation.

  11. Inorganic Scintillators for Detector Systems Physical Principles and Crystal Engineering

    CERN Document Server

    AUTHOR|(CDS)2068219; Gektin, Alexander; Korzhik, Mikhail; Pédrini, Christian

    2006-01-01

    The development of new scintillators as components of modern detector systems is increasingly defined by the end user's needs. This book provides an introduction to this emerging topic at the interface of physics and materials sciences, with emphasis on bulk inorganic scintillators. After surveying the end user's needs in a vast range of applications, ranging from astrophysics to industrial R & D, the authors move on to review scintillating mechanisms and the properties of the most important materials used. A chapter on crystal engineering and examples of recent developments in the field of high-energy physics and medical imaging introduce the reader to the practical aspects. This book will benefit researchers and scientists working in academic and industrial R & D related to the development of scintillators.

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

    Science.gov (United States)

    Lin, Xianqing; Ni, Jun

    2017-07-01

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

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Carlos Bustos

    2011-07-01

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

  16. Crystal growth in a three-phase system: diffusion and liquid-liquid phase separation in lysozyme crystal growth.

    Science.gov (United States)

    Heijna, M C R; van Enckevort, W J P; Vlieg, E

    2007-07-01

    In the phase diagram of the protein hen egg-white lysozyme, a region is present in which the lysozyme solution demixes and forms two liquid phases. In situ observations by optical microscopy show that the dense liquid droplets dissolve when crystals grow in this system. During this process the demixed liquid region retracts from the crystal surface. The spatial distribution of the dense phase droplets present special boundary conditions for Fick's second law for diffusion. In combination with the cylindrical symmetry provided by the kinetically roughened crystals, this system allows for a full numerical analysis. Using experimental data for setting the boundary conditions, a quasi-steady-state solution for the time-dependent concentration profile was shown to be valid. Comparison of kinetically rough growth in a phase separated system and in a nonseparated system shows that the growth kinetics for a three-phase system differs from a two-phase system, in that crystals grow more slowly but the duration of growth is prolonged.

  17. Synthesis, Character and Crystal Structure of the Complex {Er(DMSO)7} PW12O40

    Institute of Scientific and Technical Information of China (English)

    HAN Qiu-Xia; ZHANG Da-Li; MA Jian-Ru; WANG Jing-Ping; NIU Jing-Yang

    2007-01-01

    The synthesis, X-ray crystal structure, thermal properties and electrochemistry of the new complex formulated as {Er(DMSO)7}PW12O40 are reported. The single-crystal X-ray analysis reveals that the crystal crystallizes in the monoclinic system, space group P21/c with a=11.767(2), b=14.909(3), c=34.905(7)(A), β=98.97(3)°, Mr=3591.33, V=6049(2) (A)3, Dc=3.944g/em3, Z=4, GOOF=1.098, F(000)=6340, R=0.0490 and wR=0.1202. Crystal structure analysis indicates that the Er(Ⅲ) is seven-coordinate with a distorted pentagonal bipyramid and combines to the anion [PW12O40]3- via static electric force.

  18. Crystal growth, structural, thermal and mechanical behavior of L-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) single crystals

    Science.gov (United States)

    Mahadevan, M.; Ramachandran, K.; Anandan, P.; Arivanandhan, M.; Bhagavannarayana, G.; Hayakawa, Y.

    2014-12-01

    Single crystals of L-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) have been grown successfully from the solution of L-arginine and 4-nitrophenol. Slow evaporation of solvent technique was adopted to grow the bulk single crystals. Single crystal X-ray diffraction analysis confirms the grown crystal has monoclinic crystal system with space group of P21. Powder X-ray diffraction analysis shows the good crystalline nature. The crystalline perfection of the grown single crystals was analyzed by HRXRD by employing a multicrystal X-ray diffractometer. The functional groups were identified from proton NMR spectroscopic analysis. Linear and nonlinear optical properties were determined by UV-Vis spectrophotometer and Kurtz powder technique respectively. It is found that the grown crystal has no absorption in the green wavelength region and the SHG efficiency was found to be 2.66 times that of the standard KDP. The Thermal stability of the crystal was found by obtaining TG/DTA curve. The mechanical behavior of the grown crystal has been studied by Vicker's microhardness method.

  19. Preparative crystallization of a single chain antibody using an aqueous two-phase system.

    Science.gov (United States)

    Huettmann, Hauke; Berkemeyer, Matthias; Buchinger, Wolfgang; Jungbauer, Alois

    2014-11-01

    A simultaneous crystallization and aqueous two-phase extraction of a single chain antibody was developed, demonstrating process integration. The process conditions were designed to form an aqueous two-phase system, and to favor crystallization, using sodium sulfate and PEG-2000. At sufficiently high concentrations of PEG, a second phase was generated in which the protein crystallization occurred simultaneously. The single chain antibody crystals were partitioned to the top, polyethylene glycol-rich phase. The crystal nucleation took place in the sodium sulfate-rich phase and at the phase boundary, whereas crystal growth was progressing mainly in the polyethylene glycol-rich phase. The crystals in the polyethylene glycol-rich phase grew to a size of >50 µm. Additionally, polyethylene glycol acted as an anti-solvent, thus, it influenced the crystallization yield. A phase diagram with an undersaturation zone, crystallization area, and amorphous precipitation zone was established. Only small differences in polyethylene glycol concentration caused significant shifts of the crystallization yield. An increase of the polyethylene glycol content from 2% (w/v) to 4% (w/v) increased the yield from approximately 63-87%, respectively. Our results show that crystallization in aqueous two-phase systems is an opportunity to foster process integration.

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

    Directory of Open Access Journals (Sweden)

    Xin Gui

    2017-07-01

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

  1. Introducing uncertainty analysis of nucleation and crystal growth models in Process Analytical Technology (PAT) system design of crystallization processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan; Gernaey, Krist

    2013-01-01

    This paper presents the application of uncertainty and sensitivity analysis as part of a systematic modelbased process monitoring and control (PAT) system design framework for crystallization processes. For the uncertainty analysis, the Monte Carlo procedure is used to propagate input uncertainty......, while for sensitivity analysis, global methods including the standardized regression coefficients (SRC) and Morris screening are used to identify the most significant parameters. The potassium dihydrogen phosphate (KDP) crystallization process is used as a case study, both in open-loop and closed...

  2. A systematic framework for design of process monitoring and control (PAT) systems for crystallization processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan; Gernaey, Krist

    2013-01-01

    for generation of the supersaturation set-point for supersaturation control, as well as a tool for design of a process monitoring and control system (also called Process Analytical Technology (PAT) system). This systematic design allows one to generate the necessary problem-chemical system specific model......A generic computer-aided framework for systematic design of a process monitoring and control system for crystallization processes has been developed to study various aspects of crystallization operations.The systematic design framework contains a generic crystallizer modelling toolbox, a tool......, the necessary supersaturation set-point as well as a PAT system design including implementation of monitoring tools and control strategies in order to produce the desired target product properties notably crystal size distribution (CSD) and shape for a wide range of crystallization processes. Application...

  3. FT-IR reflection spectra of single crystals: resolving phonons of different symmetry without using polarised radiation

    OpenAIRE

    METODIJA NAJDOSKI; VLADIMIR IVANOVSKI; VLADIMIR M. PETRUSEVSKI

    2000-01-01

    Fourier-transform infrared (FT-IR) reflection spectra, asquired at nearnormal incidence, were recorded from single crystals belonging to six crystal systems: CsCr(SO4)2.12H2O (alum, cubic), K2CuCl2·2H2O (Mitscherlichite, tetragonal), CaCO3 (calcite, hexagonal), KHSO4 (mercallite, orthorhombic), CaSO4·2H2O (gypsum, monoclinic) and CuSO4·5H2O (chalcantite, triclinic). The acquired IR reflection spectra were further transformed into absorption spectra, employing the Kramers-Kronig transformation...

  4. Photonic crystal enhanced silicon cell based thermophotovoltaic systems.

    Science.gov (United States)

    Yeng, Yi Xiang; Chan, Walker R; Rinnerbauer, Veronika; Stelmakh, Veronika; Senkevich, Jay J; Joannopoulos, John D; Soljacic, Marin; Čelanović, Ivan

    2015-02-09

    We report the design, optimization, and experimental results of large area commercial silicon solar cell based thermophotovoltaic (TPV) energy conversion systems. Using global non-linear optimization tools, we demonstrate theoretically a maximum radiative heat-to-electricity efficiency of 6.4% and a corresponding output electrical power density of 0.39 W cm(-2) at temperature T = 1660 K when implementing both the optimized two-dimensional (2D) tantalum photonic crystal (PhC) selective emitter, and the optimized 1D tantalum pentoxide - silicon dioxide PhC cold-side selective filter. In addition, we have developed an experimental large area TPV test setup that enables accurate measurement of radiative heat-to-electricity efficiency for any emitter-filter-TPV cell combination of interest. In fact, the experimental results match extremely well with predictions of our numerical models. Our experimental setup achieved a maximum output electrical power density of 0.10W cm(-2) and radiative heat-to-electricity efficiency of 1.18% at T = 1380 K using commercial wafer size back-contacted silicon solar cells.

  5. Controllable Optical Bistability in a Crystal of Molecular Magnets System

    Institute of Scientific and Technical Information of China (English)

    LIU Ji-Bing; LU Xin-You; HAO Xiang-Ying; SI Liu-Gang; YANG Xiao-Xue

    2008-01-01

    We investigate the formation of opticai bistability (OB) in a crystal of molecular magnets contained in a unidirectional ring cavity. The crystal is subjected to one de magnetic field and two (probe and coupling) ac resonant magnetic field. The results show that OB can be controlled efficiently by adjusting the intensity of the control field, the detuning of probe magnetic field and the cooperation parameter. Furthermore, within certain parameter range, the optical multistablity (OM) can also be observed in the crystal medium. This investigation can be used for designing new types of nonelectronic devices for realizing switching process.

  6. Synthesis, crystal growth and spectroscopic investigation of novel metal organic crystal: β-Alanine cadmium bromide monohydrate (β-ACBM)

    Science.gov (United States)

    Renugadevi, R.; Kesavasamy, R.

    2014-07-01

    β-Alanine cadmium bromide monohydrate (β-ACBM), a new metal organic crystal has been grown from aqueous solution by slow evaporation technique. The grown crystals have been subjected to single crystal X-ray diffraction analysis to determine the crystal structure. The β-ACBM crystallized in monoclinic system with space group P21/c. The presence of protons and carbons in the β-alanine cadmium bromide monohydrate was confirmed by 1H and 13C nuclear magnetic resonance spectral analysis. The mode of vibration of different molecular groups present in β-ACBM was identified by FT-IR spectral analysis. Transparency of crystals in UV-Vis-NIR region has also been studied. The thermal characteristics of as-grown crystals were analyzed using thermo gravimetric and differential thermal analyses. The magnetic property of the grown crystal was investigated using Vibrating Sample Magnetometer (VSM) at ambient temperature. The mechanical stability of β-ACBM was evaluated by Vickers microhardness measurement.

  7. Effect of Metal Dopant on Ninhydrin—Organic Nonlinear Optical Single Crystals

    Directory of Open Access Journals (Sweden)

    R. S. Sreenivasan

    2013-01-01

    Full Text Available In the present work, metal (Cu2+-substituted ninhydrin single crystals were grown by slow evaporation method. The grown crystals have been subjected to single crystal XRD, powder X-ray diffraction, FTIR, dielectric and SHG studies. Single crystal X-ray diffraction analysis reveals that the compound crystallizes in monoclinic system with noncentrosymmetric space group P21 with lattice parameters a=11.28 Å, b=5.98 Å, c=5.71 Å, α=90∘, β=98.57, γ=90∘, and V=381 (Å3, which agrees very well with the reported value. The sharp and strong peaks in the powder X-ray diffraction pattern confirm the good crystallinity of the grown crystals. The presence of dopants marginally altered the lattice parameters without affecting the basic structure of the crystal. The UV-Vis transmittance spectrum shows that the crystal has a good optical transmittance in the entire visible region with lower cutoff wavelength 314 nm. The vibrational frequencies of various functional groups in the crystals have been derived from FT-IR analysis. Based on the shifts in the vibrations, the presence of copper in the lattice of the grown crystal is clearly established from the pure ninhydrin crystals. Both dielectric constant and dielectric loss decrease with the increase in frequency. The second harmonic generation efficiency was measured by employing powder Kurtz method.

  8. Microscopy and calorimetry as complementary techniques to analyze sugar crystallization from amorphous systems.

    Science.gov (United States)

    Mazzobre, María F; Aguilera, José M; Buera, María P

    2003-03-14

    A comparison of microscopic and macroscopic techniques to evaluate sugar crystallization kinetics is presented using amorphous lactose and lactose-trehalose mixtures. Polarized light video microscopy (PLV) and differential scanning calorimetry (DSC) were applied to measure crystallization kinetics, induction times and time for complete sugar crystallization at different storage temperatures (60-95 degrees C). DSC was also employed to measure the glass transition temperature (T(ag)) of the systems. PLV permitted direct observation, in real time, of growth of individual crystals and morphological aspects at a scale not detected by DSC. Taking the average of several microscopic observations, the results for temperature dependence of crystallization rate and time to complete lactose crystallization were similar to those obtained by DSC. Both PLV and DSC techniques showed that the presence of trehalose delayed lactose crystallization, without affecting the T(ag) value. For the analysis of sugar crystallization in amorphous systems, PLV and DSC proved to be complementary techniques. Validation of results obtained by PLV with results from DSC opens a new area of microstructural analysis of crystallizing systems.

  9. FT-IR reflection spectra of single crystals: resolving phonons of different symmetry without using polarised radiation

    Directory of Open Access Journals (Sweden)

    METODIJA NAJDOSKI

    2000-07-01

    Full Text Available Fourier-transform infrared (FT-IR reflection spectra, asquired at nearnormal incidence, were recorded from single crystals belonging to six crystal systems: CsCr(SO42.12H2O (alum, cubic, K2CuCl2·2H2O (Mitscherlichite, tetragonal, CaCO3 (calcite, hexagonal, KHSO4 (mercallite, orthorhombic, CaSO4·2H2O (gypsum, monoclinic and CuSO4·5H2O (chalcantite, triclinic. The acquired IR reflection spectra were further transformed into absorption spectra, employing the Kramers-Kronig transformation. Except for the cubic alums, the spectra strongly depend on the crystal face from which they were recorded; this is a consequence of anisotropy. Phonons of a given symmetry (E-species, in tetragonal/hexagonal and B-species, in monoclinic crystals may be resolved without using a polariser. The spectrum may be simplified in the case of an orthorhombic crystal, as well. The longitudinal-optical (LO and transversal-optical (TO mode frequencies were calculated in the case of optically isotropic and the simplified spectra of optically uniaxial crystals.

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

    Science.gov (United States)

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

    2017-06-01

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

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

    Science.gov (United States)

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

    2016-11-01

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

  12. A photoelastic measurement system for residual stress analysis in scintillating crystals by conoscopic imaging.

    Science.gov (United States)

    Montalto, L; Paone, N; Scalise, L; Rinaldi, D

    2015-06-01

    The assessment of the stress state of scintillating crystals is an important issue for producers as well as users of such materials, because residual stress may arise during growth process. In this paper, a measurement system, based on the use of a photoelastic, conoscopic optical setup, is proposed for the assessment of stress state in scintillating crystals. Local stress values can be measured on the crystal in order to observe their spatial distribution. With the proposed system, it is possible to vary the dimensions of the inspected measurement volume. It has been validated with reference to a known stress state induced in a birefringent crystal sample and it has been tested for the case of loaded and unloaded samples, showing sub-millimetric spatial resolution and stress uncertainty ≤0.25 MPa. The proposed measurement system is a valid method for the inspection of scintillating crystals required by producers and users of such materials.

  13. Additivity of water sorption, alpha-relaxations and crystallization inhibition in lactose-maltodextrin systems.

    Science.gov (United States)

    Potes, Naritchaya; Kerry, Joseph P; Roos, Yrjö H

    2012-08-01

    Water sorption of lactose-maltodextrin (MD) systems, structural relaxations and lactose crystallization were studied. Accurate water sorption data for non-crystalline lactose previously not available over a wide range of water activity, aw (maltodextrin (MD) systems were strongly affected by water and MD. At high MD contents, inhibition of crystallization was significant. Inhibition with a high dextrose equivalent (DE) MD was more pronounced possibly because of molecular number and size effects. At 0.55-0.76aw, inhibition increased with increasing MD content. At aw>0.66, the rate of lactose crystallization decreased at increasing MD contents. Different MDs with similar Tg in lactose-MD systems showed different crystallization inhibition effects. The results of the present study showed that the DE in selection of MD for applications has important effects on component crystallization characteristics.

  14. Polydisperse hard spheres: crystallization kinetics in small systems and role of local structure

    Science.gov (United States)

    Campo, Matteo; Speck, Thomas

    2016-08-01

    We study numerically the crystallization of a hard-sphere mixture with 8% polydispersity. Although often used as a model glass former, for small system sizes we observe crystallization in molecular dynamics simulations. This opens the possibility to study the competition between crystallization and structural relaxation of the melt, which typically is out of reach due to the disparate timescales. We quantify the dependence of relaxation and crystallization times on density and system size. For one density and system size we perform a detailed committor analysis to investigate the suitability of local structures as order parameters to describe the crystallization process. We find that local structures are strongly correlated with generic bond order and add little information to the reaction coordinate.

  15. A Robust Process Analytical Technology (PAT) System Design for Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Sin, Gürkan; Gernaey, Krist

    2013-01-01

    A generic computer-aided framework for systematic design of a process monitoring and control system for crystallization processes has been developed to study various aspects of crystallization operations. The design framework contains a generic multidimensional modelling framework, a tool for gen...

  16. Crystallization of Enzyme IIB of the Cellobiose-specific Phosphotransferase System of Escherichia coli

    NARCIS (Netherlands)

    van Montfort, Robert; Pijning, Tjaard; Kalk, Kornelis; Schuurman-Wolters, Gea K.; Reizer, Jonathan; Safer Jr., Milton H.; Robillard, George; Dijkstra, Bauke W.

    1994-01-01

    Crystals of enzyme IIB of the cellobiose-specific phosphotransferase system have been obtained from 15% polyethylene glycol 4000 using both streak-seeding and macroseeding techniques at 4°. Crystals were grown with the hanging drop method of vapour diffusion. Addition of 2-propanol and benzamidine/H

  17. Crystal families and systems in higher dimensions, and geometrical symbols of their point groups. I. Crystal families in five-dimensional space with two-, three-, four- and sixfold symmetries.

    Science.gov (United States)

    Veysseyre, R; Weigel, D; Phan, Th

    2008-11-01

    The aim of this paper and of the following one [Weigel, Phan & Veysseyre (2008). Acta Cryst. A64, 687-697] is to complete the list of the Weigel-Phan-Veysseyre (WPV) symbols of the point groups of space E5 that was started in previous papers and in two reports of an IUCr Subcommittee on the Nomenclature of n-Dimensional Crystallography. In this paper, some crystal families of space E5 are studied. The cells of these are right hyperprisms with as a basis either two squares, or two hexagons, or a square and a hexagon. If the basis is made up of two squares, the two families are the (monoclinic di squares)-al family (No. XVI) and the (di squares)-al family (No. XIX). If the basis is made up of two hexagons, the two families are the (monoclinic di hexagons)-al family (No. XVII) and the (di hexagons)-al family (No. XXI). If the basis is made up of one square and one hexagon, the family is the (square hexagon)-al family (No. XX). In order to link space E5 to spaces E2, E3 and E4, some results published in previous papers are recalled. In fact, most of the symbols of the point groups of space E5 can be deduced from the symbols of the four, six and 23 crystal families of spaces E2, E3 and E4, respectively.

  18. Growth and characterization of an organic nonlinear optical material—lauric acid crystal

    Science.gov (United States)

    Maheswari, J. Uma; Krishnan, C.; Kalyanaraman, S.; Selvarajan, P.

    2016-10-01

    Single crystals of pure lauric acid (LA) were harvested from ethanol solution by a slow evaporation technique. X-ray diffraction showed that the LA crystallized in the monoclinic system and was used to determine the lattice parameters. The Kurtz-Perry powder technique showed that the second-harmonic generation efficiency of LA was 0.87 times that of potassium dihydrogen phosphate. Fourier transform infrared spectral analysis was used to identify the various fatty acid functional groups present in the sample. Thermogravimetric analysis and differential thermal analysis revealed that the LA crystal is stable up to 45 °C. The mechanical strength of the sample crystal was estimated by the Vickers hardness test. Impedance analysis was carried out for the sample at different frequencies and a Nyquist plot was drawn to understand the electrical properties.

  19. Effects of crystallization and microstructure on the dc electrical conductivity in the system xCuO–(70 − x) MnO–30SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Hammad, Ahmed H. [Electron Microscope and Thin Films Department, Physics Division, National Research Center, Dokki, Cairo 12622 (Egypt); Abdel-Hameed, Salwa A.M. [Glass Research Department, National Research Center, Dokki, Cairo 12622 (Egypt); Margha, Fatma H., E-mail: fatmamargha@yahoo.com [Glass Research Department, National Research Center, Dokki, Cairo 12622 (Egypt)

    2015-04-05

    Highlights: • Crednerite (CuMnO{sub 2}) glass–ceramic material was prepared. • Morphology depends on the CuO in the composition. • The prepared samples act as semiconductor materials. - Abstract: Glass–ceramics of the systems xCuO–(70 − x) MnO–30SiO{sub 2} (mol%) (x = 10, 15, 20, 25, and 35) were successfully prepared. XRD analysis revealed the crystallization of monoclinic crednerite CuMnO{sub 2} as major phase. The crystallization of crednerite phase enhanced with incremental x value. Scanning electron microscope showed columnar particles of crednerite when x ⩽ 20 while layered shapes appeared when x = 25. Needles and rod shape appeared when x = 35. The variations in dc-conductivity with the reciprocal temperature were studied for the prepared glass–ceramic samples. The transport in such glass–ceramic systems was due to small polaron hopping (SPH) between Cu-ions. The samples show semiconductor behavior which is desired for many applications.

  20. Preparation of agglomerated crystals for direct tabletting and microencapsulation by the spherical crystallization technique with a continuous system.

    Science.gov (United States)

    Niwa, T; Takeuchi, H; Hino, T; Itoh, A; Kawashima, Y; Kiuchi, K

    1994-04-01

    Adhesive and cohesive properties of chlorpromazine hydrochloride (CP) crystals were modified to improve their powder processing, e.g., direct tabletting and microencapsulation, by agglomeration. Moreover, sustained-released gelling microcapsules of CP were devised to prolong the pharmacological effect. The spherical crystallization technique was applied to prepare agglomerates for direct tabletting and microencapsulation to use them as core materials. The ethanolic solution dissolving CP was poured into a stirred cyclohexane, yielding spherically agglomerated crystals. The resultant agglomerates were free-flowing and easily packable spheres with average diameters of 200 to 1000 microns. The agglomerates reserved the high compressibility of the original powder having a small particle size (14 microns). The compression behavior represented by Heckel's equation suggested that the agglomerates were disintegrated to individual primary crystals at low compression pressures, and then they were closely repacked and plastically deformed at higher pressures. After agglomeration, microencapsulation was continuously performed in the same batch by a phase separation method. Coacervate droplets produced by pouring cyclohexane into a dichloromethane solution, dissolving polyvinyl acetate as a coating polymer, were added to the crystallization system under stirring, to prepare the microcapsules. By filling the microcapsules in gelatin hard capsules or tabletting them, their drug release rates became retarded compared with the physical mixture treated in the same way, having the same formulation as the microcapsules. This phenomenon was due to the gelation of polyvinyl acetate of the microcapsules in the dissolution medium, whose glass transition temperature is very low. This novel sustained-release dosage form is termed "gelled microcapsules."

  1. A Generic Framework for Systematic Design of Process Monitoring and Control System for Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Meisler, Kresten Troelstrup; Sin, Gürkan

    2012-01-01

    A generic framework for systematic design of a process monitoring and control system for crystallization processes has been developed in order to obtain the desired end-product properties notably the crystal size distribution (CSD). The design framework contains a generic crystallizer modelling...... tool-box, a tool for design of operational policies as well as a tool for design of process monitoring and control systems. Through this framework, it is possible for a wide range of crystallization processes to generate the necessary problem-system specific model, the necessary operational policy...... and a Process Analytical Technology (PAT) system design including implementation of monitoring tools and control strategies in order to produce a desired product with its corresponding target properties. Application of the framework is highlighted through a case study involving the system potassium dihydrogen...

  2. Systematic classification of unseeded batch crystallization systems for achievable shape and size analysis

    Science.gov (United States)

    Acevedo, David; Nagy, Zoltan K.

    2014-05-01

    The purpose of the current work is to develop a systematic classification scheme for crystallization systems considering simultaneous size and shape variations, and to study the effect of temperature profiles on the achievable final shape of crystals for various crystallization systems. A classification method is proposed based on the simultaneous consideration of the effect of temperature profiles on nucleation and growth rates of two different characteristic crystal dimensions. Hence the approach provides direct indication of the extent in which crystal shape may be controlled for a particular system class by manipulating the supersaturation. A multidimensional population balance model (PBM) was implemented for unseeded crystallization processes of four different compounds. The effect between the nucleation and growth mechanisms on the final aspect ratio (AR) was investigated and it was shown that for nucleation dominated systems the AR is independent of the supersaturation profile. The simulation results confirmed experimentally also show that most crystallization systems tend to achieve an equilibrium shape hence the variation in the aspect ratio that can be achieved by manipulating the supersaturation is limited, in particular when nucleation is also taken into account as a competing phenomenon.

  3. Particle size dependent isothermal crystallization kinetics in a Se–Te glassy system

    Energy Technology Data Exchange (ETDEWEB)

    Svoboda, Roman, E-mail: roman.svoboda@upce.cz; Málek, Jiří

    2015-06-20

    Highlights: • Influence of particle size on isothermal crystallization of Se–Te glasses was studied by DSC. • Nature of the crystallization complexity was revealed by deconvolution procedure. • Overlapping competing surface and bulk nucleation-growth mechanisms were identified. • Presence of the A and B types of spherulitic crystallites was confirmed by DSC. • Increasing tellurium content leads to an increase of the apparent activation energy. - Abstract: Differential scanning calorimetry (DSC) was used to study the crystallization behaviour in a selenium–tellurium (Se–Te) glassy system under isothermal conditions. The particle-size-dependent isothermal crystallization kinetics were described in terms of the Johnson–Mehl–Avrami (JMA) nucleation-growth model. The complexity of the crystallization process was found to be represented by overlapping competing surface and bulk nucleation-growth mechanisms. Based on the deconvolution in terms of the JMA model, the particular crystal growth processes were identified, and the interpretation of their physical origins was performed. Presence of the A and B types of spherulitic crystallites was confirmed; the temperature range of the transition in-between these two spherulitic forms was determined to be similar as for pure selenium. Increasing tellurium content was found to cause an increase of the apparent activation energy of the overall crystallization process as well as a gradual increase of the dominance of the CNT (classical nucleation theory)-based volume-located crystal growth over the surface crystallization, which originates from mechanically induced heterogeneities.

  4. Crystallization and preliminary crystallographic analysis of recombinant human galectin-1

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Stacy A. [Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland 4222 (Australia); Scott, Ken [School of Biological Sciences, University of Auckland, Auckland (New Zealand); Blanchard, Helen, E-mail: h.blanchard@griffith.edu.au [Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland 4222 (Australia)

    2007-11-01

    Human galectin-1 has been cloned, expressed in E. coli, purified and crystallized in the presence of both lactose (ligand) and β-mercaptoethanol under six different conditions. The X-ray diffraction data obtained have enabled the assignment of unit-cell parameters for two novel crystal forms of human galectin-1. Galectin-1 is considered to be a regulator protein as it is ubiquitously expressed throughout the adult body and is responsible for a broad range of cellular regulatory functions. Interest in galectin-1 from a drug-design perspective is founded on evidence of its overexpression by many cancers and its immunomodulatory properties. The development of galectin-1-specific inhibitors is a rational approach to the fight against cancer because although galectin-1 induces a plethora of effects, null mice appear normal. X-ray crystallographic structure determination will aid the structure-based design of galectin-1 inhibitors. Here, the crystallization and preliminary diffraction analysis of human galectin-1 crystals generated under six different conditions is reported. X-ray diffraction data enabled the assignment of unit-cell parameters for crystals grown under two conditions, one belongs to a tetragonal crystal system and the other was determined as monoclinic P2{sub 1}, representing two new crystal forms of human galectin-1.

  5. Crystal origins and magmatic system beneath Ngauruhoe volcano (New Zealand) revealed by plagioclase textures and compositions

    Science.gov (United States)

    Coote, Alisha C.; Shane, Phil

    2016-09-01

    The textural variation and compositional zoning of plagioclase in pre-historic and historic basaltic andesite lava flows from Ngauruhoe volcano reveals extensive crystal recycling from a multi-level magma system. Most phenocrysts have a calcic (~ An80-90) resorbed core with diffuse or no zonation that is depleted in Fe and Mg. Some cores display patchy zonation from replacement by high An crystallization prior to resorption. The cores are mantled by oscillatory-zoned rims of lower An content (Mg. Rim zones vary in relative thickness and textural complexity, and include sieve-textured bands, and/or cyclic calcic growth following dissolution events. A subordinate crystal population display similar features, but lack a resorbed core. These latter crystals display overall rimward enrichment in An, Fe and Mg. The resorbed cores crystallized from magmas more mafic than those erupted at Ngauruhoe, and slow cooling and prolonged storage resulted in loss of An zoning patterns and depletion of Fe and Mg by diffusion. These crystals are likely to have originated from deep cumulates or intrusions, and were subsequently entrained in ascending magmas. Patchy-textured cores were produced during decompression in a water under-saturated magma and staged ascent. The diversity in crystal cores reflect different conduits and ascent histories. The crystal rims grew in a more differentiated magma reservoir, and are in equilibrium with the erupted melt. Most of the zoning patterns in the rim zone require water pressure and/or temperature changes. These changes could have been caused by convective self-mixing in a closed system and/or the intrusion of hydrous melts of similar bulk composition. Other crystals display rimward elemental enrichments consistent with mafic recharge. Previously reported rimward enrichment in 87Sr-86Sr compositions can be explained by the re-cycled origin of the crystal cores and progressive crustal assimilation at shallower depths in the magma system where

  6. Growth and characterization of a third order nonlinear optical single crystal: Ethylenediamine-4-nitrophenolate monohydrate

    Energy Technology Data Exchange (ETDEWEB)

    Dhanalakshmi, B. [Department of Physics, Asan Memorial College of Engineering and Technology, Chengalpattu 603 203, Tamil Nadu (India); Ponnusamy, S., E-mail: suruponnus@gmail.com [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603 203, Tamil Nadu (India); Muthamizhchelvan, C.; Subhashini, V. [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603 203, Tamil Nadu (India)

    2015-10-15

    Highlights: • EDA4NPH crystal possesses negative nonlinear refractive index. • The crystal exhibits high third-order NLO susceptibility. • Wide transparency of the crystal makes it suitable for NLO applications. • Dielectric studies substantiate the suitability for electro-optic applications. • The crystal possesses suitable mechanical strength for device fabrication. - Abstract: Bulk crystals of the charge-transfer complex, ethylenediamine-4-nitrophenolate monohydrate, were grown by slow solvent evaporation method from aqueous solution at room temperature. The X-ray diffraction measurements showed that the crystal belongs to centrosymmetric space group C2/c of monoclinic system. The functional groups in the complex were identified using FTIR, FTRaman and FTNMR analyses. The Z-scan measurements revealed the negative nonlinear refractive index of the crystal. The nonlinear absorption coefficient and third order nonlinear optical susceptibility calculated from the measurements were −3.5823 × 10{sup −3} cm/W and 2.3762 × 10{sup −6} esu respectively. The crystal was shown to be highly transparent above 366 nm by UV–vis spectroscopy and a yellow fluorescence was observed from PL spectrum. The TG–DTA and DSC analyses showed that the crystal is thermally stable up to 117.4 °C. The crystals were characterized by dielectric, etching and microhardness studies.

  7. Synthesis, growth and characterization of a new nonlinear optical crystal: glycinium hydrogen squarate (GHS).

    Science.gov (United States)

    Paramasivam, P; Ramachandra Raja, C

    2012-07-01

    Single crystals of glycinium hydrogen squarate (GHS) have been successfully synthesized and purity of the material has been increased by repeated recrystallization process. Single crystals were grown by slow evaporation solution growth technique using water and ethanol as solvents at room temperature. Then the grown crystal was characterized by different techniques for finding its suitability for device fabrications. The grown crystal was characterized by single crystal XRD, powder XRD, FT-IR, UV-Vis-NIR, (1)H NMR, (13)C NMR, SHG and DTA/TGA analyses respectively. From the single crystal XRD diffraction, the crystal system was identified as monoclinic. The presence of functional groups were identified by FT-IR analysis. The UV transparency cut-off wavelength of the grown crystal occurs at 342nm. (1)H NMR and (13)C NMR spectroscopic studies were employed to elucidate the structure of the grown crystal. The second harmonic generation efficiency test by Kurtz-Perry technique showed positive result. The decomposition temperature of the grown crystal was studied by DTA/TGA analysis. The results observed from the characterization analyses show its suitability for NLO applications.

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

    Directory of Open Access Journals (Sweden)

    Akihiro Suzuki

    2012-06-01

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

  9. Crystal Structure-Ionic Conductivity Relationships in Doped Ceria Systems

    DEFF Research Database (Denmark)

    Omar, Shobit; Wachsman, Eric D.; Jones, Jacob L.;

    2009-01-01

    In the past, it has been suggested that the maximum ionic conductivity is achieved in ceria, when doped with an acceptor cation that causes minimum distortion in the cubic fluorite crystal lattice. In the present work, this hypothesis is tested by measuring both the ionic conductivity and elastic...

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

    Science.gov (United States)

    Fu, Zuoling; Zhou, Shihong; Zhang, Siyuan

    2005-08-01

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

  11. Crystal structure determination of Jatrorrhizine chloride

    Institute of Scientific and Technical Information of China (English)

    LEI XianRong; YANG JianHua; LIN Xiang; DAI Qin; CHENG Qiang; GUO LingHong; LI Hui

    2009-01-01

    Optimum resolution data of powder X-ray diffraction (PXRD) for Jatrorrhizine (Jat) were collected by an X' Pert Pro MPD diffractometer with an X'celerator detector under the stepwise scanning condition as 8.255 ms and 0.00836°per step,2θrange of 50°-80° and total scanning period of 8-10 min. Indexing of the crystal system and a search of the space group from the powder X-ray diffraction data were conducted by the computational crystallography method. The pilot crystal models of Jat were globally optimized with Monte Carlo method and then refined with the Rietveld method. In parallel with PXRD test,single crystals of Jat were cultured in an aqueous solution by a slow-decreasing temperature method,then its crystal structure was determined by single crystal X-ray diffraction (SCXRD). Both crystal structures from PXRD and SCXRD are identical. The results show that the crystal structure of Jat belongs to a monoclinic system and the space group P21/c. The parameters of cell dimensions from PXRD are a=7.69(A),b= 12.55(A),c=20.89(A),β=106.53°,Z=4,and V=1933.4(A)3,meanwhile the parameters from SCXRD are a=7.72(A),b=12.61(A),c=20.99(A),β=106.38°,Z=4,and V=1961.3(A)3.

  12. Neutron interrogation systems using pyroelectric crystals and methods of preparation thereof

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Vincent; Meyer, Glenn A.; Falabella, Steven; Guethlein, Gary; Rusnak, Brian; Sampayan, Stephen; Spadaccini, Christopher M.; Wang, Li-Fang; Harris, John; Morse, Jeff

    2017-08-01

    According to one embodiment, an apparatus includes a pyroelectric crystal, a deuterated or tritiated target, an ion source, and a common support coupled to the pyroelectric crystal, the deuterated or tritiated target, and the ion source. In another embodiment, a method includes producing a voltage of negative polarity on a surface of a deuterated or tritiated target in response to a temperature change of a pyroelectric crystal, pulsing a deuterium ion source to produce a deuterium ion beam, accelerating the deuterium ion beam to the deuterated or tritiated target to produce a neutron beam, and directing the ion beam onto the deuterated or tritiated target to make neutrons using a voltage of the pyroelectric crystal and/or an HGI surrounding the pyroelectric crystal. The directionality of the neutron beam is controlled by changing the accelerating voltage of the system. Other apparatuses and methods are presented as well.

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

    Science.gov (United States)

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

    2010-03-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  15. Synthesis, growth, structural, optical, thermal and mechanical properties of an organic Urea maleic acid single crystals for nonlinear optical applications

    Science.gov (United States)

    Vinothkumar, P.; Kumar, R. Mohan; Jayavel, R.; Bhaskaran, A.

    2016-07-01

    A potential organic urea maleic acid (UMA) was synthesized and single crystals were grown at room temperature by slow evaporation and seed rotation methods. The grown crystal has been subjected to single crystal XRD analysis and found to have been crystallized in a noncentrosymmetric monoclinic crystal system with Cc as space group. The High resolution X-ray diffraction analysis revealed that the specimen is free from structural grain boundaries. The transparency of the grown crystal was confirmed by optical absorption and transmittance spectra with lower cut-off wavelength of 285 nm. The microhardness test was carried out on different planes to study the load dependent hardness values. The dislocation density of the UMA crystal was estimated from the etching studies. The dielectric permittivity and dielectric loss of the grown crystal was carried out as a function of frequency for different temperatures along three crystallographic axes. Thermal properties of UMA crystals were studied by TG-DTA analysis and it is stable upto 112 °C. The laser induced surface damage threshold of the grown crystal was measured using Nd: YAG laser. The birefringence of the crystal measured in the visible region was found to vary with the wavelength. The particle size dependent SHG of the sample was measured with different input energies by Kurtz's powder method using Nd:YAG laser.

  16. Self-organized crystallization mechanism of non-equilibrium 2:1 type phyllosilicate systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The crystallization mechanism of 2:1 type regular interstratified minerals is investigated in views of non-equilibrium thermodynamics. The structural chemistry of relative layers and their interstratified combinations is analyzed and six kinds of non-equilibrium chemical systems have been induced. The universal laws of chemical reactions which happened in the interface region of these non-equilibrium systems have been summarized. From these laws, two reaction systems crystallizing out Tosudite and Rectorite respectively have been recovered. The kinetic model of chemical reactions has been developed by means of the mass conservation law. The oscillatory solution showing regular interstratified features has also been obtained numerically. These results indicate that the difference in original chemical composition among systems can affect the chemical connotation of reactants, intermediate products and resultants, and the flow chart of chemical reaction, but cannot change their crystallization behavior of network-forming cations, bigger and smaller network-modifying cations during crystallization. Hence, their kinetic model reflecting the universal crystallization law of these cations is just the same. These systems will crystallize out regular interstratified minerals at suitable parameters, which always exist as domain with nanometer-sized in thickness and can be called the self-organized ordering structure.

  17. Crystallization and molecular-replacement solution of a truncated form of human recombinant tetranectin

    DEFF Research Database (Denmark)

    Nielsen, Betina Bryde; Kastrup, Jette Sandholm Jensen; Rasmussen, Hanne B.;

    2000-01-01

    The two C-terminal domains, TN23 (residues 17-181), of human recombinant tetranectin, a plasminogen kringle 4 binding C-type lectin, have been crystallized in two different space groups. Using PEG 8000 as precipitant and at a pH of 8.5, crystals belonging to the monoclinic space group C2 are obta.......5 A has been collected from the monoclinic crystals. Using the structure of full-length tetranectin, a molecular-replacement solution has been obtained. The crystal packing shows that TN23 crystallizes as a trimer, with one trimer in the asymmetric unit....

  18. Asymmetric crystallization upon heating and cooling in model glass-forming systems

    Science.gov (United States)

    Wang, Minglei; Zhang, Kai; Liu, Yanhui; Schroers, Jan; Shattuck, Mark; O'Hern, Corey

    2014-03-01

    We perform molecular dynamics simulations of binary Lennard-Jones (LJ) and hard-sphere (HS) systems to understand the asymmetry in the critical cooling and heating rates for crystallization observed in experiments on bulk metallic glasses, where much faster heating rates are required to prevent crystallization. For the LJ systems, we cool the systems at different rates (above the critical cooling rate Rc) to temperatures below the glass transition, and subsequently begin heating the samples at different rates to measure the critical heating rate Rh below which the system crystallizes. We perform companion studies of HS systems, except we measure the asymmetry in the critical compression and dilation rates to enhance the asymmetry. We show that the asymmetry increases with the glass-formability of the binary mixtures and explain this result by characterizing the structural order of the systems.

  19. Investigation on growth, structure and characterization of succinate salt of 8-hydroxyquinoline: an organic NLO crystal.

    Science.gov (United States)

    Thirumurugan, R; Babu, B; Anitha, K; Chandrasekaran, J

    2015-04-05

    8-Hydroxyquinolinium succinate (8-HQSU) has been synthesized and single crystals were grown from ethanol solvent by employing the technique of slow evaporation at room temperature. The structure of the grown crystal has been elucidated by single crystal X-ray diffraction analysis. It reveals that 8-HQSU crystallizes in monoclinic system with non-centro symmetric space group P2(1). FTIR, 1H and 13C NMR spectral investigations have been carried out to identify the vibrational modes of various functional groups and placement of proton and carbon in the 8-HQSU compound, respectively. UV-vis-NIR transmission spectrum shows the cutoff wavelength around 357 nm. In addition, a photoluminescence spectral analysis was carried out for 8-HQSU crystals. The thermal properties of crystals were evaluated from TGA and DTA techniques and the crystal was found to be stable up to 145°C. The dielectric studies show that the dielectric constant and dielectric loss decrease exponentially with frequency at different temperatures. Photoconductivity studies were carried out on the grown crystals it reveals the positive photo conducting nature. Powder second harmonic generation property of the crystal was confirmed by Kurtz and Perry powder SHG technique and it is found to be 1.3 times greater than that of KDP. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Synthesis, structural, optical, thermal and dielectric studies on new organic nonlinear optical crystal by solution growth technique.

    Science.gov (United States)

    Prakash, M; Geetha, D; Lydia Caroline, M

    2013-04-15

    Single crystals of L-phenylalanine-benzoic acid (LPBA) were successfully grown from aqueous solution by solvent evaporation technique. Purity of the crystals was increased by the method of recrystallization. The XRD analysis confirms that the crystal belongs to the monoclinic system with noncentrosymmetric space group P21. The chemical structure of compound was established by FT-NMR technique. The presence of functional groups was estimated qualitatively by Fourier transform infrared analysis (FT-IR). Ultraviolet-visible spectral analyses showed that the crystal has low UV cut-off at 254 nm combined with very good transparency of 90% in a wide range. The optical band gap was estimated to be 6.91 eV. Thermal behavior has been studied with TGA/DTA analyses. The existence of second harmonic generation (SHG) efficiency was found to be 0.56 times the value of KDP. The dielectric behavior of the sample was also studied for the first time.

  1. Isothermal crystallization kinetics of lidocaine in supersaturated lidocaine/polyacrylate pressure sensitive adhesive systems.

    Science.gov (United States)

    Cui, Yong; Frank, Sylvan G

    2005-09-01

    Isothermal crystallization of lidocaine (LC) in supersaturated LC/Duro-Tak 87-2287 (DT2287) polyacrylate pressure sensitive adhesive (PSA) systems has been studied by differential scanning calorimetry (DSC). It was found that crystallization of LC in supersaturated LC/DT2287 systems was governed by the nucleation process, which in turn was dependent on temperature and composition of the systems. A critical temperature T(crit) was found at approximately 26 degrees C, above which the crystallization of LC in LC/DT2287 systems becomes slow. The lack of dependence of T(crit) on the composition of the mixtures indicates that the presence of the PSA affected the kinetics (diffusion) rather than the thermodynamics of the nucleation process. A critical degree of saturation S(crit) of approximately 4 was also found, above which the nucleation rate sharply increases. Kinetic analysis based on the classical theory of nucleation indicates that nucleation of LC in the PSA medium is a diffusion-controlled process. The activation energy of crystallization had a two-phase dependence on temperature suggesting that the mechanism of crystallization may change at the transition temperatures. As the weight fraction of LC increased in the systems, the activation energy of crystallization, DeltaG(c), was minimal at approximately 15 degrees C, indicating that the nucleation of LC in the LC/DT2287 systems is at its fastest rate around this temperature. These fundamental analyses of nucleation and crystallization mechanisms are of practical significance in the design of supersaturated drug delivery systems.

  2. Growth and characterization of morpholinium dihydrogenphosphate single crystal

    Science.gov (United States)

    Babu, D. Rajan; Arul, H.; Vizhi, R. Ezhil

    2016-10-01

    Morpholinium dihydrogenphosphate (MDP) single crystals were synthesized, and were subsequently grown by controlled evaporation technique at room temperature for nonlinear optical applications. The grown crystal, which belongs to the monoclinic system with the space group P21, was subjected to single crystal X-ray diffraction to confirm the structure. UV-vis-NIR spectroscopy was done on the grown crystal and it showed good optical transparency in the entire visible region with a minimum cut-off wavelength of 289 nm. The optical band gap was computed as a function of photon energy using Tauc's plot. The refractive index of the grown crystal was determined using a Metricon Prism Coupler. The thermogravimetric (TG) and differential thermal analysis (DTA) traces disclosed the thermal stability of the compound. The mechanical strength of the crystal was investigated by a Vickers microhardness tester. Dielectric constant and dielectric loss were calculated and plotted as a function of frequency at different temperatures. The second harmonic conversion efficiency was determined using the Kurtz-Perry powder technique, and the efficiency was found to be 1.2 times greater than that of standard KDP.

  3. EPR Properties of Concentrated NdVO4 Single Crystal System.

    Science.gov (United States)

    Kaczmarek, S M; Fuks, H; Berkowski, M; Głowacki, M; Bojanowski, B

    Single crystals of NdVO4 were grown by the Czochralski method under ambient pressure in a nitrogen atmosphere. Obtained crystals were transparent with strong violet coloring. Temperature and angular dependences of electron paramagnetic resonance (EPR) spectra of the samples in the 3-103 K temperature range were analyzed applying Dyson like lineshape typically used for concentrated magnetic system. EPR-NMR program was used to find local symmetry and spin-Hamiltonian parameters of neodymium ions.

  4. A Low-Cost System Based on Image Analysis for Monitoring the Crystal Growth Process

    Directory of Open Access Journals (Sweden)

    Fabrício Venâncio

    2017-05-01

    Full Text Available Many techniques are used to monitor one or more of the phenomena involved in the crystallization process. One of the challenges in crystal growth monitoring is finding techniques that allow direct interpretation of the data. The present study used a low-cost system, composed of a commercial webcam and a simple white LED (Light Emitting Diode illuminator, to follow the calcium carbonate crystal growth process. The experiments were followed with focused beam reflectance measurement (FBRM, a common technique for obtaining information about the formation and growth of crystals. The images obtained in real time were treated with the red, blue, and green (RGB system. The results showed a qualitative response of the system to crystal formation and growth processes, as there was an observed decrease in the signal as the growth process occurred. Control of the crystal growth was managed by increasing the viscosity of the test solution with the addition of monoethylene glycol (MEG at 30% and 70% in a mass to mass relationship, providing different profiles of the RGB average curves. The decrease in the average RGB value became slower as the concentration of MEG was increased; this reflected a lag in the growth process that was proven by the FBRM.

  5. Crystal structure, growth and nonlinear optical studies of isonicotinamide p-nitrophenol: A new organic crystal for optical limiting applications

    Science.gov (United States)

    Vijayalakshmi, A.; Vidyavathy, B.; Vinitha, G.

    2016-08-01

    Isonicotinamide p-nitrophenol (ICPNP), a new organic material, was synthesized using methanol solvent. Single crystals of ICPNP were grown using a slow evaporation solution growth technique. Crystal structure of ICPNP is elucidated by single crystal X-ray diffraction analysis. It belongs to monoclinic crystal system with space group of P21/c. It forms two dimensional networks by O-H…O, N-H…O and C-H…O hydrogen bonds. The molecular structure of ICPNP was further confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical transmittance range and the lower cut-off wavelength (421 nm) with the optical band gap (2.90 eV) of the ICPNP crystal were determined by UV-vis-NIR spectral study. Thermal behavior of ICPNP was studied by thermo gravimetric and differential thermal analyses (TG/DTA). The relative dielectric permittivity was calculated for various temperature ranges. Laser damage threshold of ICPNP crystal was found to be 1.9 GW/cm2 using an Nd:YAG laser. A Z-scan technique was employed to measure the nonlinear absorption coefficient, nonlinear refractive index and nonlinear optical susceptibility. Optical limiting behavior of ICPNP was observed at 35 mW input power.

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

    Directory of Open Access Journals (Sweden)

    Hamid Khaledi

    2009-10-01

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

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

    Science.gov (United States)

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

    2010-09-15

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

  8. Bis-methyl imidazolium methylidene bis(trifluoromethanesulfonyl)imide, crystal structure, thermal and dielectric studies

    Indian Academy of Sciences (India)

    BOUMEDIENE HADDAD; TAQIYEDDINE MOUMENE; DIDIER VILLEMIN; JEAN-FRANÇOIS LOHIER; EL-HABIB BELARBI

    2016-06-01

    A new geminal di-cationic ionic liquid (IL) containing a central cationic unit methylidene capped by a basic functionality (imidazole) is synthesized. The compound was characterized by means of ${}^1$H, ${}^13$C, ${}^19$F NMR, IR and Raman spectroscopies and its crystal structure is confirmed by single crystal X-ray diffraction method. The X-ray studies on ([M(CH$_2$)IM$^{2+}$][2NTf$^−_2$ ]) show that it crystallizes in monoclinic system with space group:P 21/c. Thermal properties were investigated in the temperature range from 0 to 400$^{\\circ}$C by using differential thermal (DTA) and thermogravimetric (TGA) analyses. The frequency-dependent electrical data are discussed using complexdielectric permittivity in the frequency range of ($10^{−2}–10^6$ Hz) and in the temperature range of $−50–20^{\\circ}$C. The outstanding dielectric and thermal properties make this IL as promising candidate for electrochemical devices.

  9. Single crystal growth and magnetic excitations of transistion metal oxide CoV2 O6

    Science.gov (United States)

    Stockdale, Christopher; Wallington, F.; Taylor, J. W.; Garcia-Sakai, V.; Arevalo-Lopez, A. M.; Attfield, P.; Stock, C.

    2015-03-01

    Low-dimensional magnetic materials are an area of interest due to their unusual properties such as metamagnetism and magnetization plateaus. Solid state synthesis has produced polycrystalline CoV2O6 which exists in two polymorphs: one with a monoclinic structure, and the other with a triclinic structure. Single crystals have been grown from polycrystalline CoV2O6 using the flux method under vacuum and are large enough to aid in single crystal neutron diffraction. Magnetic excitations have been measured using powder neutron diffraction in the low temperatures regime with variable energy. The magnetic excitations have been compared between the two phases. The energy of the system has been modelled in terms of the spin-orbit coupling, structural distortions, and the crystal field and compared to neutron data.

  10. Experimental and DFT computational studies of L-alanine cadmium chloride crystals

    Science.gov (United States)

    Ignatius, I. Cicili; Dheivamalar, S.; Kirubavathi, K.; Selvaraju, K.

    2016-05-01

    In this work, we report the combined experimental and theoretical study on molecular structure and vibrational spectra of nonlinear optical crystal L-alanine cadmium chloride (LACC). The single X-ray diffraction studies have revealed that the compound crystallizes in monoclinic system C2 space group with cell parameters a = 16.270, b = 7.358, c = 7.887 and Z = 4. FTIR and Raman spectra of the nonlinear optical materials LACC have been recorded and analyzed. The optimized geometric bond length and bond angles are obtained with the help of density functional theory (DFT) (B3LYP) calculation. The optimized geometric bond lengths and bond angles obtained by using DFT show good agreement with the experimental data. Using the natural bond orbital analysis the electronic effect and hydrogen bonding were confirmed. The HOMO-LUMO energy gap and the first order hyperpolarizability were calculated and it supports the nonlinear optical activity of LACC crystal.

  11. Growth and structure of a new photonic crystal: Chlorine substituted chalcone

    Energy Technology Data Exchange (ETDEWEB)

    Sarveshwara, H. P., E-mail: sarvesh.heggadde@gmail.com; Menezes, Anthoni Praveen [Department of Physics, Mangalore Institute Of Technology And Engineering (MITE), Moodabidri-574225 (India); Raghavendra, S.; Dharmaprakash, S. M. [Department of Studies in Physics, Mangalore University, Mangalore -575199 (India); A, Jayarama [Department of Physics, Sadguru Swami Nithyananda Institute of Technology (SSNIT), Kanhangad 671315 (India)

    2015-06-24

    A new organic photonic material 3-(2, 4-dichlorophenyl)-1-(2,5-dimethylthiophen-3-yl)propan-1-one(DMTP) has been synthesized and crystallised in acetone solution. The functional groups present in the new material were identified by FTIR spectroscopy. The material is optically transparent in the wavelength range of 400–1100 nm. The crystal structure of DMTP was determined by single crystal X-ray diffraction. The title compound crystallizes in monoclinic system with a centrosymmetric space group P2{sub 1}/c. The Z-scan study revealed that the optical limiting property exhibited by the DMTP molecule is based on the reverse saturable absorption phenomena.

  12. Interlayer-type Crystal Structure of N-(1-Adamantyl)urea

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The crystal structure of N-(1-adamantyl)urea (tricyclo[3,3,1,13,7]decan-1-urea, C11H18N2O) has been determined by X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 13.070(2), b = 8.942(1), c = 9.390(1)(A), β = 109.819(8)°, V = 1032.5(2)(A)3, Mr = 194.27, Z = 4, Dc = 1.250 g/cm3, μ= 0.081 mm-1, F(000) = 424, R = 0.0427 and wR = 0.1076 for 1105 observed reflections with I > 2σ(I). The structure of the title compound consists of an adamantly cage which is a stable tricyclo structure with chair conformation and the substituted urea forms the interlayer-type crystal structure via hydrogen bonds between the molecules.

  13. Crystal structure determiningof 7-ADCA based on X-raypowder diffraction

    Institute of Scientific and Technical Information of China (English)

    HU Enping; CHENG Qiang; GUO Linghong; LI Hui

    2006-01-01

    Optimum resolution data of X-ray powder diffraction for 7-amino desacetoxy cephalospo- ranic acid(7-ADCA) were collected from an X' Pert Pro MPD diffractometer with the setup of 0.01°/s and 0.01° per step. Indexing to the crystal system and searching space group from the diffraction data were conducted by means of the computational crystallography method. The pilot crystal models of 7-ADCA were then refined by Rietveld method to obtain the exact three-dimensional structure. The results show that the crystal structure of 7-ADCA is monoclinic, space group P21 with unit cell dimensions a=13.50(A) b=6.01(A), c =5.91(A), α=γ=90.00°,β=101.96°, Z=2 and V =469.10(A)3. The fraction coordinate of each atom in the unit cell is well located and reported.

  14. Molecular and Crystal Magnetic Engineering of Polymetallic Coupling System: From Magnetic Molecules to Molecular Magnets

    Institute of Scientific and Technical Information of China (English)

    程鹏; 廖代正

    2001-01-01

    One of the main challenges in the field of molecular materials is the design of molecular ferromagnets. General design strategy includes two steps, that is molecular magnetic engineering and crystal magnetic engineering. The first step is the synthesis of ferromagnetically coupled polymetallic systems.Tne second step is the assembly of polymetallic systems with muti-dimensional structure and exhibiting a ferromagnetic transition.This paper summarized the strategies of molecular design and crystal engineering allowed to obtain such systems and our efforts in the fields of molecular magnetism and molecular-based magnets.

  15. Nanoconfinement crystallization of frustrated alkyl groups: crossover of mesophase to crystalline structure.

    Science.gov (United States)

    Shi, Haifeng; Wang, Haixia; Xin, John H; Zhang, Xingxiang; Wang, Dujin

    2011-04-07

    Crossover of mesophase to crystalline structure in the nanoconfinement crystallization process of frustrated side groups elucidates the critical crystal thickness d(c) or the length scale of side groups, which defines the transition process from mesophase (hexagonal and monoclinic phase) to crystalline phase (orthorhombic phase) of confined CH(2) sequences in a given crystal size restriction.

  16. Inorganic scintillators for detector systems physical principles and crystal engineering

    CERN Document Server

    Lecoq, Paul; Korzhik, Mikhail

    2017-01-01

    This second edition features new chapters highlighting advances in our understanding of the behavior and properties of scintillators, and the discovery of new families of materials with light yield and excellent energy resolution very close to the theoretical limit. The book focuses on the discovery of next-generation scintillation materials and on a deeper understanding of fundamental processes. Such novel materials with high light yield as well as significant advances in crystal engineering offer exciting new perspectives. Most promising is the application of scintillators for precise time tagging of events, at the level of 100 ps or higher, heralding a new era in medical applications and particle physics. Since the discovery of the Higgs Boson with a clear signature in the lead tungstate scintillating blocks of the CMS Electromagnetic Calorimeter detector, the current trend in particle physics is toward very high luminosity colliders, in which timing performance will ultimately be essential to mitigating...

  17. 3-dimensional imaging system using crystal diffraction lenses

    Science.gov (United States)

    Smither, Robert K.

    1999-01-01

    A device for imaging a plurality of sources of x-ray and gamma-ray radiation is provided. Diffracting crystals are used for focussing the radiation and directing the radiation to a detector which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for a method for imaging x-ray and gamma radiation by supplying a plurality of sources of radiation; focussing the radiation onto a detector; analyzing the focused radiation to collect data as to the type and location of the radiation; and producing an image using the data.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-04-15

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

  19. Design, construction and testing of a system for detection of toxic gases based on piezoelectric crystals.

    Science.gov (United States)

    Leyva, J A; de Cisneros, J L; de Barreda, D G; Becerra, A J

    1994-01-01

    A system for static operation of toxic gas sensors based on piezoelectric crystals was constructed as a preliminary step in the development of this type of sensor. The sensing part of the setup consists of a twin oscillating circuit assembled from commercially available electronic parts mounted on a motherboard. The oscillating circuits can accommodate two piezoelectric crystals, of which one or both can be coated with different materials, or a single one, as required. The sensing assembly (crystals plus oscillating circuits) is placed in a customized test chamber that allows one to control and reproduce its internal environment. Once assembled and fine-tuned, the proposed setup was used to test a commercially available piezoelectric crystal for sensing formaldehyde in order to expand available information on this type of sensor.

  20. Study on flow characteristics of solid/liquid system in lysozyme crystal growth

    Institute of Scientific and Technical Information of China (English)

    CUI HaiLiang; YU Yong; CHEN WanChun; KANG Qi

    2007-01-01

    During the process of lysozyme protein crystallization with batch method, the macroscopic flow field of solid/liquid system was observed by particle image velocimetry (PIV). Furthermore, a normal growth rate of (110) face and local flow field around a single protein crystal were obtained by a long work distance microscope. The experimental results showed that the average velocity, the maximal velocity of macroscopic solid/liquid system and the velooity of local flow field around single protein crystal were fluctuant. The effective boundary layer thickness δeff, the concentration at the interface Gi and the characteristic velocity V were calculated using a convection-diffusion model. The results showed that the growth of lysozyme crystal in this experiment was dominated by interfacial kinetics rather than bulk transport, and the function of buoyancy-driven flow in bulk transport was small, however, the effect of bulk transport in crystal growth had a tendency to increase with the increase of lysozyme concentration. The calculated results also showed that the order of magnitude of shear force was about 10-21 N,which was much less than the bond force between the lysozyme molecules. Therefore the shear force induced by buoyancy-driven flows cannot remove the protein molecules from the interface of crystal.

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

    Indian Academy of Sciences (India)

    Sarva Jit Singh; Sandhya Khurana

    2002-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-13

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

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Bin Zhou; Jiuhui Qu; Xu Zhao; Huijuan Liu

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Shabeer Ahmed Abbasi

    2015-04-01

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

  6. Optimization of detection system based on inorganic scintillation crystal coupled with a long lightguide

    CERN Document Server

    Globus, M; Ratner, M

    2002-01-01

    Operation characteristics of a scintillation crystal, linked with the photomultiplier by a long transparent lightguide, are considered (such detection systems are used for monitoring the seawater pollution, scintillation measurements in magnetic field, etc.). This system is optimized with respect to the refractive index of the liquid, coupling the crystal with the lightguide, and the roughness degree of the crystal surface. It is shown that the energy resolution of the system can be significantly improved by using the coupling liquid with a refractive index somewhat less than that of the lightguide (a difference of about 0.2 is optimal). Light output and especially energy resolution becomes better with an increase of the roughness degree of the reflecting surface.

  7. Growth and characterization of Sm3+ doped cerium oxalate single crystals

    Directory of Open Access Journals (Sweden)

    Minu Mary C

    2016-07-01

    Full Text Available Single crystals of Sm3+ doped cerium oxalate decahydrate were synthesized using single diffusion gel technique and the conditions influencing the size, morphology, nucleation density and quality of the crystals were optimized. Highly transparent single crystals of average size 3 mm × 2 mm × 1 mm with well-defined hexagonal morphology were grown during a time period of two weeks. X-ray powder diffraction analysis revealed that the grown crystals crystallize in the monoclinic system with space group P21/c as identical with the pure cerium oxalate. The various functional groups of the oxalate ligand and the water of crystallization were identified by Fourier transform infrared spectroscopy. The photoluminescence spectrum of the Sm3+ doped cerium oxalate indicated that the Sm3+ ions are optically active in the cerium oxalate matrix. The crystal has a strong and efficient orange red emission with a wavelength peak at 595 nm and hence can be effectively used for optical amplification. Microhardness measurements of the crystal revealed that they belong to the soft material category.

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

    Science.gov (United States)

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

    2016-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-15

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

  10. Crystals in crystals

    DEFF Research Database (Denmark)

    Christensen, Claus H.; Schmidt, I.; Carlsson, A.;

    2005-01-01

    A major factor governing the performance of catalytically active particles supported on a zeolite carrier is the degree of dispersion. It is shown that the introduction of noncrystallographic mesopores into zeolite single crystals (silicalite-1, ZSM-5) may increase the degree of particle dispersion...... of the zeolite particles, particularly after thermal treatment. When using mesoporous zeolites, the particles were evenly distributed throughout the mesopore system of the zeolitic support, even after calcination, leading to nanocrystals within mesoporous zeolite single crystals....

  11. Modified timing characteristic of a scintillation detection system with photonic crystal structures.

    Science.gov (United States)

    Liu, Jinliang; Liu, Bo; Zhu, Zhichao; Chen, Liang; Hu, Jing; Xu, Mengxuan; Cheng, Chuanwei; Ouyang, Xiaoping; Zhang, Zhongbing; Ruan, Jinlu; He, Shiyi; Liu, Linyue; Gu, Mu; Chen, Hong

    2017-03-01

    It is intuitively expected that an enhanced light extraction of a scintillator can be easily achieved by photonic crystal structures. Here, we demonstrate a modified timing characteristic for a detection system induced by enhanced light extraction with photonic crystal structures. Such improvement is due to the enhanced light extraction which can be clearly proven by the independent measurements of the light output and the timing resolution. The present investigation is advantageous to promote the development of a scintillation detection system performance based on the time-of-flight measurement.

  12. Determination of the crystal growth mechanism of KCl in ethanol?water system

    Science.gov (United States)

    Liszi, I.; Hasznosné-Nezdei, M.; Lakatos, B. G.; Sapundzhiev, Ts. J.; Popov, R. G.

    1999-03-01

    The mechanism of crystal growth of KCl in ethanol-water system is studied by Nielsen's map-model, and the growth rate is estimated by the induction time (nucleation rate, growth rate) function in a salting-out crystallization system. In the experiments, the induction time and the particle size distribution of the final product were measured, and the solid-liquid interfacial tension was calculated from the induction period data. The map of rate control of crystal-growth for the KCl-ethanol-water salting out system was constructed by taking into consideration that the liquid-vapour interfacial tension varied with the variation of the ethanol concentration, and, as a consequence, the solid-liquid interfacial tension varied as well. As a result, diffusion controlled crystal growth was obtained as a rate-determining step for supersaturation ratios 0.01<0.45. For determining the crystal growth rate, the nucleation rate was estimated from the experimental average particle number and induction period, applying the assumption that all nuclei were born during the induction period. The results, obtained by using linear and non-linear regressions, have appeared to be in good agreement with the data published in the literature.

  13. The peculiar electrical response of liquid crystal-carbon nanotube systems as seen by impedance spectroscopy

    Science.gov (United States)

    García-García, A.; Vergaz, R.; Algorri, J. F.; Geday, M. A.; Otón, J. M.

    2015-09-01

    Conductive nanoparticles, especially elongated ones such as carbon nanotubes, dramatically modify the electrical behavior of liquid crystal cells. These nanoparticles are known to reorient with liquid crystals in electric fields, causing significant variations of conductivity at minute concentrations of tens or hundreds ppm. The above notwithstanding, impedance spectroscopy of doped cells in the frequency range customarily employed by liquid crystal devices, 100 Hz-10 kHz, shows a relatively simple resistor/capacitor response where the components of the cell can be univocally assigned to single components of the electrical equivalent circuit. However, widening the frequency range up to 1 MHz or beyond reveals a complex behavior that cannot be explained with the same simple EEC. Moreover, the system impedance varies with the application of electric fields, their effect remaining after removing the field. Carbon nanotubes are reoriented together with liquid crystal reorientation when applying voltage, but barely reoriented back upon liquid crystal relaxation once the voltage is removed. Results demonstrate a remarkable variation in the impedance of the dielectric blend formed by liquid crystal and carbon nanotubes, the irreversible orientation of the carbon nanotubes and possible permanent contacts between electrodes.

  14. Mineral chemistry of the Tissint meteorite: Indications of two-stage crystallization in a closed system

    Science.gov (United States)

    Liu, Yang; Baziotis, Ioannis P.; Asimow, Paul D.; Bodnar, Robert J.; Taylor, Lawrence A.

    2016-12-01

    The Tissint meteorite is a geochemically depleted, olivine-phyric shergottite. Olivine megacrysts contain 300-600 μm cores with uniform Mg# ( 80 ± 1) followed by concentric zones of Fe-enrichment toward the rims. We applied a number of tests to distinguish the relationship of these megacrysts to the host rock. Major and trace element compositions of the Mg-rich core in olivine are in equilibrium with the bulk rock, within uncertainty, and rare earth element abundances of melt inclusions in Mg-rich olivines reported in the literature are similar to those of the bulk rock. Moreover, the P Kα intensity maps of two large olivine grains show no resorption between the uniform core and the rim. Taken together, these lines of evidence suggest the olivine megacrysts are phenocrysts. Among depleted olivine-phyric shergottites, Tissint is the first one that acts mostly as a closed system with olivine megacrysts being the phenocrysts. The texture and mineral chemistry of Tissint indicate a crystallization sequence of: olivine (Mg# 80 ± 1) → olivine (Mg# 76) + chromite → olivine (Mg# 74) + Ti-chromite → olivine (Mg# 74-63) + pyroxene (Mg# 76-65) + Cr-ulvöspinel → olivine (Mg# 63-35) + pyroxene (Mg# 65-60) + plagioclase, followed by late-stage ilmenite and phosphate. The crystallization of the Tissint meteorite likely occurred in two stages: uniform olivine cores likely crystallized under equilibrium conditions; and a fractional crystallization sequence that formed the rest of the rock. The two-stage crystallization without crystal settling is simulated using MELTS and the Tissint bulk composition, and can broadly reproduce the crystallization sequence and mineral chemistry measured in the Tissint samples. The transition between equilibrium and fractional crystallization is associated with a dramatic increase in cooling rate and might have been driven by an acceleration in the ascent rate or by encounter with a steep thermal gradient in the Martian crust.

  15. Crystal growth and structural investigation of a new metal-organic crystal: β-alanine cadmium bromide monohydrate (β-ACBM)

    Science.gov (United States)

    Renugadevi, R.; Kesavasamy, R.

    2014-09-01

    A new metal-organic crystal, β-alanine cadmium bromide monohydrate (β-ACBM) has been grown from aqueous solution by slow evaporation technique. The grown crystals have been subjected to single crystal X-ray diffraction to determine the crystal structure. The β-ACBM crystallized in monoclinic system, which belongs to the space group P21/c with a = 8.6734(6) Å, b = 13.9451(8) Å, c = 7.6801(5) Å, β = 103.713(2)o, volume = 902.44(10) Å3, Z = 4, calculated density = 2.792 Mg/m3, F(000) = 704, absorption coefficient = 11.231 mm-1, the final R = 0.0252 and wR2 = 0.0601 for 2065 observed reflections [I > 2sigma(I)]. FT-IR spectroscopy analysis was carried out in order to identify the functional groups of the title compound. The presence of proton and carbon in the β-ACBM was confirmed by 1H and 13C nuclear magnetic resonance spectral analysis. The UV-Vis-NIR transmittance spectrum has been recorded for the grown β-ACBM crystal. The refractive index of β-ACBM crystal was determined by Brewster's angle method using He-Ne laser.

  16. Design of high gain OPCPA for multiterawatt and petawatt class systems on large aperture LBO crystals

    Science.gov (United States)

    Pestryakov, E. V.; Petrov, V. V.; Trunov, V. I.; Frolov, S. A.; Kirpichnikov, A. V.; Bagayev, S. N.; Kokh, A. E.

    2011-02-01

    Comparative analysis of optimal scheme of non-collinear optical chirped-pulse parametric amplification of fewcycle femtosecond pulses from Ti:Sa laser in LBO and DKDP crystals pumped by picosecond pulses up to petawatt level is presented. A flexible code, based on the extended model of parametric amplification, which takes into account the large set of effects such as saturation, phase self-modulation, influence of beam divergence, thermal effects, and amplification of spontaneous emission was realized. A way of creating nearly 1 PW system based on LBO crystals with transform-limited pulse duration about 9 fs has been demonstrated. Comparison between DKDP and LBO crystal showed that the latter is much better for OPCPA petawatt system design than DKDP.

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

    Directory of Open Access Journals (Sweden)

    Kwang Ha

    2012-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-04-01

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

  19. Validation Ice Crystal Icing Engine Test in the Propulsion Systems Laboratory at NASA Glenn Research Center

    Science.gov (United States)

    Oliver, Michael J.

    2014-01-01

    The Propulsion Systems Laboratory (PSL) is an existing altitude simulation jet engine test facility located at NASA Glenn Research Center in Cleveland, OH. It was modified in 2012 with the integration of an ice crystal cloud generation system. This paper documents the inaugural ice crystal cloud test in PSL--the first ever full scale, high altitude ice crystal cloud turbofan engine test to be conducted in a ground based facility. The test article was a Lycoming ALF502-R5 high bypass turbofan engine, serial number LF01. The objectives of the test were to validate the PSL ice crystal cloud calibration and engine testing methodologies by demonstrating the capability to calibrate and duplicate known flight test events that occurred on the same LF01 engine and to generate engine data to support fundamental and computational research to investigate and better understand the physics of ice crystal icing in a turbofan engine environment while duplicating known revenue service events and conducting test points while varying facility and engine parameters. During PSL calibration testing it was discovered than heated probes installed through tunnel sidewalls experienced ice buildup aft of their location due to ice crystals impinging upon them, melting and running back. Filtered city water was used in the cloud generation nozzle system to provide ice crystal nucleation sites. This resulted in mineralization forming on flow path hardware that led to a chronic degradation of performance during the month long test. Lacking internal flow path cameras, the response of thermocouples along the flow path was interpreted as ice building up. Using this interpretation, a strong correlation between total water content (TWC) and a weaker correlation between median volumetric diameter (MVD) of the ice crystal cloud and the rate of ice buildup along the instrumented flow path was identified. For this test article the engine anti-ice system was required to be turned on before ice crystal

  20. An investigation into the role of polymeric carriers on crystal growth within amorphous solid dispersion systems.

    Science.gov (United States)

    Tian, Yiwei; Jones, David S; Andrews, Gavin P

    2015-04-06

    Using phase diagrams derived from Flory-Huggins theory, we defined the thermodynamic state of amorphous felodipine within three different polymeric carriers. Variation in the solubility and miscibility of felodipine within different polymeric materials (using F-H theory) has been identified and used to select the most suitable polymeric carriers for the production of amorphous drug-polymer solid dispersions. With this information, amorphous felodipine solid dispersions were manufactured using three different polymeric materials (HPMCAS-HF, Soluplus, and PVPK15) at predefined drug loadings, and the crystal growth rates of felodipine from these solid dispersions were investigated. Crystallization of amorphous felodipine was studied using Raman spectral imaging and polarized light microscopy. Using this data, we examined the correlation among several characteristics of solid dispersions to the crystal growth rate of felodipine. An exponential relationship was found to exist between drug loading and crystal growth rate. Moreover, crystal growth within all selected amorphous drug-polymer solid dispersion systems were viscosity dependent (η(-ξ)). The exponent, ξ, was estimated to be 1.36 at a temperature of 80 °C. Values of ξ exceeding 1 may indicate strong viscosity dependent crystal growth in the amorphous drug-polymer solid dispersion systems. We argue that the elevated exponent value (ξ > 1) is a result of drug-polymer mixing which leads to a less fragile amorphous drug-polymer solid dispersion system. All systems investigated displayed an upper critical solution temperature, and the solid-liquid boundary was always higher than the spinodal decomposition curve. Furthermore, for PVP-FD amorphous dispersions at drug loadings exceeding 0.6 volume ratio, the mechanism of phase separation within the metastable zone was found to be driven by nucleation and growth rather than liquid-liquid separation.

  1. Polyhedral (in-)stability of protein crystals

    Science.gov (United States)

    Nanev, Christo N.; Penkova, Anita N.

    2002-04-01

    The polyhedral (in-)stability of monoclinic hen-egg white lysozyme (HEWL) crystals, grown by means of PEG-6000, and that of orthorhombic trypsin crystals has been investigated experimentally. On the basis of a quantitative theoretical analysis, it is compared with the polyhedral (in-)stability of tetragonal HEWL and cubic ferritin crystals. The unambiguous conclusion is that the phenomenon is due to the diffusive supply of matter. This conclusion is also supported by the fact that the phenomenon has common features for both proteins and small molecular crystals.

  2. Synthesis, crystal structure analysis, molecular docking studies and density functional theory predictions of the local reactive properties and degradation properties of a novel halochalcone

    Science.gov (United States)

    Arshad, Suhana; Pillai, Renjith Raveendran; Zainuri, Dian Alwani; Khalib, Nuridayanti Che; Razak, Ibrahim Abdul; Armaković, Stevan; Armaković, Sanja J.

    2017-09-01

    In the present study, single crystals of E)-3-(3,5-dichlorophenyl)-1-(4-fluorophenyl)prop-2-en-1-one, were prepared and structurally characterized by single crystal X-ray diffraction analysis. The molecular structure crystallized in monoclinic crystal system with P21/c space group. Sensitivity of the title molecule towards electrophilic attacks has been examined by calculations of average localized ionization energies (ALIE) and their mapping to electron density surface. Further determination of atoms that could be important reactive centres has been performed by calculations of Fukui functions. Sensitivity of title molecule towards autoxidation and hydrolysis mechanisms has been assessed by calculations of bond dissociation energies and radial distribution functions (RDF), respectively. Also, in order to explore possible binding mode of the title compound towards Dihydrofolate reductase enzyme, we have utilized in silico molecular docking to explore possible binding modes of the title compound with the DHFR enzyme.

  3. Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

    NARCIS (Netherlands)

    Ferrari, A.C.; Dekker, C.; Vandersypen, L.M.K.; Van Der Zant, H.S.J.; et. al.

    2014-01-01

    We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphen

  4. Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

    DEFF Research Database (Denmark)

    Ferrari, Andrea C.; Bonaccorso, Francesco; Falko, Vladimir;

    2015-01-01

    We present the science and technology roadmap (STR) for graphene, related twodimensional (2d) crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. The roadmap was developed within the framework of the Euro...

  5. Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

    NARCIS (Netherlands)

    Ferrari, Andrea C.; Bonaccorso, Francesco; Fal'ko, Vladimir; Novoselov, Konstantin S.; Roche, Stephan; Boggild, Peter; Borini, Stefano; Koppens, Frank H. L.; Palermo, Vincenzo; Pugno, Nicola; Garrido, Jose A.; Sordan, Roman; Bianco, Alberto; Ballerini, Laura; Prato, Maurizio; Lidorikis, Elefterios; Kivioja, Jani; Marinelli, Claudio; Ryhaenen, Tapani; Morpurgo, Alberto; Coleman, Jonathan N.; Nicolosi, Valeria; Colombo, Luigi; Fert, Albert; Garcia-Hernandez, Mar; Bachtold, Adrian; Schneider, Gregory F.; Guinea, Francisco; Dekker, Cees; Barbone, Matteo; Sun, Zhipei; Galiotis, Costas; Grigorenko, Alexander N.; Konstantatos, Gerasimos; Kis, Andras; Katsnelson, Mikhail; Vandersypen, Lieven; Loiseau, Annick; Morandi, Vittorio; Neumaier, Daniel; Treossi, Emanuele; Pellegrini, Vittorio; Polini, Marco; Tredicucci, Alessandro; Williams, Gareth M.; Hong, Byung Hee; Ahn, Jong-Hyun; Kim, Jong Min; Zirath, Herbert; van Wees, Bart J.; van der Zant, Herre; Occhipinti, Luigi; Di Matteo, Andrea; Kinloch, Ian A.; Seyller, Thomas; Quesnel, Etienne; Feng, Xinliang; Teo, Ken; Rupesinghe, Nalin; Hakonen, Pertti; Neil, Simon R. T.; Tannock, Quentin; Loefwander, Tomas; Kinaret, Jari

    2015-01-01

    We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European

  6. A Study on a Partially Immersed Gold Electrode Using an Electrochemical Quartz Crystal Impedance System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The electrochemical quartz crystal impedance system (EQCIS) has been used for the study of a partially immersed Au electrode in 0.2 mol/L NaClO4 aqueous solution.The influences of the immersed area and height of the electrode on the EQCIS responses were evaluated,showing the highest response sensitivity to liquid loading at the center of the piezoelectric quartz crystal electrode.The increase in the immersed height of the Au electrode at oxygen reduction potentials during potential cycling was measured by this technique.

  7. Ab-initio calculation of elastic constants of crystalline systems with the CRYSTAL code

    Science.gov (United States)

    Perger, W. F.; Criswell, J.; Civalleri, B.; Dovesi, R.

    2009-10-01

    An automated procedure for calculating second-order elastic constants for crystalline systems of any symmetry using the CRYSTAL program is described. Second derivatives with respect to strain are evaluated numerically from analytical gradients. The internal co-ordinates are re-optimized with each applied strain. Point group symmetry is exploited to reduce the number of needed deformations according to Laue classes. A set of test cases covering many of the crystal classes is used to document the numerical accuracy of the scheme, and to define default values of the computational parameters so as to reduce the input file to a single keyword.

  8. Effective-Field Theory on High Spin Systems with Biaxial Crystal Field

    Institute of Scientific and Technical Information of China (English)

    JIANG Wei; GUO An-Bang; LI Xin; WANG Xi-Kun; BAI Bao-Dong

    2006-01-01

    Based on the effective-field theory with self-spin correlations and the differential operator technique,physical properties of the spin-2 system with biaxial crystal field on the simple cubic, body-centered cubic, as well as faced-centered lattice have been studied. The influences of the external longitudinal magnetic field on the magnetization,internal energy, specific heat, and susceptibility have been discussed in detail. The phenomenon that the magnetization in the ground state shows quantum effects produced by the biaxial transverse crystal field has been found.

  9. Effects of magnetic fluids on crystallization characterizations in a multi-component and multiphase system

    Institute of Scientific and Technical Information of China (English)

    SHU BiFen; SHEN Hui; CHEN MeiYuan; XIA JianHan; WANG Xiang; SUN JianWei

    2008-01-01

    In this study, experiments are carried out on the effects of magnetic fluids on the crystallization char- acterizations in a multi-component and multiphase system, which contains the liquid and the vapor of HCFC141b, water, water vapor, and gas hydrates. The mass transfer phenomena between the phase interfaces of water-HCFC141b and water-vapor are also researched. The experimental results show that in the presence of a rotary magnetic field, magnetic fluids can remarkably enhance the heat and mass transfer between phase interfaces and, therefore, improve the performance of crystallization, especially in improving the formation temperature and velocity.

  10. Molecular Dynamics Studies of Energy Transfer Processes in Crystal Systems.

    Science.gov (United States)

    1984-11-30

    Computer molecular dynamics studies have been carried out on the problem of attaining a fundamental understanding of shock-induced initiation of...intramolecular energy exchange in shock-loaded systems are presented. Originator-supplied keywords include: Molecular dynamics , Energy transfer, Shock front, Shock wave, Explosives, Shock structure.

  11. Crystallographic characterization of two novel crystal forms of human insulin induced by chaotropic agents and a shift in pH

    Directory of Open Access Journals (Sweden)

    Norrman Mathias

    2007-12-01

    Full Text Available Abstract Background Insulin is a therapeutic protein that is widely used for the treatment of diabetes. Its biological function was discovered more than 80 years ago and it has since then been characterized extensively. Crystallization of the insulin molecule has always been a key activity since the protein is often administered by subcutaneous injections of crystalline insulin formulations. Over the years, insulin has been crystallized and characterized in a number of crystal systems. Results Interestingly, we have now discovered two new crystal forms of human insulin. The crystals were obtained when the two chaotropic agents, urea and thiocyanate were present in the crystallization experiments, and their structures were determined by X-ray crystallography. The crystals belong to the orthorhombic and monoclinic crystal systems, with space groups C2221 and C2 respectively. The orthorhombic crystals were obtained at pH 6.5 and contained three insulin hexamers in R6 conformation in the asymmetric unit whilst the monoclinic C2 crystals were obtained at pH 7.0 and contained one R6 hexamer in the asymmetric unit. Common for the two new crystals is a hexamer-hexamer interaction that has not been found in any of the previous crystal forms of insulin. The contacts involve a tight glutamate-glutamate interaction with a distance of 2.3 Å between groups. The short distance suggests a low barrier hydrogen bond. In addition, two tyrosine-tyrosine interactions occupying a known phenol binding pocket contribute to the stabilization of the contacts. Within the crystals, distinct binding sites for urea were found, adding further to the discussion on the role of urea in protein denaturation. Conclusion The change in space group from C2221 to C2 was primarily caused by an increase in pH. The fewer number of hexamer-hexamer interactions comprising the short hydrogen bond in the C2 space group suggest that pH is the driving force. In addition, the distance between

  12. Ice Crystal Icing Engine Testing in the NASA Glenn Research Center's Propulsion Systems Laboratory: Altitude Investigation

    Science.gov (United States)

    Oliver, Michael J.

    2014-01-01

    The National Aeronautics and Space Administration (NASA) conducted a full scale ice crystal icing turbofan engine test using an obsolete Allied Signal ALF502-R5 engine in the Propulsion Systems Laboratory (PSL) at NASA Glenn Research Center. The test article used was the exact engine that experienced a loss of power event after the ingestion of ice crystals while operating at high altitude during a 1997 Honeywell flight test campaign investigating the turbofan engine ice crystal icing phenomena. The test plan included test points conducted at the known flight test campaign field event pressure altitude and at various pressure altitudes ranging from low to high throughout the engine operating envelope. The test article experienced a loss of power event at each of the altitudes tested. For each pressure altitude test point conducted the ambient static temperature was predicted using a NASA engine icing risk computer model for the given ambient static pressure while maintaining the engine speed.

  13. Computing dispersive, polarizable, and electrostatic shifts of excitation energy in supramolecular systems: PTCDI crystal.

    Science.gov (United States)

    Megow, Jörg

    2016-09-07

    The gas-to-crystal-shift denotes the shift of electronic excitation energies, i.e., the difference between ground and excited state energies, for a molecule transferred from the gas to the bulk phase. The contributions to the gas-to-crystal-shift comprise electrostatic as well as inductive polarization and dispersive energy shifts of the molecular excitation energies due to interaction with environmental molecules. For the example of 3,4,9,10-perylene-tetracarboxylic-diimide (PTCDI) bulk, the contributions to the gas-to-crystal shift are investigated. In the present work, electrostatic interaction is calculated via Coulomb interaction of partial charges while inductive and dispersive interactions are obtained using respective sum over states expressions. The coupling of higher transition densities for the first 4500 excited states of PTCDI was computed using transition partial charges based on an atomistic model of PTCDI bulk obtained from molecular dynamics simulations. As a result it is concluded that for the investigated model system of a PTCDI crystal, the gas to crystal shift is dominated by dispersive interaction.

  14. Thermo-optical properties of beryllium containing oxide crystals as materials for high power laser systems

    Science.gov (United States)

    Pestryakov, E. V.; Petrov, V. V.; Trunov, V. I.; Kirpichnikov, A. V.; Laptev, A. V.; Matrosov, V. N.

    2007-06-01

    The elastic and thermo-optical properties of chrysoberyl, beryllium hexaaluminate and beryllium-lanthanum hexaaluminate crystals have been experimentally studied. The velocities of elastic-wave propagation in the crystals are measured by acousto-optic interference method. The values of all the independent components of elastic-constant tensor are determined and used to calculate a number of important dynamic parameters of the crystals such as the Young's and shear moduli, the modulus of volume elasticity, Poisson's ratio, the Debye temperature. Also measurements of refractive indices in 25 - 75 C temperature range in VIS spectral region were performed. Using experimental data the dispersion of thermal optical coefficients (dn/dT) was calculated, these data were employed to evaluate the thermal lens in beryllium containing laser crystals. The experimental and calculated data are compared with similar parameters for well-known laser hosts. Some of beryllium containing oxide crystals was shown to be candidates for master oscillator and amplifying stages of high power femtosecond laser systems.

  15. Automatic Control System for the High Pressure CdTe Crystal Growth Furnace

    Directory of Open Access Journals (Sweden)

    Petr Praus

    2006-08-01

    Full Text Available CdTe and (CdZnTe bulk single crystals have been widely used as substrates for MBE and LPE epitaxy of infrared (HgCdTe as well as gamma- and X-ray detectors. The Cd1-xZnxTe (x = 0.04-0.1 single crystals with diameter up to 100 mm and height at most 40 mm were prepared in our laboratory in a vertical arrangement by gradual cooling of the melt (the Vertical Gradient Freezing method. Achievement of excellent crystal quality required full control of Cd pressure during the growth process and application of high Cd pressures (up to 4 bar at growth temperature. An electronic control system was designed to control both temperature and internal pressure of two zones CZT crystal growth furnace by using two high performance PID controllers/setpoint programmers. Two wire current loop serial communication bus was used for the data exchange and computer control of the furnace electronics setup. Control software was written to supervise the crystal growth process and to collect all important data and parameters.

  16. Morphological stability criterion for a spherical crystallization front in a multicomponent system with chemical reactions

    Science.gov (United States)

    Kukushkin, S. A.; Osipov, A. V.; Redkov, A. V.

    2014-12-01

    The morphological stability of a spherical crystal growing from a multicomponent medium due to the chemical reaction has been investigated. The approach used in this study is applicable to the case where the chemical compound forming the crystal does not exist in a gaseous (dissolved) form (for example, GaN). The investigation has been performed according to the classical scheme by the expansion of an infinitesimal deviation of the crystallization front from the initial shape into a series with the subsequent calculation of the time dependence of the coefficients of the expansion. It has been found that there is a similarity of the stability criteria for single-component and multicomponent crystals. In a multicomponent system, the single-component supersaturation analog determining the stability of a particle is the affinity of the chemical reaction. It has been shown that the morphological stability can also depend on the formation of other phases on the surface of the initial crystal, which is excluded in a single-component medium.

  17. Spatial separation of photogenerated electrons and holes among {010} and {110} crystal facets of BiVO4

    Science.gov (United States)

    Li, Rengui; Zhang, Fuxiang; Wang, Donge; Yang, Jingxiu; Li, Mingrun; Zhu, Jian; Zhou, Xin; Han, Hongxian; Li, Can

    2013-02-01

    Charge separation is crucial for increasing the activity of semiconductor-based photocatalysts, especially in water splitting reactions. Here we show, using monoclinic bismuth vanadate crystal as a model photocatalyst, that efficient charge separation can be achieved on different crystal facets, as evidenced by the reduction reaction with photogenerated electrons and oxidation reaction with photogenerated holes, which take place separately on the {010} and {110} facets under photo-irradiation. Based on this finding, the reduction and oxidation cocatalysts are selectively deposited on the {010} and {110} facets respectively, resulting in much higher activity in both photocatalytic and photoelectrocatalytic water oxidation reactions, compared with the photocatalyst with randomly distributed cocatalysts. These results show that the photogenrated electrons and holes can be separated between the different facets of semiconductor crystals. This finding may be useful in semiconductor physics and chemistry to construct highly efficient solar energy conversion systems.

  18. Synthesis, growth, structural, spectral, thermal, chemical etching, linear and nonlinear optical and mechanical studies of an organic single crystal 4-chloro 4-nitrostilbene (CONS): a potential NLO material.

    Science.gov (United States)

    Dinakaran, Paul M; Kalainathan, S

    2013-07-01

    4-Chloro 4-nitrostilbene (CONS) a new organic nonlinear optical material has been synthesized. Employing slow evaporation method, good optical quality single crystals (dimensions up to 6×2×3 mm(3)) have been grown using ethyl methyl ketone (EMK) as a solvent. The grown crystals have been subjected to various characterizations such as single crystal X-ray diffraction, powder XRD, Fourier Transform Infrared spectroscopy (FTIR), proton NMR, solid UV absorption, SHG studies. Single crystal X-ray diffraction reveals that the crystal system belongs to monoclinic with noncentrosymmetric space group P21. The UV-Vis absorption spectrum has been recorded and found that the cut off wavelength is 380 nm. Functional groups and the structure of the title compound have been confirmed by FTIR and (1)H NMR spectroscopic analyses respectively. Molecular mass of the CONS confirmed by the high resolution mass spectral analysis .The thermal behavior of the grown crystal has been studied by TG/DTA analysis and it shows the melting point is at 188.66 °C. Dislocations and growth pattern present in the grown crystal revealed by the etching study. The mechanical strength of the CONS crystal has been studied by Vicker's hardness measurement. The SHG efficiency of the grown crystal has been determined by Kurtz and Perry powder test which revealed that the CONS crystal (327 mV) has 15 times greater efficiency than that of KDP (21.7 mV).

  19. Synthesis, growth, structural, spectral, thermal, chemical etching, linear and nonlinear optical and mechanical studies of an organic single crystal 4-chloro 4-nitrostilbene (CONS): A potential NLO material

    Science.gov (United States)

    Dinakaran, Paul M.; Kalainathan, S.

    2013-07-01

    4-Chloro 4-nitrostilbene (CONS) a new organic nonlinear optical material has been synthesized. Employing slow evaporation method, good optical quality single crystals (dimensions up to 6 × 2 × 3 mm3) have been grown using ethyl methyl ketone (EMK) as a solvent. The grown crystals have been subjected to various characterizations such as single crystal X-ray diffraction, powder XRD, Fourier Transform Infrared spectroscopy (FTIR), proton NMR, solid UV absorption, SHG studies. Single crystal X-ray diffraction reveals that the crystal system belongs to monoclinic with noncentrosymmetric space group P21. The UV-Vis absorption spectrum has been recorded and found that the cut off wavelength is 380 nm. Functional groups and the structure of the title compound have been confirmed by FTIR and 1H NMR spectroscopic analyses respectively. Molecular mass of the CONS confirmed by the high resolution mass spectral analysis .The thermal behavior of the grown crystal has been studied by TG/DTA analysis and it shows the melting point is at 188.66 °C. Dislocations and growth pattern present in the grown crystal revealed by the etching study. The mechanical strength of the CONS crystal has been studied by Vicker's hardness measurement. The SHG efficiency of the grown crystal has been determined by Kurtz and Perry powder test which revealed that the CONS crystal (327 mV) has 15 times greater efficiency than that of KDP (21.7 mV).

  20. Spectroscopy, Crystal and Molecular Structures of New 4-Acylpyrazolone Dinitrophenylhydrazones

    Directory of Open Access Journals (Sweden)

    Omoruyi G. Idemudia

    2016-10-01

    Full Text Available Still looking at the development of new materials with unique properties and taking advantage of the nucleophilic properties of amines to form stable azomethines, dinitrophenylhydrazine was reacted with 4-ethyl-5-methyl-2-phenyl-pyrazol-3-one and then with 4-propyl-5-methyl-2-phenyl-pyrazol-3-one to get 4-ethyl-5-methyl-2-phenyl-pyrazol-3-one dinitrophenylhydrazone (Empp-Dh and 4-propyl-5-methyl-2-phenyl-pyrazol-3-one dinitrophenylhydrazone (Pmpp-Dh, respectively, via a simple condensation reaction in a one-pot synthesis system. Careful interpretations of results from elemental analysis, mass and NMR spectroscopy were in agreement with single-crystal X-ray diffraction data. Reported Schiff bases in their single-crystal solid state exist in imine keto tautomer form, each crystallizing in a monoclinic crystal system, with a space group of C2/c (No. 15 in Empp-Dh and P21/c (No. 14 in Pmpp-Dh. They have extensive intra- and inter-molecular hydrogen as well as C–H···π-ring interactions.

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

    Science.gov (United States)

    Yashima, Masatomo; Suzuki, Ryosuke O.

    2009-03-01

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

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

    Science.gov (United States)

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

    2013-12-01

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  4. Axion Crystals

    CERN Document Server

    Ozaki, Sho

    2016-01-01

    The low-energy effective theories for gapped insulators are classified by three parameters: permittivity $\\epsilon$, permeability $\\mu$, and theta angle $\\theta$. Crystals with periodic $\\epsilon$ are known as photonic crystals. We here study the band structure of photons in a new type of crystals with periodic $\\theta$ (modulo $2\\pi$) in space, which we call the axion crystals. We find that the axion crystals have a number of new properties that the usual photonic crystals do not possess, such as the helicity-dependent photonic band gaps and the nonrelativistic gapless dispersion relation at small momentum. We briefly discuss possible realizations of axion crystals in condensed matter systems as well as high-energy physics.

  5. In-Situ Observation of SiC Bulk Single Crystal Growth by XRD System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In-situ analysis for SiC bulk single crystal growth was reported using vertical X-ray diffractometer system. A furnace for SiC sublimation growth combined with the XRD system which possessed three kinds of functions including topography, rocking curve measurement and crystal growth rate monitoring was developed. These functions could contribute as a powerful tool finding the optimum growth condition by dynamic observation in the crucible. In this study, the in-situ X-ray topographs succeeded to capture dynamic elongation of defects and dislocation generated in the SiC growing crystals. The in-situ rocking curve measurement reviled appearance of mosaic structure in the SiC crystal grown with high growth rate. The in-situ growth rate monitoring also succeeded very precisely using the direct X-ray beam absorption. On the base of findings and facts obtained by the in-situ observations, the importance for the SiC growth was discussed.

  6. Crystallization and preliminary crystallographic studies of the metalloglycoprotein esterase A4 using a baculovirus expression system

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, Toshiki [Protein Design Laboratory, Yokohama City University, 1-7-29 Suehiro, Tsurumi, Yokohama 230-0045 (Japan); Shibayama, Naoya [Department of Physiology, Division of Biophysics, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 (Japan); Yoon, Young-Ho [Protein Design Laboratory, Yokohama City University, 1-7-29 Suehiro, Tsurumi, Yokohama 230-0045 (Japan); Yun, Kyung-Mook [Department of Physiology, Division of Biophysics, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 (Japan); Hamamoto, Toshiro [Department of Biochemistry, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 (Japan); Tame, Jeremy R. H.; Park, Sam-Yong, E-mail: park@tsurumi.yokohama-cu.ac.jp [Protein Design Laboratory, Yokohama City University, 1-7-29 Suehiro, Tsurumi, Yokohama 230-0045 (Japan)

    2007-09-01

    Esterase A4 (EA4) is a timer protein found in diapause eggs of the silkworm Bombyx mori. The gene for this metalloglycoprotein was cloned from B. mori eggs and expressed using a baculovirus expression system in silkworm pupae. Crystals of the purified protein have been grown that diffract to beyond 2.1 Å resolution at 100 K using synchrotron radiation. Esterase A4 (EA4) is a timer protein found in diapause eggs of the silkworm Bombyx mori. The gene for this metalloglycoprotein was cloned from B. mori eggs and expressed using a baculovirus expression system in silkworm pupae. Crystals of the purified protein have been grown that diffract to beyond 2.1 Å resolution at 100 K using synchrotron radiation. The protein crystals belong to space group P2{sub 1}, with unit-cell parameters a = 47.1, b = 73.9, c = 47.4 Å, β = 104.1°. With one dimer per asymmetric unit, the crystal volume per unit protein weight (V{sub M}) is 2.3 Å{sup 3} Da{sup −1} and the solvent content is 47%.

  7. Monoclinic form of (cyanato-κN{2,2′-[ethane-1,2-diylbis(nitrilomethylidyne]diphenolato-κ4O,N,N′,O′}manganese(III

    Directory of Open Access Journals (Sweden)

    Daopeng Zhang

    2010-12-01

    Full Text Available The title compound, [Mn(C16H14N2O2(NCO], is a monoclinic polymorph of the previously published orthorhombic form [Lu et al. (2006. Inorg. Chem. 45, 3538–3548]. The MnIII ion is chelated by a tetradentate Schiff base ligand and coordinated by the N atom of a cyanate ligand in a distorted square-pyramidal arrangement. In the crystal, there are short intermolecular Mn...Ophenolate distances of 2.752 (3 Å between pairs of inversion-related molecules.

  8. Reduction in crystal symmetry of a solid solution: A neutron diffraction study at 15 K of the host/guest system asparagine/aspartic acid

    Energy Technology Data Exchange (ETDEWEB)

    Weisinger-Lewin, Y.; Frolow, F.; Lahav, M.; Leiserowitz, L. (Weizmann Institute of Science, Rehovot (Israel)); McMullan, R.K.; Koetzle, T.F. (Brookhaven National Lab., Upton, NY (USA))

    1989-02-01

    It has been demonstrated, for the first time by diffraction methods, that a solid solution composed of host and guest molecules can exhibit a crystal symmetry lower than that of the host. The study proves that the symmetry of a solid solution is dependent not only upon the host crystal structure and the guest molecular structure but also upon the surface structure and symmetry of the host crystal. The crystal structures of (S)-asparagine monohydrate (D{sub 2}NCOCH{sub 2}CH(ND{sub 3})CO{sub 2} {times} D{sub 2}O) and of the solid solution (0.848:0.152) (S)-asparagine/(S)-aspartic acid (DO{sub 2}CCD{sub 2}CD(ND{sub 3})CO{sub 2}) monohydrate were refined by using neutron diffraction data obtained at 15 K. The space group of the pure host crystal is P2{sub 1}2{sub 1}2{sub 1} (Z = 4), whereas that of the host/guest crystal is monoclinic P12{sub 1}1 with two molecular sites per asymmetric unit. The ratios of guest/host occupancies of the two independent sites are 0.173:0.827 and 0.132:0.868. The reduction in symmetry is in accordance with the preferred adsorption of guest aspartic acid on the (010) crystal face at half of the orthorhombic, symmetry-related surface sites. Aspartic acid mimics, at the preferred (010) surface sites, molecular asparagine, participating in all hydrogen bonds. At the less-favored (010) surface sites a normal N-H{hor ellipsis}O(host) hydrogen bond is replaced by O(hydroxyl){hor ellipsis}O(host) repulsion between lone-pair electrons. 21 refs., 5 figs., 6 tabs.

  9. Phase relations, crystal structure, and phase transformation of In{sub 1−x}Nb{sub 1−x}Ti{sub 2x}O{sub 4} (0 ≤ x < 0.45) in In{sub 2}O{sub 3}–Nb{sub 2}O{sub 5}–TiO{sub 2} system

    Energy Technology Data Exchange (ETDEWEB)

    Su, Liumei; Fan, Xing [School of Materials Science and Engineering, Central South University, Changsha, 410083, Hunan (China); Education Ministry Key Laboratory of Non-ferrous Materials Science and Engineering, Central South University, Changsha, 410083, Hunan (China); Cai, Gemei, E-mail: caigemei@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha, 410083, Hunan (China); Education Ministry Key Laboratory of Non-ferrous Materials Science and Engineering, Central South University, Changsha, 410083, Hunan (China); Liu, Huashan [School of Materials Science and Engineering, Central South University, Changsha, 410083, Hunan (China); Education Ministry Key Laboratory of Non-ferrous Materials Science and Engineering, Central South University, Changsha, 410083, Hunan (China); Jin, Zhanpeng, E-mail: jin@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha, 410083, Hunan (China); Education Ministry Key Laboratory of Non-ferrous Materials Science and Engineering, Central South University, Changsha, 410083, Hunan (China)

    2015-12-05

    Phase relations, crystal structures, and phase transformation of In{sub 1−x}Nb{sub 1−x}Ti{sub 2x}O{sub 4} (0 ≤ x < 0.45) in In{sub 2}O{sub 3}–Nb{sub 2}O{sub 5}–TiO{sub 2} ternary system were investigated for the first time. A number of samples with different compositions were prepared by a solid-state reaction method, and phase assembles were analyzed by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe micro-analysis (EPMA). Five three-phase regions, ten two-phase regions, and six single-phase solid solutions were determined in this system. The solid solution of In{sub 1−x}Nb{sub 1−x}Ti{sub 2x}O{sub 4} (0 ≤ x < 0.45) is composed of both ordered monoclinic wolframite-type structure (0 ≤ x < 0.35) and disordered orthorhombic α-PbO{sub 2} type structure (0.35 < x < 0.45). Driving force for composition-driven phase transformation in In{sub 1−x}Nb{sub 1−x}Ti{sub 2x}O{sub 4} (0 ≤ x < 0.45) stems from the ordering of cations. The ever reported compound InNbTiO{sub 6} with an orthorhombic α-PbO{sub 2} type structure was amended to be a monoclinic wolframite-type structure. Present investigations will be useful for the whole ceramic community working with In{sub 2}O{sub 3}–Nb{sub 2}O{sub 5}–TiO{sub 2} ternary system as well as for the development of functional materials. - Highlights: • Phase relations of In{sub 2}O{sub 3}–Nb{sub 2}O{sub 5}–TiO{sub 2} ternary system were constructed. • Crystal structures of a novel solid solution In{sub 1−x}Nb{sub 1−x}Ti{sub 2x}O{sub 4} were determined. • Crystal structure of InNbTiO{sub 6} was amended to be a wolframite-type structure. • Composition-driven phase transformation of In{sub 1−x}Nb{sub 1−x}Ti{sub 2x}O{sub 4} was investigated.

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

    KAUST Repository

    Asayesh-Ardakani, Hasti

    2015-10-12

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

  11. Modal liquid crystal lens driven by low voltage produced from a wireless controlling and driving system

    Science.gov (United States)

    Zhang, Xinyu; Loktev, Mikhail; Vdovin, Gleb

    2005-04-01

    A wireless driving and controlling setup constructed by a coil system and a simple power metal-oxide-semiconductor field effect transistor switch circuit for modal liquid crystal lens has been designed, fabricated and characterized. Electrical and structural modeling and analysis have been applied to the design of the wireless power transforming and controlling system. Some key electrical characteristics of coils with different diameter and winding, such as resistance, impedance, capacitance, inductance, and Q factor, which determine the driving and controlling behaviors of the coil system constructed, are given. The liquid crystal lens can be operated under relatively low driving voltage ranging from about 1.5to12Vrms. Under dynamic operation, the prototype system has shown a stable driving and controlling performance to liquid crystal lens under the condition of switching mode of a few KHz. The possibility of integrating very small coils connected in series onto a small-size silicon chip as an integrated receiver in biomedicine application has been shown experimentally.

  12. Remote control system for high-perfomance computer simulation of crystal growth by the PFC method

    Science.gov (United States)

    Pavlyuk, Evgeny; Starodumov, Ilya; Osipov, Sergei

    2017-04-01

    Modeling of crystallization process by the phase field crystal method (PFC) - one of the important directions of modern computational materials science. In this paper, the practical side of the computer simulation of the crystallization process by the PFC method is investigated. To solve problems using this method, it is necessary to use high-performance computing clusters, data storage systems and other often expensive complex computer systems. Access to such resources is often limited, unstable and accompanied by various administrative problems. In addition, the variety of software and settings of different computing clusters sometimes does not allow researchers to use unified program code. There is a need to adapt the program code for each configuration of the computer complex. The practical experience of the authors has shown that the creation of a special control system for computing with the possibility of remote use can greatly simplify the implementation of simulations and increase the performance of scientific research. In current paper we show the principal idea of such a system and justify its efficiency.

  13. Asymmetric crystallization during cooling and heating in model glass-forming systems.

    Science.gov (United States)

    Wang, Minglei; Zhang, Kai; Li, Zhusong; Liu, Yanhui; Schroers, Jan; Shattuck, Mark D; O'Hern, Corey S

    2015-03-01

    We perform molecular dynamics (MD) simulations of the crystallization process in binary Lennard-Jones systems during heating and cooling to investigate atomic-scale crystallization kinetics in glass-forming materials. For the cooling protocol, we prepared equilibrated liquids above the liquidus temperature Tl and cooled each sample to zero temperature at rate Rc. For the heating protocol, we first cooled equilibrated liquids to zero temperature at rate Rp and then heated the samples to temperature T>Tl at rate Rh. We measured the critical heating and cooling rates Rh* and Rc*, below which the systems begin to form a substantial fraction of crystalline clusters during the heating and cooling protocols. We show that Rh*>Rc* and that the asymmetry ratio Rh*/Rc* includes an intrinsic contribution that increases with the glass-forming ability (GFA) of the system and a preparation-rate dependent contribution that increases strongly as Rp→Rc* from above. We also show that the predictions from classical nucleation theory (CNT) can qualitatively describe the dependence of the asymmetry ratio on the GFA and preparation rate Rp from the MD simulations and results for the asymmetry ratio measured in Zr- and Au-based bulk metallic glasses (BMG). This work emphasizes the need for and benefits of an improved understanding of crystallization processes in BMGs and other glass-forming systems.

  14. One dimensional coordination polymers: Synthesis, crystal structures and spectroscopic properties

    Science.gov (United States)

    Karaağaç, Dursun; Kürkçüoğlu, Güneş Süheyla; Şenyel, Mustafa; Şahin, Onur

    2016-11-01

    Two new one dimensional (1D) cyanide complexes, namely [M(4-aepy)2(H2O)2][Pt(CN)4], (4-aepy = 4-(2-aminoethyl)pyridine M = Cu(II) (1) or Zn(II) (2)), have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal and elemental analyses techniques. The crystallographic analyses reveal that 1 and 2 are isomorphous and isostructural, and crystallize in the monoclinic system and C2 space group. The Pt(II) ions are coordinated by four cyanide-carbon atoms in the square-planar geometry and the [Pt(CN)4]2- ions act as a counter ion. The M(II) ions display an N4O2 coordination sphere with a distorted octahedral geometry, the nitrogen donors belonging to four molecules of the organic 4-aepy that act as unidentate ligands and two oxygen atoms from aqua ligands. The crystal structures of 1 and 2 are similar each other and linked via intermolecular hydrogen bonding, Pt⋯π interactions to form 3D supramolecular network. Vibration assignments of all the observed bands are given and the spectral features also supported to the crystal structures of the complexes.

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  16. Molecular and Crystal Structure of 7-Hydroxy-6,8-dimethoxyl-coumarin

    Institute of Scientific and Technical Information of China (English)

    李超; 罗保生; 孙天恩

    2001-01-01

    The title compound is separated from the ginkgo hairy rootculture. This compound (C11H10O5, Mr=222.19), crystallizes in the monoclinic system, space group P21/n, with cell parameters: a=9.571(2), b=12.411(2), c=16.934(3)Å, β=101.92(3)°, V=1968.4Å3, Z=8, Dc=1.499g/cm3; F(000)=928.0, MoKα radiation, λ=0.71013Å, R=0.051 and wR=0.115 for 1605 independent reflections with I≥4σ (I). In the molecule, the aromatic and lactone rings are coplanar nearly. One of the two methoxyls is almost coplanar, but another one deviates from the molecular plane. There are intermolecular hydrogen bonds in the crystal.

  17. Vapor-crystal phase transition in synthesis of paracetamol films by vacuum evaporation and condensation

    Science.gov (United States)

    Belyaev, A. P.; Rubets, V. P.; Antipov, V. V.; Bordei, N. S.; Zarembo, V. I.

    2014-03-01

    We report on the structural and technological investigations of the vapor-crystal phase transition during synthesis of paracetamol films of the monoclinic system by vacuum evaporation and condensation in the temperature range 220-320 K. The complex nature of the transformation accompanied by the formation of a gel-like phase is revealed. The results are interpreted using a model according to which the vapor-crystal phase transition is not a simple first-order phase transition, but is a nonlinear superposition of two phase transitions: a first-order transition with a change in density and a second-order phase transition with a change in ordering. Micrographs of the surface of the films are obtained at different phases of formation.

  18. A ternary tetracoordinated Pd II complex with metformin and dipicolinate: Synthesis, characterization and crystal structure

    Science.gov (United States)

    Moghimi, A.; Khavassi, H. R.; Dashtestani, F.; Kordestani, D.; Ekram Jafari, A.; Maddah, B.; Moosavi, S. M.

    2011-06-01

    A proton transfer compound L, (MetH) 2(dipic), (dipicH 2 = 2,6-pyridinedicarboxylic acid and Met = Metformin (N,N-dimethylebiguanidine), was synthesized and characterized by IR, 1H and 13C NMR spectroscopy. The reaction of L with PdCl 2 in water results in the formation of novel tetracoordinated Pd II complex [Pd(dipic)(Met)]·2H 2O indicating the participation of both dipic 2- and Met as chelating ligands. This complex was characterized by single crystal X-ray analysis. The crystal system is monoclinic with space group P2 1/c. The unit cell dimensions for Pd II complex 1 is a = 8.8619(14) Å, b = 9.5072(9) Å, c = 19.153(3) Å.

  19. Tetraphenylphosphonium allyldithiocarbimates derived from Morita-Baylis-Hillman adducts: Synthesis, characterization, crystal structure and antifungal activity

    Science.gov (United States)

    Tavares, Eder C.; Rubinger, Mayura M. M.; Filho, Eclair V.; Oliveira, Marcelo R. L.; Piló-Veloso, Dorila; Ellena, Javier; Guilardi, Silvana; Souza, Rafael A. C.; Zambolim, Laércio

    2016-02-01

    Botrytis blight is a very destructive disease caused by Botrytis spp., infecting flowers, trees, vegetables and fruits. Twelve new compounds were prepared by the reaction of potassium N-aryl-sulfonyldithiocarbimates with Morita-Baylis-Hillman derivatives bearing phenyl and furyl groups. These are the first examples of allyldithiocarbimate anions and were isolated as tetraphenylphosphonium salts. The new compounds were characterized by HRMS, NMR and Infrared spectroscopy. Further, the structures of three allyldithiocarbimates were determined by single crystal X-ray diffraction. The compounds are isostructural and crystallize in the space group P21/c of the monoclinic system, and the allyldithiocarbimate anions present Z configuration. All the compounds were active against Botrytis cinerea. The best results were achieved with the tetraphenylphosphonium (Z)-3-(furan-2-yl)-2-(methoxycarbonyl)allyl-(4-chlorophenylsulfonyl)dithiocarbimate (IC50 38 μM).

  20. Crystal Structure and Characterization of 2-N-(2-Hydroxy-benzylidene) Furanmethanoamine Nickel(Ⅱ) Complex

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; XU Hong; ZHOU Hua; WEI Ping

    2005-01-01

    The Ni(Ⅱ) complex with ligand 2-N-(2-hydroxy-benzylidene) furanmethanoamine has been synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction.It crystallizes in the monoclinic system, space group C2/c with a = 2.0280(4), b =0.57700(12), c = 1.7340(4) nm, β = 94.74(3)°, Z = 4, Dc = 1.508 g/cm3, the final R = 0.0434 and wR = 0.1112 for 1843 observed reflections with I > 2σ(I).X-ray analysis revealed that the Ni(Ⅱ)ion is coordinated by two nitrogen atoms of Schiff base and two oxygen atoms of salicylaldehyde in the equatorial plane, and the coordination geometry can be described as a square.

  1. SYNTHESIS, THERMAL STUDIES AND CRYSTAL STRUCTURE OF 4-AMINOPYRIDINIUM SEMI-OXALATE HEMIHYDRATE

    Directory of Open Access Journals (Sweden)

    CECILIA CHACÓN

    2017-06-01

    Full Text Available The title compound has been synthesized by grinding in an agate mortar. Its structure was characterized by TGA-DSC studies and single-crystal X-ray diffraction. This compound crystallize in the monoclinic system with space group C2/c, Z = 4, and unit cell parameters a = 16.109(2 Å, b = 5.748(7 Å, c = 20.580(3 Å, β = 107.36(1°. The salt, C2HO4-.C5H7N+.0.5 H2O, is an ionic ensemble assisted by hydrogen bonds established between 4-aminopyridinium cations, oxalate anions and water molecules. The three components thus construct a supramolecular assembly with a three-dimensional hydrogen bonded framework.

  2. Development of an X-ray fluorescence holographic measurement system for protein crystals

    Science.gov (United States)

    Sato-Tomita, Ayana; Shibayama, Naoya; Happo, Naohisa; Kimura, Koji; Okabe, Takahiro; Matsushita, Tomohiro; Park, Sam-Yong; Sasaki, Yuji C.; Hayashi, Kouichi

    2016-06-01

    Experimental procedure and setup for obtaining X-ray fluorescence hologram of crystalline metalloprotein samples are described. Human hemoglobin, an α2β2 tetrameric metalloprotein containing the Fe(II) heme active-site in each chain, was chosen for this study because of its wealth of crystallographic data. A cold gas flow system was introduced to reduce X-ray radiation damage of protein crystals that are usually fragile and susceptible to damage. A χ-stage was installed to rotate the sample while avoiding intersection between the X-ray beam and the sample loop or holder, which is needed for supporting fragile protein crystals. Huge hemoglobin crystals (with a maximum size of 8 × 6 × 3 mm3) were prepared and used to keep the footprint of the incident X-ray beam smaller than the sample size during the entire course of the measurement with the incident angle of 0°-70°. Under these experimental and data acquisition conditions, we achieved the first observation of the X-ray fluorescence hologram pattern from the protein crystals with minimal radiation damage, opening up a new and potential method for investigating the stereochemistry of the metal active-sites in biomacromolecules.

  3. SiPM based readout system for PbWO4 crystals

    Science.gov (United States)

    Berra, A.; Bolognini, D.; Bonfanti, S.; Bonvicini, V.; Lietti, D.; Penzo, A.; Prest, M.; Stoppani, L.; Vallazza, E.

    2013-08-01

    Silicon PhotoMultipliers (SiPMs) consist of a matrix of small passively quenched silicon avalanche photodiodes operated in limited Geiger-mode (GM-APDs) and read out in parallel from a common output node. Each pixel (with a typical size in the 20-100 μm range) gives the same current response when hit by a photon; the SiPM output signal is the sum of the signals of all the pixels, which depends on the light intensity. The main advantages of SiPMs with respect to photomultiplier tubes (PMTs) are essentially the small dimensions, the insensitivity to magnetic fields and a low bias voltage. This contribution presents the performance of a SiPM based readout system for crystal calorimeters developed in the framework of the FACTOR/TWICE collaboration. The SiPM used for the test is a new device produced by FBK-irst which consists in a matrix of four sensors embedded in the same silicon substrate, called QUAD. The SiPM has been coupled to a lead tungstate crystal, an early-prototype version of the crystals developed for the electromagnetic calorimeter of the CMS experiment. New tests are foreseen using a complete module consisting of nine crystals, each one readout by two QUADs.

  4. SiPM based readout system for PbWO{sub 4} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Berra, A., E-mail: alessandro.berra@gmail.com [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca, Via Valleggio, 11-22100 Como (Italy); Bolognini, D.; Bonfanti, S. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca, Via Valleggio, 11-22100 Como (Italy); Bonvicini, V. [INFN sezione di Trieste (Italy); Lietti, D. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca, Via Valleggio, 11-22100 Como (Italy); Penzo, A. [INFN sezione di Trieste (Italy); Prest, M.; Stoppani, L. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca, Via Valleggio, 11-22100 Como (Italy); Vallazza, E. [INFN sezione di Trieste (Italy)

    2013-08-01

    Silicon PhotoMultipliers (SiPMs) consist of a matrix of small passively quenched silicon avalanche photodiodes operated in limited Geiger-mode (GM-APDs) and read out in parallel from a common output node. Each pixel (with a typical size in the 20–100 μm range) gives the same current response when hit by a photon; the SiPM output signal is the sum of the signals of all the pixels, which depends on the light intensity. The main advantages of SiPMs with respect to photomultiplier tubes (PMTs) are essentially the small dimensions, the insensitivity to magnetic fields and a low bias voltage. This contribution presents the performance of a SiPM based readout system for crystal calorimeters developed in the framework of the FACTOR/TWICE collaboration. The SiPM used for the test is a new device produced by FBK-irst which consists in a matrix of four sensors embedded in the same silicon substrate, called QUAD. The SiPM has been coupled to a lead tungstate crystal, an early-prototype version of the crystals developed for the electromagnetic calorimeter of the CMS experiment. New tests are foreseen using a complete module consisting of nine crystals, each one readout by two QUADs.

  5. Distribution of Crystal Organic Fertilizer-N in Soil-plant System

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-xin; HAN Yi-wang; WANG Yan-ting; HONG Li-fang; XU Xi-min; TANG Shen; LIN Guan-ya; LIU Wu-ding

    2002-01-01

    The distribution of crystal organic fertilizer, urea and compound fertilizer-N in soil and plant system was researched with 15N-trace under tobacco pot experiment. The results showed that the leaf yield of tobacco used crystal organic fertilizer was 23.1% and 14.6 % higher than that of urea and compound fertilizer treatments respectively. Compound fertilizer also resulted in higher yield of 8.5% comparing with the urea treatment. Nitrogen content of the plant from the crystal organic fertilizer treatment was 138.6% and 145.7% as high as that of the compound fertilizer and urea treatments respectively. The absorbed N from the organic fertilizer was 25.1% and 27.9% more than that from the compound fertilizer and urea respectively.However, the absorbed N from the soil with the organic fertilizer was 47.4% and 58.3% more than that with compound fertilizer and urea respectively. The N use efficiency of the organic fertilizer was 9.4% and 10.1%higher than that of the compound fertilizer and urea. It indicated that the crystal organic fertilizer not only had high N use efficiency, but also stimulated tobacco taking up more N from soil.

  6. Development of an X-ray fluorescence holographic measurement system for protein crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sato-Tomita, Ayana, E-mail: ayana.sato@jichi.ac.jp, E-mail: shibayam@jichi.ac.jp, E-mail: hayashi.koichi@nitech.ac.jp; Shibayama, Naoya, E-mail: ayana.sato@jichi.ac.jp, E-mail: shibayam@jichi.ac.jp, E-mail: hayashi.koichi@nitech.ac.jp; Okabe, Takahiro [Division of Biophysics, Department of Physiology, Jichi Medical University, Yakushiji, Shimotsuke 329-0498 (Japan); Happo, Naohisa [Department of Computer and Network Engineering, Graduate School of Information Sciences, Hiroshima City University, Asa-Minami-Ku, Hiroshima 731-3194 (Japan); Kimura, Koji [Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan); Matsushita, Tomohiro [Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo, Hyogo 679-5198 (Japan); Park, Sam-Yong [Drug Design Laboratory, Department of Medical Life Science, Yokohama City University, Suehiro, Tsurumi, Yokohama 230-0045 (Japan); Sasaki, Yuji C. [Department of Advanced Material Science, Graduate School of Frontier Science, The University of Tokyo, Kashiwanoha, Kashiwa 277-8561 (Japan); Hayashi, Kouichi, E-mail: ayana.sato@jichi.ac.jp, E-mail: shibayam@jichi.ac.jp, E-mail: hayashi.koichi@nitech.ac.jp [Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan); Frontier Research Institute for Materials Science, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan)

    2016-06-15

    Experimental procedure and setup for obtaining X-ray fluorescence hologram of crystalline metalloprotein samples are described. Human hemoglobin, an α{sub 2}β{sub 2} tetrameric metalloprotein containing the Fe(II) heme active-site in each chain, was chosen for this study because of its wealth of crystallographic data. A cold gas flow system was introduced to reduce X-ray radiation damage of protein crystals that are usually fragile and susceptible to damage. A χ-stage was installed to rotate the sample while avoiding intersection between the X-ray beam and the sample loop or holder, which is needed for supporting fragile protein crystals. Huge hemoglobin crystals (with a maximum size of 8 × 6 × 3 mm{sup 3}) were prepared and used to keep the footprint of the incident X-ray beam smaller than the sample size during the entire course of the measurement with the incident angle of 0°-70°. Under these experimental and data acquisition conditions, we achieved the first observation of the X-ray fluorescence hologram pattern from the protein crystals with minimal radiation damage, opening up a new and potential method for investigating the stereochemistry of the metal active-sites in biomacromolecules.

  7. Simulation of Quantum Magnetism in Mixed Spin Systems with Impurity Doped Ion Crystal

    CERN Document Server

    Ivanov, Peter A

    2011-01-01

    We propose the realization of linear crystals of cold ions which contain different atomic species for investigating quantum phase transitions and frustration effects in spin system beyond the commonly discussed case of $s=1/2$. Mutual spin-spin interactions between ions can be tailored via the Zeeman effect by applying oscillating magnetic fields with strong gradients. Further, collective vibrational modes in the mixed ion crystal can be used to enhance and to vary the strength of spin-spin interactions and even to switch those forces from a ferro- to an antiferromagnetic character. We consider the behavior of the effective spin-spin couplings in an ion crystal of spin-1/2 ions doped with high magnetic moment ions with spin S=3. We analyze the ground state phase diagram and find regions with different spin orders including ferrimagnetic states. In the most simple non-trivial example we deal with a linear $\\{$Ca$^+$, Mn$^+$, Ca$^+\\}$ crystal with spins of $\\{1/2,3,1/2}$. To show the feasibility with current st...

  8. The crystallization of metal soaps and fatty acids in oil paint model systems.

    Science.gov (United States)

    Hermans, Joen J; Keune, Katrien; van Loon, Annelies; Iedema, Piet D

    2016-04-28

    The formation and crystallization of metal soaps in oil paint layers is an important issue in the conservation of oil paintings. The chemical reactions and physical processes that are involved in releasing metal ions from pigments and fatty acids from the oil binder to form crystalline metal soap deposits have so far remained poorly understood. We have used a combination of differential scanning calorimetry (DSC) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) on model mixtures of palmitic acid, lead palmitate or zinc palmitate and linseed oil to study the transition from amorphous material to crystalline fatty acid or metal soap. This transition forms the final stage in the cascade of processes leading to metal soap-related oil paint degradation. Palmitic acid as well as the metal soaps showed nearly ideal solubility behavior. However, it was found that, near room temperature, both lead and zinc palmitate are practically insoluble in both liquid and partially polymerized linseed oil. Interestingly, the rate of metal soap and fatty acid crystallization decreased rapidly with the degree of linseed oil polymerization, possibly leading to systems where metal soaps are kinetically trapped in a semi-crystalline state. To explain the various morphologies of metal soap aggregates observed in oil paint layers, it is proposed that factors affecting the probability of crystal nucleation and the rate of crystal growth play a crucial role, like exposure to heat or cleaning solvents and the presence of microcracks.

  9. Cylindrical liquid crystal lenses system for autostereoscopic 2D/3D display

    Science.gov (United States)

    Chen, Chih-Wei; Huang, Yi-Pai; Chang, Yu-Cheng; Wang, Po-Hao; Chen, Po-Chuan; Tsai, Chao-Hsu

    2012-06-01

    The liquid crystal lenses system, which could be electrically controlled easily for autostereoscopic 2D/3D switchable display was proposed. The High-Resistance liquid crystal (HRLC) lens utilized less controlled electrodes and coated a high-resistance layer between the controlled-electrodes was proposed and was used in this paper. Compare with the traditional LC lens, the HR-LC Lens could provide smooth electric-potential distribution within the LC layer under driving status. Hence, the proposed HR-LC Lens had less circuit complexity, low driving voltage, and good optical performance also could be obtained. In addition, combining with the proposed driving method called dual-directional overdriving method, the above method could reduce the switching time by applying large voltage onto cell. Consequently, the total switching time could be further reduced to around 2second. It is believed that the LC lens system has high potential in the future.

  10. Calculation of the Slip System Activity in Deformed Zinc Single Crystals Using Digital 3-D Image Correlation Data

    Energy Technology Data Exchange (ETDEWEB)

    Florando, J; Rhee, M; Arsenlis, A; LeBlanc, M; Lassila, D

    2006-02-21

    A 3-D image correlation system, which measures the full-field displacements in 3 dimensions, has been used to experimentally determine the full deformation gradient matrix for two zinc single crystals. Based on the image correlation data, the slip system activity for the two crystals has been calculated. The results of the calculation show that for one crystal, only the primary slip system is active, which is consistent with traditional theory. The other crystal however, shows appreciable deformation on slip systems other than the primary. An analysis has been conducted which confirms the experimental observation that these other slip system deform in such a manner that the net result is slip which is approximately one third the magnitude and directly orthogonal to the primary system.

  11. Oral and transdermal drug delivery systems: role of lipid-based lyotropic liquid crystals

    OpenAIRE

    Rajabalaya, Rajan; Musa,Muhammad Nuh; Kifli, Nurolaini; Sheba R. David

    2017-01-01

    Rajan Rajabalaya, Muhammad Nuh Musa, Nurolaini Kifli, Sheba R David PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Brunei Darussalam Abstract: Liquid crystal (LC) dosage forms, particularly those using lipid-based lyotropic LCs (LLCs), have generated considerable interest as potential drug delivery systems. LCs have the physical properties of liquids but retain some of the structural characteristics of crystalline solids. They are compatible with hydrophobic and hydrophi...

  12. Synthesis, growth, characterisation and laser damage threshold studies of N,N-dimethylanilinium-3-carboxy-4-hydroxybenzenesulphonate crystal: An efficient SHG material for electro-optic applications

    Science.gov (United States)

    Rajkumar, M.; Chandramohan, A.

    2017-04-01

    An NLO active organic proton transfer complex salt, N,N-Dimethylanilinium-3-carboxy-4-hydroxybenzenesulphonate has been synthesized and single crystals grown by slow solvent evaporation solution growth technique at ambient temperature. The synthesized salt was characterized by Uv-visible absorption, UV-vis-NIR transmission spectral studies and elemental analysis. The formation of the salt and the crystal structure have been confirmed by single crystal X-ray diffraction (XRD) analysis and the title crystal belongs to monoclinic crystal system with the non-centrosymmetric space group, Pc. The FT-IR spectrum was recorded to confirm the presence of various functional groups in the grown crystal. The molecular structure of the crystal was further confirmed by 1H and 13C NMR spectra. The TG/DTA analyses were carried out to establish the thermal stability of the title crystal. The dielectric constant and dielectric loss have been studied as a function of frequency at different temperatures. The presence of SHG and its conversion efficiency was measured by employing the modified Kurtz and Perry powder technique. The laser damage threshold value of the title crystal was determined using a Nd:YAG laser with the wavelength of 1064 nm.

  13. Morphology and Growth of Methyl Stearate as a Function of Crystallization Environment

    OpenAIRE

    Camacho, DM; Roberts, KJ; Muller, FL; Thomas, D.; More, I; Lewtas, K

    2017-01-01

    In situ studies of methyl stearate growing from supersaturated n-dodecane, kerosene, and toluene solutions reveal strong evidence that solvent choice influences the crystal morphology and crystal growth kinetics. Crystals with similar habit are observed in all solvents, with the exception of lower supersaturations in kerosene, where a less symmetric morphology was observed. BFDH analysis based on the monoclinic C2 crystal structure of methyl stearate yielded the morphological indexation to be...

  14. Expression, purification and crystallization of the catalytic subunit of protein kinase CK2 from Zea mays

    DEFF Research Database (Denmark)

    Guerra, B; Niefind, K; Pinna, L A

    1998-01-01

    The catalytic (alpha) subunit of protein kinase CK2 (CK2alpha) was originally cloned and overexpressed in the Escherichia coli strain pT7-7/BL21(DE3). The protein has been purified to homogeneity and crystallized. The crystals belong to the monoclinic space group C2, they have unit-cell parameter...

  15. Crystallization and Preliminary Crystallographic Characterization of Endo-polygalacturonase II from Aspergillus niger

    NARCIS (Netherlands)

    Schröter, K.-H.; Arkema, A.; Kester, H.C.M.; Visser, J.; Dijkstra, B.W.

    1994-01-01

    The endo-polygalacturonase II from Aspergillus niger has been crystallized from an ammonium sulfate solution by the hanging drop method. The crystals belong to the monoclinic space group P2(1), with cell dimensions a = 60.6 Angstrom, b = 152.6 Angstrom, c = 74.0 Angstrom and beta = 91.2 degrees with

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

    Science.gov (United States)

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

    2016-03-01

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

  17. Crystal growth, optical and magnetic properties of the Cr-doped Cu{sub 2}SnGe{sub 3} semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Romero, H. E-mail: hectorom@ciens.ula.ve; Nieves, L.; Chourio, M.; Echeverria, R.; Carreron, I.; Ramirez, B.; Zysler, R

    2004-05-01

    Compound Cu{sub 2}SnSe{sub 3}:Cr{sub x} with nominal composition x=0.08 was grown by direct fusion in a vertical oven. At 500 deg. C was annealed during 220 h. The sample was crystallized in a monoclinic system, in the Cc space group. The temperature dependence of magnetization does not change in the (fieldcooled-zero-field-cooled) curves. At 42 K a magnetization jump is observed. The Curie temperature shifted probably due to lattice distortion. The low-temperature magnetic moment 0.37 {mu}{sub B} was calculated. A direct band gap energy was observed at 300 K.

  18. Stability and plasticizing and crystallization effects of vitamins in amorphous sugar systems.

    Science.gov (United States)

    Zhou, Yankun; Roos, Yrjö H

    2012-02-01

    Increased molecular mobility and structural changes resulting from water plasticization of glassy solids may lead to loss of the entrapped compounds from encapsulant systems. In the present study, the stability of water-soluble vitamins, vitamin B(1) (vB(1), thiamin hydrochloride) and vitamin C (vC, ascorbic acid), in freeze-dried lactose and trehalose at various water activities was studied. Water sorption of lactose-vB(1), lactose-vC, trehalose-vB(1), and trehalose-vC systems was determined gravimetrically. Glass transition and crystallization of anhydrous and plasticized sugar-vitamin systems were determined using thermal analysis. Critical water activity was calculated using water sorption and glass transition data. The retention of the vitamins was measured spectrophotometrically. The results showed that the amorphous structure protected the entrapped vitamins at low a(w). Crystallization of lactose accelerated vitamin degradation, whereas trehalose retained much higher amounts of the vitamins. Glass transition and critical water activity of solids and crystallization of component sugars should be considered in the stabilization of sensitive components.

  19. Non-covalent interactions in 2-methylimidazolium copper(II) complex (MeImH)2[Cu(pfbz)4]: Synthesis, characterization, single crystal X-ray structure and packing analysis

    Science.gov (United States)

    Sharma, Raj Pal; Saini, Anju; Kumar, Santosh; Kumar, Jitendra; Sathishkumar, Ranganathan; Venugopalan, Paloth

    2017-01-01

    A new anionic copper(II) complex, (MeImH)2 [Cu(pfbz)4] (1) where, MeImH = 2-methylimidazolium and pfbz = pentafluorobenzoate has been isolated by reacting copper(II) sulfate pentahydrate, pentafluorobenzoic acid and 2-methylimidazole in ethanol: water mixture in 1:2:2 molar ratio. This complex 1 has been characterized by elemental analysis, thermogravimetric analysis, spectroscopic techniques (UV-Vis, FT-IR) and conductance measurements. The complex salt crystallizes in monoclinic crystal system with space group C2/c. Single crystal X-ray structure determination revealed the presence of discrete ions: [Cu(pfbz)4]2- anion and two 2-methylimidazolium cation (C4H7N2)+. The crystal lattice is stabilized by strong hydrogen bonding and F⋯F interactions between cationic-anionic and the anionic-anionic moieties respectively, besides π-π interactions.

  20. Synthesis and Crystal Structure of New Coordination Compound Mn2Hg4(SCN)12%新型配合物Mn2Hg4(SCN)12的合成与晶体结构分析

    Institute of Scientific and Technical Information of China (English)

    李广慧; 方奇; 薛刚; 于文涛

    2005-01-01

    A new inorganic coordination compound Mn2Hg4(SCN)12 was synthesized. The grown crystals were characterized by elemental analysis, infrared spectroscopic analysis and powder crystal X-ray diffraction in detail. The crystal structure of Mn2Hg4(SCN)12 was determined by single-crystal X-ray diffraction. It belongs to monoclinic system, P21/c space group. The cell dimensions are: a=1.171 6 nm, b=1.431 05 nm, c=2.105 1 nm,β=100.738°,and Z=4. In the structure of it, half of Mn2+ cations have five-coordinate number, and other half of Mn2+ cations have six-coordinate number; 3/4 of Hg2+ cations are coordinated by four SCN-, 1/4 of Hg2+ cations are coordinated by three SCN- and one NCS-, all the coordination geometry of Hg2+ show slightly distorted tetrahedrons. CCDC:244939.

  1. OPTICAL OPTIMIZATION FOR LIQUID CRYSTAL TEST BY LASER-CCD SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Chang Ying; Zhu Henian; Zhang Ziliang; Yang Changxi

    2005-01-01

    For the narrowband of liner charge-coupled device (CCD) receiver and the imaging rule that cylindrical lens system can compress round facula into narrow and long one, the system is simplified and light force can concentrate on a strip facula. Considered the effective CCD length and selection of lens parameters, the system can be optimized. Correspondingly to the CCD pixels, the ray is composed of much angle information. By widening the parallel ray or increasing the lens aperture, luminous flux can be ensured when oblique incidence. Meanwhile, the effective working range can also be improved. Based on the experimental data, cylindrical system could be applied in accurate angle measurement. It has been proved feasible that the cylindrical system can be used in anchor behavior study for liquid crystal (LC) case. The low-power He-Ne laser cylindrical system can carry out the previous effect in high power laser spherical system.

  2. Optimizing nonlinear beam coupling in low-symmetry crystals.

    Science.gov (United States)

    Shumelyuk, A; Volkov, A; Odoulov, S; Grabar, A; Stoyka, I; Evans, D R

    2014-10-01

    The purpose of this paper is to find the polarizations and spatial orientations of the two interacting counterpropagating coherent light waves which ensure the largest beam coupling in monoclinic photorefractive crystal. The results of calculations are presented that are verified experimentally with Sn₂P₂S₆.

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

    Directory of Open Access Journals (Sweden)

    Mohammad Sadiq

    2015-08-01

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

  4. Crystal-field analysis for RE 3+ ions in laser materials: II. Absorption spectra and energy levels calculations for Nd 3+ ions doped into SrLaGa 3O 7 and BaLaGa 3O 7 crystals and Tm 3+ ions in SrGdGa 3O 7

    Science.gov (United States)

    Karbowiak, M.; Gnutek, P.; Rudowicz, C.; Ryba-Romanowski, W.

    2011-08-01

    Low temperature polarized absorption spectra are analyzed to achieve assignments of energy levels for Nd 3+ and Tm 3+ ions at monoclinic C s site symmetry in ABC 3O 7 crystals. Based on the concept of average optical center, the experimental energy levels for single crystals of SrLaGa 3O 7:Nd 3+ (SLG:Nd), BaLaGa 3O 7:Nd 3+ (BLG:Nd), and SrGdGa 3O 7:Tm 3+ (SGG:Tm) were analyzed in terms of the free-ion parameters and the crystal field (CF) ones, B kq. Assignments of the energy levels resolved in the spectra were done in stages applying the ascent/descent in symmetry method in CF analysis. The actual monoclinic C s site symmetry at the metal centers in ABC 3O 7 crystals and the approximated orthorhombic C 2v and tetragonal C 4v symmetry were considered. The starting values of B kq's for SLG:Nd and BLG:Nd crystals were obtained from superposition model (SPM) analysis. The final fitted crystal field parameters show high compatibility with the existing data for structurally similar ion-host systems. The obtained values of the intrinsic parameters provide basis for SPM analysis of CF parameters for rare earth ions in other similar systems, especially those exhibiting low-symmetry sites. The SPM parameters derived for SLG:Nd are used for simulation and assignment of the energy levels involved in the potential laser transitions at about 1800 nm due to Tm 3+ ions in SGG crystals. The evaluated emission cross-section is about two times lower than that obtained previously.

  5. Crystal growth of calcium carbonate with various morphologies in different amino acid systems

    Science.gov (United States)

    Xie, An-Jian; Shen, Yu-Hua; Zhang, Chun-Yan; Yuan, Zong-Wei; Zhu, Xue-Mei; Yang, Yong-Mei

    2005-12-01

    In our experiments, four kinds of amino acids, such as L-Cystine ( L-Cys), L-Tyrosine ( L-Tyr), DL-Aspartic Acid ( DL-Asp), L-Lysine ( L-Lys) and the mixed systems of L-Tyr (or L-Lys)/Mg 2+, were used as effective modifiers to mediate the crystallization of CaCO 3. The obtained crystals were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). As the results have shown, calcite was formed in L-Cys system while both calcite and spherical vaterite with various morphologies were produced in the presence of L-Tyr, DL-Asp, and L-Lys whose ability to induce the formation of vaterite was enhanced in turn. It indicated that amino acids played an important role in the process of crystal growth of CaCO 3, the addition of Mg 2+ was helpful for the formation of aragonite. The possible formation mechanism of CaCO 3 produced in different amino acid aqueous solutions was discussed in the end.

  6. Crystal growth and structural analysis of zirconium sulphoselenide single crystals

    Indian Academy of Sciences (India)

    K R Patel; R D Vaidya; M S Dave; S G Patel

    2008-08-01

    A series of zirconium sulphoselenide (ZrSSe3–, where = 0, 0.5, 1, 1.5, 2, 2.5, 3) single crystals have been grown by chemical vapour transport technique using iodine as a transporting agent. The optimum condition for the growth of these crystals is given. The stoichiometry of the grown crystals were confirmed on the basis of energy dispersive analysis by X-ray (EDAX) and the structural characterization was accomplished by X-ray diffraction (XRD) studies. The crystals are found to possess monoclinic structure. The lattice parameters, volume, particle size and X-ray density have been carried out for these crystals. The effect of sulphur proportion on the lattice parameter, unit cell volume and X-ray density in the series of ZrSSe3– single crystals have been studied and found to decrease in all these parameters with rise in sulphur proportion. The grown crystals were examined under optical zoom microscope for their surface topography study. Hall effect measurements were carried out on grown crystals at room temperature. The negative value of Hall coefficient implies that these crystals are -type in nature. The conductivity is found to decrease with increase of sulphur content in the ZrSSe3– series. The electrical resistivity parallel to c-axis as well as perpendicular to -axis have been carried out in the temperature range 303–423 K. The results obtained are discussed in detail.

  7. Overcoming the crystallization and designability issues in the ultrastable zirconium phosphonate framework system

    Science.gov (United States)

    Zheng, Tao; Yang, Zaixing; Gui, Daxiang; Liu, Zhiyong; Wang, Xiangxiang; Dai, Xing; Liu, Shengtang; Zhang, Linjuan; Gao, Yang; Chen, Lanhua; Sheng, Daopeng; Wang, Yanlong; Diwu, Juan; Wang, Jianqiang; Zhou, Ruhong; Chai, Zhifang; Albrecht-Schmitt, Thomas E.; Wang, Shuao

    2017-05-01

    Metal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. Herein, we overcome these challenges and obtain single crystals of three zirconium phosphonates that are suitable for structural analysis. These compounds are built by previously unknown isolated zirconium phosphonate clusters and exhibit combined high porosity and ultrastability even in fuming acids. SZ-2 possesses the largest void volume recorded in zirconium phosphonates and SZ-3 represents the most porous crystalline zirconium phosphonate and the only porous MOF material reported to survive in aqua regia. SZ-2 and SZ-3 can effectively remove uranyl ions from aqueous solutions over a wide pH range, and we have elucidated the removal mechanism.

  8. Entrapment of Inclusions in Diamond Crystals Grown from Fe-Ni-C System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Diamond single crystals grown from Fe-Ni-C system at high temperature-high pressure (HPHT) usually contain inclusions related to the metallic catalyst. During the diamond growth, the metallic inclusions are trapped by the growth front or are formed through reaction between the contaminants trapped in the diamond. In the present paper, the metallic inclusions related to the catalyst were systematically examined by transmission electron microscopy (TEM). The chemical composition and crystal structure of the metallic inclusions were for the first time determined by selected area electron diffraction pattern (SADP) combined with energy dispersive X-ray spectrometry (EDS). It is shown that the inclusions are mainly composed of orthorhombic FeSi2, fcc (FeNi)23C6, and orthorhombic Fe3C,hexagonal Ni3C.

  9. Photonic crystal channel drop filter based on ring-shaped defects for DWDM systems

    Science.gov (United States)

    Dideban, Ali; Habibiyan, Hamidreza; Ghafoorifard, Hassan

    2017-03-01

    This paper presents a novel configuration of channel drop filters based on two-dimensional photonic crystal slabs in silicon-on-insulator platforms. The structure is composed of two photonic crystal line-defect waveguides as input and output ports, along with an L3 cavity with ring-shaped border holes. The effects of structural parameters and fabrication errors on resonance frequency and drop efficiency are investigated. Band structure and propagation of electromagnetic field through device are calculated by plane wave expansion and finite-difference time-domain methods. The results show that the quality factor and line-width of output signal are 5690 and 0.27 nm, respectively, indicating that the proposed filter can be properly used in dense wavelength division multiplexing systems with 0.8 nm channel spacing.

  10. NATO Advanced Research Workshop on Physics and Chemistry of Finite Systems : from Clusters to Crystals

    CERN Document Server

    Khanna, S; Rao, B

    1992-01-01

    Recent innovations in experimental techniques such as molecular and cluster beam epitaxy, supersonic jet expansion, matrix isolation and chemical synthesis are increasingly enabling researchers to produce materials by design and with atomic dimension. These materials constrained by sire, shape, and symmetry range from clusters containing as few as two atoms to nanoscale materials consisting of thousands of atoms. They possess unique structuraI, electronic, magnetic and optical properties that depend strongly on their size and geometry. The availability of these materials raises many fundamental questions as weIl as technological possibilities. From the academic viewpoint, the most pertinent question concerns the evolution of the atomic and electronic structure of the system as it grows from micro clusters to crystals. At what stage, for example, does the cluster look as if it is a fragment of the corresponding crystal. How do electrons forming bonds in micro-clusters transform to bands in solids? How do the s...

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

    Science.gov (United States)

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

    2005-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-03-09

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-10-01

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

  14. Relationship between Multi-Phase Formation and Molecular Structure for Liquid Crystal System

    Institute of Scientific and Technical Information of China (English)

    LI Zhenxin; MA Heng; LI Shipu

    2005-01-01

    A mechanical model of liquid crystals ( LCs ) was used to explain the phase formation and thermal properties. The LC phases in the model are micro-machine systems consisting of an ensemble of molecular rotors, and some dynamic parameters in a semi-experiment molecular orbit method. A novel explanation on the multi-phase formation of LC system is obtained. It is found that the value of the critical rotational velocity is a key parameter for the characterization of each homologous series. The dipole moment of the molecules was also discussed.

  15. Synthesis, Crystal Structure and Antibacterial Activities of 3-[3-Methyl-(2-thienyl)methyl-enehydrazinocarbonyl]-(1H)-1,2,4-triazole

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The title compound, C9HgN5OS, was synthesized by the reaction of 3-(1H)-1,2,4-triazole hydrazine with 3-methyl-2-thiophenecarboxaldehyde in ethanol. The single crystal structure has been determined by X-ray diffraction analysis. The crystal belongs to monoclinic system,space group P21/n with a = 9.5550(10), b = 11.9847(12), c = 10.1074(11) A, β= 112.995(2)°, V=1065.47(19) A3, Z = 4, μ = 0.290 mm-1, Mr= 235.27, Dc = 1.467 g/cm3 and F(000) = 488. The structure was solved by direct methods and refined to R = 0.0449. The crystal structure involves certain antibacterial activity.

  16. Synthesis and Crystal Structure of a Two-dimensional Silver Framework Constructed by H2idc (H2idc = Iminodiacetic Acid)

    Institute of Scientific and Technical Information of China (English)

    LIN Xiu-E; CAO Rong; WANG Yan-Qin; LI Xiao-Ju; BI Wen-Hua; YUAN Da-Qiang

    2005-01-01

    A new compound formulated [Ag2(idc)](NO3)(H2O (H2idc = iminodiacetic acid) was synthesized under mild conditions and characterized by IR spectrum and single-crystal X-ray diffraction. The crystal crystallizes in the monoclinic system, space group of P21/n with a = 5.5029(2), b = 11.1316(5), c = 15.5319 (1) (A), β = 96.038(3)°, V = 946.15(6) (A)3, Z = 4, R = 0.0619 and wR = 0.1606. Its structure is a 2D polymer, whose repeat units consist of dinuclear silver cluster coordinated by two bridging iminodiacetic acids. In the complex, the Ag(I) ions adopt three coordinate fashions, and the Ag-Ag metal-metal contacts of 2.8418 (A) are observed.

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

    Science.gov (United States)

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

    2017-10-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Zhao Wen-Jie; Wang Yuan-Xu

    2009-01-01

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

  19. Choroideremia Is a Systemic Disease With Lymphocyte Crystals and Plasma Lipid and RBC Membrane Abnormalities

    Science.gov (United States)

    Zhang, Alice Yang; Mysore, Naveen; Vali, Hojatollah; Koenekoop, Jamie; Cao, Sang Ni; Li, Shen; Ren, Huanan; Keser, Vafa; Lopez-Solache, Irma; Siddiqui, Sorath Noorani; Khan, Ayesha; Mui, Jeannie; Sears, Kelly; Dixon, Jim; Schwartzentruber, Jeremy; Majewski, Jacek; Braverman, Nancy; Koenekoop, Robert K.

    2015-01-01

    Purpose Photoreceptor neuronal degenerations are common, incurable causes of human blindness affecting 1 in 2000 patients worldwide. Only half of all patients are associated with known mutations in over 250 disease genes, prompting our research program to identify the remaining new genes. Most retinal degenerations are restricted to the retina, but photoreceptor degenerations can also be found in a wide variety of systemic diseases. We identified an X-linked family from Sri Lanka with a severe choroidal degeneration and postulated a new disease entity. Because of phenotypic overlaps with Bietti's crystalline dystrophy, which was recently found to have systemic features, we hypothesized that a systemic disease may be present in this new disease as well. Methods For phenotyping, we performed detailed eye exams with in vivo retinal imaging by optical coherence tomography. For genotyping, we performed whole exome sequencing, followed by Sanger sequencing confirmations and cosegregation. Systemic investigations included electron microscopy studies of peripheral blood cells in patients and in normal controls and detailed fatty acid profiles (both plasma and red blood cell [RBC] membranes). Fatty acid levels were compared to normal controls, and only values two standard deviations above or below normal controls were further evaluated. Results The family segregated a REP1 mutation, suggesting choroideremia (CHM). We then found crystals in peripheral blood lymphocytes and discovered significant plasma fatty acid abnormalities and RBC membrane abnormalities (i.e., elevated plasmalogens). To replicate our discoveries, we expanded the cohort to nine CHM patients, genotyped them for REP1 mutations, and found the same abnormalities (crystals and fatty acid abnormalities) in all patients. Conclusions Previously, CHM was thought to be restricted to the retina. We show, to our knowledge for the first time, that CHM is a systemic condition with prominent crystals in lymphocytes and

  20. Phase Transition for a Mixed Spin-1/2 and Spin-sB System with a Transverse Crystal Field

    Institute of Scientific and Technical Information of China (English)

    JIANG Wei; XIAO Gui-Bin; WEI Guo-Zhu; DU An; ZHANG Qi

    2004-01-01

    The critical behaviors of a mixed spin-1/2 and spin-sB Ising system with a transverse crystal field are studied by use of the effective-field theory with correlations. The effect of the transverse crystal field on transition temperatures is investigated numerically for the honeycomb (z = 3) and square (z = 4) lattices. The results show that there is no tricritical point for the system.

  1. Computational crystallization.

    Science.gov (United States)

    Altan, Irem; Charbonneau, Patrick; Snell, Edward H

    2016-07-15

    Crystallization is a key step in macromolecular structure determination by crystallography. While a robust theoretical treatment of the process is available, due to the complexity of the system, the experimental process is still largely one of trial and error. In this article, efforts in the field are discussed together with a theoretical underpinning using a solubility phase diagram. Prior knowledge has been used to develop tools that computationally predict the crystallization outcome and define mutational approaches that enhance the likelihood of crystallization. For the most part these tools are based on binary outcomes (crystal or no crystal), and the full information contained in an assembly of crystallization screening experiments is lost. The potential of this additional information is illustrated by examples where new biological knowledge can be obtained and where a target can be sub-categorized to predict which class of reagents provides the crystallization driving force. Computational analysis of crystallization requires complete and correctly formatted data. While massive crystallization screening efforts are under way, the data available from many of these studies are sparse. The potential for this data and the steps needed to realize this potential are discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-01

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

  3. Molecular theory of nematic liquid crystals viewed as effect of collective excitation in ferromagnetic systems

    Institute of Scientific and Technical Information of China (English)

    Liu Jian-Jun; Shen Man; Liu Xiao-Jing; Yang Guo-Chen

    2006-01-01

    We develop a microscopic theory of the nematic phase with consideration of the effect of the collective excitation on properties of nematic liquid crystals. The model is based on the Heisenberg's exchange model of the ferromagnetic materials. Since the orientation of the molecular long axis and the angular momentum of the molecule rotating around its long axis have the same direction, operators can be introduced to research the nematic liquid crystals. Using the lattice model and the Holstein-Primakoff transformation, the Hamiltonian of the system can be obtained, which has the same form as that of the ferromagnetic substance. The relation between the order parameter and reduced temperature can be gotten. It is in good agreement with the experimental results in the low temperature region, the accordance is better than that of the molecular field theory and the computer simulation. In high temperature region close to the transition point, by considering the effect of the higher-order terms in the Hamiltonian, theoretical prediction is in better agreement with the experiment. That indicates the many-body effect is important to nematic liquid crystals.

  4. Time resolution deterioration with increasing crystal length in a TOF-PET system

    CERN Document Server

    Gundacker, S; Auffray, E; Jarron, P; Meyer, T; Lecoq, P

    2014-01-01

    Highest time resolution in scintillator based detectors is becoming more and more important. In medical detector physics L(Y)SO scintillators are commonly used for time of flight positron emission tomography (TOF-PET). Coincidence time resolutions (CTRs) smaller than 100 ps FWHM are desirable in order to improve the image signal to noise ratio and thus give benefit to the patient by shorter scanning times. Also in high energy physics there is the demand to improve the timing capabilities of calorimeters down to 10 ps. To achieve these goals it is important to study the whole chain, i.e. the high energy particle interaction in the crystal, the scintillation process itself, the scintillation light transfer in the crystal, the photodetector and the electronics. Time resolution measurements for a PET like system are performed with the time-over-threshold method in a coincidence setup utilizing the ultra-fast amplifier-discriminator NINO. With 2×2×3 mm3 LSO:Ce codoped 0.4%Ca crystals coupled to commercially avai...

  5. Investigation of active slip systems in high purity single crystal niobium

    Science.gov (United States)

    Baars, Derek

    The superconducting radio-frequency (SRF) community uses high purity niobium to manufacture SRF cavities for a variety of accelerator applications. Cavities are either made from large-grain sheets cut directly from the ingot and formed, or the ingot microstructure is broken down to form polycrystalline sheets or tubes. Reducing the number of costly electron beam welds to assemble the cavities is also desired. A greater understanding of the active slip systems and their relation to subsequent dislocation substructure would be of use in all these areas, to better understand how large grain niobium deforms and to develop more accurate computational models that will aid in the design and use of more cost-effective forming methods. Studies of slip in high-purity niobium suggest that temperature, material purity, and crystal orientation affect which slip systems are active during deformation, though have not examined the somewhat lesser purity niobium used for SRF cavities. As a step toward these goals, two sets of SRF-purity single crystal niobium samples were deformed to 40% strain in tension at room temperature. The first set was cut and welded back together. The second set consisted of deliberately orientated samples that resolved shear stress onto desired slip systems to evaluate different combinations of slip. Determining likely active slip systems was complex, though the evidence suggests that {112} slip may be dominant at yield at room temperature as suggested by theory, though {110} slip could not be ruled out.

  6. Studies on the synthesis, spectral, optical and thermal properties of l-Valine Zinc Sulphate: an organic inorganic hybrid nonlinear optical crystal.

    Science.gov (United States)

    Puhal Raj, A; Ramachandra Raja, C

    2012-11-01

    Nonlinear optical (NLO) organic inorganic hybrid l-Valine Zinc Sulphate (LVZS) was synthesized and single crystals were obtained from saturated aqueous solution by slow evaporation method at 36°C using a constant temperature bath (CTB) with an accuracy of ±0.01°C. This crystal is reported with its characterization by single crystal and powder XRD, FTIR, UV-Vis-NIR, TG/DTA analysis and SHG test. Single crystal XRD study reveals that LVZS crystallizes in monoclinic system with the lattice constants a=9.969(3) Å, b=7.238(3) Å, c=24.334(9) Å and cell volume is 1736.00Å(3). Sharp peaks observed in powder X-ray diffraction studies confirm the high degree of crystallinity of grown crystal. The incorporation of sulphate ion with l-valine is confirmed by FTIR spectrum in LVZS crystal(.) A remarkable increase in optical transparency has been observed in LVZS when compared to l-valine and zinc sulphate heptahydrate Thermal properties of LVZS have been reported by using TG/DTA analysis. Kurtz powder second harmonic generation (SHG) test confirms NLO property of the crystal and SHG efficiency of LVZS was found to be 1.34 times more than pure l-valine.

  7. Studies on the synthesis, spectral, optical and thermal properties of L-Valine Zinc Sulphate: An organic inorganic hybrid nonlinear optical crystal

    Science.gov (United States)

    Puhal Raj, A.; Ramachandra Raja, C.

    2012-11-01

    Nonlinear optical (NLO) organic inorganic hybrid L-Valine Zinc Sulphate (LVZS) was synthesized and single crystals were obtained from saturated aqueous solution by slow evaporation method at 36 °C using a constant temperature bath (CTB) with an accuracy of ±0.01 °C. This crystal is reported with its characterization by single crystal and powder XRD, FTIR, UV-Vis-NIR, TG/DTA analysis and SHG test. Single crystal XRD study reveals that LVZS crystallizes in monoclinic system with the lattice constants a = 9.969(3) Å, b = 7.238(3) Å, c = 24.334(9) Å and cell volume is 1736.00 Å3. Sharp peaks observed in powder X-ray diffraction studies confirm the high degree of crystallinity of grown crystal. The incorporation of sulphate ion with L-valine is confirmed by FTIR spectrum in LVZS crystal. A remarkable increase in optical transparency has been observed in LVZS when compared to L-valine and zinc sulphate heptahydrate Thermal properties of LVZS have been reported by using TG/DTA analysis. Kurtz powder second harmonic generation (SHG) test confirms NLO property of the crystal and SHG efficiency of LVZS was found to be 1.34 times more than pure L-valine.

  8. A Generic Framework for Systematic Design of Process Monitoring and Control System for Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli Bin; Meisler, Kresten Troelstrup; Sin, Gürkan

    , for control and monitoring purposes, an appropriate Process Analytical Technology (PAT) system ensuring that the critical process variables are measured and maintained within the design limits also needs to be integrated. The objectives of this work are to develop a generic systematic design framework...... for monitoring and control systems applicable to a wide range of crystallization processes and operational scenarios. This framework contains a generic multi-dimensional modelling framework and features for design of operational scenarios and for design of PAT systems. The generality of this approach allows...... the desired target CSD. The generated operational policies provide the supersaturation set point and by maintaining the operation at this point, the targeted CSD is achieved. The resulting problem-system specific models and the operational policies become ready for use in model-based design and control...

  9. Experimental analysis of beam pointing system based on liquid crystal optical phase array

    Science.gov (United States)

    Shi, Yubin; Zhang, Jianmin; Zhang, Zhen

    2016-12-01

    In this paper, we propose and demonstrate an elementary non-mechanical beam aiming and steering system with a single liquid crystal optical phase array (LC-OPA) and charge-coupled device (CCD). With the conventional method of beam steering control, the LC-OPA device can realize one dimensional beam steering continuously. An improved beam steering strategy is applied to realize two dimensional beam steering with a single LC-OPA. The whole beam aiming and steering system, including an LC-OPA and a retroreflective target, is controlled by the monitor. We test the feasibility of beam steering strategy both in one dimension and in two dimension at first, then the whole system is build up based on the improved strategy. The experimental results show that the max experimental pointing error is 56 μrad, and the average pointing error of the system is 19 μrad.

  10. Miniature Compressive Ultra-spectral Imaging System Utilizing a Single Liquid Crystal Phase Retarder

    Science.gov (United States)

    August, Isaac; Oiknine, Yaniv; Abuleil, Marwan; Abdulhalim, Ibrahim; Stern, Adrian

    2016-03-01

    Spectroscopic imaging has been proved to be an effective tool for many applications in a variety of fields, such as biology, medicine, agriculture, remote sensing and industrial process inspection. However, due to the demand for high spectral and spatial resolution it became extremely challenging to design and implement such systems in a miniaturized and cost effective manner. Using a Compressive Sensing (CS) setup based on a single variable Liquid Crystal (LC) retarder and a sensor array, we present an innovative Miniature Ultra-Spectral Imaging (MUSI) system. The LC retarder acts as a compact wide band spectral modulator. Within the framework of CS, a sequence of spectrally modulated images is used to recover ultra-spectral image cubes. Using the presented compressive MUSI system, we demonstrate the reconstruction of gigapixel spatio-spectral image cubes from spectral scanning shots numbering an order of magnitude less than would be required using conventional systems.

  11. An electrically tunable imaging system with separable focus and zoom functions using composite liquid crystal lenses.

    Science.gov (United States)

    Chen, Ming-Syuan; Chen, Po-Ju; Chen, Michael; Lin, Yi-Hsin

    2014-05-19

    We demonstrated an electrically tunable optical image system with separable focus function and zoom function based on three tunable focusing composite liquid crystal (LC) lenses. One LC lens in charge of the focus function helps to maintain the formed image at the same position and the other two LC lenses in charge of zoom function assist to continuously form an image at image sensor with tunable magnification of image size. The detail optical mechanism is investigated and the concept is demonstrated experimentally. The magnifications of the images can be switched continuously for the target in a range between 10 cm and 100 cm. The optical zoom ratio of this system maintains a constant~6.5:1 independent of the object distance. This study provides not only a guideline to design the image system with an electrically optical zoom, but also provide an experimental process to show how to operate the tunable focusing lenses in such an image system.

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

    NARCIS (Netherlands)

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

    2000-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  14. MECHANISM OF OPTICAL NONLINEARITY IN “LYOTROPIC LIQUID CRYSTAL — VIOLOGEN” SYSTEM

    Directory of Open Access Journals (Sweden)

    Hanna Bordyuh

    2014-06-01

    Full Text Available In the present work we analyze the characteristics of holographic grating recording and consider a mechanism of optical nonlinearity in the lyotropic liquid crystal (LLC — viologen samples. Taking into account structural and electrooptical properties of the admixture molecules it is possible to suggest that the recording is realized due to the change of polarizability of π-electron system of coloured viologen derivatives under the action of laser radiation. The main nonlinear optical parameters such as nonlinear refraction coefficient n2, cubic nonlinear susceptibility χ(3, and hyperpolarizability γ were calculated.

  15. Laboratory information management system for membrane protein structure initiative--from gene to crystal.

    Science.gov (United States)

    Troshin, Petr V; Morris, Chris; Prince, Stephen M; Papiz, Miroslav Z

    2008-12-01

    Membrane Protein Structure Initiative (MPSI) exploits laboratory competencies to work collaboratively and distribute work among the different sites. This is possible as protein structure determination requires a series of steps, starting with target selection, through cloning, expression, purification, crystallization and finally structure determination. Distributed sites create a unique set of challenges for integrating and passing on information on the progress of targets. This role is played by the Protein Information Management System (PIMS), which is a laboratory information management system (LIMS), serving as a hub for MPSI, allowing collaborative structural proteomics to be carried out in a distributed fashion. It holds key information on the progress of cloning, expression, purification and crystallization of proteins. PIMS is employed to track the status of protein targets and to manage constructs, primers, experiments, protocols, sample locations and their detailed histories: thus playing a key role in MPSI data exchange. It also serves as the centre of a federation of interoperable information resources such as local laboratory information systems and international archival resources, like PDB or NCBI. During the challenging task of PIMS integration, within the MPSI, we discovered a number of prerequisites for successful PIMS integration. In this article we share our experiences and provide invaluable insights into the process of LIMS adaptation. This information should be of interest to partners who are thinking about using LIMS as a data centre for their collaborative efforts.

  16. Synthesis and Crystal Structure of Palladium(Ⅱ) Complex with 2,2'-Bipyridine-3,3'-dicarboxylic Acid

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The title complex Pd(H2BDA)Cl2(2DMSO (C16H14Cl2N2O6PdS2, H2BDA = 2,2'- bipyridine-3,3'-dicarboxylic acid) has been synthesized and characterized by IR spectra, elemental analysis and 1H NMR spectra. Its structure was determined by single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic system, space group P21/c with a = 1.3604(6), b = 1.2606(6), c = 1.3521(6) nm, β = 103.677(7)°, V = 2.2530(17) nm3, Mr = 571.75, Z = 4, Dc = 1.686 g/cm3, μ = 1.280 mm-1, F(000) = 1136, R = 0.0405 and wR = 0.0908. The complex presents a planar quadrangle arrangement and is assembled via hydrogen bonds.

  17. Crystal Structure and Spectroscopic Studies of Bis (morpholine dithiocarbamate) Nickel (II) Complex, Ni (C4H8ONCS2) 2

    Institute of Scientific and Technical Information of China (English)

    PAN,Su(潘苏); PAN,Su; WANG,Ying(王瑛); WANG,Ying

    2001-01-01

    The title compound has been prepared and characterized by EA, IR and TG spectralstudies. The crystal structure of nickel (IⅡ) bis(morpholine dithiocarbamate) Ni(C4HsONC S2)2 is determied by X-ray diffraction methods. It crystal lizes in the monoclinic system, space groun P2n/n, with lat tice parameters a = 0.4288(1), b = 2.0526(4), c = 0.8333(2) nn, β = 97.43(3)°, and Z = 2. In the structure, central Ni atom coordination geometry is slightly distorted square-planar with the four S atoms from two morpholine dithiocarbamate ligands. The four Ni-S bond distancs are in the range of 0.2199(5)0.2201(2) nm. The IR spectral data are in agreement with the structural ones. The TG data indicate that it decomposed completely at the 766.89°C.

  18. Beta-alanine-oxalic acid (1:1) hemihydrate crystal: structure, 13C NMR and vibrational properties, protonation character.

    Science.gov (United States)

    Godzisz, D; Ilczyszyn, M; Ilczyszyn, M M

    2003-03-01

    The crystal structure of beta-alanine-oxalic acid (1:1) hemihydrate complex has been reinvestigated by X-ray diffraction method at 293 K. Formation of monoclinic crystal system belonging to C2/c space group and consisting of semi-oxalate chains, diprotonated beta-alanine dimers and water molecules bonded to both these units is confirmed. New results are obtained for distances in the carboxylic groups and hydrogen bonds. These structural observations are used for protonation degree monitoring on the carboxylic oxygen atoms. They are in accordance with our vibrational study. The 13C NMR spectra provide insights into the solid structure of this complex, character of its hydrogen bonds and the beta-alanine protonation.

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

  20. Synthesis, growth, optical and mechanical studies of ferroelectric urea-oxalic acid single crystals

    Science.gov (United States)

    Vizhi, R. Ezhil; Dhivya, R.; Babu, D. Rajan

    2016-10-01

    A single crystal of urea oxalic acid was grown by slow evaporation method. The lattice parameters are a=5.13 Å, b=12.48 Å, c=7.07 Å, β=98.13° with V=448.5 Å3 which belongs to monoclinic system with space group P21/c obtained from single crystal X-ray diffraction analysis. UV-visible spectrum was recorded from the wavelength region of 200-800 nm and its cutoff wavelength was found to be 270 nm. Optical energy band gap of 4.57 eV was determined using Tau's plot relation. Fourier transform infrared vibrational spectrum confirmed the presence of N-H asymmetric stretching which occurs at 3444 cm-1 and 1853 cm-1 arising due to the amide C=O symmetric stretching. The emission was observed at 364 nm from the photoluminescence spectrum. The mechanical stability of the grown crystal was estimated by Vickers microhardness studies and it is evident that the grown crystal belongs to soft material category. Hardness related parameters such as elastic stiffness constant, fracture mechanics, brittleness index and yield strength were also evaluated. The dielectric constant and dielectric loss of the grown crystal were carried out as a function of frequency for different temperatures.

  1. Orientations of axially coordinated imidazoles and pyridines in crystal structures of model systems of cytochromes.

    Science.gov (United States)

    Rakić, Aleksandra A; Medaković, Vesna B; Zarić, Snezana D

    2006-01-01

    Many properties of cytochromes and model systems depend on orientations of axial ligands. In this work, we elucidated the role of porphyrin substituents on orientation of axial ligands in model systems of cytochromes. The orientations of axially coordinated imidazoles and pyridines in crystal structures of model systems of cytochromes were analyzed and data were compared with previous quantum-chemical calculations. The results show that eight ethyl groups on porphyrin ring strongly favor parallel orientation, hence, in all these complexes axial ligands, pyridines or imidazoles, are mutually parallel. Four phenyl or mesityl groups at meso-carbons also favor parallel orientation but less strongly. Hence, in most of the bis-imidazole complexes the orientation is parallel, while in bis-pyridine complexes the orientation of pyridines depends on oxidation state of Fe. In bis-pyridine Fe(II) complexes orientation is parallel, in Fe(III) it is orthogonal. This analysis is in agreement with previous quantum-chemical calculations.

  2. Optical absorption enhancement in a hybrid system photonic crystal - thin substrate for photovoltaic applications.

    Science.gov (United States)

    Buencuerpo, Jeronimo; Munioz-Camuniez, Luis E; Dotor, Maria L; Postigo, Pablo A

    2012-07-02

    A hybrid approach for light trapping using photonic crystal nanostructures (nanorods, nanopillars or nanoholes) on top of an ultra thin film as a substrate is presented. The combination of a nanopatterned layer with a thin substrate shows an enhanced optical absorption than equivalent films without patterning and can compete in performance with nanostructured systems without a substrate. The designs are tested in four relevant materials: amorphous silicon (a-Si), crystalline silicon (Si), gallium arsenide (GaAs) and indium phosphide (InP). A consistent enhancement is observed for all of the materials when using a thin hybrid system (300 nm) even compared to the non patterned thin film with an anti-reflective coating (ARC). A realistic solar cell structure composed of a hybrid system with a layer of indium tin oxide (ITO) an ARC and a back metal layer is performed, showing an 18% of improvement for the nanostructured device.

  3. The development of an inspection system for defects in silicon crystal growth

    Science.gov (United States)

    Liu, Ya-Cheng; Tsai, Hsin-Yi; Hung, Min-Wei; Huang, Kuo-Cheng

    2013-03-01

    This study presents an inspection system to detect the growth defects of silicon crystals that comprise a CCD camera, an LED light source, and power modulation. The defects on multicrystalline silicon can be observed clearly while the silicon wafer were irradiated by the red LED light at a small lighting angle (i.e., 20-30°). However, the growth defects on monocrystalline silicon wafer were difficult to observe because of it low image intensity. And then, the growth defects image was significantly enhanced when the wafer was illuminated by a white LED (WLED) and rotated at a specific angle (i.e., 23°). The experimental results showed that the WLED illumination system made the growth defects more easily observable than did other LED sources (i.e., red, blue, and green LEDs). In addition, the proposed inspection system can be used for on-line fast detection for quality control of monocrystalline silicon wafer.

  4. A new massively parallel version of CRYSTAL for large systems on high performance computing architectures.

    Science.gov (United States)

    Orlando, Roberto; Delle Piane, Massimo; Bush, Ian J; Ugliengo, Piero; Ferrabone, Matteo; Dovesi, Roberto

    2012-10-30

    Fully ab initio treatment of complex solid systems needs computational software which is able to efficiently take advantage of the growing power of high performance computing (HPC) architectures. Recent improvements in CRYSTAL, a periodic ab initio code that uses a Gaussian basis set, allows treatment of very large unit cells for crystalline systems on HPC architectures with high parallel efficiency in terms of running time and memory requirements. The latter is a crucial point, due to the trend toward architectures relying on a very high number of cores with associated relatively low memory availability. An exhaustive performance analysis shows that density functional calculations, based on a hybrid functional, of low-symmetry systems containing up to 100,000 atomic orbitals and 8000 atoms are feasible on the most advanced HPC architectures available to European researchers today, using thousands of processors.

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

    Institute of Scientific and Technical Information of China (English)

    蔺玲; 邵淑英; 李静平

    2013-01-01

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

  6. Synthesis, crystal growth, structural, spectral, thermal, mechanical, linear and nonlinear optical studies of organic single crystal 4-Iodo 4-nitrostilbene (IONS): A potential NLO material

    Energy Technology Data Exchange (ETDEWEB)

    Dinakaran, Paul M.; Kalainathan, S., E-mail: kalainathan@yahoo.com

    2013-12-16

    An organic nonlinear optical material 4-Iodo 4-nitrostilbene (IONS) has been synthesized and good optical quality single crystal was grown from ethyl methyl ketone solvent by the solution growth technique. Single and powder X-ray diffraction analyses reveals that the grown crystal belongs to monoclinic crystal system with noncentrosymmetric space group ‘P2{sub 1}’ and it has good crystalline nature. Functional groups and molecular structure of the title compound were confirmed by FTIR and {sup 1}H NMR respectively. The UV–Vis–NIR absorption study reveals no absorption in the visible region and the cut-off wavelength was found to be at 412.84 nm, TG/DTA, mass spectral analysis, photoluminescence and microhardness studies have been carried out for the grown crystals and results are discussed in detail. The second harmonic efficiency of the IONS was determined by Kurtz–Perry powder technique which reveals that the IONS crystal (3.1 V) has greater efficiency i.e., 143 times to that of KDP (21.7 mV). - Highlights: • The 4-Iodo 4-nitrostilbene (IONS) material has been synthesized by Wittig reaction. • The single crystal was grown for the first time with dimensions of 9.5 × 4 × 1.5 mm{sup 3}. • SHG efficiency of IONS is 143 times greater than that of KDP crystal. • The UV–Vis absorption study reveals that the transparency was found to be good. • IONS crystal is a potential candidate for optoelectronic applications.

  7. Crystal growth and optical properties of Gd admixed Ce-doepd Lu2Si2O7 single crystals

    Science.gov (United States)

    Horiai, Takahiko; Kurosawa, Shunsuke; Murakami, Rikito; Yamaji, Akihiro; Shoji, Yasuhiro; Ohashi, Yuji; Pejchal, Jan; Kamada, Kei; Yokota, Yuui; Yoshikawa, Akira

    2017-06-01

    Ce-doped Lu2Si2O7 scintillator contains radioactive isotope 176Lu which causes an unwanted intrinsic background signal. The development of scintillators with reduced Lu concentration were required in some applications. In this study, we developed the Gd admixed lutetium pyrosilicate, where the average ion radius at the rare earth site was similar to the Tm3+ ion radius, for which the RE2Si2O7 (RE=Tm, Yb, Lu) crystal structure is stable from room temperature to melting point. We have grown (Cex Lu1-x-y Gdy)2Si2O7 (x=0.01, y=0.00, 0.05, 0.10) single crystals. Their crystal systems were monoclinic with a space group C2/m. The absorption spectra revealed the energy transitions in Ce and Gd ions might be occurred. The light output was degraded and decay time was accelerated comparing the Gd 5% admixed sample with the Gd 10% one.

  8. Ice Crystal Icing Engine Testing in the NASA Glenn Research Center's Propulsion Systems Laboratory (PSL): Altitude Investigation

    Science.gov (United States)

    Oliver, Michael J.

    2015-01-01

    The National Aeronautics and Space Administration conducted a full scale ice crystal icing turbofan engine test in the NASA Glenn Research Centers Propulsion Systems Laboratory (PSL) Facility in February 2013. Honeywell Engines supplied the test article, an obsolete, unmodified Lycoming ALF502-R5 turbofan engine serial number LF01 that experienced an un-commanded loss of thrust event while operating at certain high altitude ice crystal icing conditions. These known conditions were duplicated in the PSL for this testing.

  9. Crystal Structure and Thermal Behavior of Rubidium 3,5-dihydroxy-2,4,6-trinitrophenolate%3,5-二羟基-2,4,6-三硝基苯酚铷的晶体结构和热行为

    Institute of Scientific and Technical Information of China (English)

    陈红艳; 张同来; 乔小晶; 杨利; 张建国; 郁开北

    2006-01-01

    A novel energetic coordination compound, rubidium 3,5-dihydroxy-2,4,6-trinitrophenolate ([Rb(DHTNP)]n),has been synthesized by reaction of trinitrophloroglueinol with Rb2CO3 in aqueous solution. Its crystal structure has been determined. The crystal belongs to monoclinic system with space group C2/c. In the crystal the Rb cation is coordinated to ten oxygen atoms from seven different DHTNP- anions to form an irregular polyhedron.Two independent molecule geometry structures are found for DHTNP- anion in the complex, which differ in benzene ring and their pattern of intramolecular hydrogen bonds. The DHTNP- anion chains are interlaced with rubidium atoms as knots, and a three-dimensional infinite net structure is formed via coordination and hydrogen bonding. The hydrogen bond and cation-anion interactions are the predominant driving forces in the crystal packing. The thermal property of title complex was studied by using DSC and TG-DTG techniques. CCDC: 290623.

  10. Determining ice water content from 2D crystal images in convective cloud systems

    Science.gov (United States)

    Leroy, Delphine; Coutris, Pierre; Fontaine, Emmanuel; Schwarzenboeck, Alfons; Strapp, J. Walter

    2016-04-01

    Cloud microphysical in-situ instrumentation measures bulk parameters like total water content (TWC) and/or derives particle size distributions (PSD) (utilizing optical spectrometers and optical array probes (OAP)). The goal of this work is to introduce a comprehensive methodology to compute TWC from OAP measurements, based on the dataset collected during recent HAIC (High Altitude Ice Crystals)/HIWC (High Ice Water Content) field campaigns. Indeed, the HAIC/HIWC field campaigns in Darwin (2014) and Cayenne (2015) provide a unique opportunity to explore the complex relationship between cloud particle mass and size in ice crystal environments. Numerous mesoscale convective systems (MCSs) were sampled with the French Falcon 20 research aircraft at different temperature levels from -10°C up to 50°C. The aircraft instrumentation included an IKP-2 (isokinetic probe) to get reliable measurements of TWC and the optical array probes 2D-S and PIP recording images over the entire ice crystal size range. Based on the known principle relating crystal mass and size with a power law (m=α•Dβ), Fontaine et al. (2014) performed extended 3D crystal simulations and thereby demonstrated that it is possible to estimate the value of the exponent β from OAP data, by analyzing the surface-size relationship for the 2D images as a function of time. Leroy et al. (2015) proposed an extended version of this method that produces estimates of β from the analysis of both the surface-size and perimeter-size relationships. Knowing the value of β, α then is deduced from the simultaneous IKP-2 TWC measurements for the entire HAIC/HIWC dataset. The statistical analysis of α and β values for the HAIC/HIWC dataset firstly shows that α is closely linked to β and that this link changes with temperature. From these trends, a generalized parameterization for α is proposed. Finally, the comparison with the initial IKP-2 measurements demonstrates that the method is able to predict TWC values

  11. Lasing in a nematic liquid crystal cell with an interdigitated electrode system

    Energy Technology Data Exchange (ETDEWEB)

    Shtykov, N M; Palto, S P; Umanskii, B A; Geivandov, A R [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation)

    2015-04-30

    Waveguide lasing in a layer of a dye-doped nematic liquid crystal has been observed. The liquid-crystal layer was sandwiched between a quartz substrate and a glass cover plate on whose surface was deposited an interdigitated electrode system. This system had a period of 3.75 μm and played a dual role, namely, it created a spatial periodicity of the waveguide medium refractive index (thus creating distributed feedback) and served as a diffraction grating coupling out a part of waveguide radiation into the glass cover plate. The distributed feedback ensured lasing in the 18th diffraction order for the TE modes and in the 19th order for the TM modes of the waveguide. The generated radiation was observed at the exit from the glass plate end face at the angles to the waveguide plane of 33.1 ± 1.5° for TM modes and 21.8 ± 1.8° for TE modes. The intensity and position of the TE emission line showed no regular dependence on the voltage on the electrodes. In the case of TM radiation, an increase in the voltage led to a short-wavelength shift of the laser line and to a decrease in its intensity. (lasers)

  12. High luminous flux from single crystal phosphor-converted laser-based white lighting system

    KAUST Repository

    Cantore, Michael

    2015-12-14

    The efficiency droop of light emitting diodes (LEDs) with increasing current density limits the amount of light emitted per wafer area. Since low current densities are required for high efficiency operation, many LED die are needed for high power white light illumination systems. In contrast, the carrier density of laser diodes (LDs) clamps at threshold, so the efficiency of LDs does not droop above threshold and high efficiencies can be achieved at very high current densities. The use of a high power blue GaN-based LD coupled with a single crystal Ce-doped yttrium aluminum garnet (YAG:Ce) sample was investigated for white light illumination applications. Under CW operation, a single phosphor-converted LD (pc-LD) die produced a peak luminous efficacy of 86.7 lm/W at 1.4 A and 4.24 V and a peak luminous flux of 1100 lm at 3.0 A and 4.85 V with a luminous efficacy of 75.6 lm/W. Simulations of a pc-LD confirm that the single crystal YAG:Ce sample did not experience thermal quenching at peak LD operating efficiency. These results show that a single pc-LD die is capable of emitting enough luminous flux for use in a high power white light illumination system.

  13. Synthesis, growth and characterization of new organic crystal: 2-Aminopyridinium p-Toluenesulfonate for third order nonlinear optical applications

    Science.gov (United States)

    Bincy, I. P.; Gopalakrishnan, R.

    2014-09-01

    2-Aminopyridinium p-Toluenesulfonate (2APPTS), an organic NLO crystal, was grown for the first time by the slow evaporation solution technique. Single crystal X-ray diffraction analysis reveals that 2APPTS belongs to monoclinic crystal system with centrosymmetric space group P21/n. The determined lattice parameters are a=8.580(7) Å, b=6.419(5) Å, c=23.277(18) Å, β=100.016(3)° and volume=1262.58(3) Å3. Powder XRD study reveals the crystalline nature of the grown sample. FT-IR and FT-Raman studies were carried out to identify the functional groups present in 2APPTS. FT-NMR spectral study confirms the number of protons and carbon present in the molecular structure of the title compound. Thermal behavior and stability of 2APPTS were investigated by thermogravimetric (TG) and differential thermal analyses (DTA). Transparency of the title crystal in UV-vis-NIR region was analyzed and the optical band gap energy was found to be 3.6 eV. The mechanical properties of the grown crystals have been analyzed by the Vickers microhardness method. The etching studies reveal the growth pattern and dislocations present in the grown 2APPTS crystal. The negative third order nonlinear optical parameters like refractive index (n2), absorption coefficient (β) and susceptibility (χ(3)) were estimated by Z-scan studies.

  14. Growth and characterization of Bis(L-threonine) copper (II) monohydrate single crystals: A semiorganic second order nonlinear optical material

    Science.gov (United States)

    Subhashini, R.; Sathya, D.; Sivashankar, V.; Latha Mageshwari, P. S.; Arjunan, S.

    2016-12-01

    Highly transparent solitary nonlinear semiorganic optical material Bis(L-threonine) copper (II) monohydrate [BLTCM], was synthesized by a conventional slow evaporation solution growth technique. The grown crystals were subjected to structural, optical, electrical, thermal, mechanical, SHG and Laser damage threshold studies. Single crystal XRD shows that the material crystallizes in monoclinic system with noncentrosymmetric space group P21. FT-IR and FT-RAMAN analyses confirm the various functional groups present in the grown crystal. The transparency range of BLTCM was determined by UV-vis-NIR studies and various optical constants such as extinction coefficient (K), refractive index, optical conductivity and electric susceptibility with real and imaginary parts of dielectric constant were calculated using the transmittance data which have applications in optoelectronic devices. Dielectric studies of the crystal were carried out at different frequencies and temperatures to analyze the electrical properties. TGA and DSC analyses were performed to study the thermal behaviour of the sample. The hardness stability of the grown specimen was investigated by Vickers microhardness test. The output intensity of second harmonic generation was confirmed using the Kurtz and Perry powder method. The laser induced surface damage threshold of the crystal was measured using Nd:YAG laser.

  15. Synthesis, growth, optical and anisotropic mechanical behaviour of organic nonlinear optical imidazolium 2-chloro-4-nitrobenzoate single crystals

    Science.gov (United States)

    Krishnakumar, Varadharajan; Jayaprakash, Jeyaram; Boobas, Singaram; Komathi, Muniraj

    2016-10-01

    The title compound, imidazolium 2-chloro-4-nitrobenzoate (I2C4NB), has been synthesized and optical quality single crystals were grown with a dimension of 4 × 2 × 1 mm3 using an ethanol and acetone (1:1) mixed solvent by slow evaporation solution growth technique. The powder XRD analysis confirmed the crystal structure and found that it is crystallized in the non-centrosymmetric space group P21 with the monoclinic system. The symmetries of molecular vibrations were confirmed by FT-IR spectrum. The CHN(S) analysis confirmed the stoichiometric composition of the grown crystal. It also exhibits a good transparency in the entire visible region (300-800nm) and it was thermally stable up to 131.1 °C. The microhardness measurement shows the anisotropic nature of I2C4NB and also that it belongs to a soft material category. Photoconductivity studies reveal a linear increase of the photocurrent with respect to the applied electric field. HOMO LUMO studies were carried out for the crystal. The second harmonic generation test by the Kurtz powder method shows that the crystal exhibits phase matching and a conversion efficiency which is 2 times that of KDP.

  16. Growth, spectral, optical, thermal, and mechanical behaviour of an organic single crystal: Quinolinium 2-carboxy 6-nitrophthalate monohydrate

    Science.gov (United States)

    Mohana, J.; Ahila, G.; Bharathi, M. Divya; Anbalagan, G.

    2016-09-01

    Organic single crystals of quinolinium 2-carboxy 6-nitrophthalate monohydrate (QN) were grown by slow evaporation solution growth technique using ethanol and water as a mixed solvent. X-ray powder diffraction analysis revealed that the crystal belongs to the monoclinic crystal system with space group of P21/c. The functional groups present in the crystallized material confirmed its molecular structure. The optical transparency range and the lower cutoff wavelength were identified from the UV-vis spectrum. The optical constants were determined by UV-visible transmission spectrum at normal incidence, measured over the 200-700 nm spectral range. The dispersion of the refractive index was discussed in terms of the single-oscillator Wemple and DiDomenico model. The calculated HOMO and LUMO energies show that the charge transfer occur within the molecule. Electronic excitation properties were discussed within the framework of two level model on the basis of an orbital analysis. The nonlinear optical absorption coefficient (β) and nonlinear refraction (n2) of QN was measured by Z-scan technique and reported here. Thermal stability of QN was determined using TGA/DSC curves. Vicker's microhardness studies were carried out on the (1 1 ̅0) plane to understand the mechanical properties of the grown crystal. The microhardness measurements showed a Vickers hardness value as 18.4 kg/mm2 which is comparable to well-known organic crystal, urea.

  17. Growth and characterization of benzaldehyde 4-nitro phenyl hydrazone (BPH) single crystal: A proficient second order nonlinear optical material

    Science.gov (United States)

    Saravanan, M.; Abraham Rajasekar, S.

    2016-04-01

    The crystals (benzaldehyde 4-nitro phenyl hydrazone (BPH)) appropriate for NLO appliance were grown by the slow cooling method. The solubility and metastable zone width measurement of BPH specimen was studied. The material crystallizes in the monoclinic crystal system with noncentrosymmetric space group of Cc. The optical precision in the whole visible region was found to be excellent for non-linear optical claim. Excellence of the grown crystal is ascertained by the HRXRD and etching studies. Laser Damage Threshold and Photoluminescence studies designate that the grown crystal contains less imperfection. The mechanical behaviour of BPH sample at different temperatures was investigated to determine the hardness stability of the grown specimen. The piezoelectric temperament and the relative Second Harmonic Generation (for diverse particle sizes) of the material were also studied. The dielectric studies were executed at varied temperatures and frequencies to investigate the electrical properties. Photoconductivity measurement enumerates consummate of inducing dipoles due to strong incident radiation and also divulge the nonlinear behaviour of the material. The third order nonlinear optical properties of BPH crystals were deliberate by Z-scan method.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2011-07-01

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

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

    Science.gov (United States)

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

    2017-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-05-15

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

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

    Science.gov (United States)

    Zhang, Li; Chen, Dairong; Jiao, Xiuling

    2006-02-16

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

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

    Science.gov (United States)

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

    2012-03-01

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

  4. A generalized crystal-cutting method for modeling arbitrarily oriented crystals in 3D periodic simulation cells with applications to crystal-crystal interfaces

    Science.gov (United States)

    Kroonblawd, Matthew P.; Mathew, Nithin; Jiang, Shan; Sewell, Thomas D.

    2016-10-01

    A Generalized Crystal-Cutting Method (GCCM) is developed that automates construction of three-dimensionally periodic simulation cells containing arbitrarily oriented single crystals and thin films, two-dimensionally (2D) infinite crystal-crystal homophase and heterophase interfaces, and nanostructures with intrinsic N-fold interfaces. The GCCM is based on a simple mathematical formalism that facilitates easy definition of constraints on cut crystal geometries. The method preserves the translational symmetry of all Bravais lattices and thus can be applied to any crystal described by such a lattice including complicated, low-symmetry molecular crystals. Implementations are presented with carefully articulated combinations of loop searches and constraints that drastically reduce computational complexity compared to simple loop searches. Orthorhombic representations of monoclinic and triclinic crystals found using the GCCM overcome some limitations in standard distributions of popular molecular dynamics software packages. Stability of grain boundaries in β-HMX was investigated using molecular dynamics and molecular statics simulations with 2D infinite crystal-crystal homophase interfaces created using the GCCM. The order of stabilities for the four grain boundaries studied is predicted to correlate with the relative prominence of particular crystal faces in lab-grown β-HMX crystals. We demonstrate how nanostructures can be constructed through simple constraints applied in the GCCM framework. Example GCCM constructions are shown that are relevant to some current problems in materials science, including shock sensitivity of explosives, layered electronic devices, and pharmaceuticals.

  5. Characterization of lung tissues using liquid-crystal tunable filter and hyperspectral imaging system.

    Science.gov (United States)

    Lee, Jong-Ha; Won, Chang-Hee

    2009-01-01

    Hyperspectral imaging system has been developed to characterize lung tissue for detecting emphysematous tissues in lung volume reduction surgery. The system consists of a charge-coupled device and liquid crystal tunable filter, which is continuously tunable in the near-infrared spectral range of 650 - 1100 nm with a mean bandwidth of 5 nm. Using hyperspectral data, the spectral signature of healthy lung tissue and simulated smokers lung tissue is obtained and compared. The data show the peak absorption intensity at four different wavelengths (760, 805, 915, and 970 nm). However, the reflectance intensity of simulated smoker's lung tissue over all spectral range is considerably higher than the normal lung tissue. The differences provide the basis for the detection and characterization of emphysema from healthy lung tissue.

  6. Rheological Properties of Cubic Liquid Crystals Formed from Monoglyceride/H2O Systems

    Institute of Scientific and Technical Information of China (English)

    水玲玲; 王志宁; 郑利强

    2005-01-01

    Monoglyceride (MO) can form various liquid crystalline phases spontaneously in the presence of various amount of water at room temperature. The appropriate compositions from binary phase diagram of MO/H2O were selected to form cubic phases. The selected systems were studied at different salt concentrations and pH value using rheological methods. There was a weak effect of salt on viscoelastic properties of cubic phases formed from MO/H2O system. Hexagonal phase was formed when pH value was decreased or increased. The viscoelasticity of cubic phases was different from that of hexagonal liquid crystals. Rheological properties of MO/H2O cubic phases were stable at pH and salt concentration similar to physiological condition.

  7. Phase diagram of power law and Lennard-Jones systems: Crystal phases

    Energy Technology Data Exchange (ETDEWEB)

    Travesset, Alex [Ames Laboratory

    2014-10-28

    An extensive characterization of the low temperature phase diagram of particles interacting with power law or Lennard-Jones potentials is provided from Lattice Dynamical Theory. For power law systems, only two lattice structures are stable for certain values of the exponent (or softness) (A15, body centered cube (bcc)) and two more (face centered cubic (fcc), hexagonal close packed (hcp)) are always stable. Among them, only the fcc and bcc are equilibrium states. For Lennard-Jones systems, the equilibrium states are either hcp or fcc, with a coexistence curve in pressure and temperature that shows reentrant behavior. The hcp solid never coexists with the liquid. In all cases analyzed, for both power law and Lennard-Jones potentials, the fcc crystal has higher entropy than the hcp. The role of anharmonic terms is thoroughly analyzed and a general thermodynamic integration to account for them is proposed.

  8. Photonic liquid crystal fibers tuning by four electrode system produced with 3D printing technology

    Science.gov (United States)

    Ertman, Slawomir; Bednarska, Karolina; Czapla, Aleksandra; Woliński, Tomasz R.

    2015-09-01

    Photonic liquid crystal fiber has been intensively investigated in last few years. It has been proved that guiding properties of such fibers could be tuned with an electric field. In particular efficient tuning could be obtained if multi-electrode system allowing for dynamic change of not only intensity of the electric field, but also its direction. In this work we report a simple to build four electrode system, which is based on a precisely aligned four cylindrical microelectrodes. As an electrodes we use enameled copper wire with diameter adequate to the diameter of the fiber to be tuned. To ensure uniform and parallel alignment of the wires a special micro-profiles has been designed and then produced with filament 3D printer. The possibility of the dynamic change of the electric field direction in such scalable and cost effective electrode assembly has been experimentally confirmed.

  9. New Approach to a Practical Quartz Crystal Microbalance Sensor Utilizing an Inkjet Printing System

    Directory of Open Access Journals (Sweden)

    Yusuke Fuchiwaki

    2014-10-01

    Full Text Available The present work demonstrates a valuable approach to developing quartz crystal microbalance (QCM sensor units inexpensively for reliable determination of analytes. This QCM sensor unit is constructed by inkjet printing equipment utilizing background noise removal techniques. Inkjet printing equipment was chosen as an alternative to an injection pump in conventional flow-mode systems to facilitate the commercial applicability of these practical devices. The results demonstrate minimization of fluctuations from external influences, determination of antigen-antibody interactions in an inkjet deposition, and quantification of C-reactive protein in the range of 50–1000 ng∙mL−1. We thus demonstrate a marketable application of an inexpensive and easily available QCM sensor system.

  10. The effect of surfaces on molecular ordering in thin liquid-crystal systems

    Science.gov (United States)

    Śliwa, I.; JeŻewski, W.; Zakharov, A. V.

    2016-08-01

    A theoretical method for analyzing the interplay between pair long-range intermolecular forces and nonlocal, relatively short-range, surface interactions in liquid crystals, confined between plates of thin planar cells, is developed. It is shown that this method, as involving the concept of local orientational and translational order parameters, enables detailed investigations of the emergence of smectic A, nematic, and isotopic phases, as well as yields an insight into phase transitions between them, in cases of systems strongly affected by surfaces. The evidence of various surface effects, including the coexistence of different phases and the inward propagation of surface melting under the increase of temperature, is also given. The underlying numerical procedure, based on the algorithm of self-consistent calculations of local order parameters, is found to be very effective, allowing one to consider model systems of rather large thicknesses, corresponding to thicknesses of real sample cells.

  11. Crystal structure of putrescine aspartic acid complex

    OpenAIRE

    Ramaswamy, S.; Murthy, MRN

    1990-01-01

    Polyamines, putrescine, spermidine and spermine are ubiquitous biogenic cations believed to be important for a variety of cellular processes. In order to obtain structural information on the interaction of these amines with other biomolecules, the structure of a complex of putrescine with aspartic acid was determined using single crystal X-ray diffraction methods. The crystals belong monoclinic space group $C_2$ with $a = 21.504 \\AA$, $b = 4.779 \\AA$, $c = 8.350 \\AA$ and $\\beta = {97.63}^{\\ci...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-15

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

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

    Science.gov (United States)

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

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Lailatun Nazirah Ozair

    2010-05-01

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

  15. Chirality and its spontaneous symmetry breaking in two liquid crystal systems

    Science.gov (United States)

    Kang, Louis

    Chirality, or handedness, is a key concept spanning all fields of natural science, from biology to mathematics. Chiral structures can arise from achiral building blocks that lack a handedness if their assembly is unstable to chiral deformations, a phenomenon called spontaneous symmetry breaking. We theoretically study the role of chirality in two systems composed of liquid crystals dissolved or suspended in water, and our results match those obtained experimentally by our collaborators. In the first system, we study achiral liquid crystals whose Frank twist modulus is much lower than their splay and bend Frank moduli and which are confined in capillaries. Under homeotropic anchoring, their ground state configuration undergoes spontaneous chiral symmetry breaking when the twist modulus decreases enough relative to the splay and bend moduli. Under degenerate planar anchoring, a small twist-to-saddle-splay ratio of elastic moduli leads to degenerate twisted configurations even though an undeformed configuration is possible. Measuring the twist profile of an experimental system produces a value for the saddle-splay constant, which has been difficult to achieve previously. Under either boundary condition, domain walls and point defects, whose topological charges depend on chirality, separate domains with different degenerate configurations, and certain ones are energetically preferred over others. In the second system, we study filamentous viruses acting as colloidal liquid crystals under the influence of depletion, which promotes condensation of the viruses into 2D colloidal monolayers. These membranes have tunable chirality and show a rich array of emergent behaviors, including a transition from a circular shape to a striking starfish shape upon changing the chirality of constituent viruses, partial coalescence via domain walls through which the viruses twist by 180 degrees, and phase-separated rafts of a particular size when two virus species with different lengths

  16. 新型螺旋状一维超分子链配合物的晶体结构%The Crystal Structure of A Novel Helical Supramolecular One-Dimensional Chain Complex

    Institute of Scientific and Technical Information of China (English)

    建方方; 侯玉霞; 肖海连

    2004-01-01

    The crystal structure of quasi-one-dimensional compound Ni[S2CPyrd]2 (Pyrd=pyrrolidine) has been determined by X-ray diffraction technique. It crystallizes in the monoclinic system, space group P21/c, with lattice parameters a=0.631 6(1) nm, b=0.746 5(2) nm, c=1.576 5(4) nm, β=106.08(3)°, and Z=2. The nickel atom had a square-planar geometry. The most prominent feature in the crystal structure is that the bis(pyrrolidinedithiocarbamato) nickel(Ⅱ) forms a well-separated stacking column along the a-axis through supramolecular interaction, and they are uniformly spaced to give a helical one-dimensional chain structure. CCDC: 220648.

  17. Synthesis and Crystal Structure of Ca(Ⅰ) Complex with One-Dimensional Chain Structure%一维链状铜配合物的合成及结构表征

    Institute of Scientific and Technical Information of China (English)

    徐海军; 李冬平; 李国清

    2009-01-01

    The Copper (Ⅰ) complex [Cu(tpy)(CN)]n [L=4'-(4-cyanophenyl)-2,2' :6',2"-terpyridine] has been synthe-sized by reaction of ligand L with CuCN using solvothermal method and characterized by IR, elemental analysis and X-ray diffraction single-crystal structure analysis. The crystal structure indicates that the complex crystallizes in monoclinic system, space group P21/c with a=0.884 45(18) nm, b=0.819 55(16) nm, c=2.702 90(7) nm, β=102.780 complex has a slightly distorted tetrahedron coordination geometry. Each Cu+ is coordinated with two nitrogen atoms from two pyridine ring of 4'-(4-cyanophenyl)-2,2' :6' ,2"-terpyridine, and then linked by two CN- ligands with neighbor Cu+ forming a zigzag infinite one-dimensional chain structure. CCDC: 686952.

  18. Optical characterization of ferroelectric glycinium phosphite single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Perumal, R.; Senthil Kumar, K. [Crystal Growth Centre, Anna University, Sardar Patel Road, Chennai, Tamil Nadu 600025 (India); Moorthy Babu, S., E-mail: babu@annauniv.ed [Crystal Growth Centre, Anna University, Sardar Patel Road, Chennai, Tamil Nadu 600025 (India); Bhagavannarayana, G. [Crystal Growth and Crystallography Section, National Physical Laboratory, CSIR, Dr. K.S. Krishnan Marg, New Delhi 110012 (India)

    2010-02-04

    Single crystals of glycinium phosphite (GPI) were grown by isothermal evaporation and conventional temperature-lowering techniques. Single crystal and powder X-ray diffraction analysis confirm the monoclinic structure of the as grown crystals. The structural perfection of the as grown crystal was determined through HRXRD analysis. FTIR and Raman analysis revealed the functional groups present in the grown crystals. The optical absorption of the grown crystal was analyzed and the refractive index values for different wavelengths were measured by prism coupling technique. Thermal stability, melting temperature and phase transition temperature of the as grown crystals were identified from TGA/DSC analysis. The dielectric impedance analysis indicates the continuous phase transition nature of the grown crystals. The mechanical strength and hardening co-efficient were determined from Vicker's microhardness measurements for different loads with constant dwell time. The growth mechanism and the defects were analyzed through chemical etching analysis from various crystallographic planes and etching periods.

  19. Synthesis, crystal growth and characterization of bioactive material: 2-amino-1H-benzo[d]imidazol-3-ium salicylate single crystal-a proton transfer molecular complex

    Science.gov (United States)

    Fathima, K. Saiadali; Anitha, K.

    2017-05-01

    The 1:1 molecular adducts 2-aminobenzimidazolium salicylate (ABIS) single crystal was synthesized and grown from 2-aminobenzimidazole (ABI) as a donor and salicylic acid (SA) as an acceptor. The cell parameter was determined using single crystal X-Ray diffraction method and the complex ABIS belongs to monoclinic system. The spectroscopic studies showed that ABIS crystal was an ion pair complex. The FTIR and Raman spectra showed that the presence of O-H, C=N, C=O vibration which confirms the proton transfer from SA to ABI. The UV-Vis spectrum exhibited a visible band at 359nm for ABIS due to the salicylate anion of the molecule. Further the antimicrobial activity of ABIS complex against Staphylococcus aureus, klebsiella pneumonia, Pseudomonas eruginos and E.coli pathogens was investigated. So the complex molecule inhibits both Gram positive and Gram negative bacterial. It is found that benzimidazole with aminogroup at position 2 increases the general antimicrobial activities of ABIS crystal.

  20. Syntheses and Crystal Structures of Two VO(IV) Schiff Base Complexes with Oxyammonia Ligand

    Institute of Scientific and Technical Information of China (English)

    李连之; 许涛; 王大奇; 牛梅菊; 冀海伟

    2004-01-01

    Two novel VO(IV) Schiff base complexes, VO(SALHA)2[SALHA: salicyaldehydeoxyammonia] and VO(o-VANHA)2 [o-VANHA: o-vanillin-oxyammonia], have been synthesized with salicyaldehyde or o-vanilline, hydroxylammonium chloride and vanadyl sulfate in absolute methanol, and their crystal structures were determined by single-crystal X-ray diffraction. The vanadium(IV) centers in both complexes are five-coordinate in a distorted square pyramidal geometry. VO(SALHA)2 (C14H12N2O5V, Mr = 339.20) crystallizes in the monoclinic system, space group P21/n with a = 14.716(9), b = 7.175(5), c = 14.716(9) A, β = 113.130(7), V = 1428.8(15) A3, Z = 4, Dc = 1.577 g/cm3, β = 0.71073 A, μ(MoKα) = 0.720 mm-1, F(000) = 692, the final R = 0.0466 and wR = 0.0829 for 1561 observed reflections (I > 2σ(I)). VO(o-VANHA)2 (C16H16N2O7V, Mr = 399.25) is of monoclinic, space group P21/n with a = 11.386(12), b = 10.405(10), c = 14.627(15) A, β = 93.654(19), V = 1729(3) A3, Z = 4, Dc = 1.533 g/cm3, β = 0.71073 A, μ(MoKα) = 0.615 mm-1, F(000) = 820, the final R = 0.0513 and wR = 0.1129 for 1235 observed reflections (I > 2σ(I)).

  1. Phase transformations and phase equilibria in the Co-Sn-Ti system in the crystallization interval

    Science.gov (United States)

    Fartushna, Iu.; Bulanova, M.; Ayral, R. M.; Tedenac, J. C.; Meleshevich, K.

    2016-12-01

    The Co-Sn-Ti system was studied in the crystallization interval (below 50 at% Sn) by the methods of Scanning Electron Microscopy, microprobe analysis, Differential Thermal Analysis, X-ray diffraction. The liquidus and solidus projections and the melting diagram were constructed. Only Co2TiSn(τ1) ternary compound (Heusler phase-L12) was found in equilibria with the liquid in the concentration interval studied. Taking into account our recent data, the liquidus projection is characterized by the fields of primary crystallization of (βTi), (Co), binary-based phases Ti3Sn, Ti2Sn, Ti5Sn3, Ti6Sn5, Ti2Co, TiCo, TiCo2 (c), TiCo2 (h), TiCo3, βCo3Sn2, CoSn and ternary τ1. The solidus projection is characterized by thirteen three-phase fields, which result from invariant four-phase equilibria, five are of eutectic type (E) and eight of transition type (U) and the existence of one more region Ti2Sn3+βCoSn3+(Sn) in the solidus projection is discussed.

  2. Investigation of 2D photonic crystal structure based channel drop filter using quad shaped photonic crystal ring resonator for CWDM system

    Energy Technology Data Exchange (ETDEWEB)

    Chhipa, Mayur Kumar, E-mail: mayurchhipa1@gmail.com; Dusad, Lalit Kumar [Government Engineering College Ajmer, Rajasthan (India); Rajasthan Technical University, Kota, Rajasthan (India)

    2016-05-06

    In this paper, the design & performance of two dimensional (2-D) photonic crystal structure based channel drop filter is investigated using quad shaped photonic crystal ring resonator. In this paper, Photonic Crystal (PhC) based on square lattice periodic arrays of Gallium Indium Phosphide (GaInP) rods in air structure have been investigated using Finite Difference Time Domain (FDTD) method and photonic band gap is being calculated using Plane Wave Expansion (PWE) method. The PhC designs have been optimized for telecommunication wavelength λ= 1571 nm by varying the rods lattice constant. The number of rods in Z and X directions is 21 and 20, with lattice constant 0.540 nm it illustrates that the arrangement of Gallium Indium Phosphide (GaInP) rods in the structure which gives the overall size of the device around 11.4 µm × 10.8 µm. The designed filter gives good dropping efficiency using 3.298, refractive index. The designed structure is useful for CWDM systems. This device may serve as a key component in photonic integrated circuits. The device is ultra compact with the overall size around 123 µm{sup 2}.

  3. A comparative simulation study on three lattice systems for the phase separation of polymer-dispersed liquid crystals

    Indian Academy of Sciences (India)

    Y J Jeon; M Jamil; Hyo-Dong Lee; J T Rhee

    2008-09-01

    This article reports a comparative study of the phase separation process in a polymer-dispersed liquid crystal, based on a Metropolis Monte Carlo simulation study of three lattice systems. We propose a model for the different processes occurring in the formation of polymer-dispersed liquid crystals (PDLCs). The mechanism of PDLC is studied as a function of quench temperature, concentration and degree of polymerization of liquid crystals and polymers. The obtained resultant phase diagrams of the three systems are approximated and compared with the Flory–Huggins theory, and show a good agreement. It has been observed in the simulation results that among all the three systems, the 40 × 40 × 40 lattice showed the most accurate, reliable and stable results.

  4. Polarized infrared reflectance spectra of brushite (CaHPO4·2H2O) crystal investigation of the phosphate stretching modes.

    Science.gov (United States)

    Mevellec, Jean-Yves; Quillard, Sophie; Deniard, Philippe; Mekmene, Omar; Gaucheron, Frédéric; Bouler, Jean-Michel; Buisson, Jean-Pierre

    2013-07-01

    Polarized infrared (IR) reflectance measurements at near-normal incidence were recorded from the ac-plane of a monoclinic brushite (CaHPO4·2H2O) crystal in the 800-1200 cm(-1) spectral range (P-O stretching modes). The adjustment of these data, on the basis of a dispersion analysis (DA) model for monoclinic case, allowed the determination of oscillators parameters for the four P-O stretching observed modes of the phosphate group.

  5. Polarized infrared reflectance spectra of brushite (CaHPO4ṡ2H2O) crystal investigation of the phosphate stretching modes

    Science.gov (United States)

    Mevellec, Jean-Yves; Quillard, Sophie; Deniard, Philippe; Mekmene, Omar; Gaucheron, Frédéric; Bouler, Jean-Michel; Buisson, Jean-Pierre

    2013-07-01

    Polarized infrared (IR) reflectance measurements at near-normal incidence were recorded from the ac-plane of a monoclinic brushite (CaHPO4ṡ2H2O) crystal in the 800-1200 cm-1 spectral range (P-O stretching modes). The adjustment of these data, on the basis of a dispersion analysis (DA) model for monoclinic case, allowed the determination of oscillators parameters for the four P-O stretching observed modes of the phosphate group.

  6. The Origin and Time Dependence of the Amount and Composition of Non-Constituent Gases Present in Crystal Growth Systems

    Science.gov (United States)

    Palosz, Witold

    1998-01-01

    Presence of different, non-constituent gases may be a critical factor in crystal growth systems. In Physical Vapor Transport processes the cras(es) can be used intentionally (to prevent excessively high, unstable growth conditions), or can evolve unintentionally during the course of the process (which may lead to undesired reduction in the -rowth rate). In melt growth, particularly under low gravity conditions (reduced hydrostatic pressure) the gas present in the system may contribute to formation of voids in the growing crystals and even to a separation of the crystal and the liquid phase [1]. On the other hand, some amount of gas may facilitate 'contactless' crystal growth particularly under reduced gravity conditions [2 - 6]. Different non-constituent gases may be present in growth ampoules, and their amount and composition may change during the crystallization process. Some gases can appear even in empty ampoules sealed originally under high vacuum: they may diffuse in from the outside, and/or desorb from the ampoule walls. Residual gases can also be generated by the source materials: even very high purity commercial elements and compounds may contain trace amounts of impurities, particularly oxides. The oxides may have low volatilities themselves but their reaction with other species, particularly carbon and hydrogen, may produce volatile compounds like water or carbon oxides. The non-constituent gases, either added initially to the system or evolved during the material processing, may diffuse out of the ampoule during the course of the experiment. Gases present outside (e.g. as a protective atmosphere or thermal conductor) may diffuse into the ampoule. In either case the growth conditions and the quality of the crystals may be affected. The problem is of a particular importance in sealed systems where the amount of the gases cannot be directly controlled. Therefore a reasonable knowledge and understanding of the origin, composition, magnitude, and change with

  7. The Origin and Time Dependence of the Amount and Composition of Non-Constituent Gases Present in Crystal Growth Systems

    Science.gov (United States)

    Palosz, Witold

    1998-01-01

    Presence of different, non-constituent gases may be a critical factor in crystal growth systems. In Physical Vapor Transport processes the cras(es) can be used intentionally (to prevent excessively high, unstable growth conditions), or can evolve unintentionally during the course of the process (which may lead to undesired reduction in the -rowth rate). In melt growth, particularly under low gravity conditions (reduced hydrostatic pressure) the gas present in the system may contribute to formation of voids in the growing crystals and even to a separation of the crystal and the liquid phase [1]. On the other hand, some amount of gas may facilitate 'contactless' crystal growth particularly under reduced gravity conditions [2 - 6]. Different non-constituent gases may be present in growth ampoules, and their amount and composition may change during the crystallization process. Some gases can appear even in empty ampoules sealed originally under high vacuum: they may diffuse in from the outside, and/or desorb from the ampoule walls. Residual gases can also be generated by the source materials: even very high purity commercial elements and compounds may contain trace amounts of impurities, particularly oxides. The oxides may have low volatilities themselves but their reaction with other species, particularly carbon and hydrogen, may produce volatile compounds like water or carbon oxides. The non-constituent gases, either added initially to the system or evolved during the material processing, may diffuse out of the ampoule during the course of the experiment. Gases present outside (e.g. as a protective atmosphere or thermal conductor) may diffuse into the ampoule. In either case the growth conditions and the quality of the crystals may be affected. The problem is of a particular importance in sealed systems where the amount of the gases cannot be directly controlled. Therefore a reasonable knowledge and understanding of the origin, composition, magnitude, and change with

  8. Improvement of an automated protein crystal exchange system PAM for high-throughput data collection

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, Masahiko, E-mail: masahiko.hiraki@kek.jp; Yamada, Yusuke; Chavas, Leonard M. G. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Wakatsuki, Soichi [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 69, Menlo Park, CA 94025-7015 (United States); Stanford University, Beckman Center B105, Stanford, CA 94305-5126 (United States); Matsugaki, Naohiro [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2013-11-01

    A special liquid-nitrogen Dewar with double capacity for the sample-exchange robot has been created at AR-NE3A at the Photon Factory, allowing continuous fully automated data collection. In this work, this new system is described and the stability of its calibration is discussed. Photon Factory Automated Mounting system (PAM) protein crystal exchange systems are available at the following Photon Factory macromolecular beamlines: BL-1A, BL-5A, BL-17A, AR-NW12A and AR-NE3A. The beamline AR-NE3A has been constructed for high-throughput macromolecular crystallography and is dedicated to structure-based drug design. The PAM liquid-nitrogen Dewar can store a maximum of three SSRL cassettes. Therefore, users have to interrupt their experiments and replace the cassettes when using four or more of them during their beam time. As a result of investigation, four or more cassettes were used in AR-NE3A alone. For continuous automated data collection, the size of the liquid-nitrogen Dewar for the AR-NE3A PAM was increased, doubling the capacity. In order to check the calibration with the new Dewar and the cassette stand, calibration experiments were repeatedly performed. Compared with the current system, the parameters of the novel system are shown to be stable.

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

    Science.gov (United States)

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

    2012-10-01

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

  10. Remote System for Detection of Low-Levels of Methane Based on Photonic Crystal Fibres and Wavelength Modulation Spectroscopy

    Directory of Open Access Journals (Sweden)

    J. P. Carvalho

    2009-01-01

    Full Text Available In this work we described an optical fibre sensing system for detecting low levels of methane. The properties of hollow-core photonic crystal fibres are explored to have a sensing head with favourable characteristics for gas sensing, particularly in what concerns intrinsic readout sensitivity and gas diffusion time in the sensing structure. The sensor interrogation was performed applying the Wavelength Modulation Spectroscopy technique, and a portable measurement unit was developed with performance suitable for remote detection of low levels of methane. This portable system has the capacity to simultaneously interrogate four remote photonic crystal fibre sensing heads.

  11. Zero temperature magnetic phase diagram of Wigner crystal in anisotropic two-dimensional electron systems

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Chenggang [Department of Electrical Engineering, Princeton University, Princeton, NJ 08544 (United States)], E-mail: zcf@ornl.gov; Bhatt, Ravin N. [Department of Electrical Engineering, Princeton Center for Theoretical Physics, and Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, NJ 08544 (United States)

    2008-04-01

    We study the effect of mass anisotropy on the magnetic ordering of the Wigner crystal phase of low density electron systems in two dimensions at T=0. We apply the instanton approximation to various ring exchange processes, which includes the lowest order Gaussian fluctuations beyond the WKB approximation. The multi-particle exchange frequencies are calculated with effective mass anisotropy, both with and without ensuing lattice distortions. We find that when sufficient mass anisotropy is present, the two-spin exchange process between the nearest neighbors becomes more frequent than the three particle processes. Therefore, its corresponding antiferromagnetic exchange exceeds the ferromagnetic exchange from the three-spin process and becomes dominant. Numerical diagonalization of small clusters with two, three, and four-spin exchange terms shows a transition from a ferromagnetic to an antiferromagnetic ground state with increasing mass anisotropy.

  12. Prediction of photonic crystal fiber characteristics by Neuro-Fuzzy system

    Science.gov (United States)

    Pourmahyabadi, M.; Mohammad Nejad, S.

    2009-10-01

    The most common methods applied in the analysis of photonic crystal fibers (PCFs) are finite difference time/frequency domain (FDTD/FDFD) method and finite element method (FEM). These methods are very general and reliable (well tested). They describe arbitrary structure but are numerically intensive and require detailed treatment of boundaries and complex definition of calculation mesh. So these conventional models that simulate the photonic response of PCFs are computationally expensive and time consuming. Therefore, a practical design process with trial and error cannot be done in a reasonable amount of time. In this article, an artificial intelligence method such as Neuro-Fuzzy system is used to establish a model that can predict the properties of PCFs. Simulation results show that this model is remarkably effective in predicting the properties of PCF such as dispersion, dispersion slope and loss over the C communication band.

  13. Contamination and Radiation Effects on Nonlinear Crystals for Space Laser Systems

    Science.gov (United States)

    Abdeldayem, Hossain A.; Dowdye, Edward; Jamison, Tracee; Canham, John; Jaeger, Todd

    2005-01-01

    Space Lasers are vital tools for NASA s space missions and military applications. Although, lasers are highly reliable on the ground, several past space laser missions proved to be short-lived and unreliable. In this communication, we are shedding more light on the contamination and radiation issues, which are the most common causes for optical damages and laser failures in space. At first, we will present results based on the study of liquids and subsequently correlate these results to the particulates of the laser system environment. We present a model explaining how the laser beam traps contaminants against the optical surfaces and cause optical damages and the role of gravity in the process. We also report the results of the second harmonic generation efficiency for nonlinear optical crystals irradiated with high-energy beams of protons. In addition, we are proposing to employ the technique of adsorption to minimize the presence of adsorbing molecules present in the laser compartment.

  14. Highly-stable monolithic femtosecond Yb-fiber laser system based on photonic crystal fibers

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Turchinovich, Dmitry

    2010-01-01

    of around 297 fs duration. Our laser shows exceptional stability. No Q-switched modelocking events were detected during 4-days long observation. An average fluctuation of only 7.85 · 10−4 over the mean output power was determined as a result of more than 6-hours long measurement. The laser is stable towards......A self-starting, passively stabilized, monolithic all polarizationmaintaining femtosecond Yb-fiber master oscillator / power amplifier with very high operational and environmental stability is demonstrated. The system is based on the use of two different photonic crystal fibers. One is used...... in the oscillator cavity for dispersion balancing and nonlinear optical limiting, and another one is used for low nonlinearity final pulse recompression. The chirped-pulse amplification and recompression of the 232-fs, 45-pJ/pulse oscillator output yields a final direct fiber-end delivery of 7.3-nJ energy pulses...

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

    Science.gov (United States)

    Lucas, Thomas J.

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

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

    Science.gov (United States)

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

    2013-12-03

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

  17. Synthesis by two methods and crystal structure determination of a new pyrochlore-related compound Sm{sub 2}FeTaO{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Martinez, Leticia M., E-mail: lettorresg@yahoo.com [Departamento de Ecomateriales y Energia, Facultad de Ingenieria Civil, Universidad Autonoma de Nuevo Leon, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Ruiz-Gomez, Miguel A. [Departamento de Ecomateriales y Energia, Facultad de Ingenieria Civil, Universidad Autonoma de Nuevo Leon, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, Av. Manuel Nava 6, San Luis Potosi, S.L.P. 78290 (Mexico); Figueroa-Torres, M.Z.; Juarez-Ramirez, Isaias [Departamento de Ecomateriales y Energia, Facultad de Ingenieria Civil, Universidad Autonoma de Nuevo Leon, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Moctezuma, Edgar [Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, Av. Manuel Nava 6, San Luis Potosi, S.L.P. 78290 (Mexico); and others

    2012-04-16

    Graphical abstract: The monoclinic (space group C2/c) structure of a new compound, Sm{sub 2}FeTaO{sub 7} shows an alternating Sm-O and Fe/Ta-O layers. In the Fe/Ta-O layer, Fe/Ta1 and Fe/Ta3 cations are coordinated by six oxygen atoms, forming irregular octahedral interconnected into a hexagonal tungsten bronze (HTB) type network. The HTB layer is a fundamental framework in the pyrohlore-related structure. Highlights: Black-Right-Pointing-Pointer Pyrochlore-related compound Sm{sub 2}FeTaO{sub 7} prepared by solid state reaction and sol-gel. Black-Right-Pointing-Pointer Sm{sub 2}FeTaO{sub 7} crystallizes with a monoclinic crystal structure and space group C2/c. Black-Right-Pointing-Pointer The compound is synthesized by sol-gel at lower temperature and time than solid state. Black-Right-Pointing-Pointer Surface area of sol-gel Sm{sub 2}FeTaO{sub 7} is 10 times higher than that prepared by solid state. - Abstract: This paper reports on the synthesis of a new pyrochlore-related compound Sm{sub 2}FeTaO{sub 7} by both solid state reaction and sol-gel synthesis routes. Structural features were determined by X-ray powder diffraction and Rietveld refinement and were corroborated using Transmission Electron Microscopy (TEM). The results revealed that Sm{sub 2}FeTaO{sub 7} crystallized in the monoclinic system with space group C2/c and the following cell parameters: a = 13.1307(5) Angstrom-Sign , b = 7.5854(3) Angstrom-Sign , c = 11.6425(4) Angstrom-Sign and {beta} = 100.971(2) Degree-Sign . The monoclinic structure of Sm{sub 2}FeTaO{sub 7} showed an arrangement of alternating Sm-O and Fe/Ta-O layers and two types of irregular octahedra of Fe/Ta-O, which are interconnected into a hexagonal tungsten bronze (HTB)-type network. On the other hand, Sm{sub 2}FeTaO{sub 7} prepared by sol-gel was obtained with lower particle sizes than the solid state produced compound. The difference in particle size causes a difference of one order of magnitude in the specific surface area. In

  18. Phase relations and crystal structures in the system Ta-V-Ge.

    Science.gov (United States)

    Khan, Atta U; Bursik, J; Rogl, P

    2012-05-28

    Phase equilibria have been derived for the isothermal section of the Ta-V-Ge system at 1500 °C (for concentrations phases have been identified within the isothermal section, out of which three were characterized by Rietveld refinement of X-ray powder diffraction data. τ(1)-(Ta(1-x)V(x))(5)Ge(3) (0.21 ≤ x ≤ 0.63) adopts the Mn(5)Si(3)-type and τ(2)-Ta(Ta(x)V(1-x-y)Ge(y))(2), x = 0.02, y = 0.12 was found to be a MgZn(2)-type Laves phase. Detailed transmission electron microscopy (TEM) in several crystallographic directions confirmed lattice parameters and crystal symmetry of this phase and rejected the presence of any superstructure. τ(3)-Ta(9-x+y)V(4+x-y-z)Ge(1+z), x = 0.32, y = 0.51, z = 0.98 crystallizes with the Nb(9)Co(4)Ge-type, whereas the structure of τ(4) is not yet known. Although a MgCu(2)-type cubic Laves phase is not present in the Ta-V binary at this temperature, additions of Ge stabilize this phase in the ternary system: C15-Ta(Ta(x)V(1-x-y)Ge(y))(2), x = 0.04, y = 0.05. V(11)Ge(8) (Cr(11)Ge(8) type) shows a large solubility up to (Ta(x)V(1-x))(11)Ge(8), x = 0.64 at 1500 °C.

  19. Crystal structure of the type IV secretion system component CagX from Helicobacter pylori

    Science.gov (United States)

    Zhang, Jin; Fan, Fei; Zhao, Yanhe; Sun, Lifang; Liu, Yadan; Wu, Yunkun

    2017-01-01

    Helicobacter pylori, a Gram-negative bacterial pathogen prevalent in the human population, is the causative agent of severe gastric diseases. An H. pylori type IV secretion (T4S) system encoded by the cytotoxin-associated gene pathogenicity island (cagPAI) is responsible for communication with host cells. As a component of the cagPAI T4S system core complex, CagX plays an important role in virulence-protein translocation into the host cells. In this work, the crystal structure of the C-terminal domain of CagX (CagXct), which is a homologue of the VirB9 protein from the VirB/D4 T4S system, is presented. CagXct is only the second three-dimensional structure to be elucidated of a VirB9-like protein. Another homologue, TraO, which is encoded on the Escherichia coli conjugative plasmid pKM101, shares only 19% sequence identity with CagXct; however, there is a remarkable similarity in tertiary structure between these two β-sandwich protein domains. Most of the residues that are conserved between CagXct and TraO are located within the protein core and appear to be responsible for the preservation of this domain fold. The studies presented here will contribute to our understanding of different bacterial T4S systems. PMID:28291753

  20. Ground-state characterizations of systems predicted to exhibit L11 or L13 crystal structures

    Science.gov (United States)

    Nelson, Lance J.; Hart, Gus L. W.; Curtarolo, Stefano

    2012-02-01

    Despite their geometric simplicity, the crystal structures L11 (CuPt) and L13 (CdPt3) do not appear as ground states experimentally, except in Cu-Pt. We investigate the possibility that these phases are ground states in other binary intermetallic systems, but overlooked experimentally. Via the synergy between high-throughput and cluster-expansion computational methods, we conduct a thorough search for systems that may exhibit these phases and calculate order-disorder transition temperatures when they are predicted. High-throughput calculations predict L11 ground states in the systems Ag-Pd, Ag-Pt, Cu-Pt, Pd-Pt, Li-Pd, Li-Pt, and L13 ground states in the systems Cd-Pt, Cu-Pt, Pd-Pt, Li-Pd, Li-Pt. Cluster expansions confirm the appearance of these ground states in some cases. In the other cases, cluster expansion predicts unsuspected derivative superstructures as ground states. The order-disorder transition temperatures for all L11/L13 ground states were found to be sufficiently high that their physical manifestation may be possible.

  1. High sensitivity automated multiplexed immunoassays using photonic crystal enhanced fluorescence microfluidic system.

    Science.gov (United States)

    Tan, Yafang; Tang, Tiantian; Xu, Haisheng; Zhu, Chenqi; Cunningham, Brian T

    2015-11-15

    We demonstrate a platform that integrates photonic crystal enhanced fluorescence (PCEF) detection of a surface-based microspot fluorescent assay with a microfluidic cartridge to achieve simultaneous goals of high analytic sensitivity (single digit pg/mL), high selectivity, low sample volume, and assay automation. The PC surface, designed to provide optical resonances for the excitation wavelength and emission wavelength of Cyanines 5 (Cy5), was used to amplify the fluorescence signal intensity measured from a multiplexed biomarker microarray. The assay system is comprised of a plastic microfluidic cartridge for holding the PC and an assay automation system that provides a leak-free fluid interface during introduction of a sequence of fluids under computer control. Through the use of the assay automation system and the PC embedded within the microfluidic cartridge, we demonstrate pg/mL-level limits of detection by performing representative biomarker assays for interleukin 3 (IL3) and Tumor Necrosis Factor (TNF-α). The results are consistent with limits of detection achieved without the use of the microfluidic device with the exception that coefficients of variability from spot-to-spot are substantially lower than those obtained by performing assays with manual manipulation of assay liquids. The system's capabilities are compatible with the goal of diagnostic instruments for point-of-care settings.

  2. Lamellar liquid crystal polymerization of sodium oleate/oleic acid/octadiene/water system

    Institute of Scientific and Technical Information of China (English)

    GUO, Rong; FU, Qing-Hong

    2000-01-01

    In the lamellar liquid crystallization (LLC) phase of NaOL/OLA/H2O system, the small angle X-ray diffraction measurements show that the oleic acid is solubilized in the oil layer at first and then into the ampliphile layer. The octadiene added is also located partly in the oil layer and partly in the amphiphile layer in the LLC. With the addition of octadiene as cross-linking agent, the LLC phase of NaOL/OLA/H2O system was polymerized under the initiation of AIBN with the protection of pure nitrogen at 60℃. Most of the double bond absorption of the monomers in IR spectra disappeared after polymerization. The polymerization takes place not only in the middle of the amphiphile layer between the double bonds of NaOL or OLA and those of octadiene, but also in the oil layer of LLC between the double bonds of OLA and those of octadiene. Interlayer spacing measurements on the copolymer proved d values decreased by about 1 ~ 2 nm compared with those of the corresponding system before the polymerization,indicating a disruption of the ordered structure by the polymerization. The copolymer still has superior surface activity with the critical micellar concentration (CMC) decreased almost to the half of the value for the system before the polymerization.

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

    Science.gov (United States)

    Nandi, Moumita; Mandal, Prabhat

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

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

    Science.gov (United States)

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

    2014-10-01

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

  5. The development of a 2D ultrasonic array system for the in situ inspection of single crystal turbine blades

    Science.gov (United States)

    Lane, C. J. L.; Dunhill, A. K.; Drinkwater, B. W.; Wilcox, P. D.

    2012-05-01

    Modern jet-engine turbine blades are cast from single crystals of nickel-based superalloys because of the excellent mechanical properties that these materials exhibit at high temperatures. However, the anisotropic behavior of single crystals causes difficulties when using ultrasound to inspect these components for defects that could potentially initiate in-service. This paper describes the development of a 2D ultrasonic array system for the in situ inspection of these components. The problems associated with the inspection of anisotropic single crystal materials such as the directional dependence of the ultrasonic velocity, beam directivities in anisotropic media and the variation in the crystallographic orientation, are all addressed in this paper. In addition, constraints regarding access to the inspection location within the engine are discussed. Finally, the defect detection sensitivity and sizing capability of the developed system is evaluated.

  6. New features of different frequency generating systems due to the use of electrodeless rigidly mounted VBA quartz crystal resonator

    Science.gov (United States)

    Jendly, A.; Graf, E.; Busca, G.; Brownsea, D. A.

    1984-01-01

    The BVA 5 MHz crystal equipped frequency sources exhibit a new blend of performances such as 10 to 11 daily stability, 5x10-13 short term stability (1 to 30 s time intervals) and close to the carrier low phase noise (1 Hz : -120 dBc, 10 Hz : -140 dBc), whereby retaining the customary crystal oscillator benefits of small volume, high reliability and low price, as opposed to more sophisticated frequency generators which would be required to achieve comparable performances. Examples illustrating the impact of the Oscilloquartz BVA oven-controlled crystal oscillator in different frequency generating systems are presented: cesium frequency standards; hydrogen frequency standard; a precision distribution sub-system for satellite ground stations; and high hierarchy exchanges of digital networks, synchronized by the master-slave method are discussed.

  7. Structural, thermal and dielectric properties of cobaltous malonate single crystals grown in limited diffusion media

    Energy Technology Data Exchange (ETDEWEB)

    Lincy, A.; Mahalakshmi, V.; Tinto, A.J.; Thomas, J. [Smart Materials Analytic Research and Technology (SMART), Department of Physics, St. Berchmans College, Changanassery 686101, Kerala (India); Saban, K.V., E-mail: smartlabindia@gmail.co [Smart Materials Analytic Research and Technology (SMART), Department of Physics, St. Berchmans College, Changanassery 686101, Kerala (India)

    2010-11-15

    Well-faceted crystals of cobaltous malonate (C{sub 6} H{sub 12} Co{sub 2} O{sub 12}) have been grown by the controlled diffusion of ionic species in hydrosilica gel. Single crystal X-ray diffraction studies show that the crystal belongs to the monoclinic system with space group C2/m. The unit cell dimensions are a=12.6301(9) A, b=7.3857(9) A, c=7.2945(7) A, {alpha}={gamma}=90{sup o}, {beta}=120.193(9){sup o}. The functional groups, elucidated from the FT-IR spectrum, are in conformity with the information derived from the X-ray diffraction studies. The thermal behaviour of the material has been investigated using TG-DTA in the temperature range 30-1050 deg. C. The optical band gap of the sample is estimated using diffuse reflectance spectroscopy (DRS). The dielectric constant and dielectric loss of the crystal have been studied over wide temperature and frequency ranges. AC conductivity measurements reveal a thermally activated process and the mechanism behind the conduction process has been discussed.

  8. Synthesis, growth, structure and characterization of chalcone crystal: A novel organic NLO material

    Science.gov (United States)

    Agilandeshwari, R.; Meenatchi, V.; Meenakshisundaram, S. P.

    2016-08-01

    Single crystals of a chalcone, (E)-3-(4-bromophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (BHP), were grown by the slow evaporation solution growth technique. The structure is elucidated by single-crystal X-ray diffraction analysis and the crystal belongs to the monoclinic system with noncentrosymmetric space group P21. Optical studies reveal that the absorption is minimum in the visible region and the cut-off wavelength is at ∼468 nm. The band-gap energy was estimated by the application of the Kubelka-Munk algorithm. The powder X-ray diffraction pattern reveals the good crystallinity of the as-grown specimen. The vibrational patterns in FT-IR are used to identify the functional groups and thermal studies indicate the stability of the material. The second harmonic generation efficiency (SHG), as estimated by Kurtz and Perry powder technique, reveals the superior nonlinear optical character of this material. Hirshfeld surface analysis is done to quantify the intermolecular interactions, responsible for developing a nonlinear atmosphere. As-grown crystals were further characterized by SEM, NMR, mass spectrometry and elemental analysis.

  9. Synthesis and Crystal Structure of 5-Diazo-4-ethoxycarbonyl-3-methylthio Pyrazol

    Institute of Scientific and Technical Information of China (English)

    邹小毛; 胡方中; 杨华铮

    2004-01-01

    The crystal of the title compound, 5-diazo-4-ethoxycarbonyl-3-methylthio pyrazole, has been prepared and determined by X-ray diffraction. The crystal belongs to the monoclinic system, space group C2/c with a = 29.174(8), b = 4.7592(12), c = 15.956(4) A, β =117.632(4)°, C7H8N4O2S, Mr = 212.23, V = 1962.7(9) A3, Z = 8, Dx = 1.436 g/cm3, S = 1.000,μ(MoKα) = 0.31 mm-1, T = 298(2) K, F(000) = 880, R = 0.0658 and wR = 0.1741 for 1091independent reflections with I ≥ 2σ(I). The crystal of the title compound is formed with π-πinteractions through electrostatic attractions. Moreover, no HSO4- exists in the crystal structure.Therefore, only diazo pyrazole was obtained rather than either diazonium salt of the corresponding pyrazole or diazoaminopyrazole when 5-amino-4-ethoxycarbonyl-3-methylthio pyrazole was diazotized with sodium nitrite, catalyzed by sulfuric acid at 0 ℃.

  10. Synthesis, crystal and supramolecular structure of rac-N-acetyl-2- thiohydantoin-asparagine

    Directory of Open Access Journals (Sweden)

    Gerzon E. Delgado

    2014-05-01

    Full Text Available The title compound, C7H9N3O3S, also known as rac-N-acetyl-5-propionamide-2-thioxo-imidazolidin-4-one, crystallize in the monoclinic system with space group P21/n (Nº14, Z=4, and unit cell parameters a= 9.338 (7 Å, b= 7.545 (5 Å, c= 13.212 (10 Å, E= 97.10 (2°, V= 932.8 (12 Å3. The acetyl group and the mean plane of the ureido group form an angle of 81.0 (2°. In the supramolecular structure, the molecules are joined by N--H···O hydrogen bonds into cyclic structures with graph-set R2 2(14 and R2 2(16, forming a three-dimensional network.

  11. Crystal Structure Analysis of 6,7-di-O-Methyl-Quercetagetin-3-O--D-Glucopyranoside dihydrate Isolated from Urena sinuata L

    Directory of Open Access Journals (Sweden)

    Adakarleny Sosa

    2011-12-01

    Full Text Available In the present work, the structural analysis of 6,7-di-O-methyl-quercetagetin-3-O-β-D-glucopyranoside dihydrate (I, which was isolated from Urena sinuata L. (dog wart collected in Táchira-Venezuela, was achieved by single crystal X-ray diffraction. Compound I crystallizes in the monoclinic system, space group C2 (No. 5 with unit cell parameters a = 29.289(3 Å; b = 6.6352(7 Å; c = 14.6533(13 Å; β = 113.636(6°; V = 2608.8(5 Å3; Z = 4. The structure refinement converged to R = 0.0421, wR2 = 0.1195, S = 1.02. This is the first X-ray report of this compound obtained from U. sinuata L.

  12. Synthesis, Crystal Structure and Electrochemical Properties of a Cadmium(II) Complex with α-Furoic Acid and 1,10-Phenanthroline

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shao-Hua; LI Chang-Hong; LI Wei; YANG Ying-Qun

    2008-01-01

    A new cadmium complex [Cd(phen)3]·(ClO4)2·(α-FRA)·(H2O)3 was prepared by self-assembly of α-furoic acid, 1,10-phenanthroline (phen), and cadmium perchlorate. It crystal- lizes in the monoclinic system, space group P21/n, with a = 1.28130(15), b = 2.5957(3), c = 1.35449(16) nm, β = 109.395(2)o, V = 4.2492(9) nm3, Dc = 1.491 g/cm3, Z = 4, F(000) = 1926, GOOF = 1.023, the final R = 0.0729 and wR = 0.2086. The crystal structure analysis indicates that the cadmium ion is coordinated with six nitrogen atoms from six 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. The cyclic voltametric behavior of the com- plex was also investigated.

  13. Synthesis of Quinoxaline 1,4-di-N-Oxide Analogues and Crystal Structure of 2-Carbomethoxy-3-hydroxyquinoxaline-di-N-oxide

    Directory of Open Access Journals (Sweden)

    Minmin Zhang

    2011-08-01

    Full Text Available A series of quinoxaline 1,4-di-N-oxide analogues were prepared from benzofurazan N-oxide derivatives and β-diketone ester compounds by the improved Beirut reaction. The structures of the target products were characterized by NMR, MS, IR and elemental analysis measurements, and that of 2-carbomethoxy-3-hydroxyquinoxaline- di-N-oxide was further confirmed by single-crystal X-ray diffraction. Its crystal structure belongs to the monoclinic system, space group C2/c with a = 14.4320 (12 Å, b = 10.7514 (9 Å, c = 13.2728 (11 Å, V = 1958.5 (3 Å 3, Z = 8. The X-ray crystallographic analysis reveals that quinoxaline 1,4-di-N-oxide displays acyloin-endiol tautomerism.

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

    OpenAIRE

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

    2016-01-01

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

  15. Soft x-ray backlighting of cryogenic implosions using a narrowband crystal imaging system (invited).

    Science.gov (United States)

    Stoeckl, C; Bedzyk, M; Brent, G; Epstein, R; Fiksel, G; Guy, D; Goncharov, V N; Hu, S X; Ingraham, S; Jacobs-Perkins, D W; Jungquist, R K; Marshall, F J; Mileham, C; Nilson, P M; Sangster, T C; Shoup, M J; Theobald, W

    2014-11-01

    A high-performance cryogenic DT inertial confinement fusion implosion experiment is an especially challenging backlighting configuration because of the high self-emission of the core at stagnation and the low opacity of the DT shell. High-energy petawatt lasers such as OMEGA EP promise significantly improved backlighting capabilities by generating high x-ray intensities and short emission times. A narrowband x-ray imager with an astigmatism-corrected bent quartz crystal for the Si Heα line at ∼1.86 keV was developed to record backlit images of cryogenic direct-drive implosions. A time-gated recording system minimized the self-emission of the imploding target. A fast target-insertion system capable of moving the backlighter target ∼7 cm in ∼100 ms was developed to avoid interference with the cryogenic shroud system. With backlighter laser energies of ∼1.25 kJ at a 10-ps pulse duration, the radiographic images show a high signal-to-background ratio of >100:1 and a spatial resolution of the order of 10 μm. The backlit images can be used to assess the symmetry of the implosions close to stagnation and the mix of ablator material into the dense shell.

  16. Synthesis and crystal structure investigations of ternary oxides in the Na–Pu–O system

    Energy Technology Data Exchange (ETDEWEB)

    Bykov, D.M., E-mail: d.bykov@tudelft.nl [European Commission, Joint Research Center-Institute for Transuranium Elements, 76125 Karlsruhe (Germany); Raison, P.E., E-mail: philippe.raison@ec.europa.eu [European Commission, Joint Research Center-Institute for Transuranium Elements, 76125 Karlsruhe (Germany); Konings, R.J.M.; Apostolidis, C. [European Commission, Joint Research Center-Institute for Transuranium Elements, 76125 Karlsruhe (Germany); Orlova, M. [University of Innsbruck, Faculty of Geo- and Atmospheric Sciences, A-6020 Innsbruck (Austria)

    2015-02-15

    Highlights: • Crystalline phases in the Na–Pu–O system were obtained by solid state synthesis. • Structures of these phases were studied by the powder X-ray diffraction. • New crystalline forms of Na{sub 5}PuO{sub 5} and Na{sub 3}PuO{sub 4} were observed for the first time. • High-temperature X-ray diffraction studies were performed for Na{sub 4}PuO{sub 5} and Na{sub 5}PuO{sub 6}. • Phase diagram for the ternary Na–Pu–O system was reassessed. - Abstract: Ternary oxides of sodium and plutonium in oxidation states from +4 to +7 have been synthesized by solid state reactions at elevated temperatures in pure argon or oxygen atmospheres. Crystal structures of the obtained phases have been investigated by the Rietveld method using conventional X-ray powder diffraction technique. The structural analogs were found among the families of complex oxides of alkali elements and cerium, ruthenium, antimony, uranium/neptunium and osmium. The new results were compared to earlier literature data for the Na–Pu–O system.

  17. Unconventional High-Performance Laser Protection System Based on Dichroic Dye-Doped Cholesteric Liquid Crystals

    Science.gov (United States)

    Zhang, Wanshu; Zhang, Lanying; Liang, Xiao; Le Zhou; Xiao, Jiumei; Yu, Li; Li, Fasheng; Cao, Hui; Li, Kexuan; Yang, Zhou; Yang, Huai

    2017-01-01

    High-performance and cost-effective laser protection system is of crucial importance for the rapid advance of lasers in military and civilian fields leading to severe damages of human eyes and sensitive optical devices. However, it is crucially hindered by the angle-dependent protective effect and the complex preparation process. Here we demonstrate that angle-independence, good processibility, wavelength tunability, high optical density and good visibility can be effectuated simultaneously, by embedding dichroic anthraquinone dyes in a cholesteric liquid crystal matrix. More significantly, unconventional two-dimensional parabolic protection behavior is reported for the first time that in stark contrast to the existing protection systems, the overall parabolic protection behavior enables protective effect to increase with incident angles, hence providing omnibearing high-performance protection. The protective effect is controllable by dye concentration, LC cell thickness and CLC reflection efficiency, and the system can be made flexible enabling applications in flexible and even wearable protection devices. This research creates a promising avenue for the high-performance and cost-effective laser protection, and may foster the development of optical applications such as solar concentrators, car explosion-proof membrane, smart windows and polarizers. PMID:28230153

  18. Simulated human eye retina adaptive optics imaging system based on a liquid crystal on silicon device

    Institute of Scientific and Technical Information of China (English)

    Jiang Bao-Guang; Cao Zhao-Liang; Mu Quan-Quan; Hu Li-Fa; Li Chao; Xuan Li

    2008-01-01

    In order to obtain a clear image of the retina of model eye, an adaptive optics system used to correct the wave-front error is introduced in this paper. The spatial light modulator that we use here is a liquid crystal on a silicon device instead of a conversional deformable mirror. A paper with carbon granule is used to simulate the retina of human eye. The pupil size of the model eye is adjustable (3-7 mm). A Shack-Hartman wave-front sensor is used to detect the wave-front aberration. With this construction, a value of peak-to-valley is achieved to be 0.086 λ, where A is wavelength.The modulation transfer functions before and after corrections are compared. And the resolution of this system after correction (691p/m) is very close to the diffraction limit resolution. The carbon granule on the white paper which has a size of 4.7μm is seen clearly. The size of the retina cell is between 4 and 10 μm. So this system has an ability to image the human eye's retina.

  19. Advanced Optical Diagnostics for Ice Crystal Cloud Measurements in the NASA Glenn Propulsion Systems Laboratory

    Science.gov (United States)

    Bencic, Timothy J.; Fagan, Amy; Van Zante, Judith F.; Kirkegaard, Jonathan P.; Rohler, David P.; Maniyedath, Arjun; Izen, Steven H.

    2013-01-01

    A light extinction tomography technique has been developed to monitor ice water clouds upstream of a direct connected engine in the Propulsion Systems Laboratory (PSL) at NASA Glenn Research Center (GRC). The system consists of 60 laser diodes with sheet generating optics and 120 detectors mounted around a 36-inch diameter ring. The sources are pulsed sequentially while the detectors acquire line-of-sight extinction data for each laser pulse. Using computed tomography algorithms, the extinction data are analyzed to produce a plot of the relative water content in the measurement plane. To target the low-spatial-frequency nature of ice water clouds, unique tomography algorithms were developed using filtered back-projection methods and direct inversion methods that use Gaussian basis functions. With the availability of a priori knowledge of the mean droplet size and the total water content at some point in the measurement plane, the tomography system can provide near real-time in-situ quantitative full-field total water content data at a measurement plane approximately 5 feet upstream of the engine inlet. Results from ice crystal clouds in the PSL are presented. In addition to the optical tomography technique, laser sheet imaging has also been applied in the PSL to provide planar ice cloud uniformity and relative water content data during facility calibration before the tomography system was available and also as validation data for the tomography system. A comparison between the laser sheet system and light extinction tomography resulting data are also presented. Very good agreement of imaged intensity and water content is demonstrated for both techniques. Also, comparative studies between the two techniques show excellent agreement in calculation of bulk total water content averaged over the center of the pipe.

  20. Growth, spectral, linear and nonlinear optical characteristics of an efficient semiorganic acentric crystal: L-valinium L-valine chloride

    Energy Technology Data Exchange (ETDEWEB)

    Nageshwari, M.; Jayaprakash, P.; Kumari, C. Rathika Thaya [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604407, Tamil Nadu (India); Vinitha, G. [Department of Physics, School of Advanced Sciences, VIT Chennai, 600127 Tamil Nadu (India); Caroline, M. Lydia, E-mail: lydiacaroline2006@yahoo.co.in [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604407, Tamil Nadu (India)

    2017-04-15

    An efficient nonlinear optical semiorganic material L-valinium L-valine chloride (LVVCl) was synthesized and grown-up by means of slow evaporation process. Single crystal XRD evince that LVVCl corresponds to monoclinic system having acentric space group P2{sub 1}. The diverse functional groups existing in LVVCl were discovered with FTIR spectral investigation. The UV-Visible and photoluminescence spectrum discloses the optical and electronic properties respectively for the grown crystal. Several optical properties specifically extinction coefficient, reflectance, linear refractive index, electrical and optical conductivity were also determined. The SEM analysis was also carried out and it portrayed the surface morphology of LVVCl. The calculated value of laser damage threshold was 2.59 GW/cm{sup 2}. The mechanical and dielectric property of LVVCl was investigated employing microhardness and dielectric studies. The second and third order nonlinear optical characteristics of LVVCl was characterized utilizing Kurtz Perry and Z scan technique respectively clearly suggest its suitability in the domain of optics and photonics. - Graphical abstract: Good quality transparent single crystals of L-valinium L-valine chloride single crystal was grown by slow evaporation technique. The grown crystals were analyzed using different instrumentation methods to check its usefulness for the device fabrication. The determination of nonlinear refractive index (n{sub 2}), absorption coefficient (β) and third order nonlinear susceptibility was determined by Z scan technique, highlighted that LVVCl can serve as a promising candidate for opto electronic and nonlinear optical applications.

  1. Synthesis, structural and spectral characterization of a novel NLO crystal N,N‧-diphenylguanidinium picrate: diacetone solvate

    Science.gov (United States)

    Shanmugavadivu, T.; Dhandapani, M.; Naveen, S.; Lokanath, N. K.

    2017-09-01

    An organic NLO active material N,N‧-diphenylguanidinium picrate: diacetone solvate (C13H14N3+. C6H2N3O7-. 2C3H6O) (DPGPD) was synthesized and single crystals were grown by slow evaporation-solution growth technique at room temperature. DPGPD crystallizes in monoclinic crystal system with noncentrosymmetric space group, Cc confirmed by single crystal X-ray diffraction analysis. The presence of various functional groups was identified from FT-IR spectral analysis and the proton transfer during the formation of compound was confirmed by NMR spectroscopic techniques. The thermal stability was investigated by TG/DTA analyses. Optical transmittance was measured by UV-Vis-NIR spectroscopy and band gap energy was calculated. Photoluminescence spectrum was used to explore its applicability towards laser diodes. Dielectric property of the material was ascertained at different temperatures and it is found that the grown crystal has higher dielectric constant in low frequencies. Photoconductivity study revealed that DPGPD exhibits positive photoconductivity. SHG property was found to be 0.6 times higher than that of KDP.

  2. Studies on growth and characterization of a novel nonlinear optical and ferroelectric material - N,N-dimethylurea picrate single crystal

    Science.gov (United States)

    Shanthi, A.; Krishnan, C.; Selvarajan, P.

    2014-05-01

    A novel organic nonlinear optical (NLO) material viz. N,N-dimethylurea picrate (NNDMP) was grown by the slow evaporation technique using N,N-dimethyl formamide as a solvent. The solubility of the grown sample has been estimated for various temperatures. The XRD study reveals that the grown crystal crystallizes in the monoclinic crystal system and the corresponding lattice parameters were determined. The relative second harmonic generation (SHG) efficiency of the NNDMP was found to be 1.045 times that of KDP by Kurtz-Perry powder technique. FTIR and FT-Raman spectral analyses explain the various functional groups present in the sample. The optical spectral analysis of the grown crystal has been performed by UV-vis-NIR spectroscopy and the band gap energy was found out. The thermogravimetric analysis and differential thermal analysis (TG/DTA) reveal that the NNDMP crystal is stable at up to 172 °C. A prominent first-order ferroelectric to paraelectric phase transition at 323 K has been observed and activation energy was determined for the AC conduction process in the sample.

  3. Crystal structure, vibrational, spectral investigation, quantum chemical DFT calculations and thermal behavior of Diethyl [hydroxy (phenyl) methyl] phosphonate

    Science.gov (United States)

    Ouksel, Louiza; Chafaa, Salah; Bourzami, Riadh; Hamdouni, Noudjoud; Sebais, Miloud; Chafai, Nadjib

    2017-09-01

    Single Diethyl [hydroxy (phenyl) methyl] phosphonate (DHPMP) crystal with chemical formula C11H17O4P, was synthesized via the base-catalyzed Pudovik reaction and Lewis acid as catalyst. The results of SXRD analyzes indicate that this compound crystallizes into a mono-clinic system with space group P21/n symmetry and Z = 4. The crystal structure parameters are a = 9.293 Å, b = 8.103 Å, c = 17.542 Å, β = 95.329° and V = 1315.2 Å3, the structure displays one inter-molecular O-H⋯O hydrogen bonding. The UV-Visible absorption spectrum shows that the crystal exhibits a good optical transmission in the visible domain, and strong absorption in middle ultraviolet one. The vibrational frequencies of various functional groups present in DHPMP crystal have been deduced from FT-IR and FT-Raman spectra and then compared with theoretical values performed with DFT (B3LYP) method using 6-31G (p, d) basis sets. Chemical and thermodynamic parameters such as: ionization potential (I), electron affinity (A), hardness (σ), softness (η), electronegativity (χ) and electrophilicity index (ω), are also calculated using the same theoretical method. The thermal decomposition behavior of DHPMP, studied by using thermogravimetric analysis (TDG), shows a thermal stability until to 125 °C.

  4. A Review of Interface Electronic Systems for AT-cut Quartz Crystal Microbalance Applications in Liquids

    Directory of Open Access Journals (Sweden)

    Antonio Arnau

    2008-01-01

    Full Text Available From the first applications of AT-cut quartz crystals as sensors in solutionsmore than 20 years ago, the so-called quartz crystal microbalance (QCM sensor isbecoming into a good alternative analytical method in a great deal of applications such asbiosensors, analysis of biomolecular interactions, study of bacterial adhesion at specificinterfaces, pathogen and microorganism detection, study of polymer film-biomolecule orcell-substrate interactions, immunosensors and an extensive use in fluids and polymercharacterization and electrochemical applications among others. The appropriateevaluation of this analytical method requires recognizing the different steps involved andto be conscious of their importance and limitations. The first step involved in a QCMsystem is the accurate and appropriate characterization of the sensor in relation to thespecific application. The use of the piezoelectric sensor in contact with solutions stronglyaffects its behavior and appropriate electronic interfaces must be used for an adequatesensor characterization. Systems based on different principles and techniques have beenimplemented during the last 25 years. The interface selection for the specific application isimportant and its limitations must be known to be conscious of its suitability, and foravoiding the possible error propagation in the interpretation of results. This article presentsa comprehensive overview of the different techniques used for AT-cut quartz crystalmicrobalance in in-solution applications, which are based on the following principles:network or impedance analyzers, decay methods, oscillators and lock-in techniques. Theelectronic interfaces based on oscillators and phase-locked techniques are treated in detail,with the description of different configurations, since these techniques are the most used inapplications for detection of analytes in solutions, and in those where a fast sensorresponse is necessary.

  5. Hydration of the lower stratosphere by ice crystal geysers over land convective systems

    Directory of Open Access Journals (Sweden)

    S. Khaykin

    2008-08-01

    Full Text Available The possible impact of deep convective overshooting over land has been explored by six simultaneous soundings of water vapour, particles and ozone in the lower stratosphere next to MesoScale Convective Systems (MCSs during the monsoon season over West Africa in Niamey, Niger in August 2006. The water vapour measurements were carried out using a fast response FLASH-B Lyman-alpha hygrometer. The high vertical resolution observations of this instrument show the presence of enhanced water vapour layers between the tropopause at 370 K and the 450 K level. Most of these moist layers are shown connected with overshooting events occurring upwind as identified from satellite IR images, over which the air mass probed by the sondes passed during the three previous days. In the case of a local overshoot identified by echo top turrets up to 18.5 km by the MIT C-band radar also in Niamey, tight coincidence was found between enhanced water vapour, ice crystal and ozone dip layers indicative of fast uplift of tropospheric air across the tropopause. The water vapour mixing ratio in the enriched layers, up to 8 ppmv higher than that of saturation at the tropopause, and the coincidence with the presence of ice crystals strongly suggest hydration of the lower stratosphere by geyser-like injection of ice particles over overshooting turrets. The pile-like structure of the water vapour seen by the high-resolution hygrometer in contrast to smooth profiles reported by a coarse vertical-resolution satellite observation, suggests that the hydration mechanism described above may be responsible for the known summer seasonal increase of moisture in the lower stratosphere. If this interpretation is correct, hydration by ice geysers across the tropopause may be an important contributor to the stratospheric water vapour budget.

  6. Crystal structure, equation of state, and elasticity of hydrous aluminosilicate phase, topaz-OH (Al2SiO4(OH)2) at high pressures

    Science.gov (United States)

    Mookherjee, Mainak; Tsuchiya, Jun; Hariharan, Anant

    2016-02-01

    We examined the equation of state and high-pressure elasticity of the hydrous aluminosilicate mineral topaz-OH (Al2SiO4(OH)2) using first principles simulation. Topaz-OH is a hydrous phase in the Al2O3-SiO2-H2O (ASH) ternary system, which is relevant for the mineral phase relations in the hydrated sedimentary layer of subducting slabs. Based on recent neutron diffraction experiments, it is known that the protons in the topaz-OH exhibit positional disorder with half occupancy over two distinct crystallographic sites. In order to adequately depict the proton environment in the topaz-OH, we examined five crystal structure models with distinct configuration for the protons in topaz-OH. Upon full geometry optimization we find two distinct space group, an orthorhombic Pbnm and a monoclinic P21/c for topaz-OH. The topaz-OH with the monoclinic P21/c space group has a lower energy compared to the orthorhombic Pbmn space group symmetry. The pressure-volume results for the monoclinic topaz-OH is well represented by a third order Birch-Murnaghan formulation, with V0mon = 348.63 (±0.04) Å3, K0mon = 164.7 (±0.04) GPa, and K0mon = 4.24 (±0.05). The pressure-volume results for the orthorhombic topaz-OH is well represented by a third order Birch-Murnaghan formulation, with V0orth = 352.47 (±0.04) Å3, K0orth = 166.4 (±0.06) GPa, and K0orth = 4.03 (±0.04). While the bulk moduli are very similar for both the monoclinic and orthorhombic topaz-OH, the shear elastic constants and the shear moduli are very sensitive to the position of the proton, orientation of the O-H dipole, and the space group symmetry. The S-wave anisotropy for the orthorhombic and monoclinic topaz-OH are also quite distinct. In the hydrated sedimentary layer of subducting slabs, transformation of a mineral assemblage consisting of coesite (SiO2) and diaspore (AlOOH) to topaz-OH (Al2SiO4(OH)2) is likely to be accompanied by an increase in density, compressional velocity, and shear wave velocity. However

  7. Properties of the Sodium Naproxen-Lactose-Tetrahydrate Co-Crystal upon Processing and Storage.

    Science.gov (United States)

    Sovago, Ioana; Wang, Wenbo; Qiu, Danwen; Raijada, Dhara; Rantanen, Jukka; Grohganz, Holger; Rades, Thomas; Bond, Andrew D; Löbmann, Korbinian

    2016-04-19

    Co-crystals and co-amorphous systems are two strategies to improve the physical properties of an active pharmaceutical ingredient and, thus, have recently gained considerable interest both in academia and the pharmaceutical industry. In this study, the behavior of the recently identified sodium naproxen-lactose-tetrahydrate co-crystal and the co-amorphous mixture of sodium, naproxen, and lactose was investigated. The structure of the co-crystal is described using single-crystal X-ray diffraction. The structural analysis revealed a monoclinic lattice, space group P21, with the asymmetric unit containing one molecule of lactose, one of naproxen, sodium, and four water molecules. Upon heating, it was observed that the co-crystal transforms into a co-amorphous system due to the loss of its crystalline bound water. Dehydration and co-amorphization were studied using synchrotron X-ray radiation and thermogravimetric analysis (TGA). Subsequently, different processing techniques (ball milling, spray drying, and dehydration) were used to prepare the co-amorphous mixture of sodium, naproxen, and lactose. X-ray powder diffraction (XRPD) revealed the amorphous nature of the mixtures after preparation. Differential scanning calorimetry (DSC) analysis showed that the blends were single-phase co-amorphous systems as indicated by a single glass transition temperature. The samples were subsequently tested for physical stability under dry (silica gel at 25 and 40 °C) and humid conditions (25 °C/75% RH). The co-amorphous samples stored at 25 °C/75% RH quickly recrystallized into the co-crystalline state. On the other hand, the samples stored under dry conditions remained physically stable after five months of storage, except the ball milled sample stored at 40 °C which showed signs of recrystallization. Under these dry conditions, however, the ball-milled co-amorphous blend crystallized into the individual crystalline components.

  8. Crystal growth and characterization of the CdGaCrSe{sub (4-X)}S{sub (X)} system

    Energy Technology Data Exchange (ETDEWEB)

    Sagredo, V.; Betancourt, L.; Chalbaud, L.M. de [Laboratorio de Magnetismo en Solidos, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)

    2004-10-01

    Single-crystal of the CdGaCrSe{sub (4-X)}S{sub (X)} system (x=0; 1; 2; 3; 4) were grown by the chemical vapour-phase transport technique. The crystals were obtaine by using CdCl{sub 2} as transporting agent for the composition with x=1, and CrCl{sub 3} for those with x=0; 2; 3 and 4. X-ray powder diffraction analysis indicated that some of the samples crystallizes in the tetragonal system with space group I-4 (CdGaCrSe{sub 3}S, x=1; CdGaCrSe{sub 2}S{sub 2}, x=2), or in a cubic system with space group Fd-3m (CdGaCrSeS {sub 3}, x=3; CdGaCrS {sub 4}, x = 4), however the sample of CdGaCrSe {sub 4}(x=0) crystallizes in rhombohedral system. Magnetic measurements show significant changes in the magnetic interactions behaviour probably due to the anionic substitutions. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Influence of spin-orbit interactions on the cubic crystal-field states of the d4 system*

    OpenAIRE

    Radwanski, R. J.; Ropka, Z.

    2002-01-01

    It has been shown that for the highly-correlated d4 electronic system the spin-orbit interactions produce, even in case of the cubic crystal-field interactions, a singlet ground state. Its magnetic moment grows rapidly with the applied magnetic field approaching 4 uB for the Eg state, but only 3 uB for the T2g state. The applicability of the present results to the Mn3+ ion in LaMnO3 is discussed. Keywords: crystal-field, spin-orbit, orbital moment. PACS: 71.70.E, 75.10.D

  10. Defect detection in LiNbO3 crystals using cross Nicol optical system with heating function

    Science.gov (United States)

    Hoshino, Yasushi; Shimizu, Hajime; Arishima, Koichi; Kozawaguchi, Haruki

    2017-07-01

    LiNbO3 crystals are important for applications such as optical devices and surface acoustic wave filters. However, defects in such crystals can negatively affect device characteristics. Consequently, control of defects is important during device manufacturing. In this study, a new defect detection method using a cross Nicol optical system with a heating function and defect image enhancement is proposed. Experiments confirmed that defects detected by this method correspond to those imaged by X-ray topography. It was found that additional defects are formed by charge induced during heating.

  11. Water sorption-induced crystallization, structural relaxations and strength analysis of relaxation times in amorphous lactose/whey protein systems

    OpenAIRE

    Fan, Fanghui; Mou, Tian; Nurhadi, Bambang; Roos, Yrjö H.

    2016-01-01

    Water sorption-induced crystallization, α-relaxations and relaxation times of freeze-dried lactose/whey protein isolate (WPI) systems were studied using dynamic dewpoint isotherms (DDI) method and dielectric analysis (DEA), respectively. The fractional water sorption behavior of lactose/WPI mixtures shown at aw ≤ 0.44 and the critical aw for water sorption-related crystallization (aw(cr)) of lactose were strongly affected by protein content based on DDI data. DEA results showed that the α-rel...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-15

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

  13. Differential optical spectropolarimetric imaging system assisted by liquid crystal devices for skin imaging

    Science.gov (United States)

    Aharon, Ofir; Abdulhalim, Ibrahim; Arnon, Ofer; Rosenberg, Lior; Dyomin, Victor; Silberstein, Eldad

    2011-08-01

    Skin cancer diagnosis depends not only on histopathological examination but also on visual inspection before and after the excision of suspected lesion. Neoplasm is accompanied with changes in birefringence of collagen, pleomorphicity, and hyperchromatic state of epithelial nuclei. These phenomena can be measured by spectral and polarization changes of light backscattered by the examined tissue. A new differential spectropolarimetric system is proposed using liquid crystal devices, one as a tunable filter and the other as a polarization rotator, both operating at wide spectral ranges from the visible to the near-infrared. Since collagen's fibrils texture orientation depends on its location in the skin and since it is not well organized, our system scans the bipolarization states by continuously rotating the linearly polarized light incident on a skin lesion, and collecting differential contrasts between sequenced images when simultaneously averaging the statistical readout of a video camera. This noninvasive method emphasizes areas on skin where the neoplasm, or tumor, minimizes the statistical polarization change of the scattered light from the lesion. The module can be considered as an assistant tool for epiluminescence microscopy. Images of skin tumors were captured in vivo before the patients having their surgery and compared to histopathological results.

  14. Crystal Structure of Hcp from Acinetobacter baumannii: A Component of the Type VI Secretion System.

    Science.gov (United States)

    Ruiz, Federico M; Santillana, Elena; Spínola-Amilibia, Mercedes; Torreira, Eva; Culebras, Esther; Romero, Antonio

    2015-01-01

    The type VI secretion system (T6SS) is a bacterial macromolecular machine widely distributed in Gram-negative bacteria, which transports effector proteins into eukaryotic host cells or other bacteria. Membrane complexes and a central tubular structure, which resembles the tail of contractile bacteriophages, compose the T6SS. One of the proteins forming this tube is the hemolysin co-regulated protein (Hcp), which acts as virulence factor, as transporter of effectors and as a chaperone. In this study, we present the structure of Hcp from Acinetobacter baumannii, together with functional and oligomerization studies. The structure of this protein exhibits a tight β barrel formed by two β sheets and flanked at one side by a short α-helix. Six Hcp molecules associate to form a donut-shaped hexamer, as observed in both the crystal structure and solution. These results emphasize the importance of this oligomerization state in this family of proteins, despite the low similarity of sequence among them. The structure presented in this study is the first one for a protein forming part of a functional T6SS from A. baumannii. These results will help us to understand the mechanism and function of this secretion system in this opportunistic nosocomial pathogen.

  15. Crystal Structure of Hcp from Acinetobacter baumannii: A Component of the Type VI Secretion System.

    Directory of Open Access Journals (Sweden)

    Federico M Ruiz

    Full Text Available The type VI secretion system (T6SS is a bacterial macromolecular machine widely distributed in Gram-negative bacteria, which transports effector proteins into eukaryotic host cells or other bacteria. Membrane complexes and a central tubular structure, which resembles the tail of contractile bacteriophages, compose the T6SS. One of the proteins forming this tube is the hemolysin co-regulated protein (Hcp, which acts as virulence factor, as transporter of effectors and as a chaperone. In this study, we present the structure of Hcp from Acinetobacter baumannii, together with functional and oligomerization studies. The structure of this protein exhibits a tight β barrel formed by two β sheets and flanked at one side by a short α-helix. Six Hcp molecules associate to form a donut-shaped hexamer, as observed in both the crystal structure and solution. These results emphasize the importance of this oligomerization state in this family of proteins, despite the low similarity of sequence among them. The structure presented in this study is the first one for a protein forming part of a functional T6SS from A. baumannii. These results will help us to understand the mechanism and function of this secretion system in this opportunistic nosocomial pathogen.

  16. Optical design of ultrashort throw liquid crystal on silicon projection system

    Science.gov (United States)

    Huang, Jiun-Woei

    2017-05-01

    An ultrashort throw liquid crystal on silicon (LCoS) projector for home cinema, virtual reality, and automobile heads-up display has been designed and fabricated. To achieve the best performance and highest-quality image, this study aimed to design wide-angle projection optics and optimize the illumination for LCoS. Based on the telecentric lens projection system and optimized Koehler illumination, the optical parameters were calculated. The projector's optical system consisted of a conic aspheric mirror and image optics using either symmetric double Gauss or a large-angle eyepiece to achieve a full projection angle larger than 155 deg. By applying Koehler illumination, image resolution was enhanced and the modulation transfer function of the image in high spatial frequency was increased to form a high-quality illuminated image. The partial coherence analysis verified that the design was capable of 2.5 lps/mm within a 2 m×1.5 m projected image. The throw ratio was less than 0.25 in HD format.

  17. Liquid Crystals

    Science.gov (United States)

    1990-01-01

    Thermochromic liquid crystals, or TLCs, are a type of liquid crystals that react to changes in temperature by changing color. The Hallcrest/NASA collaboration involved development of a new way to visualize boundary layer transition in flight and in wind tunnel testing of aircraft wing and body surfaces. TLCs offered a new and potentially better method of visualizing the boundary layer transition in flight. Hallcrest provided a liquid crystal formulation technique that afforded great control over the sensitivity of the liquid crystals to varying conditions. Method is of great use to industry, government and universities for aerodynamic and hydrodynamic testing. Company's principal line is temperature indicating devices for industrial use, such as non-destructive testing and flaw detection in electric/electronic systems, medical application, such as diagnostic systems, for retail sale, such as room, refrigerator, baby bath and aquarium thermometers, and for advertising and promotion specials. Additionally, Hallcrest manufactures TLC mixtures for cosmetic applications, and liquid crystal battery tester for Duracell batteries.

  18. Dynamics and evolution of the plumbing system source of three major pumiceous eruptions in Dominica (Lesser Antilles): crystal system analysis and diffusion modeling on orthopyroxenes.

    Science.gov (United States)

    Solaro, Clara; Balcone-Boissard, Hélène; Boudon, Georges; Martel, Caroline; Morgan, Daniel

    2016-04-01

    Modern volcanology studies have demonstrated that the crystal "cargo" of magmas can be used to unravel the dynamics of magmatic plumbing systems and constrain timescales of magmatic processes. Specifically, several studies focusing on large silicic eruptions (10 to 100 km3 DRE/eruption) have shown that crystal populations may be rapidly re-mobilized over short timescales of decades to centuries prior to eruption, making these systems more dynamic than previously believed. We present a petrological study of three, major, pumiceous, dacitic eruptions produced on Dominica (Lesser Antilles Arc) in the last 50ky: Layou (~50ka), Roseau (~30ka) and Rosalie (~20ka). We combine crystal texture and chemical analyses with modeling of diffusional relaxation of chemical gradients in orthopyroxene crystals. A systems analysis approach is used to decipher remobilization processes of crystals before each eruption, and to map the plumbing system evolution over time. Timescales are calculated by Fe2+-Mg interdiffusion modeling on selected orthopyroxenes, by inter-calibration of high resolution BSE-images and EMPA analysis profiles. Textural analyses show that for each of the three eruptions about 80-85% of orthopyroxenes are unzoned, while about 15-20% exhibit normal, reverse and multiple zoning. Systems analysis of the zoned crystals reveals the presence of four different magmatic environments (ME): En46-51(ME1), En52-53(ME2), En54-58(ME3) and En59-63(ME4). During the eruptive history, the main magmatic environment, represented by the 80% of unzoned orthopyroxenes, moves from ME2 (for Layou and Roseau) to ME3 (for Rosalie), indicating a shift of the system to less-evolved compositions. For all eruptions, a main crystal transfer pathway can be identified between ME2-ME3, describing a progressive sinking of crystals from the main environment En52-53(ME2) to the less-evolved En54-58 (ME3), which receives crystals, and, by the Rosalie eruption, becomes the volumetrically most

  19. Development of Auto-Seeding System Using Image Processing Technology in the Sapphire Crystal Growth Process via the Kyropoulos Method

    Directory of Open Access Journals (Sweden)

    Churl Min Kim

    2017-04-01

    Full Text Available The Kyropoulos (Ky and Czochralski (Cz methods of crystal growth are used for large-diameter single crystals. The seeding process in these methods must induce initial crystallization by initiating contact between the seed crystals and the surface of the melted material. In the Ky and Cz methods, the seeding process lays the foundation for ingot growth during the entire growth process. When any defect occurs in this process, it is likely to spread to the entire ingot. In this paper, a vision system was constructed for auto seeding and for observing the surface of the melt in the Ky method. An algorithm was developed to detect the time when the internal convection of the melt is stabilized by observing the shape of the spoke pattern on the melt material surface. Then, the vision system and algorithm were applied to the growth furnace, and the possibility of process automation was examined for sapphire growth. To confirm that the convection of the melt was stabilized, the position of the island (i.e., the center of a spoke pattern was detected using the vision system and image processing. When the observed coordinates for the center of the island were compared with the coordinates detected from the image processing algorithm, there was an average error of 1.87 mm (based on an image with 1024 × 768 pixels.

  20. Crystal structure, optical and thermal studies of a new organic nonlinear optical material: L-Histidinium maleate 1.5-hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Gonsago, C. Alosious [Department of Physics, A. J. College of Engineering, Chennai 603103 (India); Albert, Helen Merina [Department of Physics, Sathyabama University, Chennai 600119 (India); Karthikeyan, J. [Department of Chemistry, Sathyabama University, Chennai 600119 (India); Sagayaraj, P. [Department of Physics, Loyola College, Chennai 600034 (India); Pragasam, A. Joseph Arul, E-mail: drjosephsu@gmail.com [Department of Physics, Sathyabama University, Chennai 600119 (India)

    2012-07-15

    Highlights: ► L-Histidinium maleate 1.5-hydrate, a new organic crystal has been grown for the first time. ► The crystal structure is reported for the first time (CCDC 845975). ► The crystal belongs to monoclinic system with space group P2{sub 1}, Z = 4, a = 11.4656(7) Å, b = 8.0530(5) Å, c = 14.9705(9) Å and β = 101.657(2)°. ► The optical absorption study substantiates the complete transparency of the crystal. ► Kurtz powder SHG test confirms the nonlinear property of the crystal. -- Abstract: A new organic nonlinear optical material L-histidinium maleate 1.5-hydrate (LHM) with the molecular formula C{sub 10}H{sub 16}N{sub 3}O{sub 7.5} has been successfully synthesized from aqueous solution by slow solvent evaporation method. The structural characterization of the grown crystal was carried out by single crystal X-ray diffraction at 293(2) K. In the crystal, molecules are linked through inter and intramolecular N-H⋯O and O-H⋯O hydrogen bonds, generate edge fused ring motif. The hydrogen bonded motifs are linked to each other to form a three dimensional network. The FT-IR spectroscopy was used to identify the functional groups of the synthesized compound. The optical behavior of the grown crystal was examined by UV–visible spectral analysis, which shows that the optical absorption is almost negligible in the wavelength range 280–1300 nm. The nonlinear optical property was confirmed by the powder technique of Kurtz and Perry. The thermal behavior of the grown crystal was analyzed by thermogravimetric analysis.

  1. Bis(1,3-dimethyl-1H-imidazolium hexafluorosilicate: the second monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Maxim V. Borzov

    2013-08-01

    Full Text Available The title compound, 2C5H9N2+·SiF62−, (I, crystallized as a new polymorph, different from the previously reported one (Ia [Light et al. (2007 private communication (refcode: NIQFAV. CCDC, Cambridge, England]. The symmetry [space groups P21/n for (I and C2/c for(Ia] and crystal packing patterns are markedly different for this pair of polymorphs. In (I, all imidazolium cations in the lattice are nearly parallel to each other, whereas a herringbone arrangement can be found in (Ia. In (I, each SiF62– dianion forms four short C—H...F contacts with adjacent C5H9N2+ cations, resulting in the formation of layers parallel to the ac plane. In (Ia, the C—H...F contacts are generally longer and result in the formation of layers along the bc plane.

  2. A second monoclinic polymorph of ethylenediammonium bis(hydrogen squarate monohydrate

    Directory of Open Access Journals (Sweden)

    Louiza Zenkhri

    2011-05-01

    Full Text Available The title compound, C2H10N22+·2HC4O4−·H2O, a new polymorph of ethylenediammonium bis(hydrogen squarate monohydrate, was synthesized by slow evaporation of an acid solution. The asymetric unit contains two hydrogen squarate anions, two half-molecules of protonated ethylenediamine arranged around a twofold axis and one water molecule. In the crystal, N—H...O and O—H...O hydrogen bonds between the hydrogen squarate anions, protonated N atoms from the amine group and water molecules lead to a three-dimensional framework. In particular, the cohesion between the squarate groups is ensured by very short intermolecular hydrogen bonds bonds. The title compound crystallized together with the previously reported polymorph [Mathew et al. (2002. J. Mol. Struct. 641, 263–279].

  3. From high-temperature orientationally disordered mixed crystals to low-temperature complex formation in the two-component system (CH3)3CBr + Cl3CBr.

    Science.gov (United States)

    Barrio, María; Negrier, Philippe; Tamarit, Josep Ll; Mondieig, Denise

    2011-02-24

    The phase diagram of the two-component systems (CH(3))(3)CBr + Cl(3)CBr has been experimentally determined by means of differential scanning calorimetry and X-ray powder diffraction techniques from the low-temperature ordered phases to the liquid state. Before melting, both components have the same orientationally disordered (OD) face-centered cubic (FCC) and rhombohedral (R) phases, and the two-phase equilibria [FCC + L] and [R + FCC] are accounted for by means of the existence of an isomorphic relationship between the OD phases of pure compounds. The thermodynamic assessment of such equilibria enables us to get the excess properties of the involved OD phases and to rationalize the existence of a maximum and a minimum in the [R + FCC] equilibrium on the basis of the contribution of the entropic term in the excess Gibbs energy function. At low temperature, two complexes, (CH(3))(3)CBr:Cl(3)CBr (1:1) and (CH(3))(3)CBr:2Cl(3)CBr (1:2), appear. The structures of 1:1 and 1:2 complexes have been determined to be monoclinic (P2(1)/n, c, Z = 4) and hexagonal (P6(3), Z = 6). Within both "ordered" structures, the Cl(3)CBr entities of the asymmetric unit were found to be disordered so that sites have fractional occupancies of 0.75 and 0.25 for Cl and Br atoms, in the same way that it occurs for the low-temperature monoclinic (C2/c, Z = 32) phase of Cl(3)CBr. Finally, the existence of complexes is connected with the special intermolecular interactions appearing between a methyl group and a halogen, as previously inferred by Calvet et al. [T. Calvet et al. J. Chem. Phys. 1999, 110, 4841].

  4. Protein crystallization in stirred systems--scale-up via the maximum local energy dissipation.

    Science.gov (United States)

    Smejkal, Benjamin; Helk, Bernhard; Rondeau, Jean-Michel; Anton, Sabine; Wilke, Angelika; Scheyerer, Peter; Fries, Jacqueline; Hekmat, Dariusch; Weuster-Botz, Dirk

    2013-07-01

    Macromolecular bioproducts like therapeutic proteins have usually been crystallized with µL-scale vapor diffusion experiments for structure determination by X-ray diffraction. Little systematic know-how exists for technical-scale protein crystallization in stirred vessels. In this study, the Fab-fragment of the therapeutic antibody Canakinumab was successfully crystallized in a stirred-tank reactor on a 6 mL-scale. A four times faster onset of crystallization of the Fab-fragment was observed compared to the non-agitated 10 µL-scale. Further studies on a liter-scale with lysozyme confirmed this effect. A 10 times faster onset of crystallization was observed in this case at an optimum stirrer speed. Commonly suggested scale-up criteria (i.e., minimum stirrer speed to keep the protein crystals in suspension or constant impeller tip speed) were shown not to be successful. Therefore, the criterion of constant maximum local energy dissipation was applied for scale-up of the stirred crystallization process for the first time. The maximum local energy dissipation was estimated by measuring the drop size distribution of an oil/surfactant/water emulsion in stirred-tank reactors on a 6 mL-, 100 mL-, and 1 L-scale. A comparable crystallization behavior was achieved in all stirred-tank reactors when the maximum local energy dissipation was kept constant for scale-up. A maximum local energy dissipation of 2.2 W kg(-1) was identified to be the optimum for lysozyme crystallization at all scales under study.

  5. Structural and thermoelectric properties of SiGe/Al multilayer systems during metal induced crystallization

    Science.gov (United States)

    Lindorf, M.; Rohrmann, H.; Span, G.; Raoux, S.; Jordan-Sweet, J.; Albrecht, M.

    2016-11-01

    While the process of metal induced crystallization (MIC) is widely used in the fabrication of thin film electronic devices, its application to the field of thermoelectrics is fairly new. Especially, its implementation in the field of the classic thermoelectric material SiGe could lead to a low cost approach by combining the benefits of low thermal budget, self-doping, and thin film and sputter deposition compatibility. In this work, samples consisting of SiGe/Al multilayers deposited on aluminum oxide based substrates have been prepared. Special emphasis was put on the ratio of Al to SiGe and the resulting changes in transport properties during annealing. On one hand, a certain amount of Al is needed to ensure a complete MIC process for the SiGe, but on the other hand, an excess of Al results in a metallic system with low thermoelectric efficiency. In-situ characterization during annealing of the samples was carried out via x-ray diffraction, electrical resistivity, and Seebeck measurements.

  6. Surface induced constant composition crystal growth kinetics studies. The brushite gypsum system

    Science.gov (United States)

    Hina, A.; Nancollas, G. H.; Grynpas, M.

    2001-02-01

    The possible oriented growth of one crystalline phase on the surface of another is especially important in systems containing both phosphate and sulfate salts of calcium. Whether the overgrowth results from a true epitaxial relationship is dependent on factors such as the thermodynamic driving forces and the free energies of the surfaces. Despite the fact that calcium sulfate dihydrate (CSD, gypsum) and calcium hydrogen phosphate dihydrate (DCPD, brushite) show many crystallographic and structural analogies, their surface reactions are quite different. The nucleation and growth of gypsum on brushite surfaces has been investigated in supersaturated solutions of calcium sulfate dihydrate at 25.0°C using the constant composition (CC) method. During the kinetics experiments, the harvested solid phases were examined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDS). Induction periods, τ, preceding the initial formation of gypsum crystals at the brushite surfaces, varied markedly with relative supersaturation, σ. A thin layer wicking method was used to investigate the interfacial free energies of the growing phases, and these data were also calculated from the kinetics results. The interfacial free energy, γ, estimated from initial growth rates was 8.4 mJ m -2, while that calculated from the induction times was 8.9 mJ m -2. These values were in agreement with those determined directly using thin layer wicking.

  7. A single-solenoid pulsed-magnet system for single-crystal scattering studies.

    Science.gov (United States)

    Islam, Zahirul; Capatina, Dana; Ruff, Jacob P C; Das, Ritesh K; Trakhtenberg, Emil; Nojiri, Hiroyuki; Narumi, Yasuo; Welp, Ulrich; Canfield, Paul C

    2012-03-01

    We present a pulsed-magnet system that enables x-ray single-crystal diffraction in addition to powder and spectroscopic studies with the magnetic field applied on or close to the scattering plane. The apparatus consists of a single large-bore solenoid, cooled by liquid nitrogen. A second independent closed-cycle cryostat is used for cooling samples near liquid helium temperatures. Pulsed magnetic fields close to ~30 T with a zero-to-peak-field rise time of ~2.9 ms are generated by discharging a 40 kJ capacitor bank into the magnet coil. The unique characteristic of this instrument is the preservation of maximum scattering angle (~23.6°) on the entrance and exit sides of the magnet bore by virtue of a novel double-funnel insert. This instrument will facilitate x-ray diffraction and spectroscopic studies that are impractical, if not impossible, to perform using split-pair and narrow-opening solenoid magnets. Furthermore, it offers a practical solution for preserving optical access in future higher-field pulsed magnets.

  8. Oral and transdermal drug delivery systems: role of lipid-based lyotropic liquid crystals.

    Science.gov (United States)

    Rajabalaya, Rajan; Musa, Muhammad Nuh; Kifli, Nurolaini; David, Sheba R

    2017-01-01

    Liquid crystal (LC) dosage forms, particularly those using lipid-based lyotropic LCs (LLCs), have generated considerable interest as potential drug delivery systems. LCs have the physical properties of liquids but retain some of the structural characteristics of crystalline solids. They are compatible with hydrophobic and hydrophilic compounds of many different classes and can protect even biologicals and nucleic acids from degradation. This review, focused on research conducted over the past 5 years, discusses the structural evaluation of LCs and their effects in drug formulations. The structural classification of LLCs into lamellar, hexagonal and micellar cubic phases is described. The structures of these phases are influenced by the addition of surfactants, which include a variety of nontoxic, biodegradable lipids; these also enhance drug solubility. LLC structure influences drug localization, particle size and viscosity, which, in turn, determine drug delivery properties. Through several specific examples, we describe the applications of LLCs in oral and topical drug formulations, the latter including transdermal and ocular delivery. In oral LLC formulations, micelle compositions and the resulting LLC structures can determine drug solubilization and stability as well as intestinal transport and absorption. Similarly, in topical LLC formulations, composition can influence whether the drug is retained in the skin or delivered transdermally. Owing to their enhancement of drug stability and promotion of controlled drug delivery, LLCs are becoming increasingly popular in pharmaceutical formulations.

  9. Crystal structure of Legionella pneumophila type IV secretion system effector LegAS4.

    Science.gov (United States)

    Son, Jonghyeon; Jo, Chang Hwa; Murugan, Ravichandran N; Bang, Jeong Kyu; Hwang, Kwang Yeon; Lee, Woo Cheol

    2015-10-02

    The SET domain of LegAS4, a type IV secretion system effector of Legionella pneumophila, is a eukaryotic protein motif involved in histone methylation and epigenetic modulation. The SET domain of LegAS4 is involved in the modification of Lys4 of histone H3 (H3K4) in the nucleolus of the host cell, thereby enhancing heterochromatic rDNA transcription. Moreover, LegAS4 contains an ankyrin repeat domain of unknown function at its C-terminal region. Here, we report the crystal structure of LegAS4 in complex with S-adenosyl-l-methionine (SAM). Our data indicate that the ankyrin repeats interact extensively with the SET domain, especially with the SAM-binding amino acids, through conserved residues. Conserved surface analysis marks Glu159, Glu203, and Glu206 on the SET domain serve as candidate residues involved in interaction with the positively charged histone tail. Conserved surface residues on the ankyrin repeat domain surround a small pocket, which is suspected to serve as a binding site for an unknown ligand.

  10. Oral and transdermal drug delivery systems: role of lipid-based lyotropic liquid crystals

    Science.gov (United States)

    Rajabalaya, Rajan; Musa, Muhammad Nuh; Kifli, Nurolaini; David, Sheba R

    2017-01-01

    Liquid crystal (LC) dosage forms, particularly those using lipid-based lyotropic LCs (LLCs), have generated considerable interest as potential drug delivery systems. LCs have the physical properties of liquids but retain some of the structural characteristics of crystalline solids. They are compatible with hydrophobic and hydrophilic compounds of many different classes and can protect even biologicals and nucleic acids from degradation. This review, focused on research conducted over the past 5 years, discusses the structural evaluation of LCs and their effects in drug formulations. The structural classification of LLCs into lamellar, hexagonal and micellar cubic phases is described. The structures of these phases are influenced by the addition of surfactants, which include a variety of nontoxic, biodegradable lipids; these also enhance drug solubility. LLC structure influences drug localization, particle size and viscosity, which, in turn, determine drug delivery properties. Through several specific examples, we describe the applications of LLCs in oral and topical drug formulations, the latter including transdermal and ocular delivery. In oral LLC formulations, micelle compositions and the resulting LLC structures can determine drug solubilization and stability as well as intestinal transport and absorption. Similarly, in topical LLC formulations, composition can influence whether the drug is retained in the skin or delivered transdermally. Owing to their enhancement of drug stability and promotion of controlled drug delivery, LLCs are becoming increasingly popular in pharmaceutical formulations. PMID:28243062

  11. Excitonic emission of CuInS{sub 2} crystals using confocal microscopy system

    Energy Technology Data Exchange (ETDEWEB)

    Horikawa, Yusuke; Matsuo, Shingo; Wakita, Kazuki [Department of Electrical, Electronics and Computer Engineering, Chiba Institute of Technology, 2-17-1, Tsudanuma, Narashino, Chiba 275-0016 (Japan); Shim, YongGu [Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, Naka-ku, Sakai, Osaka 599-8531 (Japan)

    2013-08-15

    Photoluminescence (PL) spectra in the band-edge region on bulk single-crystals of CuInS{sub 2} grown by the traveling heater method have been investigated using a confocal microscopy system. The observed PL spectra are separated into two Lorentzian peaks which are assigned to be A and B free excitons, by the analysis of the excitation intensity dependence of the emissions. Consequently, we present the behaviour of B free exciton within a wide range of temperatures. The time-resolved emissions of A free exciton have also been examined. The decay of the emissions is analyzed using a double exponential curve. Fast and slow components are attributed to nonradiative relaxation and radiative recombination, respectively. The decay-time constant of the slow component corresponds to the radiative lifetime of A free exciton and is obtained over the wide temperature region until 300 K. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. High contrast switching of transmission due to electrohydrodynamic effect in stacked thin systems of liquid crystals.

    Science.gov (United States)

    Serak, Svetlana V; Hrozhyk, Uladzimir; Hwang, Jeoungyeon; Tabiryan, Nelson V; Steeves, Diane; Kimball, Brian R

    2016-10-20

    We study the opportunity of using electrohydrodynamic instabilities in a nematic liquid crystal mixture with negative dielectric anisotropy for controlling laser beams. Switching between naturally transparent and diffuse light scattering states is achieved by application of low frequency, low amplitude voltages. The specifics of diffuse light scattering state depending on the orientation and thickness of the liquid crystal layer are revealed. The switching occurs on a milliseconds time scale. Combination of thin, flexible liquid crystal cells allows polarization independent, high contrast, fast switching in a broad band of visible wavelengths.

  13. Photonic Crystal Fibres as the Transmission Medium for Future Optical Communication Systems

    DEFF Research Database (Denmark)

    Zsigri, Beata

    2006-01-01

    During this Ph.D. work, air-silica photonic crystal fibres(PCFs) have been investigated for telecommunication applications. PCFs have a complicated cladding structure, where air holes, running along the entire fibre length, ensure light guidance. Photonic crystal fibres can be classified into two......, and exploited for building fully functional, entirely PCF based optical transmission links and networks. The first 40 Gbit/s transmission over 5.6 km PCF with mid-span spectral inversion dispersion compensation realised in a highly nonlinear photonic crystal fibre is demonstrated. The first optical network...

  14. Subwavelength photonic crystal waveguide with trapezoidal shaped dielectric pillars in optical systems

    Science.gov (United States)

    Xu, Xiaochuan; Chen, Ray T.

    2017-02-07

    A method for reducing loss in a subwavelength photonic crystal waveguide bend is disclosed. The method comprising: forming the subwavelength photonic crystal waveguide bend with a series of trapezoidal shaped dielectric pillars centered about a bend radius; wherein each of the trapezoidal shaped dielectric pillars comprise a top width, a bottom width, and a trapezoid height; wherein the length of the bottom width is greater than the length of the top width; and wherein the bottom width is closer to the center of the bend radius of the subwavelength photonic crystal waveguide bend than the top width. Other embodiments are described and claimed.

  15. Subwavelength photonic crystal waveguide with trapezoidal shaped dielectric pillars in optical systems

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xiaochuan; Chen, Ray T.

    2017-02-07

    A method for reducing loss in a subwavelength photonic crystal waveguide bend is disclosed. The method comprising: forming the subwavelength photonic crystal waveguide bend with a series of trapezoidal shaped dielectric pillars centered about a bend radius; wherein each of the trapezoidal shaped dielectric pillars comprise a top width, a bottom width, and a trapezoid height; wherein the length of the bottom width is greater than the length of the top width; and wherein the bottom width is closer to the center of the bend radius of the subwavelength photonic crystal waveguide bend than the top width. Other embodiments are described and claimed.

  16. Automatic Control System for the High Pressure CdTe Crystal Growth Furnace

    OpenAIRE

    Petr Praus; Eduard Belas; Jiri Bok; Roman Fesh; Jan Franc; Pavel Hoschl

    2006-01-01

    CdTe and (CdZn)Te bulk single crystals have been widely used as substrates for MBE and LPE epitaxy of infrared (HgCd)Te as well as gamma- and X-ray detectors. The Cd1-xZnxTe (x = 0.04-0.1) single crystals with diameter up to 100 mm and height at most 40 mm were prepared in our laboratory in a vertical arrangement by gradual cooling of the melt (the Vertical Gradient Freezing method). Achievement of excellent crystal quality required full control of Cd pressure during the growth process and ap...

  17. Collimating Montel mirror as part of a multi-crystal analyzer system for resonant inelastic x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jungho; Shi, Xianbo; Casa, Diego; Qian, Jun; Huang, XianRong; Gog, Thomas

    2016-07-01

    Advances in resonant inelastic x-ray scattering (RIXS) have come in lockstep with improvements in energy resolution. Currently, the best energy resolution at the Ir-L3 edge stands at ~25 meV, which is achieved using a diced Si spherical analyzer. An angular dispersion analyzer system using multiple flat crystals provides a promising way to achieve higher energy resolution, namely 10 meV or better, thereby overcoming the intrinsic energy resolution limit of diced spherical crystal analyzers. One essential component for a practical use of such multi-crystal systems is the xray collimation optics. In this work, a laterally graded, parabolic collimation Montel mirror was designed with larger than 10 mrad acceptance, collimating the x-ray beam to smaller than 100 μrad divergence at the Ir-L3 absorption energy. The x-ray collimation performance was investigated at beamline 27-ID of the Advanced Photon Source, using incident photons from a Diamond (111) monochromator illuminating a controlled 40 mrad divergence scattering source of 5 μm diameter. A flat Si (111) crystal served as the analyzer. It is found from experimental data and ray-tracing simulations, combined with metrology results, that the manufactured Montel mirror satisfies the required specifications of angular acceptance and collimated x-ray divergence for a high resolution RIXS spectrometer at the Ir-L3 edge.

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

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

    Indian Academy of Sciences (India)

    Anil Kumar; Sarvajit Singh; Jagdish Singh

    2002-06-01

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

  1. Insights into the Mount St. Helens Magma Plumbing System from Coarse-grained, Crystal-rich Enclaves

    Science.gov (United States)

    Wanke, M.; Bachmann, O.; Ellis, B. S.; Guillong, M.; Clynne, M. A.; Pallister, J. S.

    2016-12-01

    Co-magmatic plutonic enclaves provide information about the conditions of magmatic storage and magmatic processes. The deposits of Mount St. Helens contain a variety of coarse-grained, crystal-rich enclaves, dominantly derived from the Tertiary basement. However, zircons in two enclaves returned ages of 5-108 ka (n=29) and 45-486 ka (n=16), overlapping with zircon ages from the volcanics. From textures and mineralogy, we define five enclave types, interpreted as crystal mush from the current magmatic system: hbl-gabbros with ad-cumulate structure (type 1), dioritic meso-cumulates with partly decomposed minerals (type 2), and dioritic rocks enriched in incompatible elements (type 3). All three occur in Pine Creek dacite domes ( 2900 BP), and comprise amphibole, plagioclase, orthopyroxene and oxides (±apatite and zircon) with variable amounts of residual melt. A heterad-cumulate (type 4) from 1980 dacite consists of olivine, plagioclase, ortho- and clinopyroxene (±oxides and apatite) with poikilitic overgrowth of amphibole. Inclusions of pyroxene-plagioclase-oxide-bearing crystal aggregates (type 5) are found in Late Pine Creek andesites ( 2600 BP). Compositional similarity between amphiboles in type 1 and 2 cumulates and those from their dacitic host rock suggests these cumulates co-erupted with their extracted melt. Modelled trace element compositions of coexisting liquids indicate that the high-Al amphibole cores (up to 14.5 wt.% Al2O3) crystallized from andesitic melts that are parental to the dacites. In contrast, andesites erupted during the same eruptive period lack amphibole suggesting drier/shallower crystallization resulting in the predominant fractionation of pyroxene seen in type 5 inclusions. Different cumulates represent residues from basaltic andesitic to dacitic melts. Mid to upper crustal pressures determined via barometry are consistent with crystallization within the bottle-shaped magma reservoir ( 7-20 km) imaged during the recent activity.

  2. Domino Knoevenagel/Michael synthesis of 2,2'-arylmethylenebis(3- hydroxy-5,5-dimethyl-2-cyclohexen-1-one) derivatives catalyzed by silica-diphenic acid and their single crystal X-ray analysis

    Indian Academy of Sciences (India)

    RUPALI VAID; MONIKA GUPTA; RAJNI KANT; VIVEK K GUPTA

    2016-06-01

    An efficient and eco-friendly procedure has been developed for the synthesis of various 2,2'- arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives which were isolated and characterizedby melting point, IR,$^{ 1}H-NMR$,$^{ 13}$C-NMR and mass spectrometric techniques. Out of the fourteencompounds synthesized, four compounds yielded crystals suitable for single crystal X-ray analysis whichshowed that 2,2'-phenylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) crystallizes in the tetragonalsystem with space group I41/a, 2,2’-(3-nitrophenyl)methylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) crystallizes in the monoclinic system with space group P21/n, 2,2’-(4-nitrophenyl)methylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) crystallizes in the orthorhombic system with space group Pca21and 2,2’-(4-chlorophenyl)methylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) crystallizes in the monoclinicspace group P21/c.

  3. Crystal Structure of 2-Ethylimidazole-1-sulfonyl Azide: A New Azidation Reagent

    Directory of Open Access Journals (Sweden)

    Herwig Schottenberger

    2012-03-01

    Full Text Available Crystalline 2-ethylimidazole-1-sulfonyl azide was designed as a convenient reagent with improved thermal stability for electrophilic azidation of carbanions. The compound crystallized in the monoclinic space group P21/c. The molecules are arranged into chains by short C–H...O contacts along a two-fold screw axis. The quaternary 1-azidosulfonyl-2-ethyl-3-methylimidazolium tetrafluoroborate crystallized in Fdd2 with two independent ion pairs which engage in C–H...F interactions.

  4. System and method for forming synthetic protein crystals to determine the conformational structure by crystallography

    Science.gov (United States)

    Craig, George D.; Glass, Robert; Rupp, Bernhard

    1997-01-01

    A method for forming synthetic crystals of proteins in a carrier fluid by use of the dipole moments of protein macromolecules that self-align in the Helmholtz layer adjacent to an electrode. The voltage gradients of such layers easily exceed 10.sup.6 V/m. The synthetic protein crystals are subjected to x-ray crystallography to determine the conformational structure of the protein involved.

  5. Disentangling the secondary relaxations in the orientationally disordered mixed crystals: cycloheptanol + cyclooctanol two-component system

    OpenAIRE

    2010-01-01

    The dynamics of the pure compounds and mixed crystals formed between cycloheptanol (cC7-ol) and cyclooctanol (cC8-ol) has been studied by means of broadband dielectric spectroscopy at temperatures near and above the orientational glass transition temperature. Both compounds are known to display at least one orientationally disordered (OD) phase of simple cubic symmetry, and within this phase, a continuous formation of mixed crystals was demonstrated in the past (Rute, M. A. et al. J. Phys. Ch...

  6. Crystal Structures and Antimicrobial Activity of Two Phosphorus Compounds

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    One phosphorus heterocycle compound 1, C13H13N2OPS, was synthesized by the reaction of Lawesson's reagent (LR) with o-phenylene diamine. The crystal belongs to the orthorhombic system, space group P212121 with a = 5.5274(11), b = 8.1603(16), c = 28.830(6) (A), V =1300.4(4) (A)3, Z = 4, Mr= 276.28, Dc = 1.411 g/cm3, F(000) = 576,μ = 0.360 mm-1, R = 0.0259 and wR = 0.0652 for 1414 observed reflections with I > 2σ(I). While compound 2, C14H17N2O2PS, was obtained as a ring-cleavage product of compound 1. This crystal is of monoclinic system, space group P21/c with a = 9.5619(19), b = 21.879(4), c = 7.3618(15) (A), β= 103.03(3)°, V=1500.4(5) (A)3,Z = 4, Mr= 308.33, Dc = 1.365 g/cm3, F(000) = 648, μ = 0.325 mm-1, R = 0.0383 and wR =0.0742for 2283 observed reflections with I > 2σ(I). Phosphorus atom in each compound bonds with sulfur and carbon atoms using sp3 hybrid orbitals, and crystals of these two compounds are formed and stabilized by intermolecular hydrogen bonds and Van der Waals' forces. The special structure of compound 1 leads to its good antimicrobial activity against staphylococcus aureus.

  7. Collimating Montel mirror as part of a multi-crystal analyzer system for resonant inelastic X-ray scattering.

    Science.gov (United States)

    Kim, Jungho; Shi, Xianbo; Casa, Diego; Qian, Jun; Huang, XianRong; Gog, Thomas

    2016-07-01

    Advances in resonant inelastic X-ray scattering (RIXS) have come in lockstep with improvements in energy resolution. Currently, the best energy resolution at the Ir L3-edge stands at ∼25 meV, which is achieved using a diced Si(844) spherical crystal analyzer. However, spherical analyzers are limited by their intrinsic reflection width. A novel analyzer system using multiple flat crystals provides a promising way to overcome this limitation. For the present design, an energy resolution at or below 10 meV was selected. Recognizing that the angular acceptance of flat crystals is severely limited, a collimating element is essential to achieve the necessary solid-angle acceptance. For this purpose, a laterally graded, parabolic, multilayer Montel mirror was designed for use at the Ir L3-absorption edge. It provides an acceptance larger than 10 mrad, collimating the reflected X-ray beam to smaller than 100 µrad, in both vertical and horizontal directions. The performance of this mirror was studied at beamline 27-ID at the Advanced Photon Source. X-rays from a diamond (111) monochromator illuminated a scattering source of diameter 5 µm, generating an incident beam on the mirror with a well determined divergence of 40 mrad. A flat Si(111) crystal after the mirror served as the divergence analyzer. From X-ray measurements, ray-tracing simulations and optical metrology results, it was established that the Montel mirror satisfied the specifications of angular acceptance and collimation quality necessary for a high-resolution RIXS multi-crystal analyzer system.

  8. Prevalence for the universal distribution of relaxation times near the glass transitions in experimental model systems: Rodlike liquid crystals and orientationally disordered crystals

    OpenAIRE

    Martínez García, Julio Cesar; Tamarit Mur, José Luis; Rzosca, S. J.

    2011-01-01

    Recently, Nielsen et al. [J. Chem. Phys. 130, 154508 (2009); Philos. Mag. 88, 4101 (2008)] demonstrated a universal pattern for the high frequency wing of the loss curve for primary relaxation time on approaching the glass transition for organic liquids. In this contribution it is presented that a similar universality occurs for glass-forming liquid crystals and orientationally disordered crystals (plastic crystals). Empirical correlations of the found behavior are also briefly di...

  9. Prevalence for the universal distribution of relaxation times near the glass transitions in experimental model systems: Rodlike liquid crystals and orientationally disordered crystals

    OpenAIRE

    2011-01-01

    Recently, Nielsen et al. [J. Chem. Phys. 130, 154508 (2009); Philos. Mag. 88, 4101 (2008)] demonstrated a universal pattern for the high frequency wing of the loss curve for primary relaxation time on approaching the glass transition for organic liquids. In this contribution it is presented that a similar universality occurs for glass-forming liquid crystals and orientationally disordered crystals (plastic crystals). Empirical correlations of the found behavior are also briefly di...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-02-25

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

  12. Design Optimization of a Small-animal SPECT System Using LGSO Continuous Crystal and a Micro Parallel-hole Collimator

    CERN Document Server

    Kim, Joong Hyun; Kim, Soo Mee; Hong, Seong Jong; Lee, Jae Sung

    2015-01-01

    The aim of this study was to optimize the design of a monolithic LGSO scintillation crystal and micro parallel-hole collimator for the development of a small-animal single photon emission computed tomography (SPECT) system with compact size, low-cost and reasonable performance through Monte Carlo simulation. L0.9GSO crystals with surface area of 50 mm X 50 mm were investigated for the design optimization. The intrinsic detection efficiency, intrinsic spatial resolution, and intrinsic energy resolution of crystals were estimated for different crystal thicknesses and photon energies (using I-125 and Tc-99m sources). Two kinds of surface treatments (providing polished and rough surfaces) were compared by optical photon simulation. The standard deviation of the angle between a micro-facet and the mean surface was set to 0.1 and 6.0 for polished and rough surfaces, respectively. For comparison, the intrinsic performance of NaI(Tl) was also investigated. A multi-photomultiplier tube was designed with 16 X 16 anode ...

  13. A further study of crystallization of lithium perchlorate from LiClO₄-NaCl-H₂O system

    Directory of Open Access Journals (Sweden)

    Goran Tadic

    2010-11-01

    Full Text Available The aim of this paper is to define feasible process pathways of fractional crystallization of NaCl and LiClO₄·3H₂0 from LiClO₄-NaCl-H₂O system using the information on the equilibrium of the LiClO₄-NaCl-H₂O system at different temperatures, as well as the information on the composition of the starting solution obtained by electrolysis and double exchange with LiCl. The paper also synthesizes a feasible process structure that can be applied for the process of fractional crystallization, and gives a simulation of the process by calculating the material balance of the process. The parameters of relevant process paths that were obtained prove that the process presented in this paper is feasible in practice and applicable in industry.

  14. Dielectric response of pure and doped-GaSe crystals studied by an indigenously developed broadband THz-TDS system

    Science.gov (United States)

    Das, Amit C.; Bhattacharya, S.; Mandal, K. C.; Mondal, S.; Jewariya, M.; Ozaki, T.; Bhaktha, S. N. B.; Datta, P. K.

    2016-04-01

    Publisher's Note: This paper, originally published on 12 July 2016, was replaced with a corrected/revised version on 26 July 2016. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance. We have developed a terahertz time domain spectroscopy system (THz TDS). For THz generation, optical rectification process and for detection, electro-optic sampling processes are used. Identical cut ZnTe crystals are used for both generation and detection of THz radiation.This spectroscopy system can be used for the noninvasive and contactless electrical and optical characterizations of various samples. In this work spectroscopic measurements of pure, Chromium and Indium doped GaSe crystals within 0.4 THz to 3 THz range are taken by the developed set-up to study the dielectric response of the samples.

  15. Synthesis and Crystal Structure of N3-(Dimethylpyrimidine)-N4-(tri-O-acetyl-xylosyl)Thiourea

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Ming; JIA Gao-Feng; ZHAO Wei-Guo; PANG Yan-Jun; QI Jin-Liang; WANG Xiu-Qiang; YANG Yong-Hua; ZHANG Suo-Qin; ZHU Ling; WANG Si-Si; LI Xin-Yuan; FANG Qian-Rong; YIN Ya-Le; LIU Hao-Yan; LI Yao-Xian

    2008-01-01

    The crystal structure of the title compound(C18H24N4O7S,Mr=440.47)was prepared by the condensation of 2,3,4-tri-O-acetyl-β-D-xylopyranosyl isothiocyanate with 4,6-dime-thylpyrimidin-2-amine and structurally determined by single-crystal X-ray diffraction.The crystal belongs to the monoclinic system,space group P21 with a=7.5500(17),b=10.498(2),c=14.208(3)(A),β=99.929(4)°,V=1109.2(4)(A)3,Z=2,Dc=1.319 g/cm3,μ=0.191,F(000)=464,Flack=0.00(15),R=0.0684 and wR=0.1103.In the crystal structure,the xylose ring adopts a4C1 chair conformation.Due to the hydrogen bonding interaction between N(4)-H(4A)and N(1),the pyrimidine ring is well positioned.

  16. Aging-driven decomposition in zolpidem hemitartrate hemihydrate and the single-crystal structure of its decomposition products.

    Science.gov (United States)

    Vega, Daniel R; Baggio, Ricardo; Roca, Mariana; Tombari, Dora

    2011-04-01

    The "aging-driven" decomposition of zolpidem hemitartrate hemihydrate (form A) has been followed by X-ray powder diffraction (XRPD), and the crystal and molecular structures of the decomposition products studied by single-crystal methods. The process is very similar to the "thermally driven" one, recently described in the literature for form E (Halasz and Dinnebier. 2010. J Pharm Sci 99(2): 871-874), resulting in a two-phase system: the neutral free base (common to both decomposition processes) and, in the present case, a novel zolpidem tartrate monohydrate, unique to the "aging-driven" decomposition. Our room-temperature single-crystal analysis gives for the free base comparable results as the high-temperature XRPD ones already reported by Halasz and Dinnebier: orthorhombic, Pcba, a = 9.6360(10) Å, b = 18.2690(5) Å, c = 18.4980(11) Å, and V = 3256.4(4) Å(3) . The unreported zolpidem tartrate monohydrate instead crystallizes in monoclinic P21 , which, for comparison purposes, we treated in the nonstandard setting P1121 with a = 20.7582(9) Å, b = 15.2331(5) Å, c = 7.2420(2) Å, γ = 90.826(2)°, and V = 2289.73(14) Å(3) . The structure presents two complete moieties in the asymmetric unit (z = 4, z' = 2). The different phases obtained in both decompositions are readily explained, considering the diverse genesis of both processes.

  17. Hollow-core photonic crystal fiber based multifunctional optical system for trapping, position sensing, and detection of fluorescent particles.

    Science.gov (United States)

    Shinoj, V K; Murukeshan, V M

    2012-05-15

    We demonstrate a novel multifunctional optical system that is capable of trapping, imaging, position sensing, and fluorescence detection of micrometer-sized fluorescent test particles using hollow-core photonic crystal fiber (HC-PCF). This multifunctional optical system for trapping, position sensing, and fluorescent detection is designed such that a near-IR laser light is used to create an optical trap across a liquid-filled HC-PCF, and a 473 nm laser is employed as a source for fluorescence excitation. This proposed system and the obtained results are expected to significantly enable an efficient integrated trapping platform employing HC-PCF for diagnostic biomedical applications.

  18. Synthesis and Crystal Structure of the First Hybrid Manganese Phosphate with 1-D Framework of Dinuclear Structure

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel hybrid manganese phosphate, [(bipy)Mn(H2PO4)2] (bipy = 2,2'-bipyridine) 1, was synthesized, and its structure is characteristic of 1-D framework involving a dinuclear structure made up of edge-sharing Mn(II) octahedra. 1 crystallizes in the monoclinic system, space group C2/c with a = 12.230(2), b = 17.800(4), c = 13.530(3)(A), β = 105.00(3)o, V = 2845.0(10)(A)3, Z = 8. Dc = 1.892 g/cm3, F(000) = 1640, Mr = 405.10, μ(MoKα) = 1.198 mm-1, R = 0.0306 and wR = 0.0657 for 2093 observed reflections (I > 2σ(I)).

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    马淑兰; 朱文祥; 董淑静; 郭倩玲; 佘远斌

    2003-01-01

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

  1. Crystal Structure and Luminescence Property of Lanthanide Complexes with 2-Fluorobenzoic Acid and 2,2'-Bipyridine

    Institute of Scientific and Technical Information of China (English)

    Li Xia; Zhang Zhuoyong; Song Haibin

    2005-01-01

    The two compounds of [Ln(2-FBA)3·2,2'-bpy]2 (2-FBA=2-fluorobenzoato, 2,2'-bpy=2,2'-bipyridine, Ln=Eu(1), Dy(2)) were synthesized and their structures were determined by X-ray diffraction method. Crystallized complexes 1 and 2 are isomorphous, monoclinic system with P21/n space group. The two complexes are binuclear molecule with an inversion center. The two lanthanide ions are linked by four bridged 2-FBA ligands and each lanthanide ion is further bonded to one chelated bidentate 2-FBA ligand and one 2,2'-bipyridine molecule. The coordination number of metal ion is eight. The europium complex exhibits strong red fluorescence. 5D0→7Fj (j= 1~4) transition emission of Eu3+ ion was observed.

  2. A new series of lanthanide coordination polymers with 2,2‧-bipyridine and glutaric acid: Synthesis, crystal structures and properties of [Ln(bipy)(glut)(NO3)

    Science.gov (United States)

    Wang, Chunguang; Xing, Yongheng; Li, Zhangpeng; Li, Jing; Zeng, Xiaoqing; Ge, Maofa; Niu, Shuyun

    2009-08-01

    A series of new lanthanide coordination polymers, with the formula [Ln(bipy)(glut)(NO 3)] (Ln = Eu ( 1), Tb ( 2), Sm ( 3), Pr ( 4); bipy = 2,2'-bipyridine; H 2glut = glutaric acid), have been synthesized under the hydrothermal condition and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, and single-crystal X-ray diffraction. Structural analyses reveal that all four complexes are isostructural and crystallized in monoclinic system, P2 1/ c space group. For these complexes, the Ln 3+ are all linked through glutaric acid ligands to form 1D chain-like polymeric structures, and bipy and NO3- are coordinated on two sides of the chains. The thermogravimetric analysis of 1 and photoluminescent properties of 1 and 2 are discussed in detail.

  3. Crystal structure of the ternary semiconductor compound thallium gallium sulfide, TlGaS{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)]. E-mail: gerzon@ula.ve; Mora, A.J. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Perez, F.V. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Departamento de Fisica, Facultad de Ciencias, Universidad del Zulia, Zulia (Venezuela); Gonzalez, J. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)

    2007-04-01

    Thallium gallium sulfide, TlGaS{sub 2}, a semiconductor compound, was prepared by solid-state reaction technique. Its crystal structure was determined by single-crystal X-ray diffraction. This material crystallizes in the monoclinic system with space group C2/c (No. 15), Z=16 and unit cell parameters a=10.2990(8)A, b=10.2840(8)A, c=15.1750(18)A, {beta}=99.603(4){sup o}. The structural refinement converged to R(F)=0.0999, R(F{sup 2})=0.0764 and S=1.067. The structure consists of a three-dimensional arrangement of distorted TlS{sub 8} and GaS{sub 4} polyhedrons. Four GaS{sub 4} tetrahedra form adamantine-like units of the type Ga{sub 4}S{sub 10}, which in turn connect through the corners forming layers that run along the [100] direction.

  4. Crystal,Thermal Behavior and Electrochemical Property of Dichloro-tri(N-ethylimidazole)-cadmium

    Institute of Scientific and Technical Information of China (English)

    LIU Guang-Ye; LIU Fa-Qian; CHEN Hong-Na; LI Shao-Xiang; LI Rong-Xun; HUANG Su-Yi

    2008-01-01

    The title compound Cd(Eim)3CL2(Eim=N-ethylimidazole)I has been synthesized and structurally characterized by single-crystal X-ray diffraction.The compound crystallizes in the monoclinic system,space group P21 with a=8.0460(16),b=29.186(6),c=8.8960(18)(A),β=100.06(3)°,C15H24CdCl2N6,Mr=471.71,V=2056.9(7)(A)3,Z=4,Dc=1.523g/cm3,μ=1.330mm-1,F(000)=952,the final R=0.0455 and wR=0.0723.The title compound crystallizes with two molecules in the asymmetric unit.Each CdⅡion is coordinated by three Eim ligands and two Cl anions in a trigonal bipyramidal geometry in two molecules.The weak intermolecular C-H…Cl hydrogen bonds link the molecules into two independent hydrogen-bonded chains running along the c axis.According to the cyclic voltammogram measurement in H2O,the electrode reaction should be a quasi-reversible process.

  5. Growth, crystal structure and thermal properties of calcium bis(malate) dihydrate

    Energy Technology Data Exchange (ETDEWEB)

    Jini, T. [Department of Physics, St. Berchmans College, Changanassery 686 101, Kerala (India); Saban, K.V. [Department of Physics, St. Berchmans College, Changanassery 686 101, Kerala (India); Varghese, G. [Department of Physics, St. Berchmans College, Changanassery 686 101, Kerala (India); Naveen, S. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India); Sridhar, M.A. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India)]. E-mail: mas@physics.uni-mysore.ac.in; Prasad, J.S. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India)

    2007-05-16

    A new coordination compound crystal of calcium with malic acid is prepared by gel aided solution growth. Single crystal X-ray diffraction studies revealed that the structural formula of the compound is Ca(C{sub 4}H{sub 4}O{sub 5}){sub 2}.2H{sub 2}O. It crystallizes in the monoclinic system with space group C2/c, Z = 4, with unit cell parameters a = 15.916(9) A, b = 5.886(3) A, c = 13.046(6) A and {beta} = 90.678(4){sup o}. Data were collected by oscillation method and full-matrix least squares refinement was applied to the model converging to final R indices R {sub 1} = 0.0416 and {omega}R {sub 2} = 0.1255. Compound forms a layer-type polymeric structure, stabilized by intermolecular hydrogen bonding. Ca{sup 2+} is eight-fold coordinated. Malate is coordinated to Ca{sup 2+} tridendate-bidendate through two carboxylates and monodendate through oxygen atom of the hydroxyl group. Thermal behavior investigated using TG and DTA studies is in conformity with the proposed structure.

  6. Synthesis and Crystal Structure of 4-Salicylimine-3, 5-bis(2-hydroxyphenyl)-1, 2, 4-triazole

    Institute of Scientific and Technical Information of China (English)

    吉保明; 杜明霞; 朱玉; 王洋

    2002-01-01

    The title compound, 4-salicylimine-3, 5-bis(2-hydroxyphenyl)-1, 2, 4-triazole, was obtained by the condensation reaction of 4-amino-3, 5-bis(2-hydroxyphenyl)-1, 2, 4-triazole with salicylaldehyde in methanol. The crystal structure (C21H16N4O3, Mr = 372.38) belongs to monoclinic system, space group P21/n with a = 10.507(2), b = 16.878(3), c = 11.199(2) ?, β = 110.86(3)(, V = 1855.9(6) ?3, Z = 4, Dc = 1.333 g/cm3, F(000) = 776, μ(MoKα) = 0.092 mm-1, R = 0.0552 and wR = 0.1095 for 1920 reflections ( I > 2.0σ(I) ). The analytical results of crystal structure show that there are two different non-covalent interactions in the compound. One is hydrogen bond, and the other (-( stacking interaction. These two types of non-covalent interactions play an important role in the packing of crystal.

  7. Synthesis and Crystal Structure of Na2TiO3

    Institute of Scientific and Technical Information of China (English)

    MAO Shao-Yu; REN Xiao-Xia; ZHOU Zhao-Hui

    2008-01-01

    The crystal structure of a sodium titanium oxide Na2TiO3 obtained by high temperature solid state reaction method was determined from single-crystal X-ray diffraction study. The compound crystallizes in the monoclinic system, space group C2/c, Mr = 141.88, a = 9.885(1), b = 6.4133(8), c = 5.5048(7) (A), β = 115.50(3)°, V = 314.99(7) (A)3, Z = 4, Dc = 2.992 g/cm3, λ = 0.71073 (A), μ = 27.80 cm-1, F(000) = 272, T = 295 K, R = 0.0189 and wR = 0.0512 for 30 variables and 370 contributing unique reflections. The three-dimensional structure in Na2TiO3 is constructed by the TiO(1)4O(2) and NaO(1)3O(2)2 groups. The titanium atoms are grouped in the form of trigonal bipyramid and arranged along the c axis by sharing the edges. The structure is compared with other structures of related A2BO3 compounds.

  8. Spectral properties of Tm,Ho:LiYF4 laser crystal

    Institute of Scientific and Technical Information of China (English)

    LI Chun; ZHANG Ying; ZHANG Xuejian; ZENG Fanming; Mauro Tonelli; LIU Jinghe

    2011-01-01

    The LiYF4 single crystal codoped with thulium and holmium ions was successfully grown by the Cz method. The optimal technical parameters obtained were as follows: the pulling rate was 0.16 mm/h; the rotation speed was 3 rpm; the cooling rate was 15 ℃/h. The result of XRD curve showed that as-grown Tm,Ho:LiYF4 laser crystal belonged to the monoclinic system with scheelite-type structure and space group 141/a. The cell parameters calculated were: a=0.52160 nm, c=1.09841 nm and Z=4. Absorption and fluorescence spectra of Tm,Ho:LiYF4 laser crystal at room temperature were measured and analysed. The absorption cross section, FWHM and absorption coefficient at 779.3 nm calculated were 7.44× 10 21 cm2, 8.7 nm and 2.23 cm-1, respectively. An intensive fluorescence emission peak appeared near 2045 nm. The emission cross section and fluorescence lifetime were 0.87× 10-20 cm2 and 10.8 ms, respectively. The ratio of Tm-Ho transfer to its back-transfer process was 10.6.

  9. Structure Prediction Based on Hydrophobic to Hydrophilic Volume Ratios in Small Molecule Amphiphilic Organic Crystals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The structure type for the crystal of 4,4'-bis-(2-hydroxy-ethoxyl)-biphenyl 1 has been predicted by using the previously developed interfacial model for small organic molecules. Based on the calculated hydrophobic to hydrophilic volume of 1, this model predicts the crystal structure to be of lamellar or bicontinuous type, which has been confirmed by the X-ray single-crystal structure analysis (C20H26O6, monoclinic, P21/c, a = 16.084(1), b = 6.0103(4), c = 9.6410(7)(A), β = 103.014(2)°, V = 908.1(1)(A)3, Z = 2, Dc = 1.325 g/cm3, F(000)=388, μ = 0.097 mm-1, MoKα radiation, λ = 0.71073 (A), R = 0.0382 and wR = 0.0882 with I > 2σ(I) for 7121 reflections collected, 1852 unique reflections and 170 parameters). As predicted, the hydrophobic and hydrophilic portions of 1 form in the lamellae. The same interfacial model is applied to other amphilphilic small molecule organic systems for structural type prediction.

  10. Synthesis and Crystal Structure of 2,3-Dihydroxymethyl-N-cyclohexylaziridine

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-Bo; YU Zhao-Lian; LI Sen-Lan; CHEN Qing-Hua

    2005-01-01

    The title compound, 2(S),3(R)-dihydroxymethyl-N-cyclohexylaziridine 1, has been synthesized via tandem Micheal addition and internal nucleophilic substitution reactions of 5-methoxy-3-bromo-2(5H)-furanones 2 with cyclohexylamine 3 and subsequent reduction of intermediate 5, Its crystal structure was determined by single-crystal X-ray diffraction.Crystal data:C1oH19NO2, Mr = 185.26, monoclinic system, space group P21/n, a = 8.0620(16), b = 7.2013(14), c = 18.555(4)(。A), β= 102.30(3)°, V= 1052.5(4)(。A)3, Z= 4, Dc= 1.169 g/cm3, ~MoKα) = 0.071073 nm,μ = 0.080 mm- 1 and F(000) = 408.The structure was refined to R = 0.0439 and wR = 0.1178 for 1839 observed reflections (I > 2σ(I)).The crystallographic structure of 1 shows that the functionalized aziridine ring links two hyroxymethyl groups.

  11. Crystal structure of the pilotin from the enterohemorrhagic Escherichia coli type II secretion system.

    Science.gov (United States)

    Korotkov, Konstantin V; Hol, Wim G J

    2013-05-01

    Bacteria contain several sophisticated macromolecular machineries responsible for translocating proteins across the cell envelope. One prominent example is the type II secretion system (T2SS), which contains a large outer membrane channel, called the secretin. These gated channels require specialized proteins, so-called pilotins, to reach and assemble in the outer membrane. Here we report the crystal structure of the pilotin GspS from the T2SS of enterohemorrhagic Escherichia coli (EHEC), an important pathogen that can cause severe disease in cases of food poisoning. In this four-helix protein, the straight helix α2, the curved helix α3 and the bent helix α4 surround the central N-terminal helix α1. The helices of GspS create a prominent groove, mainly formed by side chains of helices α1, α2 and α3. In the EHEC GspS structure this groove is occupied by extra electron density which is reminiscent of an α-helix and corresponds well with a binding site observed in a homologous pilotin. The residues forming the groove are well conserved among homologs, pointing to a key role of this groove in this class of T2SS pilotins. At the same time, T2SS pilotins in different species can be entirely different in structure, and the pilotins for secretins in non-T2SS machineries have yet again unrelated folds, despite a common function. It is striking that a common complex function, such as targeting and assembling an outer membrane multimeric channel, can be performed by proteins with entirely different folds. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Development of a novel liquid crystal based cell traction force transducer system.

    Science.gov (United States)

    Soon, C F; Youseffi, M; Berends, R F; Blagden, N; Denyer, M C T

    2013-01-15

    Keratinocyte traction forces play a crucial role in wound healing. The aim of this study was to develop a novel cell traction force (CTF) transducer system based on cholesteryl ester liquid crystals (LC). Keratinocytes cultured on LC induced linear and isolated deformation lines in the LC surface. As suggested by the fluorescence staining, the deformation lines appeared to correlate with the forces generated by the contraction of circumferential actin filaments which were transmitted to the LC surface via the focal adhesions. Due to the linear viscoelastic behavior of the LC, Hooke's equation was used to quantify the CTFs by associating Young's modulus of LC to the cell induced stresses and biaxial strain in forming the LC deformation. Young's modulus of the LC was profiled by using spherical indentation and determined at approximately 87.1±17.2kPa. A new technique involving cytochalasin-B treatment was used to disrupt the intracellular force generating actin fibers, and consequently the biaxial strain in the LC induced by the cells was determined. Due to the improved sensitivity and spatial resolution (∼1μm) of the LC based CTF transducer, a wide range of CTFs was determined (10-120nN). These were found to be linearly proportional to the length of the deformations. The linear relationship of CTF-deformations was then applied in a bespoke CTF mapping software to estimate CTFs and to map CTF fields. The generated CTF map highlighted distinct distributions and different magnitude of CTFs were revealed for polarized and non-polarized keratinocytes. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Growth, optical, thermal, mechanical and dielectric studies of sodium succinate hexahydrate (β phase) single crystal: A promising third order NLO material

    Science.gov (United States)

    Mageshwari, P. S. Latha; Priya, R.; Krishnan, S.; Joseph, V.; Das, S. Jerome

    2016-11-01

    A third order nonlinear optical (NLO)single crystals of sodium succinate hexahydrate (SSH) (β phase) has been grown by a slow evaporation growth technique using aqueous solution at ambient temperature. The lattice parameters and morphology of SSH were determined by single crystal X-ray diffraction analysis. SSH crystallizes in centrosymmetric monoclinic system with space group P 21 / c and the crystalline purity was analyzed by powder X-ray diffraction analysis. The UV-vis-NIR spectrum reveals that the crystal is transparent in the entire visible region. The recorded FT-IR spectrum verified the presence of various functional groups in the material. NMR analysis of the grown crystal confirms the structural elucidation and detects the major and minor functional groups present in the title compound. ICP-OES analysis proved the presence of sodium in SSH. TG-DTA/DSCanalysis was used to investigate the thermal stability of the material. The dielectric permittivity and dielectric loss of SSH were carried out as a function of frequency for different temperatures and the results were discussed. The mechanical stability was evaluated from Vicker's microhardness test. The third order nonlinear optical properties of SSH has been investigated employing Z-scan technique with He-Ne laser operating at 632.8 nm wavelength.

  14. Spectral, optical, thermal, Hirshfeld, antimicrobial studies and computational calculations of a new organic crystal, 1H-benzo[d]imidazol-3-ium-3,5-dinitrobenzoate

    Science.gov (United States)

    Sathya, K.; Dhamodharan, P.; Dhandapani, M.

    2017-06-01

    Single crystals of 1H-benzo[d]imidazol-3-ium-3,5-dinitrobenzoate (BDNB) were grown by reacting 3,5-dinitrobenzoic acid and benzimidazole by slow evaporation method. UV-Vis-NIR spectral studies of the BDNB show that the crystal is excellently transparent in entire visible region. Chemically and magnetically equivalent protons in BDNB were identified by 1H NMR technique. The carbon frame work of the molecule was established by 13C NMR spectroscopy. Proton transfer mechanism was confirmed by the presence of N+H group in BDNB by FT-IR spectroscopic technique. TG/DTA analyses confirmed that the crystal is stable up to172 °C. Single crystal XRD analysis was carried out to ascertain the molecular structure and the crystal belongs to monoclinic system with space group P21/c. Computational studies that include optimization of molecular geometry, natural bond analysis, Mulliken population analysis and HOMO-LUMO analysis were performed using B3LYP method at 6-31 g level. The low HOMO-LUMO energy gap of BDNB confirms high reactivity of BDNB. Hirshfeld analysis expose that O⋯H/H⋯O interactions are the prominent interactions. Theoretical calculations indicate that first order hyperpolarizability is 16 times greater than urea. The results show that the BDNB may be used for opto-electronic applications. The antimicrobial and antioxidant analyses shows concentration of the compound increases inhibition activity also increases.

  15. Third order optical non-linear (Z-scan), birefringence, photoluminescence, mechanical and etching studies on melaminium levulinate monohydrate (MLM) single crystal for optical device applications

    Science.gov (United States)

    Sivakumar, N.; Anbalagan, G.

    2016-10-01

    Z-scan studies on the grown crystal was investigated by diode-pumped Nd; YAG laser. Nonlinear refractive index (n2) and third-order nonlinear optical susceptibility (χ3) values of MLM were found to be -1.0 × 10-8 cm2/W and 1.36 × 10-6 esu respectively. Powder X-ray diffraction analysis depicted that the crystal belongs to monoclinic system with space group P21/c. Birefringence study revealed the optical dispersion behavior of MLM crystal. Linear refractive index on (10-1) plane was measured by prism coupling technique and was estimated to be 1.4705. Hardness study was carried out along three different planes which exhibit hardness anisotropy of 41.11%. Meyer's index values of the grown crystal for the (10-1), (010) and (111) planes were found to be 2.39, 2.61 and 2.04 respectively. Etching studies on the prominent (10-1) growth plane was explained by two dimensional layer growth mechanisms. Photoluminescence study was performed on MLM crystal to explore its efficacy towards optical device fabrications.

  16. Development and evaluation of a LOR-based image reconstruction with 3D system response modeling for a PET insert with dual-layer offset crystal design

    Science.gov (United States)

    Zhang, Xuezhu; Stortz, Greg; Sossi, Vesna; Thompson, Christopher J.; Retière, Fabrice; Kozlowski, Piotr; Thiessen, Jonathan D.; Goertzen, Andrew L.

    2013-12-01

    In this study we present a method of 3D system response calculation for analytical computer simulation and statistical image reconstruction for a magnetic resonance imaging (MRI) compatible positron emission tomography (PET) insert system that uses a dual-layer offset (DLO) crystal design. The general analytical system response functions (SRFs) for detector geometric and inter-crystal penetration of coincident crystal pairs are derived first. We implemented a 3D ray-tracing algorithm with 4π sampling for calculating the SRFs of coincident pairs of individual DLO crystals. The determination of which detector blocks are intersected by a gamma ray is made by calculating the intersection of the ray with virtual cylinders with radii just inside the inner surface and just outside the outer-edge of each crystal layer of the detector ring. For efficient ray-tracing computation, the detector block and ray to be traced are then rotated so that the crystals are aligned along the X-axis, facilitating calculation of ray/crystal boundary intersection points. This algorithm can be applied to any system geometry using either single-layer (SL) or multi-layer array design with or without offset crystals. For effective data organization, a direct lines of response (LOR)-based indexed histogram-mode method is also presented in this work. SRF calculation is performed on-the-fly in both forward and back projection procedures during each iteration of image reconstruction, with acceleration through use of eight-fold geometric symmetry and multi-threaded parallel computation. To validate the proposed methods, we performed a series of analytical and Monte Carlo computer simulations for different system geometry and detector designs. The full-width-at-half-maximum of the numerical SRFs in both radial and tangential directions are calculated and compared for various system designs. By inspecting the sinograms obtained for different detector geometries, it can be seen that the DLO crystal

  17. Disentangling the secondary relaxations in the orientationally disordered mixed crystals: cycloheptanol + cyclooctanol two-component system.

    Science.gov (United States)

    Martínez-García, Julio C; Tamarit, Josep Ll; Pardo, Luis C; Barrio, María; Rzoska, Sylwester J; Droz-Rzoska, Aleksandra

    2010-05-13

    The dynamics of the pure compounds and mixed crystals formed between cycloheptanol (cC7-ol) and cyclooctanol (cC8-ol) has been studied by means of broadband dielectric spectroscopy at temperatures near and above the orientational glass transition temperature. Both compounds are known to display at least one orientationally disordered (OD) phase of simple cubic symmetry, and within this phase, a continuous formation of mixed crystals was demonstrated in the past (Rute, M. A. et al. J. Phys. Chem. B 2003, 107, 5914). The dielectric loss spectra of cC7-ol and cC8-ol show, in addition to the well-pronounced alpha-relaxation peaks with a continuous temperature shift (characteristic of the freezing of the molecular dynamics), secondary relaxations (beta and gamma for cC8-ol and gamma for cC7-ol) which are intramolecular in nature. The dynamics of several OD mixed crystals was recently studied (Singh, L. P.; Murthy, S. S. N. J. Phys. Chem. B 2008, 112, 2606), and surprisingly enough one of the secondary relaxations was not evidenced. We show here by means of a careful set of measurements for several mixed crystals and of a detailed analysis procedure the existence of the secondary relaxations for the mixed crystals. The results, moreover, doubtless reinforce the physical origin of each of the secondary relaxations.

  18. Unidirectional Wave Propagation in Low-Symmetric Colloidal Photonic-Crystal Heterostructures

    Directory of Open Access Journals (Sweden)

    Vassilios Yannopapas

    2015-03-01

    Full Text Available We show theoretically that photonic crystals consisting of colloidal spheres exhibit unidirectional wave propagation and one-way frequency band gaps without breaking time-reversal symmetry via, e.g., the application of an external magnetic field or the use of nonlinear materials. Namely, photonic crystals with low symmetry such as the monoclinic crystal type considered here as well as with unit cells formed by the heterostructure of different photonic crystals show significant unidirectional electromagnetic response. In particular, we show that the use of scatterers with low refractive-index contrast favors the formation of unidirectional frequency gaps which is the optimal route for achieving unidirectional wave propagation.

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

    Directory of Open Access Journals (Sweden)

    Güneş Demirtaş

    2011-06-01

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

  20. Ice crystal characterization in cirrus clouds: a sun-tracking camera system and automated detection algorithm for halo displays

    Science.gov (United States)

    Forster, Linda; Seefeldner, Meinhard; Wiegner, Matthias; Mayer, Bernhard

    2017-07-01

    Halo displays in the sky contain valuable information about ice crystal shape and orientation: e.g., the 22° halo is produced by randomly oriented hexagonal prisms while parhelia (sundogs) indicate oriented plates. HaloCam, a novel sun-tracking camera system for the automated observation of halo displays is presented. An initial visual evaluation of the frequency of halo displays for the ACCEPT (Analysis of the Composition of Clouds with Extended Polarization Techniques) field campaign from October to mid-November 2014 showed that sundogs were observed more often than 22° halos. Thus, the majority of halo displays was produced by oriented ice crystals. During the campaign about 27 % of the cirrus clouds produced 22° halos, sundogs or upper tangent arcs. To evaluate the HaloCam observations collected from regular measurements in Munich between January 2014 and June 2016, an automated detection algorithm for 22° halos was developed, which can be extended to other halo types as well. This algorithm detected 22° halos about 2 % of the time for this dataset. The frequency of cirrus clouds during this time period was estimated by co-located ceilometer measurements using temperature thresholds of the cloud base. About 25 % of the detected cirrus clouds occurred together with a 22° halo, which implies that these clouds contained a certain fraction of smooth, hexagonal ice crystals. HaloCam observations complemented by radiative transfer simulations and measurements of aerosol and cirrus cloud optical thickness (AOT and COT) provide a possibility to retrieve more detailed information about ice crystal roughness. This paper demonstrates the feasibility of a completely automated method to collect and evaluate a long-term database of halo observations and shows the potential to characterize ice crystal properties.

  1. Ice crystal characterization in cirrus clouds: a sun-tracking camera system and automated detection algorithm for halo displays

    Directory of Open Access Journals (Sweden)

    L. Forster

    2017-07-01

    Full Text Available Halo displays in the sky contain valuable information about ice crystal shape and orientation: e.g., the 22° halo is produced by randomly oriented hexagonal prisms while parhelia (sundogs indicate oriented plates. HaloCam, a novel sun-tracking camera system for the automated observation of halo displays is presented. An initial visual evaluation of the frequency of halo displays for the ACCEPT (Analysis of the Composition of Clouds with Extended Polarization Techniques field campaign from October to mid-November 2014 showed that sundogs were observed more often than 22° halos. Thus, the majority of halo displays was produced by oriented ice crystals. During the campaign about 27 % of the cirrus clouds produced 22° halos, sundogs or upper tangent arcs. To evaluate the HaloCam observations collected from regular measurements in Munich between January 2014 and June 2016, an automated detection algorithm for 22° halos was developed, which can be extended to other halo types as well. This algorithm detected 22° halos about 2 % of the time for this dataset. The frequency of cirrus clouds during this time period was estimated by co-located ceilometer measurements using temperature thresholds of the cloud base. About 25 % of the detected cirrus clouds occurred together with a 22° halo, which implies that these clouds contained a certain fraction of smooth, hexagonal ice crystals. HaloCam observations complemented by radiative transfer simulations and measurements of aerosol and cirrus cloud optical thickness (AOT and COT provide a possibility to retrieve more detailed information about ice crystal roughness. This paper demonstrates the feasibility of a completely automated method to collect and evaluate a long-term database of halo observations and shows the potential to characterize ice crystal properties.

  2. Modeling of a Turbofan Engine with Ice Crystal Ingestion in the NASA Propulsion System Laboratory

    Science.gov (United States)

    Veres, Joseph P.; Jorgenson, Philip C. E.; Jones, Scott M.; Nili, Samaun

    2017-01-01

    The main focus of this study is to apply a computational tool for the flow analysis of the turbine engine that has been tested with ice crystal ingestion in the Propulsion Systems Laboratory (PSL) at NASA Glenn Research Center. The PSL has been used to test a highly instrumented Honeywell ALF502R-5A (LF11) turbofan engine at simulated altitude operating conditions. Test data analysis with an engine cycle code and a compressor flow code was conducted to determine the values of key icing parameters, that can indicate the risk of ice accretion, which can lead to engine rollback (un-commanded loss of engine thrust). The full engine aerothermodynamic performance was modeled with the Honeywell Customer Deck specifically created for the ALF502R-5A engine. The mean-line compressor flow analysis code, which includes a code that models the state of the ice crystal, was used to model the air flow through the fan-core and low pressure compressor. The results of the compressor flow analyses included calculations of the ice-water flow rate to air flow rate ratio (IWAR), the local static wet bulb temperature, and the particle melt ratio throughout the flow field. It was found that the assumed particle size had a large effect on the particle melt ratio, and on the local wet bulb temperature. In this study the particle size was varied parametrically to produce a non-zero calculated melt ratio in the exit guide vane (EGV) region of the low pressure compressor (LPC) for the data points that experienced a growth of blockage there, and a subsequent engine called rollback (CRB). At data points where the engine experienced a CRB having the lowest wet bulb temperature of 492 degrees Rankine at the EGV trailing edge, the smallest particle size that produced a non-zero melt ratio (between 3 percent - 4 percent) was on the order of 1 micron. This value of melt ratio was utilized as the target for all other subsequent data points analyzed, while the particle size was varied from 1 micron - 9

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

    DEFF Research Database (Denmark)

    Laufek, Frantisek; Pazout, Richard; Makovicky, Emil

    2007-01-01

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

  4. Mathematical modeling and fuzzy availability analysis for serial processes in the crystallization system of a sugar plant

    Science.gov (United States)

    Aggarwal, Anil Kr.; Kumar, Sanjeev; Singh, Vikram

    2017-08-01

    The binary states, i.e., success or failed state assumptions used in conventional reliability are inappropriate for reliability analysis of complex industrial systems due to lack of sufficient probabilistic information. For large complex systems, the uncertainty of each individual parameter enhances the uncertainty of the system reliability. In this paper, the concept of fuzzy reliability has been used for reliability analysis of the system, and the effect of coverage factor, failure and repair rates of subsystems on fuzzy availability for fault-tolerant crystallization system of sugar plant is analyzed. Mathematical modeling of the system is carried out using the mnemonic rule to derive Chapman-Kolmogorov differential equations. These governing differential equations are solved with Runge-Kutta fourth-order method.

  5. Mathematical modeling and fuzzy availability analysis for serial processes in the crystallization system of a sugar plant

    Science.gov (United States)

    Aggarwal, Anil Kr.; Kumar, Sanjeev; Singh, Vikram

    2016-08-01

    The binary states, i.e., success or failed state assumptions used in conventional reliability are inappropriate for reliability analysis of complex industrial systems due to lack of sufficient probabilistic information. For large complex systems, the uncertainty of each individual parameter enhances the uncertainty of the system reliability. In this paper, the concept of fuzzy reliability has been used for reliability analysis of the system, and the effect of coverage factor, failure and repair rates of subsystems on fuzzy availability for fault-tolerant crystallization system of sugar plant is analyzed. Mathematical modeling of the system is carried out using the mnemonic rule to derive Chapman-Kolmogorov differential equations. These governing differential equations are solved with Runge-Kutta fourth-order method.

  6. A Small-Animal PET System Based on LYSO Crystal Arrays, PS-PMTs and a PCI DAQ Board

    Science.gov (United States)

    Alva-Sanchez, H.; Murrieta, T.; Moreno-Barbosa, E.; Brandan, M. E.; Ruiz-Trejo, C.; Martinez-Davalos, A.; Rodriguez-Villafuerte, M.

    2010-02-01

    A positron emission tomography system for small animals has been designed for research purposes, and developed at Instituto de Fi¿sica, UNAM, Mexico. Its detection modules are based on pixelated scintillator LYSO crystal arrays coupled to Hamamatsu H8500 position-sensitive photomultiplier tubes. The front-end electronics are based on nuclear instrumentation modules (NIM) and in-house built readout circuits. Peak signal digitization is performed with a commercial analogue-to-digital acquisition (DAQ) board. The system has been characterized for spatial, timing and energy resolution, system dead time, absolute sensitivity, scatter fraction and noise equivalent count rate (NEC). The results indicate that the detection modules are able to identify individual crystals (out of 400) with up to 8-to-1 peak-to-valley ratios with individual crystal energy resolution ranging from 7 to 15% at 511 keV. The timing resolution is 1.9 ns and the system dead time was found to be 16.8 ¿s and 42.1 ¿s for 0.5 ml and 10 ml volume sources, respectively. The measured absolute system sensitivity is 0.11% and the scatter fraction from a glass capillary inside a 2.5 cm diameter mouse phantom is 21.5%. A true NEC maximum value was not achieved with the system due to saturation of the PS-PMT output signals for activities above 0.27 mCi. Results from a Na18 F PET bone scan of a 30 g mouse are shown.

  7. Hidden image recovery using a biased photorefractive crystal in the Fourier plane of an optical imaging system.

    Science.gov (United States)

    Gan, Haiyong; Xu, Nan; Li, Jianwei; Xu, Tao; Wang, Yanping; Sun, Zhixu; Ma, Chong; Wang, Jinjin; Song, Feng; Sun, Ming; Li, Li; Sheng, Chuanxiang

    2015-02-09

    Self-diffraction can be induced using a biased photorefractive crystal in the Fourier plane of an imaging system where the light beam intensity is naturally high due to the concentration effect of an optical lens. The spatial frequency spectrum of the output image is proportional to the optical power density distribution in the Fourier plane. A photorefractive crystal with small size can be used and hence an reduced amount of biased voltage is needed to obtain significant diffraction effect in the image plane. When the input image is an overlay of a signal and a noise pattern, theoretic model reveals that the induced diffraction in the Fourier plane may be preferably applied on the noise pattern. In order to illustrate the effect experimentally, a signal from a weakly illuminated object is coupled with an overwhelming noise pattern and then the hidden signal is successfully recovered using a SBN61 crystal with an applied voltage of 800 V in the Fourier plane. Such technology can be employed in encrypted spatial communication systems for security purposes.

  8. High index of refraction via quantum interference in a three- level system of Er3+-doped yttrium aluminium garnet crystal

    Institute of Scientific and Technical Information of China (English)

    He Qiong-Yi; Wang Tie-Jun; Gao Jin-Yue

    2006-01-01

    A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er3+-doped yttrium aluminium garnet (YAG) crystal, which is achieved for a probe field between the excited state 4Ⅰ13/2 and ground state 4Ⅰ15/2 by adjusting a strong coherent driving field between the upper excited state 4Ⅰ11/2 and 4Ⅰ15/2· It is found that the changes of the frequency of the coherent driving field and the concentration of Er3+ ions in the YAG crystal can maximize the index of refraction accompanied by vanishing absorption. This result could be useful for the dispersion compensation in fibre communication, laser particle acceleration, high precision magnetometry and so on.

  9. Crystallization in Pd40Ni40P20 glass

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Saksl, K.; Nishiyama, N.

    2002-01-01

    Phase segregation and the effect of pressure on crystallization of bulk and ribbon Pd40Ni40P20 glasses have been studied by means of differential scanning calorimetry (DSC) and x-ray diffraction. The DSC measurements show only one glass transition event in the samples annealed at different...... temperatures in the supercooled liquid region. Phase analyses reveal at least five crystalline phases crystallized from the glass: monoclinic; body-centered tetragonal; orthorhombic; Ni2Pd2P and fcc-(Ni,Pd) solid solution phases. In the pressure range from 0 to 4.2 GPa, the crystallization temperature...... increases with pressure having a slope of 11 K/GPa. The eutectic crystallization reaction mode and crystalline phases formed are unchanged in the pressure range used. The enhancement of the crystallization temperature with increasing pressure in the glass can be explained by the suppression of atomic...

  10. Structural Characteristics and Crystallization of Metallic Glass Sputtered Films by Using Zr System Target

    Directory of Open Access Journals (Sweden)

    Katsuyoshi Kondoh

    2008-01-01

    Full Text Available Zr-Al-Ni-Cu thin films were deposited by the radio-frequency sputtering method at low substrate temperature using three kinds of targets: Zr55Al10Ni5Cu30 bulk metallic glass target (α-BMG target, crystallized bulk metallic glass target (c-BMG target, and an elemental composite target composed of each Zr, Al, Ni chips, and Cu plate. XRD profiles of the films prepared when using these targets indicated that all of the films showed amorphous structures. While XRD profiles of the films using α- and c-BMG targets revealed a broad peak of 2θ=38 degree in the same way as the α-BMG target indicating amorphous structures, that of the film using elemental composite targets showed a broad peak of 2θ=42 degree, which is higher compared to the latter material. As a result of annealing the films at various temperatures for 900 seconds, the film using the α-BMG target showed a crystallization temperature of 748 K, higher than that of BMG with 723 K, while the other films had lower crystallization temperatures below 723 K. XRD profiles also indicated that the crystallized compounds of the films were different from those of BMG target.

  11. High spatial resolution X-ray and gamma ray imaging system using diffraction crystals

    Science.gov (United States)

    Smither, Robert K.

    2011-05-17

    A method and a device for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation are provided. The device comprises a plurality of arrays, with each array comprising a plurality of elements comprising a first collimator, a diffracting crystal, a second collimator, and a detector.

  12. Crystal structure of alpha poly-p-xylylene.

    Science.gov (United States)

    Kubo, S.; Wunderlich, B.

    1971-01-01

    A crystal structure of alpha poly-p-xylylene is proposed with the help of data of oriented crystals grown during polymerization. The unit cell is monoclinic with the parameters a = 8.57 A, b = 10.62 A, c = 6.54 A (chain axis), and beta = 101.3 deg. Four repeating units per cell lead to a calculated density of 1.185 g/cu cm and a packing density of 0.71. The probable space group is P2 sub 1/m.

  13. Crystal landscape in the orcinol:4,4′-bipyridine system: synthon modularity, polymorphism and transferability of multipole charge density parameters

    Directory of Open Access Journals (Sweden)

    Ritesh Dubey

    2014-01-01

    Full Text Available Polymorphism in the orcinol:4,4′-bipyridine cocrystal system is analyzed in terms of a robust convergent modular phenol...pyridine supramolecular synthon. Employing the Synthon Based Fragments Approach (SBFA to transfer the multipole charge density parameters, it is demonstrated that the crystal landscape can be quantified in terms of intermolecular interaction energies in the five crystal forms so far isolated in this complex system. There are five crystal forms. The first has an open, divergent O—H...N based structure with alternating orcinol and bipyridine molecules. The other four polymorphs have different three-dimensional packing but all of them are similar at an interaction level, and are based on a modular O—H...N mediated supramolecular synthon that consists of two orcinol and two bipyridine molecules in a closed, convergent structure. The SBFA method, which depends on the modularity of synthons, provides good agreement between experiment and theory because it takes into account the supramolecular contribution to charge density. The existence of five crystal forms in this system shows that polymorphism in cocrystals need not be considered to be an unusual phenomenon. Studies of the crystal landscape could lead to an understanding of the kinetic pathways that control the crystallization processes, in other words the valleys in the landscape. These pathways are traditionally not considered in exercises pertaining to computational crystal structure prediction, which rather monitors the thermodynamics of the various stable forms in the system, in other words the peaks in the landscape.

  14. The phase transition sequence and the location of the morphotropic phase boundary region in (1-x)[Pb (Mg sub 1 sub / sub 3 Nb sub 2 sub / sub 3)O sub 3 ]-xPbTiO sub 3 single crystal

    CERN Document Server

    Guo Yi Ping; Ling Di; Xu Hai Qing; He Tian Hou; Yin Zhi Wen

    2003-01-01

    Piezoelectric constant and temperature-dependent dielectric constant measurements have been performed on (110)-oriented (1-x)Pb (Mg sub 1 sub / sub 3 Nb sub 2 sub / sub 3)O sub 3 -xPbTiO sub 3 crystals with different compositions under different poling fields. The width of the morphotropic phase boundary region (0.30monoclinic M sub A -monoclinic M sub C -tetragonal phase transition sequence was observed directly from the dielectric constant versus temperature results for (001)-poled rhombohedral crystals with compositions near the rhombohedral-monoclinic phase boundary. The structure of the morphotropic phase is shown to be monoclinic with space group P sub m. (letter to the editor)

  15. Optomechanical oscillator pumped and probed by optically two isolated photonic crystal cavity systems.

    Science.gov (United States)

    Tian, Feng; Sumikura, Hisashi; Kuramochi, Eiichi; Taniyama, Hideaki; Takiguchi, Masato; Notomi, Masaya

    2016-11-28

    Optomechanical control of on-chip emitters is an important topic related to integrated all-optical circuits. However, there is neither a realization nor a suitable optomechanical structure for this control. The biggest obstacle is that the emission signal can hardly be distinguished from the pump light because of the several orders' power difference. In this study, we designed and experimentally verified an optomechanical oscillation system, in which a lumped mechanical oscillator connected two optically isolated pairs of coupled one-dimensional photonic crystal cavities. As a functional device, the two pairs of coupled cavities were respectively used as an optomechanical pump for the lumped oscillator (cavity pair II, wavelengths were designed to be within a 1.5 μm band) and a modulation target of the lumped oscillator (cavity pair I, wavelengths were designed to be within a 1.2 μm band). By conducting finite element method simulations, we found that the lumped-oscillator-supported configurations of both cavity pairs enhance the optomechanical interactions, especially for higher order optical modes, compared with their respective conventional side-clamped configurations. Besides the desired first-order in-plane antiphase mechanical mode, other mechanical modes of the lumped oscillator were investigated and found to possibly have optomechanical applications with a versatile degree of freedom. In experiments, the oscillator's RF spectra were probed using both cavity pairs I and II, and the results matched those of the simulations. Dynamic detuning of the optical spectrum of cavity pair I was then implemented with a pumped lumped oscillator. This was the first demonstration of an optomechanical lumped oscillator connecting two optically isolated pairs of coupled cavities, whose biggest advantage is that one cavity pair can be modulated with an lumped oscillator without interference from the pump light in the other cavity pair. Thus, the oscillator is a suitable

  16. Monoclinic form I of clopidogrel hydrogen sulfate from powder diffraction data

    Directory of Open Access Journals (Sweden)

    Vladimir V. Chernyshev

    2010-08-01

    Full Text Available The asymmetric unit of the title compound, C16H17ClNO2S+·HSO4−, (I [systematic name: (+-(S-5-[(2-chlorophenyl(methoxycarbonylmethyl]-4,5,6,7-tetrahydrothieno[3,2-c]pyridin-5-ium hydrogen sulfate], contains two independent cations of clopidogrel and two independent hydrogensulfate anions. The two independent cations are of similar conformation; however, this differs from that observed in orthorhombic form (II [Bousquet et al. (2003. US Patent No. 6 504 030]. The H—N—Cchiral—H fragment shows a trans conformation in both independent cations in (I and a gauche conformation in (II. In (I, classical intermolecular N—H...O and O—H...O hydrogen bonds link two independent cations and two independent anions into an isolated cluster, in which two cations interact with one anion only via N—H...O hydrogen bonds. Weak intermolecular C—H...O hydrogen bonds further consolidate the crystal packing.

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

    Science.gov (United States)

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

    2006-03-01

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

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

    Science.gov (United States)

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

    2016-11-01

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

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

    Science.gov (United States)

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

    2010-07-29

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

  20. Growth, spectral, thermal, laser damage threshold, microhardness, dielectric, linear and nonlinear optical properties of an organic single crystal: L-phenylalanine DL-mandelic acid

    Energy Technology Data Exchange (ETDEWEB)

    Jayaprakash, P. [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India); Peer Mohamed, M. [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India); Department of Physics, C. Abdul Hakeem College, Melvisharam 632 509, Tamil Nadu (India); Krishnan, P. [Department of Physics, St. Joseph’s College of Engineering, Chennai 600 119, Tamil Nadu (India); Nageshwari, M.; Mani, G. [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India); Lydia Caroline, M., E-mail: lydiacaroline2006@yahoo.co.in [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India)

    2016-12-15

    Single crystals of L-phenylalanine dl-mandelic acid [C{sub 9}H{sub 11}NO{sub 2}. C{sub 8}H{sub 8}O{sub 3}], have been grown by the slow evaporation technique at room temperature using aqueous solution. The single crystal XRD study confirms monoclinic system for the grown crystal. The functional groups present in the grown crystal have been identified by FTIR and FT-Raman analyses. The optical absorption studies show that the crystal is transparent in the visible region with a lower cut-off wavelength of 257 nm and the optical band gap energy E{sub g} is determined to be 4.62 eV. The Kurtz powder second harmonic generation was confirmed using Nd:YAG laser with fundamental wavelength of 1064 nm. Further, the thermal studies confirmed no weight loss up to 150°C for the as-grown crystal. The photoluminescence spectrum exhibited three peaks (414 nm, 519 nm, 568 nm) due to the donation of protons from carboxylic acid to amino group. Laser damage threshold value was found to be 4.98 GW/cm{sup 2}. The Vickers microhardness test was carried out on the grown crystals and there by Vickers hardness number (H{sub v}), work hardening coefficient (n), yield strength (σ{sub y}), stiffness constant C{sub 11} were evaluated. The dielectric behavior of the crystal has been determined in the frequency range 50 Hz–5 MHz at various temperatures.