Journal of Applied Crystallography

Volume 40, Part 4 (August 2007)

	Cover illustration: Molecular electrostatic potential of thymidine mapped on the charge density isosurface at 0.5 e Å-3 using MolIso. Courtesy of C. B. Huebschle & P. Luger [J. Appl. Cryst. (2006), 39, 901-904].

• editorial
• research papers
• short communications
• computer programs
• laboratory notes
• meeting reports
• meetings

editorial

research papers

J. Appl. Cryst. (2007). 40, 642-649  [ doi:10.1107/S0021889807016299 ] An in situ method for the study of strain broadening using synchrotron X-ray diffraction C. C. Tang, P. A. Lynch, R. W. Cheary and S. M. Clark Synopsis: A tensionometer for in situ powder diffraction studies of foils under stress has been constructed and used in a copper foil on beamline 2.3 of the Daresbury SRS. Both peak asymmetry and broadening were observed which was interpreted as being due to a cellular structure with cell walls and cell interiors possessing high and low dislocation densities. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 650-657  [ doi:10.1107/S0021889807021097 ] Unambiguous reconstruction of the complex amplitude reflection coefficient of a laterally homogeneous crystal using analyser-based phase-contrast imaging D. J. Vine, D. M. Paganin, K. M. Pavlov and S. G. Podorov Synopsis: A theoretical approach is developed to invert analytically a hard X-ray analyser-based phase-contrast image of a known weak object to recover the complex amplitude reflection coefficient of a locally homogeneous crystal. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 658-674  [ doi:10.1107/S0021889807021206 ] Phaser crystallographic software A. J. McCoy, R. W. Grosse-Kunstleve, P. D. Adams, M. D. Winn, L. C. Storoni and R. J. Read Synopsis: A description is given of Phaser-2.1: software for phasing macromolecular crystal structures by molecular replacement and single-wavelength anomalous dispersion phasing. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 675-683  [ doi:10.1107/S0021889807022935 ] Revision and extension of the standard laboratory technique for X-ray diffraction measurement of residual stress gradients C. L. Azanza Ricardo, M. D'Incau and P. Scardi Synopsis: A new procedure is proposed to determine sub-surface residual stress gradients by laboratory X-ray diffraction measurements at different depths using a chemical layer-removal technique. The standard correction algorithm for stress relaxation due to layer removal is improved by including corrections for X-ray absorption, and by the addition of constraints imposed by the mechanical equilibrium conditions. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 684-693  [ doi:10.1107/S0021889807025113 ] In situ simultaneous Raman/high-resolution X-ray powder diffraction study of transformations occurring in materials at non-ambient conditions E. Boccaleri, F. Carniato, G. Croce, D. Viterbo, W. van Beek, H. Emerich and M. Milanesio Synopsis: A novel Raman/high-resolution X-ray powder diffraction setup has been designed for the investigation of solid-state transformations occurring in materials under in situ non-ambient conditions. The setup was tested by studying the kinetics of the fluorene-TCNQ synthesis, the thermal swelling and degradation of a stearate-hydrotalcite, and the photocycloaddition reaction of (E)-furylidenoxindole. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 694-701  [ doi:10.1107/S0021889807023163 ] Calibration in a closed system: the case of X-ray diffraction analysis T. Lwin Synopsis: A functional relationship model approach is applied to the problem of calibration in a closed system. It accounts for all the variation due to sampling and measurement error in the peak intensities in quantitative X-ray diffraction analysis. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 702-709  [ doi:10.1107/S0021889807028087 ] Temperature phase changes in solid bicyclo[3.3.1]nonane-2,6-dione and bicyclo[3.3.1]nonane-3,7-dione from powder X-ray diffraction data M. Brunelli, M. A. Neumann, A. N. Fitch and A. J. Mora Synopsis: Increased instrumental intensity and resolution, and new effort in devising indexing algorithms, make it possible to detect, even from a biphasic mixture, the correct unit cell, and to solve (by direct methods or with direct-space algorithms) the crystal and molecular structure. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 710-715  [ doi:10.1107/S0021889807030014 ] On the numerical corrections of time-of-flight neutron powder diffraction data M. Avdeev, J. Jorgensen, S. Short and R. B. Von Dreele Synopsis: An improvement in the quality of Rietveld refinements with neutron time-of-flight data is possible by using a look-up table for the variation of peak positions and exponential profile function coefficients rather than using the empirical relations for these values. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 716-718  [ doi:10.1107/S0021889807023382 ] Indexation scheme for oriented molecular thin films studied with grazing-incidence reciprocal-space mapping D.-M. Smilgies and D. R. Blasini Synopsis: Thin supported films of small aromatic molecules have been found to display a pronounced polymorphism. An effective scheme is described to find and index all thin-film reflections based on previously known molecular structures, thereby identifying reflections due to novel thin-film phases. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 719-724  [ doi:10.1107/S002188980702078X ] Dislocation effects in powder diffraction M. Leoni, J. Martinez-Garcia and P. Scardi Synopsis: A general approach to model line broadening effects due to dislocations in powder diffraction patterns is proposed for materials of any symmetry. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 725-729  [ doi:10.1107/S0021889807024995 ] Growth units and growth habit of -BaB2O4 crystal S. Wan, X. Zhang, S. Zhao, Q. Zhang, J. You, H. Chen, G. Zhang and S. Yin Synopsis: The structure of the melt near the -BaB2O4 crystal-melt interface was studied by high-temperature Raman spectroscopy. The growth units were determined and the crystal growth habit was predicted. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 730-734  [ doi:10.1107/S0021889807025101 ] High-temperature structural evolution of hexagonal multiferroic YMnO3 and YbMnO3 I.-K. Jeong, N. Hur and Th. Proffen Synopsis: High-temperature neutron powder diffraction studies are performed to understand the origin of ferroelectricity in hexagonal multiferroic YMnO3 and YbMnO3. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 735-742  [ doi:10.1107/S0021889807027240 ] Modelling of diffraction from fibre texture gradients in thin polycrystalline films M. Birkholz Synopsis: The effect of an inhomogeneous fibre texture on the integrated intensity of a Bragg reflection is derived. The presented formalism allows for the determination of fibre texture gradients as they typically occur during the growth of thin polycrystalline films. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 743-748  [ doi:10.1107/S0021889807027501 ] Advances in space-group determination from powder diffraction data A. Altomare, M. Camalli, C. Cuocci, C. Giacovazzo, A. G. G. Moliterni and R. Rizzi Synopsis: The EXPO2004 approach for determining the extinction symbol from powder diffraction data has been improved. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 749-755  [ doi:10.1107/S0021889807028051 ] A synchrotron X-ray study of structural ordering in the microwave dielectric ceramic system: Ba(Ni1/3Nb2/3)O3-Ba(Zn1/3Nb2/3)O3 R. J. Cernik, M. Barwick, F. Azough and R. Freer Synopsis: Two crystalline phases (cubic Pmm and trigonal Pm1) have been found to coexist in both the BZN and BNN end members and mixed phases of Ba(Ni1/3Nb2/3)O3-Ba(Zn1/3Nb2/3)O3 (BNN-BZN). Online 13 July 2007

J. Appl. Cryst. (2007). 40, 756-760  [ doi:10.1107/S002188980702660X ] Real-space form factor of spherical particles in kinematic and dynamic scattering V.-O. de Haan, J. Plomp and A. A. van Well Synopsis: The real-space sample correlation function for a sphere is derived for kinematic and dynamic scattering. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 761-770  [ doi:10.1107/S0021889807029937 ] Crystal structures and thermal expansion of -MgSO4 and -MgSO4 from 4.2 to 300 K by neutron powder diffraction A. D. Fortes, I. G. Wood, L. Vocadlo, H. E. A. Brand and K. S. Knight Synopsis: Powder neutron refinements of two MgSO4 polymorphs are presented, and their highly anisotropic thermal expansivity is analysed using a Debye model. Online 13 July 2007

short communications

computer programs

J. Appl. Cryst. (2007). 40, 773-777  [ doi:10.1107/S0021889807021875 ] PSAP: protein structure analysis package B. Balamurugan, M. N. A. Md. Roshan, B. Shaahul Hameed, K. Sumathi, R. Senthilkumar, A. Udayakumar, K. H. Venkatesh Babu, M. Kalaivani, G. Sowmiya, P. Sivasankari, S. Saravanan, C. Vasuki Ranjani, K. Gopalakrishnan, K. N. Selvakumar, M. Jaikumar, T. Brindha, D. Michael and K. Sekar Synopsis: An internet computing engine has been developed to analyze three-dimensional protein molecules. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 778-781  [ doi:10.1107/S0021889807023874 ] Identification of domains in protein crystal structures O. Carugo Synopsis: A flexible program that identifies domains on the basis of the crystal structure of multi-domain proteins is presented. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 782-785  [ doi:10.1107/S002188980702420X ] ORNL_SAS: software for calculation of small-angle scattering intensities of proteins and protein complexes E. Tjioe and W. T. Heller Synopsis: ORNL_SAS is software for calculating solution small-angle scattering intensity profiles from any structure provided in the Protein Data Bank format and can also compare the results with experimental data. Online 13 July 2007

laboratory notes

J. Appl. Cryst. (2007). 40, 791-795  [ doi:10.1107/S0021889807022248 ] Apparatus for the simultaneous measurement of the X-ray absorption factor developed for a small-angle X-ray scattering beamline T. Morita, Y. Tanaka, K. Ito, Y. Takahashi and K. Nishikawa Synopsis: A novel apparatus has been developed that enables the simultaneous determination of the absorption factor during measurement of small-angle X-ray scattering intensities of a sample. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 796-798  [ doi:10.1107/S0021889807024661 ] A simple hermetic sample holder for X-ray diffraction analysis of uranium hydride B. Ao, X. Wang, Y. Wei and Y. Zhang Synopsis: A simple hermetic sample holder that fits the Philips X'Pert Pro X-ray diffractometer is described. It may be used to study the aging effects of uranium tritide during storage. Online 13 July 2007

J. Appl. Cryst. (2007). 40, 799-807  [ doi:10.1107/S0021889807023059 ] A single-crystal time-of-flight neutron diffractometer at a spallation neutron source M. Takahashi, K. Ohshima and M. Arai Synopsis: FOX, a single-crystal time-of-flight Laue diffractometer constructed at KENS in KEK for studies of structural and magnetic disorder and phase transitions, is described. Online 13 July 2007

meeting reports

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