Journal of Applied Crystallography

 

J. Appl. Cryst. (2008). 41, 663-668  [ doi:10.1107/S0021889808014994 ]

Critical opalescence points to thermodynamic instability: relevance to small-angle X-ray scattering of resorcinol-formaldehyde gel formation at low pH

C. J. Gommes, N. Job, J.-P. Pirard, S. Blacher and B. Goderis

Synopsis: In situ small-angle X-ray scattering exhibits a non-monotonic evolution during the formation of resorcinol-formaldehyde gels. The data can be analyzed in terms of critical fluctuations, which points to a reaction-induced phase separation process.

Online 6 June 2008

 

J. Appl. Cryst. (2008). 41, 669-674  [ doi:10.1107/S0021889808014386 ]

Reciprocal-space imaging of a real quasicrystal. A feasibility study with PILATUS 6M

T. Weber, S. Deloudi, M. Kobas, Y. Yokoyama, A. Inoue and W. Steurer

Synopsis: The reciprocal space of the perfect icosahedral quasicrystal Al₆₄Cu₂₃Fe₁₃ was explored employing synchrotron radiation and a novel type of single-photon-counting X-ray pixel detector, PILATUS 6M, which allows noise-free data collection with the extraordinarily large dynamic range of 20 bit.

Online 6 June 2008

 

J. Appl. Cryst. (2008). 41, 675-679  [ doi:10.1107/S0021889808015781 ]

Anomalous small-angle scattering from nanoquasicrystalline precipitates in Zr₈₀Pt₂₀ ribbons

H. Okuda, T. Fukumoto, J. Saida, S. Ochiai, S. Sasaki and H. Masunaga

Synopsis: Anomalous small-angle scattering of quasicrystals in a Zr-Pt binary alloy was examined at the Zr K absorption edge. Small differences in both density and composition were found between the quasicrystals and the amorphous matrix.

Online 14 June 2008

 

J. Appl. Cryst. (2008). 41, 680-689  [ doi:10.1107/S0021889808013046 ]

Synchrotron X-ray powder diffraction and extended X-ray absorption fine structure spectroscopy studies on nanocrystalline ZrO₂-CaO solid solutions

I. O. Fábregas, D. G. Lamas, N. E. Walsöe de Reca, M. C. A. Fantini, A. F. Craievich and R. J. Prado

Synopsis: The relationship between long- and short-range order in nanocrystalline ZrO₂-CaO solid solutions was investigated by synchrotron radiation X-ray powder diffraction and extended X-ray absorption fine structure spectroscopy.

Online 14 June 2008

 

J. Appl. Cryst. (2008). 41, 690-694  [ doi:10.1107/S0021889808018025 ]

A novel electrochemical cell for in situ neutron diffraction studies of electrode materials for lithium-ion batteries

F. Rosciano, M. Holzapfel, W. Scheifele and P. Novák

Synopsis: A new electrochemical cell for in situ neutron diffraction measurements on materials for lithium-ion batteries is presented.

Online 1 July 2008

 

J. Appl. Cryst. (2008). 41, 695-700  [ doi:10.1107/S0021889808017883 ]

Experimental verification of dynamical diffraction focusing by a bent crystal wedge in Laue geometry

V. Mocella, C. Ferrero, J. Hrdý, J. Wright, S. Pascarelli and J. Hoszowska

Synopsis: An experimental verification is presented of the fact that focusing by bent crystals in Laue geometry is strongly improved by combining geometrical focusing with Borrmann triangle focusing effects, as suggested from the X-ray dynamical diffraction theory.

Online 1 July 2008

 

J. Appl. Cryst. (2008). 41, 701-704  [ doi:10.1107/S0021889808019092 ]

Unfolding a two-dimensional powder diffraction image: conformal mapping

A. Cervellino, C. Giannini, A. Guagliardi and M. Ladisa

Synopsis: A new procedure aimed at unfolding a two-dimensional powder diffraction image into both a one-dimensional azimuthal and a radial scan is presented.

Online 1 July 2008

 

J. Appl. Cryst. (2008). 41, 705-714  [ doi:10.1107/S0021889808013277 ]

Simultaneous reverse Monte Carlo refinements of local structures in perovskite solid solutions using EXAFS and the total scattering pair-distribution function

V. Krayzman, I. Levin and M. G. Tucker

Synopsis: Reverse Monte Carlo refinements using a combined real-space fit of the neutron/X-ray total scattering pair-distribution function and the extended X-ray absorption fine structure were developed and implemented as an extension to the public domain computer software RMCProfile. The effectiveness of the method was tested using perovskite Ca(Zr,Ti)O₃ solid solutions.

Online 6 June 2008

 

J. Appl. Cryst. (2008). 41, 715-722  [ doi:10.1107/S0021889808015021 ]

A method for merging of ultra-small-angle X-ray scattering and smeared small-angle X-ray scattering patterns of fibers

N. Stribeck and U. Nöchel

Synopsis: The combination of two-dimensional scattering patterns measured with different instruments requires collimation correction. The method is demonstrated by small- and ultra-small-angle X-ray scattering of polymer fiber materials.

Online 6 June 2008

 

J. Appl. Cryst. (2008). 41, 723-728  [ doi:10.1107/S002188980801265X ]

A high-resolution small-angle light scattering instrument for soft matter studies

K. Nishida, H. Ogawa, G. Matsuba, T. Konishi and T. Kanaya

Synopsis: A small-angle light scattering instrument with a high resolution at low angles and a high signal-to-noise ratio has been developed. The characteristics of this instrument make it suitable for soft matter studies.

Online 6 June 2008

 

J. Appl. Cryst. (2008). 41, 729-737  [ doi:10.1107/S0021889808011898 ]

Absorption correction based on a three-dimensional model reconstruction from visual images

R. M. F. Leal, S. C. M. Teixeira, V. Rey, V. T. Forsyth and E. P. Mitchell

Synopsis: A new method has been developed for the application of absorption corrections to macromolecular crystallographic X-ray diffraction data. The approach uses a three-dimensional crystal model generated photographically so that path lengths through the crystal, the solvent and the crystal mount system can be determined reliably. Data from an insulin crystal at low incident beam energy have been recorded and processed using this approach.

Online 6 June 2008

 

J. Appl. Cryst. (2008). 41, 738-746  [ doi:10.1107/S002188980801279X ]

Intergrowth of several solid phases from the Y-Ni-B-C system in a large YNi₂B₂C crystal

T. Weissbach, T. Leisegang, A. Kreyssig, M. Frontzek, J.-U. Hoffmann, D. Souptel, A. Köhler, G. Behr, P. Paufler and D. C. Meyer

Synopsis: Diffraction patterns obtained by X-ray and neutron diffraction are presented for several crystalline phases of the Y-Ni-B-C system.

Online 14 June 2008

 

J. Appl. Cryst. (2008). 41, 747-753  [ doi:10.1107/S0021889808015768 ]

Rotation axis analysis of deformed crystals by X-rays and electrons

A. Borbély, C. Maurice and J. H. Driver

Synopsis: The misorientation distributions about given rotation axes in deformed Cu single crystals are shown to be the same for X-ray diffraction (as standard rocking curves) and for high-resolution electron backscattered diffraction (as virtual rocking curves calculated from the orientation data). A new rotation axis imaging scheme is proposed for electron backscattered diffraction maps to highlight specific features of the deformation-induced sub-boundaries.

Online 21 June 2008

 

J. Appl. Cryst. (2008). 41, 754-760  [ doi:10.1107/S0021889808012417 ]

A focusing Laue diffractometer for the investigation of bulk crystals

M. Stockmeier and A. Magerl

Synopsis: A focusing Laue diffractometer is presented for high-energy X-rays of up to 300 keV in a laboratory environment. The long attenuation length for high-energy X-rays allows for the non-destructive investigation of structural issues and bulk properties of single crystals.

Online 21 June 2008

 

J. Appl. Cryst. (2008). 41, 761-767  [ doi:10.1107/S0021889808016609 ]

Removing bias from solvent atoms in electron density maps

E. N. Brown

Synopsis: A method is presented for creating an omit-map on the solvent of an X-ray crystal structure; this map can be used to refine and remove poorly resolved water molecules.

Online 21 June 2008

 

J. Appl. Cryst. (2008). 41, 768-775  [ doi:10.1107/S0021889808018256 ]

Positioning errors during stepped scans in X-ray crystallography

R. Shayduk and W. Braun

Synopsis: The positioning errors in an X-ray measurement with data acquisition during motor movements have been analyzed. The results show that during most scans in standard geometries data can be acquired even during uncoordinated motor movements between the measurement points without loss of accuracy.

Online 16 July 2008

 

J. Appl. Cryst. (2008). 41, 776-783  [ doi:10.1107/S0021889808019365 ]

The local post-perovskite structure and its temperature dependence: atom-pair distances in CaIrO₃ revealed through analysis of the total X-ray scattering at high temperatures

C. D. Martin

Synopsis: The temperature-dependent post-perovskite structure model of MgSiO₃ is reinvestigated through analysis of the total X-ray scattering from CaIrO₃. In contrast to the results of a previous Rietveld structure refinement, showing a negative thermal expansion of Ir-O and Ca-O bond lengths, atom-pair distances in the pair-distribution function prove that these distances between atom pairs increase with temperature.

Online 16 July 2008

 

J. Appl. Cryst. (2008). 41, 784-790  [ doi:10.1107/S0021889808020074 ]

Finding crystal structures from few diffraction data by a combination of a random search with genetic algorithms

A. Immirzi, L. Erra and C. Tedesco

Synopsis: A new procedure for performing structural analysis of crystalline materials from diffraction data by random search and genetic algorithms is described.

Online 16 July 2008

 

J. Appl. Cryst. (2008). 41, 791-797  [ doi:10.1107/S0021889808018451 ]

Cryocrystallography in capillaries: critical glycerol concentrations and cooling rates

M. Warkentin, V. Stanislavskaia, K. Hammes and R. E. Thorne

Synopsis: The minimum glycerol concentrations required to obtain vitreous ice during plunge cooling of capillaries in liquid propane and nitrogen are determined as a function of capillary diameter and cooling rate. Capillary-based cryocrystallography will require much larger cryoprotectant concentrations than can be achieved with loop or microfabricated X-ray mount-based methods.

Online 1 July 2008

 

J. Appl. Cryst. (2008). 41, 798-799  [ doi:10.1107/S0021889808016282 ]

Point-focusing monochromator crystal realized by hot plastic deformation of a Ge wafer

H. Okuda, K. Nakajima, K. Fujiwara, K. Morishita and S. Ochiai

Synopsis: A point-focusing Johansson monochromator crystal prepared by hot-pressing a Ge single-crystal wafer is demonstrated. By using 333 diffraction, Cu K radiation was focused onto a small spot.

Online 14 June 2008

 

J. Appl. Cryst. (2008). 41, 800-802  [ doi:10.1107/S002188980801635X ]

Branching and twinning in -cristobalite dendrites: an electron backscatter diffraction study

S. Zhao, M. Yang, H. Xu and S. Zhang

Synopsis: Electron backscatter diffraction and pole figures have been used to determine that the branches in -cristobalite dendrite extend along [100] and [010] but not along <001>. A new kind of twinning is found between two -cristobalite dendrites: the twin axes are [110], [111] and [1], and the twin planes are (111) and (1).

Online 14 June 2008

 

J. Appl. Cryst. (2008). 41, 803-807  [ doi:10.1107/S0021889808016373 ]

Maximum disorientation angles between crystals of any point groups and their corresponding rotation axes

Y. He and J. J. Jonas

Synopsis: The maximum disorientation angles between crystals of the 32 point groups were evaluated (together with their corresponding rotation axes) by constructing the fundamental zones of Rodrigues-Frank space. Only ten different maximum angles are possible for the 528 pairs of lattices.

Online 21 June 2008

 

J. Appl. Cryst. (2008). 41, 808-810  [ doi:10.1107/S002188980801385X ]

VCIF2: extended CIF validation software

G. Todorov and H. J. Bernstein

Synopsis: A database-based approach to validation of CIFs to ensure compliance with data-range and enumeration specifications, to ensure compliance with parent-child relationships, and to detect missing and duplicated tags is presented.

Online 6 June 2008

 

J. Appl. Cryst. (2008). 41, 811-814  [ doi:10.1107/S0021889808015616 ]

A toolkit for publishing enhanced figures

B. McMahon and R. M. Hanson

Synopsis: A description is provided of a software utility for creating interactive figures derived from crystal structures using the Java program Jmol.

Online 1 July 2008

 

J. Appl. Cryst. (2008). 41, 815-817  [ doi:10.1107/S0021889808016956 ]

QUALX: a computer program for qualitative analysis using powder diffraction data

A. Altomare, C. Cuocci, C. Giacovazzo, A. Moliterni and R. Rizzi

Synopsis: QUALX is a new computer program for phase identification using powder diffraction data. Its main features are very effective automation, a user-friendly environment and free availability.

Online 16 July 2008

 

J. Appl. Cryst. (2008). 41, 818-821  [ doi:10.1107/S0021889808015999 ]

Fast and easy Bragg reflex search for Berg-Barrett topography of misoriented crystals

B. Andreas, U. Kuetgens and P. Becker

Synopsis: A fast search method for Bragg reflexes of misoriented crystals in Berg-Barrett topography is presented.

Online 14 June 2008

 

J. Appl. Cryst. (2008). 41, 822-824  [ doi:10.1107/S0021889808020165 ]

A versatile sample-environment cell for non-ambient X-ray scattering experiments

P. J. Chupas, K. W. Chapman, C. Kurtz, J. C. Hanson, P. L. Lee and C. P. Grey

Synopsis: A versatile and compact flow-cell/furnace that enables control of the sample atmosphere and temperature for in-situ X-ray scattering experiments is described.

Online 16 July 2008

 

J. Appl. Cryst. (2008). 41, 825  [ doi:10.1107/S0021889808020712 ]

Andrew Richard Lang (1924-2008)

Online 16 July 2008

 

J. Appl. Cryst. (2008). 41, 826-827  [ doi:10.1107/S0021889808015987 ]

X-ray diffraction by polycrystalline materials

Online 14 June 2008