Journal of Applied Crystallography

 

J. Appl. Cryst. (2004). 37, 187-192  [ doi:10.1107/S0021889803028048 ]

Elucidation of zeolite microstructure by synchrotron X-ray diffuse scattering

B. J. Campbell, T. R. Welberry, R. W. Broach, H. Hong and A. K. Cheetham

Synopsis: Diffuse scattering data from natural mordenite crystals are shown to exhibit a complex distribution of weak features which have been mapped out using a synchrotron X-ray source and a CCD detector. Comparison with computer-simulated diffuse scattering patterns yields a detailed three-dimensional columnar defect structure and reveals that roughly one third of the mordenite's columnar defects cooperate to form a block-mosaic pattern of {110} stacking faults.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 193-199  [ doi:10.1107/S0021889803028395 ]

Polarization switching in BaTiO₃ thin films measured by X-ray diffraction exploiting anomalous dispersion

S. J. van Reeuwijk, K. Karakaya, H. Graafsma and S. Harkema

Synopsis: The polarization state of BaTiO₃ thin films was switched by employing external electric fields. Using the anomalous signal of the Ba atom, the structural differences between the two polarization states were determined from X-ray diffraction experiments.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 200-203  [ doi:10.1107/S0021889803028553 ]

The contrast of inclusions compared with that of micropipes in back-reflection synchrotron white-beam topographs of SiC

W. M. Vetter and M. Dudley

Synopsis: X-ray topographic images of inclusions in SiC are described, and compared with similar images of micropipes and with computer simulations. The natures of both types of defect image are discussed.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 204-209  [ doi:10.1107/S002188980302908X ]

The use of error-correcting codes for the decomposition of a powder diffraction pattern

A. Altomare, R. Caliandro, C. Cuocci, I. da Silva, C. Giacovazzo, A. G. G. Moliterni and R. Rizzi

Synopsis: Error-correcting codes are used to increase the efficiency of powder pattern decomposition techniques in phasing procedures.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 210-215  [ doi:10.1107/S0021889803029595 ]

Guidelines for the implementation of XY variable-geometry converging multichannel collimation in a specific SANS facility

F. M. A. Margaça, A. N. Falcão and F. G. Carvalho

Synopsis: The performance of SANS instruments using a combination of variable-geometry converging multichannel collimator units is discussed. Guidelines for the implementation of XY variable-geometry converging multichannel collimation are given.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 216-222  [ doi:10.1107/S0021889803029686 ]

Angle calculations for a z-axis/(2S+2D) hybrid diffractometer

O. Bunk and M. M. Nielsen

Synopsis: Angle calculations are presented for a new `hybrid' diffractometer that consists of a base instrument that can be combined with two different detector arms. The inclusion of a second sample rotation stage is discussed.

Online 17 March 2004

    

J. Appl. Cryst. (2004). 37, 223-230  [ doi:10.1107/S0021889804000020 ]

Scattering from cylinders with globular end-caps

H. Kaya

Synopsis: Analytical expressions for the scattering form factor and radius of gyration for a cylinder with globular end-caps are presented. The possible applications of the form factor in colloidal and biological systems are discussed.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 231-242  [ doi:10.1107/S002188980400038X ]

High-throughput powder diffraction. I. A new approach to qualitative and quantitative powder diffraction pattern analysis using full pattern profiles

C. J. Gilmore, G. Barr and J. Paisley

Synopsis: Statistical tests based on Pearson and Spearman coefficients and the Kolmogorov-Smirnov test are used to match powder diffraction patterns qualitatively using the full peak profiles. The method can be extended to quantitative analysis using least squares via singular value decomposition.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 243-252  [ doi:10.1107/S0021889804000391 ]

High-throughput powder diffraction. II. Applications of clustering methods and multivariate data analysis

G. Barr, W. Dong and C. J. Gilmore

Synopsis: A correlation matrix is generated to compare full profile powder patterns. This is followed by cluster analysis, multivariate data analysis and data visualization to classify the patterns into groups and thus to identify polymorphs and mixtures.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 253-257  [ doi:10.1107/S0021889804000627 ]

Protein crystallography with spallation neutrons: collecting and processing wavelength-resolved Laue protein data

P. Langan and G. Greene

Synopsis: Methods for collecting and processing wavelength-resolved Laue data at the protein crystallography station at Los Alamos Neutron Science Center have been developed.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 258-264  [ doi:10.1107/S0021889804001062 ]

Ab initio protein phasing: the Patterson deconvolution method in SIR2002

M. C. Burla, R. Caliandro, B. Carrozzini, G. L. Cascarano, L. De Caro, C. Giacovazzo and G. Polidori

Synopsis: The Patterson deconvolution method has been implemented in the SIR2002 program, allowing the ab initio solution of protein crystal structures in a very short computing time.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 265-269  [ doi:10.1107/S002188980400158X ]

Using image analysis for automated crystal positioning in a synchrotron X-ray beam for high-throughput macromolecular crystallography

P. Andrey, B. Lavault, F. Cipriani and Y. Maurin

Synopsis: A fully automated image analysis method for detecting and centring protein crystals for X-ray crystallography is described.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 270-278  [ doi:10.1107/S0021889804001748 ]

Periodic dislocation configuration analysis by lattice distortion evaluation: micromechanical approach and X-ray diffraction line broadening

H. Bougrab, K. Inal, H. Sabar and M. Berveiller

Synopsis: This work concerns dislocation microstructure analysis in order to assess stored elastic energy using Fourier coefficients of diffraction lines. These coefficients are related to the lattice distortion heterogeneity evaluated using a micromechanical approach.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 279-287  [ doi:10.1107/S0021889804001761 ]

Automatic classification of protein crystallization images using a curve-tracking algorithm

M. Bern, D. Goldberg, R. C. Stevens and P. Kuhn

Synopsis: A curve-tracking computer algorithm to classify crystallization images automatically is described.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 288-294  [ doi:10.1107/S0021889804002353 ]

Structure determination of diclofenac in a diclofenac-containing chitosan matrix using conventional X-ray powder diffraction data

N. Muangsin, M. Prajuabsook, P. Chimsook, N. Chantarasiri, K. Siraleartmukul, N. Chaichit and S. Hannongbua

Synopsis: The crystal structure of diclofenac embedded in a diclofenac-containing chitosan matrix has been determined from conventional X-ray powder diffraction data.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 295-299  [ doi:10.1107/S0021889804002791 ]

A time-resolved SAXS study on the crystalline morphology of long-term stored isotactic polypropylene

J.-T. Xu, Y.-J. Zhang and Z.-Q. Fan

Synopsis: The crystalline morphology of a long-term stored metallocene isotactic polypropylene (mPP) is compared with that of a freshly crystallized sample. It is found that both and crystal forms occur in the long-term stored mPP, whereas freshly crystallized mPP contains only the crystal form; it is inferred that the crystal stacks of the and forms in the long-term stored mPP are arranged according to the block mode.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 300-311  [ doi:10.1107/S0021889804003140 ]

An evaluation of methods of diffraction-line broadening analysis applied to ball-milled molybdenum

I. Lucks, P. Lamparter and E. J. Mittemeijer

Synopsis: Crystallite sizes and microstrains in ball-milled molybdenum, as determined from diffraction-line broadening analysis, depend on the method of analysis. Broadening due to microstrain can be simulated with a strain field model.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 312-318  [ doi:10.1107/S0021889803029625 ]

A cell for the in situ study of electrocrystallization

A. Parkin, S. F. Johnstone, A. R. Mount, S. Parsons, C. R. Pulham and D. Sanders

Synopsis: A new cell for studying electrocrystallization in situ on a diffractometer is reported, in which the working electrode, fabricated from a propelling pencil lead encased in glass, is designed to sit in the path of the incident X-ray beam so that processes occurring at its tip can be studied using diffraction methods. Practical difficulties of both design and data collection are discussed, as well as advantages and limitations of the method.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 319-324  [ doi:10.1107/S0021889804002535 ]

A helium-purged beam path to improve soft and softer X-ray data quality

M. Polentarutti, R. Glazer and K. Djinovic Carugo

Synopsis: A helium-purged beam path implemented at the Elettra X-ray diffraction beamline is described. The advantages of its use are analysed for diffraction data collected at wavelengths in the range 1.5-2.65 Å.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 325-326  [ doi:10.1107/S0021889803028127 ]

Comments on Small-angle neutron scattering analysis of the precipitation behaviour in a maraging steel by Staron, Jamnig, Leitner, Ebner & Clemens (2003)

Z. Guo and W. Sha

Synopsis: Comment on Staron, Jamnig, Leitner, Ebner & Clemens [J. Appl. Cryst. (2003), 36, 415-419].

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 327-330  [ doi:10.1107/S0021889804001773 ]

Imaging modulated reflections from a semi-crystalline state of profilin:actin crystals

J. J. Lovelace, K. Narayan, J. K. Chik, H. D. Bellamy, E. H. Snell, U. Lindberg, C. E. Schutt and G. E. O. Borgstahl

Synopsis: The rotation method and fine -slicing have been used to visualize the modulated diffraction pattern of a semi-crystalline state of profilin:actin.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 331-334  [ doi:10.1107/S0021889804002924 ]

A new algorithm for performing three-dimensional searches of the Cambridge Structural Database

J. A. Chisholm and S. Motherwell

Synopsis: A new search algorithm, 3DSEARCH, is presented that can identify challenging extended chemical queries from three-dimensional crystal structure data. Timing information is presented for example searches, which demonstrate the ability of the algorithm to identify queries containing several substructures and several intermolecular connections.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 335-338  [ doi:10.1107/S0021889804003528 ]

CIF applications. XV. enCIFer: a program for viewing, editing and visualizing CIFs

F. H. Allen, O. Johnson, G. P. Shields, B. R. Smith and M. Towler

Synopsis: enCIFer is an interactive program which permits files in CIF format to be viewed, and syntax errors to be located and corrected for both individual and looped data items. The software also allows new data to be incorporated and the structure(s) contained in a small-molecule CIF to be visualized and manipulated.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 339-340  [ doi:10.1107/S0021889804001785 ]

Hot pressing of germanium monochromator crystals

S. F. Treviño and D. F. R. Mildner

Synopsis: Hot pressing of germanium (311) single crystal at 1073 K at a pressure of 10.7 MPa gives typical mosaic widths of 0.5° in one direction and 0.2° in the other.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 341-344  [ doi:10.1107/S0021889804001268 ]

Mesoscopic crystallography of shear-aligned soft materials

I. W. Hamley, V. Castelletto, O. O. Mykhaylyk and A. J. Gleeson

Synopsis: The development of a novel device for examining the three-dimensional structure of shear-aligned soft materials using small-angle X-ray scattering is reported.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 345  [ doi:10.1107/S0021889804001530 ]

A new method of cleaning X-ray tubes from solid carbonates

R. Kruszynski and P. Anielak

Synopsis: A new fast chemical method for cleaning X-ray tubes from deposited carbonates, based on the high affinity of citric acid toward calcium and magnesium, is presented.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 346  [ doi:10.1107/S0021889803028929 ]

VRML general position diagrams of the magnetic subperiodic groups

N. R. Cordisco and D. B. Litvin

Synopsis: Three-dimensional general position diagrams of all magnetic subperiodic groups have been developed. Each diagram can be rotated and zoomed to aid in the visualization of the general position diagram and includes both the general positions of the atoms and the general orientations of the associated magnetic moments.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 347-348  [ doi:10.1107/S0021889804000858 ]

XDSi: a graphical interface for the data processing program XDS

P. Kursula

Synopsis: A Tcl/Tk graphical user interface has been developed for the X-ray diffraction data processing package XDS. The interface simplifies routine tasks, such as input file retrieval and editing, examination of the output and file format conversion.

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 349-350  [ doi:10.1107/S0021889804004376 ]

Erwin Félix Lewy-Bertaut (1913-2003)

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 350-351  [ doi:10.1107/S0021889804004443 ]

Félix Bertaut, space groups and the International Tables for Crystallography

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 351  [ doi:10.1107/S0021889804002584 ]

Sivaraj Ramaseshan (1923-2003)

Online 17 March 2004

 

J. Appl. Cryst. (2004). 37, 352-353  [ doi:10.1107/S0021889803028358 ]

Crystal growth for beginners

Online 17 March 2004