Journal of Applied Crystallography

 

J. Appl. Cryst. (2003). 36, 181-187  [ doi:10.1107/S0021889802021131 ]

Deconvolution of instrumental aberrations for synchrotron powder X-ray diffractometry

T. Ida, H. Hibino and H. Toraya

Synopsis: A method to deconvolute the instrumental aberration functions from the experimental powder X-ray data measured with a high-resolution synchrotron powder diffractometer has been developed. The effects of the diffractometer aberration and asymmetry caused by the beamline optics have been eliminated from the entire observed diffraction pattern of LaB₆ powder.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 188-192  [ doi:10.1107/S0021889802021374 ]

A novel lattice-spacing comparator with resolution of 10^-8

X. Zhang, H. Sugiyama, M. Ando, Y. Imai and Y. Yoda

Synopsis: A novel, fast and stable system for measuring the lattice spacing of a silicon crystal employs self selection of monochromatic X-rays by a monolithic double channel-cut crystal monochromator (MDCM), producing silicon 264 and 624 diffraction, which can lead to a stable, highly collimated and narrow-bandwidth beam. When utilizing the 264 and 624 Bragg reflections of a silicon sample, the angular distance between the two associated Bragg peaks must be extremely small, so that the diffraction angle can be determined with high precision and the traveling time from one peak to the other can be considerably reduced by the order of at least three compared with the established classical Bond method.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 193-205  [ doi:10.1107/S0021889802022100 ]

A procedure towards the automatic solution of crystal structures by means of topological analysis of Fourier maps

A. Menéndez-Velázquez and S. García-Granda

Synopsis: Topological analysis of Fourier maps, when carried out at room temperature, can provide conclusive proof of atom connectivity in crystal structure determination. Thus, topological analysis may unambiguously assign a chemical structure to a molecule by determining the number and kind of critical points in its electronic charge distribution, points where = 0.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 206-212  [ doi:10.1107/S0021889802022288 ]

Multiple-data-set Rietveld analysis using isotopes in powder neutron diffraction. 2. Positional and anisotropic thermal displacement parameter determinations in CuO (tenorite) at 2 K and 300 K

P. F. Henry, H. Nowell, M. T. Weller and C. C. Wilson

Synopsis: The use of isotopic-substitution neutron diffraction (ISND) with combined-data-set Rietveld analysis from powder data is described, using isotopically copper-substituted tenorite (CuO) as the test case. It is found that structural model parameters are determined to a higher precision and accuracy from combined refinements compared with separate single-data-set analysis of each of the isotopically substituted samples, with decreases in estimated uncertainties typically of 30%.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 213-219  [ doi:10.1107/S002188980202263X ]

X-ray interferometer using wavefront division

H. Yamazaki and T. Ishikawa

Synopsis: The properties of an X-ray Laue-case wavefront-dividing interferometer are analysed by the time-dependent dynamical diffraction theory. The interference fringes recorded for partially coherent incident X-rays agreed well with the analysis.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 220-229  [ doi:10.1107/S0021889802022628 ]

An intensity evaluation method: EVAL-14

A. J. M. Duisenberg, L. M. J. Kroon-Batenburg and A. M. M. Schreurs

Synopsis: A priori calculation of three-dimensional reflection boundaries for intensity integration is presented.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 230-238  [ doi:10.1107/S0021889802022641 ]

Solution of organic crystal structures from powder diffraction by combining simulated annealing and direct methods

A. Altomare, R. Caliandro, C. Giacovazzo, A. G. G. Moliterni and R. Rizzi

Synopsis: A new procedure for the determination of organic structures from powder diffraction data is presented. It uses direct-space techniques combined with information supplied by direct methods.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 239-243  [ doi:10.1107/S0021889802023208 ]

A Monte Carlo approach to crystal structure determination from powder diffraction data

V. Brodski, R. Peschar and H. Schenk

Synopsis: A new direct-space method for ab initio solution of crystal structures from powder diffraction data based on global minimization of R_wp and potential-energy cost functions is presented.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 244-248  [ doi:10.1107/S0021889802023361 ]

Local structure at a ferrofluid surface: chain-like aggregates revealed by non-specular X-ray reflection

I. Takahashi, N. Tanaka and S. Doi

Synopsis: The fractal dimension of surface-induced aggregates of super-paramagnetic colloidal particles and the surface-tension coefficient of a ferrofluid were simultaneously obtained by non-specular X-ray reflection. The temperature variation of the fractal dimension indicated the stabilization of self-organized chain-like aggregates by the loss of branches.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 249-254  [ doi:10.1107/S002188980202335X ]

A sensitive method to detect strain in silicon crystals using X-ray dynamical diffraction

T. Saka

Synopsis: A sensitive method to detect long-range strain in otherwise perfect crystalline materials is demonstrated using X-ray dynamical diffraction. A specimen is set vertically under the symmetrical Laue condition and rotated along the scattering vector.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 255-259  [ doi:10.1107/S0021889802023555 ]

Analytical use of the stereographic Wulff net for single-crystal orientation for 1-, 2- and 3-rotated cuts

E. Michalski and A. Majchrowski

Synopsis: A useful set of expressions that allow the analytical use of the stereographic Wulff net, e.g. for orientation in the Laue method, for 1-, 2- and 3-rotated cuts of single crystals fastened on a two-axis goniometric holder are derived. Application of the derived expressions in everyday crystallographic practice is illustrated by examples.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 260-268  [ doi:10.1107/S0021889803000748 ]

Phase transformation kinetic study and microstructure characterization of ball-milled m-ZrO₂-10 mol% a-TiO₂ by Rietveld method

H. Dutta, S. K. Manik and S. K. Pradhan

Synopsis: The microstructures of unmilled, ball-milled and annealed samples of a ZrO₂-10 mol% anatase TiO₂ mixture have been characterized by employing Rietveld's X-ray powder structure refinement methodology. The particle size, root mean square (r.m.s.) lattice strain, lattice parameters, molar fraction, etc., of individual phases have been estimated from Rietveld analysis and are utilized to interpret the results.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 269-279  [ doi:10.1107/S0021889803000918 ]

A Michelson interferometer for X-rays capable of high-order measurement

M. Nusshardt and U. Bonse

Synopsis: The new Michelson interferometer presented here is shown to perform hard X-ray Fourier spectroscopy over a range of more than 2700 orders. Based on the know-how gained in this study, an extension to 40000 orders appears feasible.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 280-285  [ doi:10.1107/S002188980300092X ]

Energetic materials: variable-temperature crystal structure of -NTO

N. B. Bolotina, E. Zhurova and A. A. Pinkerton

Synopsis: The thermal expansion tensor and the temperature variation of the principal structure parameters of -NTO have been determined at five temperatures in the range 100-298 K from single-crystal X-ray diffraction data. Rigid-body analysis of the molecular thermal motion in the same range was performed using the libration and translation tensors.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 286-294  [ doi:10.1107/S0021889803001031 ]

Instrument line-profile synthesis in high-resolution synchrotron powder diffraction

O. Masson, E. Dooryhée and A. N. Fitch

Synopsis: An accurate method for synthesizing the instrumental line profile of high-resolution synchrotron powder diffraction instruments is presented. It is shown that the instrumental profile can be modelled by the convolution of four physical aberration functions: the equatorial intensity distribution, the monochromator and analyser transfer functions, and the axial divergence aberration function.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 295-300  [ doi:10.1107/S0021889803001134 ]

Automated profile analysis for single-crystal diffraction data

R. J. Angel

Synopsis: A practical implementation of profile fitting for the automated integration of step-scanned single-crystal diffraction data is described.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 301-307  [ doi:10.1107/S002188980300150X ]

Mixed valences in nanometric ferrites investigated by resonant powder diffraction

J. Lorimier, F. Bernard, J.-C. Niepce, N. Guigue-Millot, O. Isnard and J.-F. Bérar

Synopsis: An investigation of the valence distribution in nanometric ferrites using anomalous powder diffraction is presented.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 308-314  [ doi:10.1107/S0021889803001997 ]

A procedure for setting up high-throughput nanolitre crystallization experiments. I. Protocol design and validation

T. S. Walter, J. Diprose, J. Brown, M. Pickford, R. J. Owens, D. I. Stuart and K. Harlos

Synopsis: Equipment and protocols used for setting up crystallizations in 96-well plates as 100 nl drops using ink-jet technologies to dispense solutions of a wide range of viscosities are described.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 315-318  [ doi:10.1107/S0021889803002012 ]

A procedure for setting up high-throughput nanolitre crystallization experiments. II. Crystallization results

J. Brown, T. S. Walter, L. Carter, N. G. A. Abrescia, A. R. Aricescu, T. D. Batuwangala, L. E. Bird, N. Brown, P. P. Chamberlain, S. J. Davis, E. Dubinina, J. Endicott, J. A. Fennelly, R. J. C. Gilbert, M. Harkiolaki, W.-C. Hon, F. Kimberley, C. A. Love, E. J. Mancini, R. Manso-Sancho, C. E. Nichols, R. A. Robinson, G. C. Sutton, N. Schueller, M. C. Sleeman, G. B. Stewart-Jones, M. Vuong, J. Welburn, Z. Zhang, D. K. Stammers, R. J. Owens, E. Y. Jones, K. Harlos and D. I. Stuart

Synopsis: An initial tranche of results from day-to-day use of a robotic system for setting up 100 nl-scale vapour-diffusion sitting-drop protein crystallizations is described.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 319-325  [ doi:10.1107/S0021889803002358 ]

Reconstruction of grain boundaries in polycrystals by filtered back-projection of diffraction spots

H. F. Poulsen and S. Schmidt

Synopsis: The filtered back-projection approach is coupled with the indexing program GRAINDEX to provide three-dimensional reconstruction of grain boundaries.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 326-332  [ doi:10.1107/S0021889803002383 ]

Structural refinements of the individual grains within polycrystals and powders

S. Schmidt, H. F. Poulsen and G. B. M. Vaughan

Synopsis: A method for simultaneous structural refinement of embedded grains is presented and verified by a study of -Al₂O₃.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 333-337  [ doi:10.1107/S0021889803002395 ]

Resolution, truncation and smearing of the one-dimensional spin echo small-angle scattering instrument

P. Yuan and J. Zhao

Synopsis: The off-plane scatterings in one-dimensional spin echo small-angle neutron scattering as well as the inhomogeneity of the precession fields cause smearing effects in the correlation functions. Desmearing procedures developed for the traditional small-angle scattering instruments can be used to restore the true parameters of the scattering particle.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 338-347  [ doi:10.1107/S0021889803002279 ]

Analysis of the small-angle intensity scattered by a porous and granular medium

O. Spalla, S. Lyonnard and F. Testard

Synopsis: It is shown how the specific porous surface and porous volume fraction of micrometric grains can be extracted from small-angle X-ray experiments even when the thickness and compactness of the sample are unknown.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 348-349  [ doi:10.1107/S0021889802023452 ]

Large-angle convergent-beam setup for femtosecond X-ray crystallography

D. Boschetto, C. Rischel, I. Uschmann, J. Perez, S. Fourmaux, D. Hulin, E. Förster and A. Rousse

Synopsis: Convergent-beam monochromatic X-ray diffraction is implemented with large-angle reflective X-ray optics and a femtosecond plasma X-ray source.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 350-351  [ doi:10.1107/S0021889803001651 ]

Easy editing of Protein Data Bank formatted files with EMACS

C. S. Bond

Synopsis: pdb-mode is a set of commands for the EMACS editor that aid the processing of PDB-formatted coordinate files during structure solution, refinement and analysis.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 352-355  [ doi:10.1107/S0021889802023099 ]

Bulk-solvent correction for fast translation search in molecular replacement: service programs for AMoRe and CNS

A. Fokine, G. Capitani, M. G. Grütter and A. Urzhumtsev

Synopsis: A new software package, called BULK, implements a bulk-solvent correction in the translation-search step of the molecular replacement packages AMoRe and CNS.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 356-365  [ doi:10.1107/S0021889802023348 ]

X-Cell: a novel indexing algorithm for routine tasks and difficult cases

M. A. Neumann

Synopsis: X-Cell is the first powder indexing algorithm that uses systematic absences and explicit impurity tolerance levels to perform an exhaustive search of possible unit cells. The zero-point shift is determined as part of the central successive dichotomy procedure and a multi-step approach facilitates the indexing of long and flat unit cells.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 366-367  [ doi:10.1107/S0021889803001158 ]

A 1300 K furnace for in situ X-ray microtomography

D. Bellet, B. Gorges, A. Dallery, P. Bernard, E. Pereiro and J. Baruchel

Synopsis: A furnace covering the temperature range from 298 to 1300 K has been designed and constructed to study in situ the structural evolution of materials by using synchrotron X-ray microtomography.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 368  [ doi:10.1107/S0021889803001432 ]

ISOMER-X: a program for the analysis of high-energy X-ray diffraction experiments

J. Urquidi, C. J. Benmore, J. Neuefeind and B. Tomberli

Synopsis: The program ISOMER-X, which can be used to obtain the pseudonuclear static structure factor for disordered materials (e.g. glasses and liquids), is described.

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 369  [ doi:10.1107/S0021889803002784 ]

Diffraction des rayons X sur échantillons polycristallins

Online 15 March 2003

 

J. Appl. Cryst. (2003). 36, 370  [ doi:10.1107/S0021889803002772 ]

Orientation of single crystals by back-reflection Laue pattern simulation

Online 15 March 2003