issue contents

Journal logoJOURNAL OF
ISSN: 1600-5767

December 2011 issue

Highlighted illustration

Cover illustration: Selected images of optical birefringence recorded during the heating of dodecasil-3C crystals. Courtesy of Lethbridge et al. [J. Appl. Cryst. (2010), 43, 168-175].

research papers

J. Appl. Cryst. (2011). 44, 1143-1151
doi: 10.1107/S0021889811042154
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The standard ab initio VLD phasing algorithm has been improved; small to medium-size structures and proteins can be solved with greater efficiency.

J. Appl. Cryst. (2011). 44, 1152-1156
doi: 10.1107/S002188981104310X
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A complete list of distinct twist boundaries and zones of tilt boundaries for low-Σ coincident site lattice misorientations is provided. For these misorientations, maps of twist and tilt boundary planes are drawn. The maps allow for ascribing twist or tilt boundaries to peaks on experimental boundary distributions, and indicate boundaries with two-dimensional periodicities.

J. Appl. Cryst. (2011). 44, 1157-1163
doi: 10.1107/S0021889811035837
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The scattering pattern from micrometre-sized phase-shifting objects is calculated by using its Radon transform and Fraunhofer diffraction, and good agreement is found (in the case of a homogeneous sphere) for particle sizes up to 50 µm.

J. Appl. Cryst. (2011). 44, 1164-1168
doi: 10.1107/S0021889811041173
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A method to identify the type and the Burgers vector of dislocations visualized via transmission electron microscopy is proposed. The basic principle of the method is to use previous knowledge of the crystal structure to calculate the possible dislocation line vectors in the transmission electron microscope screen coordinate system and compare them with the observed dislocation lines.

J. Appl. Cryst. (2011). 44, 1169-1172
doi: 10.1107/S0021889811040763
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It is shown that an extremely inclined X-ray double-crystal monochromator can diffract a beam with the required wavelength and at the same time may reflect a great deal of unwanted radiation in a broad range of Bragg angles. The properties of such a device are discussed.

J. Appl. Cryst. (2011). 44, 1173-1181
doi: 10.1107/S002188981104115X

J. Appl. Cryst. (2011). 44, 1182-1189
doi: 10.1107/S0021889811038143
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A new method for determination of the orientation matrix of Laue X-ray data is presented. The method is based on matching of the patterns of central reciprocal lattice rows projected on a unit sphere centered on the origin of the reciprocal lattice of the Laue data set with the corresponding pattern of a monochromatic data set on the same material.

J. Appl. Cryst. (2011). 44, 1190-1197
doi: 10.1107/S0021889811041069
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The effect of initial cold-rolling reduction on the microtexture development of retained austenite in an aluminium-containing transformation-induced plasticity (TRIP) steel has been studied.

J. Appl. Cryst. (2011). 44, 1198-1204
doi: 10.1107/S0021889811041446
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A study of the differential evolution global optimization algorithm applied to fitting X-ray reflectivity data is presented. The results are summarized as rules of thumb for tuning the optimization algorithm.

J. Appl. Cryst. (2011). 44, 1205-1210
doi: 10.1107/S0021889811042294
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Rietveld refinements have been performed on diffraction diagrams collected on nanomaterials under grazing incidence X-ray diffraction.

J. Appl. Cryst. (2011). 44, 1211-1216
doi: 10.1107/S0021889811042221
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This article introduces an efficient method for X-ray diffraction data collection mapping on a given curved surface.

J. Appl. Cryst. (2011). 44, 1217-1221
doi: 10.1107/S0021889811042944
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A method is introduced for surface structure refinement using both anomalous and normal diffraction data simultaneously.

J. Appl. Cryst. (2011). 44, 1222-1226
doi: 10.1107/S0021889811043366
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The orientation relationship between austenite and 5M martensite in Ni–Mn–Ga alloys has been unambiguously determined by experimental measurements and crystallographic calculation without residual austenite.

J. Appl. Cryst. (2011). 44, 1227-1237
doi: 10.1107/S0021889811036910
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The thermal expansion coefficient of a marble is directly related to the preferred crystallographic orientation of its constituent minerals (calcite and dolomite). The thermal properties also depend on the existence of impurities and the presence of dislocations in single calcite and dolomite crystals.

J. Appl. Cryst. (2011). 44, 1238-1245
doi: 10.1107/S0021889811037447
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Small- and ultra-small-angle neutron scattering measurements show that the pore wall of porous TiO2 is not sharp but is rather diffuse.

J. Appl. Cryst. (2011). 44, 1246-1254
doi: 10.1107/S0021889811037411
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Several sets of special directions (SDs) for cubic lattices are proposed, which could be utilized in both theoretical and experimental investigations. These sets allow for the construction in the whole Brillouin zone of some quantities known for a limited number of such SDs.

short communications

J. Appl. Cryst. (2011). 44, 1255-1258
doi: 10.1107/S0021889811035709
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The use of quasi-mosaic crystals for the focusing of hard X-rays at high resolution in a Laue lens is proposed. Comparison with traditional mosaic crystals with the same size and energy passband shows that quasi-mosaic crystals increase the signal-to-noise ratio by about an order of magnitude; moreover, for quasi-mosaic crystals no mosaic defocusing occurs.

CIF applications

J. Appl. Cryst. (2011). 44, 1259-1263
doi: 10.1107/S0021889811041161
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iotbx.cif is a comprehensive toolbox for the development of applications that make use of the CIF format.

computer programs

J. Appl. Cryst. (2011). 44, 1264-1271
doi: 10.1107/S0021889811035758
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DADIMODO is a program for refining atomic models of multidomain proteins or complexes against small-angle X-ray scattering data. Interdomain distance and orientational restraints, such as those derived from NMR measurements, can be included in the optimization process.

J. Appl. Cryst. (2011). 44, 1272-1276
doi: 10.1107/S0021889811038970
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VESTA is a three-dimensional visualization system for crystallographic studies and electronic state calculations. It has been upgraded to the latest version, VESTA 3, which implements many new features.

J. Appl. Cryst. (2011). 44, 1277-1280
doi: 10.1107/S0021889811046188
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SAAF is a tool for analyzing small-angle neutron scattering data using analytical model functions. One of its features is the ability to perform de-smearing on data sets with variable and convoluted instrument resolutions.

J. Appl. Cryst. (2011). 44, 1281-1284
doi: 10.1107/S0021889811043202
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ShelXle is a user-friendly graphical user interface for SHELXL. It combines an editor with syntax highlighting for SHELXL-associated files with an interactive graphical display for visualization of a three-dimensional structure.

J. Appl. Cryst. (2011). 44, 1285-1287
doi: 10.1107/S0021889811041768
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The program ANODE determines anomalous (or heavy-atom) densities by reversing the usual procedure for experimental phase determination. Instead of adding a phase shift to the heavy-atom phases to obtain a starting value for the native protein phase, this phase shift is subtracted from the native phase to obtain the heavy-atom substructure phase.

laboratory notes

J. Appl. Cryst. (2011). 44, 1288-1290
doi: 10.1107/S0021889811039057
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A sample holder for rough characterization of protein powder by in-house X-ray powder diffraction has been designed. The holder is further adaptable to X-ray absorption spectroscopy measurements, enabling the combination of the two techniques.

J. Appl. Cryst. (2011). 44, 1291-1293
doi: 10.1107/S0021889811039537
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A new modification of the zero-background holder is proposed for handling small bulk samples.

J. Appl. Cryst. (2011). 44, 1294-1296
doi: 10.1107/S0021889811045225
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A new cuvette has been designed, possessing eight identical chambers, which enables fast acquisition of a data set in biological solution scattering experiments and extrapolation of the data set to infinite dilution within 20 min.

J. Appl. Cryst. (2011). 44, 1297-1299
doi: 10.1107/S0021889811042373
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A compact pneumatic device is presented here, capable of simultaneously applying heat (up to ∼470 K) and stress (up to 500 N) to an evacuated fibre sample. Initial results shows slight but significant effects of stress and heating on the internal void structure of poly(p-phenylene terephthalamide) fibres.

book reviews

J. Appl. Cryst. (2011). 44, 1300
doi: 10.1107/S0021889811039902

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