Journal of Applied Crystallography

Volume 35, Part 5 (October 2002)



[Issue Author Index][Volume Author Index]
[Cover illustration] Cover illustration: The crystal structure of titanite, CaTiOSiO4, viewed down the direction of the octahedral TiO6 chains. The full green lines indicate a unit cell of the two-dimensional Ising model, used to predict diffuse scattering intensity observable in layers normal to the chain direction. Ti atoms are shown in green, Ca in light grey, O in blue. The thinner red lines are Si-O bonds, the thick red lines Ti-O1 bonds. Courtesy of T. Malcherek, C. Paulmann, M. C. Domeneghetti & U. Bismayer [J. Appl. Cryst. (2001), 34, 108-113].

research papers


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 517-525  [ doi:10.1107/S0021889802008725 ]

Preparation and microstructure characterization of ball-milled ZrO2 powder by the Rietveld method: monoclinic to cubic phase transformation without any additive

S. Bid and S. K. Pradhan

Synopsis: The phase transformation kinetics of high-energy ball-milled monoclinic ZrO2 have been studied in detail by Rietveld powder structure refinement analysis.

Online 18 September 2002


 

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 526-532  [ doi:10.1107/S0021889802009056 ]

Patterson oriented automatic structure determination: superposition pseudosymmetry

F. Pavelcík and O. Pivovarcikova

Synopsis: An automatic structure determination method based on an interpretation of the Patterson function has been improved by utilizing information on superposition pseudosymmetry, detected using MIF (multiple implication function) groups. A new method of structure determination based on an enantioselective cross-vector function and on a sum atomic minimum superposition is introduced.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 533-537  [ doi:10.1107/S0021889802009202 ]

Experimental error caused by sample displacement in time-of-flight neutron diffractometry

X.-L. Wang, Y. D. Wang and J. W. Richardson

Synopsis: Sample-displacement-induced errors are found to arise largely from a change in the diffraction constant, 1/Lsin[theta], where L is the total flight path. Modeling of the experimental data indicates that in order to achieve a precision of 10-4, a typical requirement for strain measurements, for a wide angular range of detectors, the sample should be positioned to within ~0.1 mm of the diffractometer center.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 538-545  [ doi:10.1107/S0021889802009238 ]

The development and application of a method to quantify the quality of cryoprotectant solutions using standard area-detector X-ray images

M. B. McFerrin and E. H. Snell

Synopsis: An X-ray based method to quantify cryoprotectant conditions was developed and applied to determine the concentration of glycerol, PEG400, ethylene glycol and 1,2-propanediol necessary to form an amorphous glass at 100 K with the 98 solutions of Hampton Crystal Screens I and II. For solutions requiring high concentrations, cryoprotectant conditions were also determined for (2R,3R)-(-)-2,3-butanediol.

Online 18 September 2002


 

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 546-551  [ doi:10.1107/S0021889802009287 ]

RINGS: a new search/match database for identification by polycrystalline electron diffraction

D. R. Denley and H. V. Hart

Synopsis: A relational database has been built for the identification of polycrystalline solids by selected area electron diffraction (SAED) and elemental analysis. The effects of double diffraction are fully incorporated into the database through the use of reduced unit cells to calculate d spacings.

Online 18 September 2002


 

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 552-555  [ doi:10.1107/S0021889802009299 ]

ZONES: a search/match database for single-crystal electron diffraction

H. V. Hart

Synopsis: A relational database has been built for the identification of single crystals by selected area electron diffraction (SAED) and elemental analysis. The effects of double diffraction are fully incorporated into the database through the use of reduced unit cells to calculate d spacings and included angles.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 556-564  [ doi:10.1107/S0021889802009536 ]

Contrast factors of dislocations in the hexagonal crystal system

I. C. Dragomir and T. Ungár

Synopsis: Using a linear function of the fourth-order invariants of the hkl indices, the dislocation contrast factors have been evaluated numerically and compiled for a number of common hexagonal materials. A procedure is presented to match experimentally determined contrast factor parameters with the numerically obtained parameter values.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 565-570  [ doi:10.1107/S0021889802009780 ]

Simple optics to decrease beam divergence and improve energy resolution for laboratory X-ray sources

M. Kunz, P. Pattison and H. Reifler

Synopsis: An asymmetric Ge(111) monochromator and two Cr-coated tapered mirrors help to improve the beam quality of a sealed-tube Mo X-ray beam if compared with a pyrolitic graphite monochromator.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 571-576  [ doi:10.1107/S0021889802010415 ]

Quantitative phase analysis of strongly textured alloy mixtures using neutron diffraction

E. J. Shin, B. S. Seong, C. H. Lee and M. Y. Huh

Synopsis: Based on the Rietveld profile refinement of neutron diffraction patterns and a new texture analysis method, a quantitative phase analysis method is proposed and examined in the case of artificially produced multiphase alloys having strong textures.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 577-580  [ doi:10.1107/S0021889802010555 ]

X-ray structure determination of the rare earth oxides (Er1-uGdu)2O3 applying the Rietveld method

Z. Heiba, H. Okuyucu and Y. S. Hascicek

Synopsis: Nanosized polycrystalline mixed rare earth oxides could be synthesized by the sol-gel technique. Replacing Er and Gd by each other introduces slight changes in the atomic coordinates, but changes the lattice parameter non-linearly.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 581-588  [ doi:10.1107/S0021889802010610 ]

The resolution function for a time-of-flight hybrid neutron spectrometer with crystal monochromator and chopper

I. Ionita

Synopsis: A procedure for computing the resolution function for a time-of-flight hybrid neutron spectrometer with crystal monochromator and chopper using the matrix computation technique is presented. Some ideal focusing conditions deduced by compensating the major contributions to the variances of the scan variable are given; these ideal conditions can be used as a zeroth-order approximation in a numerical optimization procedure.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 589-593  [ doi:10.1107/S0021889802010695 ]

Analysis of asymmetric broadening of X-ray diffraction peak profiles caused by randomly distributed polarized dislocation dipoles and dislocation walls

I. Groma and G. Monnet

Synopsis: The asymmetric X-ray peak broadening caused by different types of randomly distributed polarized dislocation dipoles and dislocation walls is investigated. For these dislocation arrangements, the diffraction vector dependences of the asymmetric part of the intensity distributions are determined.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 594-599  [ doi:10.1107/S0021889802011160 ]

Non-destructive microstructural analysis with depth resolution: application to seashells

E. Zolotoyabko and J. P. Quintana

Synopsis: Energy-variable X-ray diffraction at a synchrotron beamline was used in order to control the X-ray penetration depth and thus to study structural parameters in polycrystalline and textured materials with depth resolution. This approach is applied to investigate the depth evolution of microstructure in the nacre layer of bivalvia seashells.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 600-605  [ doi:10.1107/S0021889802011172 ]

A standardless X-ray diffraction method for the quantitative analysis of multiphase mixtures. II. Application to non-infinitely thick samples

E. T. Gomez, T. Sanfeliu and J. Rius

Synopsis: To extend an earlier method of `least-squares' determination of calibration constants that uses only the diffracted intensities and the calculated absorption coefficients of the components to the case of airborne particulates, two possibilities for correcting the measured intensities are explored: either by direct measurement of the sample transmission, or alternatively, by using refined transmission values. In the latter case no experimental values are necessary.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 606-614  [ doi:10.1107/S0021889802011470 ]

A high-resolution X-ray diffractometer for the study of imperfect materials

A. Boulle, O. Masson, R. Guinebretière, A. Lecomte and A. Dauger

Synopsis: A high-resolution X-ray diffractometer, based on a rotating anode generator, a four-bounce monochromator, a five-movement sample holder and a curved position-sensitive detector and devoted to the study of imperfect materials (mainly oxides and ceramics), is presented. The setup allows rapid acquisition of a reciprocal-space map (in less than 10 h) even for very poorly diffracting materials.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 615-623  [ doi:10.1107/S0021889802013699 ]

Resolution of neutron three-axis spectrometers using acceptance diagrams

L. D. Cussen

Synopsis: Acceptance diagrams permit the optimum choice of beam elements for three-axis spectrometers.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 624-633  [ doi:10.1107/S0021889802011007 ]

X-ray scattering of non-graphitic carbon: an improved method of evaluation

W. Ruland and B. Smarsly

Synopsis: In this paper the theory of scattering from non-graphitic carbon is revised, appropriate scattering functions are derived for the fitting procedure, and examples of application using an improved method of evaluation are presented.

Online 18 September 2002


short communications


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 634-636  [ doi:10.1107/S0021889802011214 ]

Structural and anisotropic thermal expansion correlation of Li2ZrO3 at different temperatures

Z. K. Heiba and K. El-Sayed

Synopsis: Structural and thermal expansion studies of Li2ZrO3 were carried out by recording X-ray powder diffraction patterns at five temperatures: 82, 198, 300, 423 and 573 K. Large anisotropic changes in the lattice parameters were found as a function of temperature, with slight changes in the fractional coordinates of the different atoms, and anisotropic changes in the interatomic distances between the different cations.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 637-640  [ doi:10.1107/S0021889802012001 ]

From test tube to plate: a simple procedure for the rapid preparation of microcrystallization experiments using the cubic phase method

P. Nollert

Synopsis: A semi-automated microprocedure for setting up membrane protein crystallization trials using lipidic cubic phases is described. In a proof-of-concept experiment, crystals of bacteriorhodopsin were grown under newly found conditions.

Online 18 September 2002


computer programs


 

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 641-643  [ doi:10.1107/S0021889802010580 ]

OMNIBUS: a program for reduction, modelling and viewing X-ray single-crystal data from various four-circle diffractometers

E. Galdecka

Synopsis: In the OMNIBUS program, various data reduction methods are offered to the user. Special attention is paid to those which are based on data modelling with a `learnt profile'.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 644-647  [ doi:10.1107/S0021889802011937 ]

COMPANG: automated comparison of orientations

L. Urzhumtseva and A. Urzhumtsev

Synopsis: COMPANG is an interactive program that allows the comparison of multiple lists of orientations, for example the peaks of rotation functions.

Online 18 September 2002


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 648-649  [ doi:10.1107/S002188980201292X ]

The PRIDE server for protein three-dimensional similarity

K. Vlahovicek, O. Carugo and S. Pongor

Synopsis: A Web server is presented that allows one to compare, cluster, and search similar protein structures.

Online 18 September 2002


laboratory notes


thumbnail of article figure

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 650-651  [ doi:10.1107/S002188980201347X ]

X-ray beam steering with flexible polycapillaries

U. W. Arndt and S. W. Scotcher

Synopsis: X-ray beams from a fine-focus X-ray tube can be displaced by appreciable amounts without a serious intensity loss by passing these beams through a glass capillary or polycapillary, the tip of which is translated mechanically under fine control.

Online 18 September 2002


computer program abstracts


 

[HTML version][PDF version]  [Buy article online]

J. Appl. Cryst. (2002). 35, 652  [ doi:10.1107/S0021889802013997 ]

WINOPTACT: a computer program to calculate optical rotatory power and refractive indices from crystal structure data

A. M. Glazer

Synopsis: WINOPTACT, a computer program to enable calculations of optical rotation and refractive indices from a known crystal structure, is described.

Online 18 September 2002


 

J. Appl. Cryst. (2002). 35, 653-654

forthcoming meetings and short courses


Copyright © International Union of Crystallography
IUCr Webmaster