Journal of Applied Crystallography

 

J. Appl. Cryst. (2002). 35, 655-663  [ doi:10.1107/S0021889802013420 ]

Generic representation and evaluation of properties as a function of position in reciprocal space

K. Cowtan

Synopsis: A generalized approach is described for evaluating arbitrary functions of position in reciprocal space. This offers both greater convenience and often superior results for a small but ubiquitous component of almost every crystallographic computation.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 664-668  [ doi:10.1107/S0021889802016497 ]

Diffraction thermometry and differential thermal analysis

E. H. Kisi and D. P. Riley

Synopsis: A unit-cell parameter anomaly observed during the precipitation and growth of Ti₃SiC₂ from a Si-substituted TiC phase is interpreted as the release of latent heat. The observations are used to propose a powder diffraction method for conducting differential thermal analysis as part of in situ phase transition studies.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 669-673  [ doi:10.1107/S0021889802014012 ]

Unexpected molecular structure from laboratory powder diffraction data

V. V. Chernyshev, A. V. Yatsenko, A. M. Kuvshinov and S. A. Shevelev

Synopsis: Starting from erroneous two-dimensional structures, it was possible to obtain the correct solution of the structure of a compound by the use of a combination of a systematic grid search and bond-restrained Rietveld refinement. Based on the correct molecular structure thus obtained, the crystal structures of two related compounds were routinely solved by the grid search technique.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 674-676  [ doi:10.1107/S0021889802013973 ]

Crystallization of protein-protein complexes

S. Radaev and P. D. Sun

Synopsis: A survey of the crystallization conditions is carried out for all known protein-protein complexes to date. Based on the survey results, a sparse screen matrix is proposed to facilitate the crystallization of protein complexes.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 677-683  [ doi:10.1107/S0021889802014917 ]

Polycapillary focusing optic for small-sample neutron crystallography

W. M. Gibson, A. J. Schultz, H. H. Chen-Mayer, D. F. R. Mildner, T. Gnäupel-Herold, M. E. Miller, H. J. Prask, R. Vitt, R. Youngman and J. M. Carpenter

Synopsis: A polycapillary focusing optic has been tested both on a monochromatic and a polychromatic beam of neutrons. An intensity gain of as much as 5.8 ± 0.9 was observed.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 684-688  [ doi:10.1107/S0021889802015261 ]

Separating the recrystallization and deformation texture components by high-energy X-rays

Y. D. Wang, X.-L. Wang, A. D. Stoica, J. D. Almer, U. Lienert and D. R. Haeffner

Synopsis: Measurements on partially recrystallized samples using a monochromatic high-energy synchrotron beam show that recrystallized grains generate sharp diffraction spots, whereas the intensity from the deformed matrix varies smoothly along the Debye-Scherrer rings. Based on these observations, a method has been developed to separate the recrystallization texture components from those originating from the deformation matrix.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 689-695  [ doi:10.1107/S0021889802016175 ]

Surface-relaxation contributions to axial screw dislocation contrast in synchrotron white-beam X-ray topographs of SiC

W. M. Vetter and M. Dudley

Synopsis: X-ray topographic images of micropipes in SiC arising from surface-relaxation effects are described, followed by computer simulations using the ray-tracing method.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 696-701  [ doi:10.1107/S0021889802013985 ]

Calculation of crystal truncation rod structure factors for arbitrary rational surface terminations

T. P. Trainor, P. J. Eng and I. K. Robinson

Synopsis: A method is presented for determining a surface coordinate system which results in a reciprocal lattice that is simply defined in terms of the surface termination. Based on this surface coordinate system, a general formalism for the calculation of crystal truncation rod structure factors is derived, which may be easily applied to any surface that can be represented as a rational plane of a bulk crystal system.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 702-712  [ doi:10.1107/S0021889802015376 ]

An acceptance-diagram description of beams from focusing monochromators

L. D. Cussen

Synopsis: Acceptance diagrams simplify the description of beams from focusing monochromators.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 713-719  [ doi:10.1107/S0021889802016072 ]

Theory of two-dimensional focusing of a spherical X-ray wave by Bragg diffraction by two bent crystals

T. Tchen

Synopsis: The dynamical theory of the diffractional Bragg focusing in a system of cylindrically bent crystals is developed. Two-dimensional focusing `point-to-point' is shown to be possible under certain conditions.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 720-726  [ doi:10.1107/S0021889802016709 ]

An automated system to mount cryo-cooled protein crystals on a synchrotron beamline, using compact sample cassettes and a small-scale robot

A. E. Cohen, P. J. Ellis, M. D. Miller, A. M. Deacon and R. P. Phizackerley

Synopsis: A system, implemented at SSRL, for automatically mounting and dismounting pre-frozen crystals at a synchrotron beamline is described. The system is based on a small industrial robot and compact cylindrical sample cassettes.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 727-733  [ doi:10.1107/S0021889802013675 ]

A simple simulator of protein crystallization

V. Gopalakrishnan, B. G. Buchanan and J. Rosenberg

Synopsis: The development of an approximate physical model that can be used for simulating different types of protein crystallization behavior in response to varying physico-chemical environments is presented.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 734-743  [ doi:10.1107/S0021889802015236 ]

FOX, `free objects for crystallography': a modular approach to ab initio structure determination from powder diffraction

V. Favre-Nicolin and R. Cerný

Synopsis: A new tool for ab initio structure determination from powder diffraction is presented. It uses global-optimization algorithms and is suitable for any type of crystal structure (organic, inorganic including automatic correction of special positions), and can combine several data sets.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 744-749  [ doi:10.1107/S0021889802017405 ]

FULLPAT: a full-pattern quantitative analysis program for X-ray powder diffraction using measured and calculated patterns

S. J. Chipera and D. L. Bish

Synopsis: FULLPAT is a quantitative X-ray diffraction methodology that merges the advantages of existing full-pattern fitting methods with the traditional reference intensity ratio (RIR) method. Like the Rietveld quantitative analysis method, it uses complete diffraction patterns, including the background; however, FULLPAT can explicitly analyze all phases in a sample including partially ordered or amorphous phases such as glasses, clay minerals, or polymers.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 750  [ doi:10.1107/S0021889802015388 ]

SF2CNS: general purpose program to calculate CNS-formatted maps easily

A. Urzhumtsev and L. Urzhumtseva

Synopsis: The general-purpose program SF2CNS calculates the Fourier syntheses in the CNS format starting directly from structure factors written in various formats, without the need for any format converter or the use of CNS itself.

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 751  [ doi:10.1107/S0021889802016576 ]

2003 Herman Skolnik Award to Frank Allen

Online 13 November 2002

 

J. Appl. Cryst. (2002). 35, 751  [ doi:10.1107/S0021889802016588 ]

Ron Jenkins (1932-2002)

Online 13 November 2002