Journal of Applied Crystallography

Volume 34, Part 2 (April 2001)



[Issue Author Index][Volume Author Index]
[Cover illustration] Cover illustration: Diffuse scattering around a 200 Bragg peak from a Cu-Ti single crystal (the intensities are in ln scale, the plane is (001), with the [100] direction horizontal, and the Bragg peak is masked by the blue beam stop). Courtesy of O. Lyon, C. Servant & J. P. Simon [J. Appl. Cryst. (2000), 33, 928-937].

research papers


 

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

J. Appl. Cryst. (2001). 34, 97-101  [ doi:10.1107/S0021889800017362 ]

Clear strategy screens for macromolecular crystallization

A. M. Brzozowski and J. Walton

Synopsis: Two complementary 6 × 4 matrix `clear strategy screens' have been developed and tested on a number of previously non-crystallized proteins. The screens yielded diffraction-quality crystals of a wide range of proteins (enzymes, transcription factors, structural proteins, etc.) in cases where the applications of commercially available screens were unsuccessful.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 102-107  [ doi:10.1107/S0021889800020495 ]

Estimation of cobalt coating layer thickness on acicular Fe3O4 powder using HR-TEM

K. Sakai, H. Saguchi and T. Nishimura

Synopsis: The thicknesses of cobalt coating layers grown on four different types of acicular Fe3O4 particles were estimated from the analysis of lattice images and from the determination of the Co depth profile using high-resolution transmission electron microscopy (HR-TEM) coupled with an EDX system. It was observed that the coating thickness might vary with the crystallite size resulting from the growth mechanism of the coating layer.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 108-113  [ doi:10.1107/S0021889800017763 ]

Diffuse scattering anisotropy and the P21/a [left right arrow] A2/a phase transition in titanite, CaTiOSiO4

T. Malcherek, C. Paulmann, M. C. Domeneghetti and U. Bismayer

Synopsis: Diffuse scattering near the displacive order-disorder phase transition in titanite, CaTiOSiO4, has been observed using synchrotron radiation and it is interpreted in terms of a two-dimensional ordering of linearly correlated Ti displacements.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 114-118  [ doi:10.1107/S0021889800017908 ]

Determination of the crystallized fractions of a largely amorphous multiphase material by the Rietveld method

X. Orlhac, C. Fillet, P. Deniard, A. M. Dulac and R. Brec

Synopsis: The Rietveld method has proved to be a very effective means to characterize and quantify the crystalline phases and the amorphous phase in glass ceramic materials using X-ray powder diffraction data. The technique was applied to a borosilicate glass of the type used for high-level nuclear-waste containment, in order to measure the proportions of the crystallized phases after heat treatment and, thus, to qualify the thermal stability of the glass.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 119-129  [ doi:10.1107/S0021889800018239 ]

Characterization of H defects in the aluminium-hydrogen system using small-angle scattering techniques

C. E. Buckley, H. K. Birnbaum, J. S. Lin, S. Spooner, D. Bellmann, P. Staron, T. J. Udovic and E. Hollar

Synopsis: Small- and ultra-small-angle neutron scattering (SANS, USANS) and small-angle X-ray scattering (SAXS) were employed to study the nature and agglomeration of H-vacancy complexes in the Al-H system. The SAXS results were ambiguous owing to double Bragg scattering, but the SANS and USANS investigation, coupled with results from inelastic neutron scattering, and transmission and scanning electron microscopy, revealed the existence of a large size distribution of hydrogen bubbles on the surface and in the bulk of the Al-H system.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 130-135  [ doi:10.1107/S0021889800018227 ]

Global indicators of X-ray data quality

M. S. Weiss

Synopsis: Some global criteria that indicate the overall quality of diffraction data are presented. They are discussed and evaluated with respect to their performance in various crystallographic tasks.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 136-143  [ doi:10.1107/S0021889800019956 ]

Asymmetries of the Voigt line shape

H. Flores-Llamas

Synopsis: Two power series expansions are obtained for two cases of asymmetric Voigt line shapes: a linear combination of the Voigt line shape (VLS) and its derivatives, valid for small asymmetries, and the sum of the VLS and an odd-parity line shape, valid for intermediate asymmetries. An improved line shape, defined as a linear combination of the traditional VLS with the odd-parity line shape, is also presented.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 144-151  [ doi:10.1107/S0021889800021105 ]

Peak profile function for synchrotron X-ray diffractometry

T. Ida, H. Hibino and H. Toraya

Synopsis: A formula of the instrumental function for a synchrotron X-ray diffractometer has been derived. The experimental profiles of standard Si powder are well reproduced by the model profile function given by the convolution of a Lorentzian function with the instrumental function, within experimental uncertainty.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 152-156  [ doi:10.1107/S0021889801001157 ]

Treatment of grazing-incidence small-angle X-ray scattering data taken above the critical angle

A. Martorana, A. Longo, F. d'Acapito, C. Maurizio, E. Cattaruzza and F. Gonella

Synopsis: The grazing-incidence X-ray scattering geometry is analysed with regard to the correction for refraction when the angle of incidence is slightly larger than the critical angle and considering the smearing of the recorded pattern depending on the size of the illuminated sample region.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 157-165  [ doi:10.1107/S0021889801001352 ]

Kinematical two-dimensional multiple-diffraction intensity profiles. Application to [omega]-[psi] scans of silicon and diamond obtained with synchrotron radiation

E. Rossmanith, A. Hupe, R. Kurtz, H. Schmidt and H.-G. Krane

Synopsis: Two-dimensional multiple-diffraction patterns calculated within the framework of the kinematical theory are compared with [omega]-[psi] scans of silicon and diamond measured with synchrotron radiation.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 166-171  [ doi:10.1107/S0021889801002072 ]

An X-ray interferometer with a large and variable path length difference

K. Fezzaa and W.-K. Lee

Synopsis: The first chromatic hard X-ray interferometer with a large and variable path length difference has been built and successfully tested.

Online 1 April 2001


 

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

J. Appl. Cryst. (2001). 34, 172-177  [ doi:10.1107/S0021889800019993 ]

A comparison of various commonly used correlation functions for describing total scattering

D. A. Keen

Synopsis: The formalism that describes total-scattering correlation functions is developed using a consistent notation and is compared with other, frequently encountered, formalisms. It is hoped that this will lead to increased transparency for newcomers to the field of total scattering.

Online 1 April 2001


 

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

J. Appl. Cryst. (2001). 34, 178-186  [ doi:10.1107/S0021889801000668 ]

The reliability index R2 as a versatile tool in structure analysis of inorganic and small molecular compounds

P. T. Beurskens, R. Israël, R. de Gelder, G. Beurskens and R. A. G. de Graaff

Synopsis: R_2 can be used as a selection criterion at various stages of the process of structure determination. In both of the programs DIRDIF and AUTOFOUR, R_2 is used: to select starting models, to improve the model selected and to discriminate between possible atomic positions during structure expansion. It is shown that the use of the R_2 function facilitates the structure analysis of inorganic and small molecular compounds.

Online 1 April 2001


 

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

J. Appl. Cryst. (2001). 34, 187-195  [ doi:10.1107/S0021889801002060 ]

Elastic strain and stress determination by Rietveld refinement: generalized treatment for textured polycrystals for all Laue classes

N. C. Popa and D. Balzar

Synopsis: Diffraction line shifts in Rietveld refinement are modeled via a series of generalized spherical harmonics. Strain and stress tensors can be determined through the refinement of strain-related coefficients simultaneously with other parameters.

Online 1 April 2001


 

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

J. Appl. Cryst. (2001). 34, 196-202  [ doi:10.1107/S0021889801002485 ]

Rietveld quantitative amorphous content analysis

A. G. De La Torre, S. Bruque and M. A. G. Aranda

Synopsis: Amorphous phases do not diffract coherently, but from the overestimation of an appropriate crystalline standard added to the sample, the amorphous content can be measured with an accuracy close to 1%.

Online 1 April 2001


cryocrystallography papers


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Supplementary Material]  [Buy article online]

J. Appl. Cryst. (2001). 34, 203-207  [ doi:10.1107/S0021889800018987 ]

A perdeuterated cryoprotectant for neutron studies and a demonstration of its use for neutron powder diffraction on L-(-)-ephedrine hemihydrate

F. C. Krebs, M. Jørgensen, B. Lebech and K. Frydenvang

Synopsis: The use of a noncrystalline perdeuterated cryoprotectant for neutron studies is evaluated in the context of solvent-containing molecular crystals.

Online 1 April 2001


short communications


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 208-209  [ doi:10.1107/S0021889801000450 ]

Temperature dependence of lattice constants of the rare-earth hexaborides EuB6 and GdB6

Y. Takahashi, M. Fujimoto, M. Tsuchiko and K.-I. Ohshima

Synopsis: By analysing the low-temperature X-ray patterns, it is found that the lattice constants of EuB6 and GdB6 decrease monotonously with decreasing temperature. The linear thermal expansion coefficients for the two compounds were also obtained by analysing the temperature dependence of the lattice constants.

Online 1 April 2001


computer programs


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 210-213  [ doi:10.1107/S0021889801002242 ]

EXPGUI, a graphical user interface for GSAS

B. H. Toby

Synopsis: A description of the EXPGUI graphical user interface for the GSAS package is presented.

Online 1 April 2001


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 214-223  [ doi:10.1107/S0021889801001753 ]

Refinement of proteins at subatomic resolution with MOPRO

B. Guillot, L. Viry, R. Guillot, C. Lecomte and C. Jelsch

Synopsis: The program MOPRO has been developed for charge density analysis of macromolecules. The advantage of using restraints in the charge density analysis of both small and large molecules is discussed, and the algorithmic optimizations and the parallelization of the program are presented.

Online 1 April 2001


laboratory notes


thumbnail of article figure

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

J. Appl. Cryst. (2001). 34, 224  [ doi:10.1107/S0021889800018951 ]

A very simple and cheap greasing device for crystallization plates

N. Watanabe

Synopsis: A greasing device to facilitate the application of grease to a 24-well crystallization plate is presented.

Online 1 April 2001


international union of crystallography


 

[HTML version][PDF version]  [Open access]

J. Appl. Cryst. (2001). 34, 225  [ doi:10.1107/S002188980100053X ]

Reduced-price subscriptions to IUCr journals

Online 1 April 2001


crystallographers


 

[HTML version][PDF version]  [Open access]

J. Appl. Cryst. (2001). 34, 225  [ doi:10.1107/S0021889801004642 ]

Harry Brumberger (1926-2000)

Online 1 April 2001


 

[HTML version][PDF version]  [Open access]

J. Appl. Cryst. (2001). 34, 225  [ doi:10.1107/S0021889801004630 ]

Ludo Frevel Crystallography Scholarship

Online 1 April 2001


 

J. Appl. Cryst. (2001). 34, 226-228

forthcoming meetings and short courses


Copyright © International Union of Crystallography
IUCr Webmaster