The Resolution Function in Diffuse X-ray Reflectivity

It is shown that a simple interpretation of diffuse and specular reflectivity is possible if the resolution function is separable for two directions in the scattering plane.

Texture Approximation or Texture Modelling with Components Represented by the von Mises–Fisher Matrix Distribution on SO(3) and the Bingham Distribution on S⁴⁺₊

The von Mises–Fisher matrix distribution on SO(3) provides a versatile mathematical model for both analysis and component-fit methods in texture analysis, even though a theoretical justification is missing.

In Situ Small-Angle X-ray Scattering Observations of Pt/NaY Catalysts During Processing: Sintering of Pt

Sintering of Pt on NaY zeolite support during processing is examined via in situ small-angle X-ray scattering, which indicates that the particle-size distribution of Pt in the reduced and finished catalyst is determined during the earliest stages of calcination.

Thin-Film Study using Low-Incidence and Bragg–Brentano Texture Goniometry. Application to Mono- and Bilayers of Al and Al/Fe

Intensity corrections are described when the textures of thin layers are studied in low-incidence geometry. These corrections are applied to aluminium and iron thin films or bilayers deposited on steel or silicon.

Reflection Asymmetric Powder Diffraction with Flat-Plate Sample using a Curved Position-Sensitive Detector (INEL CPS 120)

The specific influence of the asymmetric diffraction geometry on peak position, profile shape and intensity determination is studied when a curved position-sensitive detector and a conventional pseudoparallel incident beam are used.

The Use of Small-Angle Scattering and the Maximum-Entropy Method for Shape-Model Determination from Distance-Distribution Functions

With the a priori assumption of a special type of structure model, the unknown parameters are calculated using analytical real- space functions and slit-distorted small-angle scattering curves.

Analysis of Slit-Smeared Small-Angle Scattering Data from Interacting Systems via Indirect-Transformation Methods

The indirect-transformation method in reciprocal space (ITR) and the indirect-transformation method are used in the analysis of small-angle X-ray scattering (SAXS) curves from semidilute aqueous solutions of fragmented DNA. In particular, the ITR method is used to desmear those SAXS curves where interparticle interference effects are present, with the aim of obtaining the interference function.

Absorption Corrections of Powder Diffraction Intensities Recorded in Transmission Geometry

The absorption behaviour of X-rays scattered by samples in transmission geometry is analyzed and a correction procedure is proposed. The given expressions were tested by their application in Rietveld analysis.

X-ray Moiré Topography on SIMOX Structures

From Moiré fringes observed on X-ray diffraction topographs of SIMOX (separation by implantation of oxygen) structures, the in-plane components of the triclinic relative strain are determined.

A New Kösters Prism Interferometer for Simultaneous Determination of Refractive Index and Thermal Expansion of Crystals as a Function of Temperature

Measurements of refractive index and thermal expansion as a function of temperature, which were conducted using a new Kösters prismn interferometer, are described and presented for quartz, barium sodium niobate and indium-doped potassium titanyl arsenate.

Glycerol concentrations required for cryoprotection of 50 typical protein crystallization solutions

Measurement has been made of the minimum glycerol concentration required to cryoprotect 50 typical protein crystallization solutions for use in macromolecular cryocrystallographic diffraction data collection at around 100 K.

Application of the Rietveld method in the study of the reaction of formation of Y₂BaCuO₅

By use of the Rietveld method and the formation-reaction equations as constraint, a straightforward numerical procedure to improve the quantitative analysis of a compound was obtained.

On the insensitivity of the asymptotic behaviour of small-angle neutron and X-ray scattering data to multiple scattering

A simple general argument is given showing the independence of the asymptotic behaviour of small-angle scattering from any amount of multiple scattering. The argument is valid as long as the intensity drops faster than 1/q².

Distributions of rotation axes for randomly oriented symmetric objects. Erratum

Correction to J. Appl. Cryst. (1996), 29, 164–169.

Visualization of macromolecular crystal packing using Virtual Reality Modelling Language (VRML)

A program (XPACK.PL) written in Perl that transforms Brook- haven Protein Data Bank structure files into three-dimensional crystal packing Virtual Reality Modelling Language (VRML) world files is discussed.

CIF Applications. V. CIFtbx2: extended tool box for manipulating CIFs

CIFtbx2 is a new version of a Fortran subroutine library for programmers developing CIF applications. The functions for reading and writing CIF data in CIFtbx have been expanded and facilities for handling macromolecular CIF data and dictionaries have been added.

Two methods of expanding the measurement abilities of a four-circle diffractometer

Implementation into the control program of very flexible scans in hkl and angular space is presented. With the analysing tool, it can be used for determination of real structures in thin films, superstructures etc.

Design of a new flat sample holder for air-sensitive substances fitting to an Enraf-Nonius FR552 Guinier camera

Apparatus for investigating air-sensitive powder samples with a flat sample holder fitting in an Enraf-Nonius FR552 Guinier camera is described.

A simple device for studying macromolecular crystals under moderate gas pressures (0.1–10 MPa)

A simple device for studying crystalline samples under moderate gaseous pressure has been used to produce several xenon derivatives of proteins providing useful phasing information.

New Editor-in-Chief of IUCr journals

New Commercial Products

Silicon carbide and related materials 1995 edited by S. Nakashima, H. Matsunami, S. Yoshida and H. Harima

Defect recognition and image processing in semiconductors 1995 edited by A. R. Mickelson

Growth of crystals. Vol. 20. edited by E. I. Givargizov and A. M. Melnikova