Materials Literature
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Superparamagnetic microspheres with an Fe3O4@SiO2 core and a perpendicularly aligned mesoporous SiO2 shell were synthesized through a surfactant-templating sol-gel approach. The microspheres possess high magnetization (53.3 emu/g), high surface area (365 m2/g), large pore volume (0.29 cm3/g), and uniform mesopore (2.3…
The uses of powder diffraction in the study of Portland cements and new eco-cements (those that release less CO2 in their fabrication processes) are highlighted. Firstly, the uses of powder diffraction for analysing the anhydrous commercial cements (Portland, calcium aluminate and calcium sulfoaluminate) are reviewed.…
Powder diffraction is the mostly widely used crystallographic method, with applications spanning all aspects of structural science. This new volume of International Tables for Crystallography covers all aspects of the technique with over 50 chapters written by experts in the field. Consisting of seven parts, this volu…
This chapter provides an overview and summary of the wide variety of methods that are available for crystal structure determination from powder diffraction data, and is intended to serve as an easy-to-read introduction to the subject. Each method is discussed briefly and illustrated with examples of solved crystal str…
This chapter discusses the theoretical background and the practical tools for solving structures from powder-diffraction data using reciprocal-space methods. In particular, it describes the basic concepts of direct methods, Patterson methods, charge flipping and maximum-entropy methods. Developments of these methods a…
Conventionally, crystallography is based on two extreme sample morphologies: perfect single crystals and homogeneous powders. In the last decade, however, methods have been developed to treat polycrystalline specimens as an ensemble of individual crystals, creating the possibility to rigorously characterize such sampl…
This chapter reviews the basic concepts, models, methods and approaches in the investigation of the stress and strain in polycrystalline materials by diffraction. The chapter contains eight sections that can be grouped into three parts. In the first part (Sections 5.2.1–5.2.3), the specific quantities for single cryst…
Today's home-laboratory X-ray diffractometers can be used for a wide range of applications, from X-ray scattering from any solids or liquids with any degree of order to X-ray absorption (radiography) and X-ray emission (XRF) techniques. This chapter gives an overview of commonly used instrumentation, with the focus on…
'The importance of x-ray small-angle scattering in colloid research' published in 'Dispersed Systems'
Dimeric biphenyl liquid crystals with trisiloxane containing spacers were studied. Both the tail lengths and the spacer lengths to a central hexamethyltrisiloxane group were varied. In most cases a SmC-phase was found with an anticlinic interlayer relation. One of the compounds appears to have a SmA-phase, which could…
A survey of computer programs for powder diffraction is presented. For each program a brief description of its use, a primary reference and a URL or contact e-mail address that should enable the reader to get easy access to the required software are given.
We demonstrate the microwave detection effect in a granular La0.7Ca0.3MnO3 sample. Dc voltage generated by the sample in response to microwave irradiation below the Curie temperature is found to be dependent on the applied magnetic field. The magnetic field dependence of the dc voltage has a broad peak resembling an a…
This chapter gives an overview of the types of information available from powder diffraction as well as explaining the fundamental origins of the features containing that information.
The history and features of the crystallographic databases [the Powder Diffraction File (PDF), the Cambridge Structural Database (CSD), the Inorganic Crystal Structure Database (ICSD), Pearson's Crystal Data (PCD), CRYSTMET, the Protein Data Bank (PDB) and the Crystallography Open Database (COD)] that are useful for p…
We have investigated Focal Conic Domains (FCD) in several materials that have a transition from a SmA to a nematic phase (N): the focal lines are seldom an ideal ellipse and an ideal hyperbola, and suffer large transformations (in shape and in size) when approaching the transition to the nematic phase, or appear imper…
A thermoreversible (physical) gel of a nematic liquid crystal in its planar configuration is investigated. The transition temperatures of the gel are thermally and rheologically determined. The temperature for the nematic-isotropic transition is higher than that for the gel-sol transition, allowing the network to grow…
The methods for studying nanometre-scale structure in materials from powder diffraction data are often referred to as `total scattering' or atomic pair distribution function (PDF) analysis. This chapter aims to present the background theory in a rigorous but intuitive way. Different approaches to modelling the data ar…
Electron-stimulated reactions in thin [<3 ML (monolayer)] water films adsorbed on TiO(2)(110) are investigated. Irradiation with 100 eV electrons results in electron-stimulated dissociation and electron-stimulated desorption (ESD) of adsorbed water molecules. The molecular water ESD yield increases linearly with water…
A low-cost computer-based tensile testing apparatus is described that allows a graphical display of force–extension curves during the stretching of specimens in real time. The experiment is based on a graphics tablet combined with a force sensor. It can be used in a material science laboratory to investigate elastic a…
The paper reports on the effect of substituting Mn for Fe on the magnetostrictive and related properties of Fe 81− x Mn x Ga 19 alloys. Samples of composition were prepared in polycrystalline form and were all single phase BCC. It is shown that the magnetostriction observed in Fe 81 Ga 19 can be enhanced up to about 1…