The Angstrom Laboratory

INORGANIC CHEMISTRY, THE ANGSTROM LABORATORY, UPPSALA UNIVERSITY, BOX 538, S-751 21 UPPSALA, SWEDEN... 

Bengt NOLANG The Angstrom Laboratory Department of Materials Chemistry Uppsala University Uppsala (Sweden)... 

Department of Physics, Chalmers University of Technology, S-412 96 Gote-borg, Sweden. Present address The Angstrom Laboratory, Uppsala University, Box 534, Uppsala, SE-751 21, Sweden... 

Gunnar A. Niklasson Department of Materials Science The Angstrom Laboratory... 

Wenjun Qiu is an Associate Professor in The Angstrom Laboratory, Uppsala University, Sweden. 

X-rays have wavelengths in the angstrom range, are sufficiently energetic to penetrate solids, and are well suited to probe their internal structure. XRD is used to identify bulk phases, to monitor the kinetics of bulk transformations, and to estimate particle sizes. An attractive feature is that the technique can be applied in situ. We will first discuss XRD as done in the laboratory and then discuss newer applications of XRD as are available by using synchrotron radiation. The theory of X-ray diffraction is given in textbooks of solid state physics [1,2] and in specialized books [3-6]. 

Because the particles must be very small, not more than a few hundred angstroms for most substances, there have been few laboratory observations of structure in ultraviolet extinction spectra of small, nonmetallic particles. Particles of the required size are difficult to make. Grinding them from the bulk, with the attendant problem of separation, is almost hopeless. Various smokes can be made, MgO particularly easily, but not of all substances that might be of interest. 

The presence of proteoglycans in the extrafibrillar compartment would result in water depletion in the intrafibrillar compartment when the salinity of the synovial joint, or of the bath in laboratory experiments, is decreased. Therefore there should be mechanisms that retain intrafibrillar water within fibrils. Here, hydration forces that act at short distances, a few angstroms, are postulated to be the main factor that limit the exchangeability of intrafibrillar water. 

Since 1997 different scientific institutions at Uppsala University have joined in a center for education and research within fields connected to materials science. The laboratory is named after Anders Johan Angstrom (Figures 10.9 and 10.10) whose achievements were described above, and also after his son Knut Angstrom, also professor in Uppsala. The son Knut devoted a great part of his research to the radiation from the sun [10.10]. 

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