Strontium structural change

In addition to the chemical interactions described above, microstructural changes in the electrode can lead to performance degradation after long operation time. For example sintering of the porous structure can degrade electrode performance. In the case of LSM cathodes, the sintering ability is found to be related to the strontium dopant level and stoichiometric composition of (La, Sr)xMn03. In addition, LSM with A-site deficient compositions (x < 1) sinters more readily than their B-site deficient counterparts (x > 1) [198, 199],... 

Vanadates For the isostructural strontium and barium ortho-vanadates the V-—0 vibrational frequencies decrease with increasing effective nuclear charge [51]. Similar orthovanadates with the apatite structure have for a given halogen ion decreasing frequencies of the VO4 ion in the order Ca>Sr >Ba ((62) and Table 4]. However, it is impossible to see any trend towards the tiivalent lanthanide cations (59). The IR bands are so wide in this case that small changes cannot be measured. 

In addition to contact with the burial environment, the trophy head samples had been burned, presumably during ritual activities in the structures in which they were found (/, 21, 22). Although experimental data has shown that postmortem burning can change the 5I3C values in bone collagen, this is not the case for strontium isotope ratios (78). 

The tri-calcium, barium, and strontium phosphates are members of an isostructural series M3(P04)2, where M = Ca, Ba, Sr, etc. The minerals formed by Ca are very important in bioceramics, and because Ba and Sr are fission products (i.e., formed as by-products in nuclear reactions), apatite minerals play a major role in their stabilization for disposal (see Chapter 17). Within these common structures, however, calcium phosphate goes through several phase changes at different temperatures. These phases are labeled as (3, a, a, etc. The reader is referred to Refs. [1,2] for details. 

According to Pearson (2), B-strontium has the body-centered-cubic structure, isotypic with W, designated as CIg. In the alkaline earth metal series, B-calcium, B-berylliura, and barium have the same structure. Note that we now use the name beta (3) for the phase of Sr stable near unlike Pearson who retains the historical name gamma. The change arose when Peterson and... 

Historically, strontium metal was produced only in very small quantities. Rapid growth of metal production occurred during the late 1980s, however, owing to use as a eutectic modifier in aluminum—silicon casting alloys. The addition of strontium changes the microstructure of the alloy so that the silicon is present as a fibrous structure, rather than as hard acicular particles. This results in improved ductility and strength in cast aluminum automotive parts such as wheels, intake manifolds, and cylinder heads. 

In this work, erbium doped strontium barium niobate glasses have been irradiated with a femtosecond laser. The properties of these glasses and the changes induced by a cw laser have been studied in a previous paper . Optical measurements show the changes of the local structure in a localized area after the irradiation and they arc compared with the bulk glass ceramic sample obtained by thermal treatment with a furnace. 

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