Extended X-ray absorption fine-structure (EXAFS) of a complex oxide structure: a full multiple scattering analysis of the Au L3-edge EXAFS of Au2O3

Crystalline Au₂O₃ was obtained by hydrothermal synthesis at 3000 atm and its extended X-ray absorption fine-structure (EXAFS) at the Au L₃-edge was measured at room temperature. A detailed full multiple scattering (MS) analysis using FEFF8 theory shows that only a small number of scattering paths contribute significantly to the EXAFS of Au₂O₃. Because of the complex unit cell (low local symmetry) of the Au₂O₃ structure, contributions of MS paths are almost negligible. The results indicate that FEFF8 theory provides a good reference for the analysis of Au-O phases.     

The incorporation of rigid diol monomers into poly(butylene terephthalate) via solid‐state copolymerization and melt copolymerization

Incorporation of 2,2‐bis[4‐(2‐hydroxyethoxy)phenyl]propane (Dianol 220®) into poly(butylene terephthalate) (PBT) via solid‐state copolymerization (SSP) showed that Dianol, besides being the reactant, also acts as a swelling agent for rigid amorphous PBT chain segments. Being swollen, these amorphous chain segments become sufficiently mobile to contribute to the SSP process. The thermal behavior of the resulting copolyesters is comparable with melt copolymerized copolymers, although having a different chemical microstructure. The main reason is a full miscibility in the melt of unmodified PBT chain segments and modified chain segments, which eliminates the advantages of a blocky microstructure for the SSP copolyesters. However, incorporation of 2,2′‐biphenyldimethanol (BDM) into PBT resulted in a higher crystallization temperature compared with PBT–Dianol copolymers of equal composition. Preordering of polymer chains in the melt by incorporating rigid, phase separating BDM‐moieties, preferably via SSP to obtain a non‐random distribution, may be the origin of the enhanced crystallization temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1203–1217, 2008     

Illusory possibilities and imagining counterparts

Given Kripke’s semantic views, a statement, such as ‘Water is H₂O’, expresses a necessary a posteriori truth. Yet it seems that we can conceive that this statement could have been false; hence, it appears that we can conceive impossible states of affairs as holding. Kripke used a de dicto strategy and a de re strategy to address three illusions that arise with respect to necessary a posteriori truths: (1) the illusion that a statement such as ‘Water is H₂O’ possibly expresses a falsehood, (2) the illusion that conceivability can fail to latch on to a genuine metaphysical possibility, and (3) the illusion that one can access a real metaphysical possibility by conceiving that water is not H₂O. In this paper I argue that while Kripke’s de dicto strategy dispels (1), his strategies do not enable him to dispel (2) and (3).