{'fraction_non_alphanumeric': 0.02992957746478873, 'fraction_numerical': 0.03609154929577465, 'mean_word_length': 4.492753623188406, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Extended X-ray absorption fine structure of high Tc ceramic superconductors

X-ray absorption studies of the high Tc ceramics YBa2Cu3Ox, GdBa2Cu3Ox, La1.8Sr0.2CuO4, La1.8Ba0.2CuO4, and BaBi0.25Pb0.75O3 give near neighbour environments that agree well with recent diffraction results. No significant changes are seen in either the near edge structure or the local environment from 4.2 K to 688 K for YBa2Cu3Ox or from 4.2 K to 300 K for the other types of structures that would suggest a phonon softening or a structural transition. Additional structure in the near edge region indicates that oxygen is removed from the Cu-O chains in YBa2Cu3Ox when the sample is heated in a non-oxygen atmosphere. The in-plane or in-chain Cu-O bonds in the copper oxide based compounds and the (Bi, Pb)-O bonds in Ba-Bi-Pb-O form the most rigid parts of the structures. Their vibrational frequencies correspond to Einstein temperatures that are similar in magnitude and fall in the range of 500-700 K. No correlation is found between the local types of vibrational properties and Tc, which varies an order of magnitude for the three types of compounds.