Thomas C. Lippmann

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The local point symmetry of the short-range order in simple monatomic liquids remains a fundamental open question in condensed-matter science. For more than 40 years it has been conjectured that liquids with centrosymmetric interactions may be composed of icosahedral building blocks. But these proposed mobile, randomly orientated structures have remained(More)
One-third of the world’s coral reefs have disappeared over the last 30 years, and a further third is under threat today from various stress factors. The main global stress factors on coral reefs have been identified as changes in sea surface temperature (SST) and changes in surface seawater aragonite saturation (Ωarag). Here, we use a climate model of(More)
The electron-density distribution of the high-pressure polymorph of SiO2, stishovite [a = 4.177 (1), c = 2.6655 (5) A, space group P4(2)/mnm, Z = 2], has been redetermined by single-crystal diffractometry using synchrotron radiation of 100.42 and 30.99 keV, respectively, in order to obtain essentially absorption- and extinction-free data. Room-temperature(More)
The triple-crystal diffractometer installed at HASYLAB beamline BW5 with a high-field wiggler of critical energy 27 keV for DORIS III, operated at 4.5 GeV electron energy, is described. Samples can be mounted in large cryostats or furnaces normally used in neutron scattering experiments. The instrument has been successfully applied to measure structure(More)
The GKSS Forschungszentrum Geesthacht, Germany, will setup a new high-energy beamline specialized for texture, strain and imaging measurements for materials science at the Hamburger Synchrotronstrahlungslabor HASYLAB of the Deutsches Elektronen-Synchrotron DESY. Four different experiments will be installed at the new wiggler HARWI-II. The high pressure cell(More)
Extruded magnesium was investigated to study the texture variation along the cross section of round and rectangular extruded samples. Our experiments were carried out at the high-field wiggler beam line BW5 (HASYLAB at DESY in Hamburg, Germany). The penetration power of 100 keV synchrotron radiation was sufficient to study extruded rods of 14 mm in diameter(More)
Using high-energy synchrotron radiation, structure factors of YBa(2)Cu(3)O(6.98) were measured at $\lambda$ = 0.124 A. Charge densities were derived using generalized structure factors and VALRAY and compared to densities refined from theoretical structure factors, which were calculated using the LAPW method and WIEN2k. Refinement agreement indices were(More)
______________________ Date iii DEDICATION This thesis is dedicated to John Fandel, my father, whose compassion, support, and diligence has shaped me into the person I am today and Maggi Fandel, my mother, whose candor and vivacious personality have taught me not to lose sight of the lighter things in life. iv ACKNOWLEDGEMENTS I would like to thank my(More)
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