By providing the capabilities for high-resolution, high-energy and time-resolved powder X-ray diffraction, beamline P02.1 is a versatile tool to tackle various problems in materials science, crystallography and chemistry.
Performance description of the Extreme Conditions Beamline (ECB, P02.2) at PETRA III that is optimized for micro-diffraction at simultaneous high pressure and high and low temperatures created in different diamond anvil cells environments. Additional information of the capabilities of the Extreme Conditions Science Infrastructure for DAC work is provided.
Alkaline folates in water, with or without added NaCl, form columnar mesophases; the columns are composed of a stacked array of folate tetramers held together by Hoogsteen-type hydrogen bonds and stacking interactions. There is a considerable difference in both the liquid crystalline polymorphism and the columnar characteristics in pure water and those in 1 mol L-1 NaCl solutions. In pure water, the tetramer-tetramer interaction is weak, the columnar length changes slowly with the folate concentration, and only the hexagonal mesophase is observed. In 1 mol L-1 NaCl, the tetramer-tetramer interaction is stronger, a cholesteric mesophase is observed, and, even at relatively low folate concentration, the length of the columns is significant (ca. 20 disks at the isotropic-to-cholesteric transition). In both cases, the columns are finite at all concentrations investigated. The formation of a cholesteric mesophase with a pitch of ca. 14 pm indicates that the tetramers do not pile up in register but are rotated one with respect to the other to give a chiral column similar both to the four-stranded helix of poly(G) and to thecolumnar aggregates formed by homoguanylic oligodeoxynucleotides.
In this paper, we report the formation of a series Zr-(Cu,Ag)-Al bulk metallic glasses (BMGs) with diameters at least 20 mm and demonstrate the formation of about 25 g amorphous metallic ingots in a wide Zr-(Cu,Ag)-Al composition range using a conventional arc-melting machine. The origin of high glass-forming ability (GFA) of the Zr-(Cu,Ag)-Al alloy system has been investigated from the structural, thermodynamic and kinetic points of view. The high GFA of the Zr-(Cu,Ag)-Al system is attributed to denser local atomic packing and the smaller difference in Gibbs free energy between amorphous and crystalline phases. The thermal, mechanical and corrosion properties, as well as elastic constants for the newly developed Zr-(Cu,Ag)-Al BMGs, are also presented. These newly developed Ni-free Zr-(Cu,Ag)-Al BMGs exhibit excellent combined properties: strong GFA, high strength, high compressive plasticity, cheap and non-toxic raw materials and biocompatible property, as compared with other BMGs, leading to their potential industrial applications.
The resonant scattering and diffraction beamline P09 at PETRA III is designed for X-ray experiments requiring small beams, energy tunability, variable polarization and high photon flux. It is highly flexible in terms of beam size and offers full higher harmonic suppression. A state-of-the-art double phase-retarder set-up provides variable linear or circular polarization. A high-precision Psi-diffractometer and a heavy-load diffractometer in horizontal Psi-geometry allow the accommodation of a wide variety of sample environments. A 14 T cryo-magnet is available for scattering experiments in magnetic fields.
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