Single-crystal high-pressure X-ray diffraction studies on the protein crystals of orthorhombic and tetragonal hen egg-white lysozyme polymorphs were carried out using a Merrill-Bassett diamond-anvil cell, image-plate detector and synchrotron radiation. The orthorhombic crystal has been squeezed to 85.5% of its ambient pressure volume at about 1.0 GPa; the crystal compresses anisotropically, and...

In situ neutron powder diffraction measurements show that the orthorhombic-to-tetragonal phase transition in YBa2Cu307 —,which occurs near 700 C in a pure oxygen atmosphere, is an order-disorder transition in which the disordering of oxygen atoms into a normally vacant site destroys the one-dimensional Cu-0 chains present in the room-temperature orthorhombic structure. For both structures, the ...

Electromechanical property measurements and microstructure observations using optical microscopy were performed on a [001] c oriented k33 resonator made of 91%Pb(Zn1/3Nb2/3)O3-9%PbTiO3 single crystal, which was polarized under different electric fields. At room temperature, when the poling field is 1100 V/mm, the electromechanical coupling factor k33 is 0.90 and piezoelectric coefficient d33 is...

Cytochrome c(2) serves as the secondary electron donor that reduces the photo-oxidized bacteriochlorophyll dimer in photosynthetic bacteria. Cytochrome c(2) from Rhodobacter sphaeroides has been crystallized in three different forms. At high ionic strength, crystals of a hexagonal space group (P6(1)22) were obtained, while at low ionic strength, triclinic (P1) and tetragonal (P4(1)2(1)2) crysta...

The high-pressure polymorphs of CuI have attracted much attention due to the somewhat contradictory identification of their structures by means of x-ray diffraction measurements and theoretical calculations. In this paper, we report the results of a theoretical investigation of polymorphs of CuI including zinc-blende, rhombohedral, tetragonal, rocksalt and orthorhombic phases. We find that CuI...

High-temperature phases of hafnium dioxide have exceptionally high dielectric constants and large bandgaps, but quenching them to room temperature remains a challenge. Scaling the bulk form to nanocrystals, while successful in stabilizing the tetragonal phase of isomorphous ZrO2, has produced nanorods with a twinned version of the room temperature monoclinic phase in HfO2. Here we use in situ h...

Abstract: Zirconia solid electrolytes with nonequilibrium composite structure were prepared by impregnation of a porous 8YSZ matrix with a solution of Zirconia. Microstructures were characterized by XRD and SEM. The electrical properties were studied by impedance spectroscopy as a function of temperature. Biaxial flexural strength and fracture toughness of composite samples were measured by rin...

Well-aligned, densely distributed ZrO2 nanorod arrays were fabricated using a non-catalytic, templatefree metal–organic chemical vapour deposition process at a reaction temperature of 1000 C. The reaction temperature was found to play a key role in product morphology, with particle thin films obtained at 550 C and nanorod arrays produced at 1000 C. Increasing the reaction temperature led to the...

The pressure effects on the lattice parameters and elastic constants of the tetragonal RNi2B2C (R=Y, Lu) are investigated by means of the first principles. The predicted lattice constants and elastic constants of YNi2B2C and LuNi2B2C at 0 GPa agree well with the available data. By the elastic stability criteria under isotropic pressure, it is predicted that YNi2B2C and LuNi2B2C with tetragonal ...

Methylammonium lead iodide perovskite has attracted considerable recent interest for solution processable solar cells and other optoelectronic applications. The orthorhombic-to-tetragonal phase transition in perovskite can significantly alter its optical, electrical properties and impact the corresponding applications. Here, we report a systematic investigation of the size-dependent orthorhombi...