Materials Literature
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Identifying the symmetry of the superconducting order parameter in the recently-discovered ferro-oxypnictide family of superconductors, RFeAsO$_{1-x}$F$_{y}$, where $R$ is a rare earth, is a high priority. Many of the proposed order parameters have internal $\pi$ phase shifts, like the d-wave order found in the cuprat…
Brittle-ductile transition (BDT) behaviour was investigated in low carbon steel deformed by an accumulative roll-bonding (ARB) process. The temperature dependence of its fracture toughness was measured by conducting four-point bending tests at various temperatures and strain rates. The fracture toughness increased whi…
Tensile tests and strain rate jump tests have been carried out at low temperatures (77 K ∼ room temperature (RT)) using pure Cu specimens that were severely deformed by accumulative roll bonding (ARB). The dependence of the flow stress on the temperature and the strain rate has been investigated and the strain rate se…
Composite polymers, which are nylon6 materials with aluminum powders dispersed homogeneously, are prepared. Influences of water absorption on Charpy impact value of composite polymers have been investigated. Although the aluminum dispersion from zero to 40 vol%Al decreases the impact value, the water absorbing treatme…
Excess amount of Mg was intentionally added to fabricate supersaturated ultra-fine grained Al-Mg alloy by high pressure torsion (HPT). Their microstructures and mechanical properties were examined by X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and Vickers microhardness test. It was confirm…
Abstract A urea‐based bis‐silylated bipyridine ligand derived from 4,4′‐diamino‐2,2′‐bipyridine has been prepared. Organic–inorganic hybrid materials with a high loading of lanthanide 2,2‐bipyridine moieties were obtained by using the silylated bipyridine as the only siloxane network precursor in the presence of lanth…
The microstructural evolution and the corresponding mechanical properties of a 5052 Al alloy processed by cryogenic rolling followed by warm rolling were investigated. The application of cryogenic rolling combined with warm rolling at 448 K showed a significant improvement of tensile strength up to 452 MPa. The kineti…
Mg-0.7 at%Zn-1.4 at%Y alloys annealed at low temperatures after quenching in water from 520°C were studied by high-resolution transmission electron microscopy (HRTEM) and high-angle annular detector dark-field scanning transmission electron microscopy (HAADF-STEM). Stacking faults, thin bands of a 14H-type long period…
We report $^{57}$Fe-NMR studies on the oxygen-deficient iron (Fe)-based oxypnictide superconductor LaFeAsO$_{0.7}$ ($T_{c}=$ 28 K) enriched by $^{57}$Fe isotope. In the superconducting state, the spin component of $^{57}$Fe-Knight shift $^{57}K$ decreases almost to zero at low temperatures and the nuclear spin-lattice…
High purity Al (99.99%) was subjected to severe plastic deformation through twist extrusion at room temperature. Microstructures were examined for 1 pass and 4 passes on the cross section perpendicular to the longitudinal axis of billets using optical microscopy and electron back scatter diffraction analysis. It was s…
The paper focuses on producing of ultrafine-grained (UFG) structure in the Al 6061 alloy by a new severe plastic deformation (SPD) technique, developed recently in our laboratory, namely equal channel angular pressing with parallel channels (ECAP-PC). The evolution of microstructure at ECAP-PC was examined and was pro…
A 100 mm-diameter ring sample of high purity Al (99.99%) was processed by high-pressure torsion (HPT). It was confirmed that the results of hardness measurements were consistent with those obtained using disk samples and demonstrated that scaling-up the HPT process was feasible using the ring-shaped sample. Evaluating…
Abstract The Nazarov cyclization of two types of pyrrole derivatives was effectively catalyzed by 5 mol% alumina‐supported iron(III) perchlorate [Fe(ClO 4 ) 3 ⋅Al 2 O 3 ] which provided the desired cyclization with high trans selectivity in good to excellent yield. The cyclized product was next reacted with a vinyl ke…
We report transport, thermal, and magnetic measurements on single crystalline samples of FeGa 3 prepared by a Ga self flux method. The electrical resistivity and Hall coefficient at temperatures above 300 K display semiconducting behaviors with energy gaps of 0.47 and 0.54 eV, respectively, whose values agree with the…
The crystal structures and magnetic properties of two new Co(II) molecular magnets, [Co(N(3))(2)(btzb)] (1) and [Co(N(3))(2)(btze)(2)] (2), are described and discussed (btzb=1,4-bis(tetrazol-1-yl)butane and btze=1,4-bis(tetrazol-1-yl)ethane). In the materials, (4,4) layers with mu-1,3-azide bridges are cross-linked by…
Summary Productivity and grazing pressure interact in determining autotroph diversity, because high productivity increases the capability of a plant community to compensate for grazing losses. However, further factors may play a role in shaping diversity, including primary producer nutrient stoichiometry and grazer ac…
Abstract This work reports the temperature‐dependent Raman scattering study of mutiferroic BiFeO 3 (BFO) bulk ceramics in a wide temperature range of 93–843 K. The polycrystalline samples are sintered at four different temperatures and characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), v…
We report resistivity measurement under pressure in single crystals of SrFe_2As_2, which is one of the parent materials of Fe-based superconductors. The structural and antiferromagnetic (AFM) transition of T_0 = 198 K at ambient pressure is suppressed under pressure, and the ordered phase disappears above P_c ~ 3.6-3.…
Pure Fe (99.96%) was processed by high pressure torsion (HPT) using disc and ring samples. When the microhardness and tensile properties are plotted against the equivalent strain, the individual properties fall well on unique single curves, level off at the equivalent strain of ∼40. At the saturated level, the tensile…
An exchange correlation energy functional involving fractional power of the one-body reduced density matrix [Phys. Rev. B {\bf 78}, 201103 (2008)] is applied to finite systems and to the homogeneous electron gas. The performance of the functional is assessed for the correlation and atomization energies of the molecule…