Materials Literature
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Density functional theory with local density approximation including on-site Coulomb interaction has been used to calculate the formation energy of the neutral and charged vacancy in germanium as a function of the Fermi level. The calculations suggest that vacancies in germanium are multiple-level acceptors with a fir…
Defect and phase equilibria have been investigated through the ferroelectric phase transition behavior of pure and equilibrated nonstoichiometric BaTiO 3 powders. The paraelectric–ferroelectric phase transition temperature ( T C – T ) was found to vary systematically with materials fabricated with different Ba/Ti rati…
We investigated the ceramics samples of multiferoic solid solution of relaxor ferroelectric Pb(Fe2∕3W1∕3)O3 with ferroelectric PbTiO3 (abbreviated as PFW-xPT; x=0, 0.25, and 0.37) by means of acoustic emission (AE) method and simultaneously using the dielectric measurement below 700K. A distinct AE response has been d…
Abstract The effect of freeze–thaw cycles and chitosan type (water‐soluble or insoluble) on the morphological and mechanical characteristics of poly(vinyl alcohol) (PVA)/chitosan hydrogels was investigated with scanning electron microscopy (SEM), uniaxial testing, and a biaxial tubular vessel inflation experiment. SEM…
Residual stresses develop in the sol-gel-derived ferroelectric thin films during the transformation of the metal-organic gel to the metal oxide upon thermal treatment and due to the thermal and elastic mismatch between the Pb(Zrx,Ti1−x)O3 (PZT) film and the substrate materials during cooling. In this study, residual s…
ZnO micro-/nano-structure film composed of urchin-like hierarchical ZnO units with bamboo-like branches has been successfully constructed on Zn foil substrate by a simple one-step thermal evaporation process using a mixture of ZnS and graphite powder as a source. Field-emission scanning electron microscope (FE-SEM) ob…
A combination of microscopic and macroscopic methods enables an insight into polarization reversal in the copolymer of vinylidene fluoride and trifluoroethylene. Piezoforce microscopy together with switching charge measurements suggests that the polarization reversal is impeded by the restricted geometry of the domain…
In order to improve the photoluminescence property of Eu(3+)-doped nanoparticles, Y(2)O(3):Eu(3+) nanoparticles were synthesized using the Pechini-type sol-gel method, then coated with SiO(2) shells by using the Stöber method for different coating times. The SiO(2)-coated nanoparticles were characterized by x-ray diff…
Abstract Seaweed (SW) is employed as filler to prepare composites on the basis of a polypropylene (PP) matrix in the ratio of 10 : 90, 20 : 80, 30 : 70, 40 : 60, and 50 : 50 (wt % SW : wt % PP) by compounding and injection molding. The tensile, bending and impact properties of the composites were investigated. The 30%…
A magnetic loading technique was used to ramp load pure aluminum and 6061 aluminum alloy to peak stresses of approximately 29GPa. The peak loading rate was approximately 106∕s, followed by unloading from peak stress at a rate of about 105∕s. The pure aluminum samples had impurity levels ranging from about 10ppmto0.5wt…
Cerium-doped lutetium pyrosilicate Lu2Si2O7:Ce3+ (LPS:Ce) single crystal samples grown via Czochralski method were annealed under air and H2 atmospheres from 350to1600°C. The x-ray excited luminescence spectra and UV as well as thermal stimulated luminescence spectra were measured. It was found that the luminescence e…
Abstract Amyloidfasern gehören zu den wichtigsten selbstorganisierten Strukturen in der Natur. Zahlreiche Proteine und Peptide mit unterschiedlichen Aminosäuresequenzen bilden unter verschiedenen Bedingungen solche sehr stabilen und hochgradig organisierten Assoziate, die man in Phasenzuständen von Flüssigkristallen b…
We report on a negative-zero-positive metamaterial based on an omega-type microstructure with special attention on the nonvanishing group velocity for a zero refractive index. We first investigate the dispersion characteristics by full wave analysis, by stressing the necessary conditions of equality between the electr…
The field effect transistor based on carbon nanotubes (CNT) is a very promising candidate for post-CMOS microelectronics. Transport in the CNT channel is dominated by the Schottky barriers existing at the metal source contacts. The nature of the metal and the geometry of the contact appear to influence strongly the el…
The interfacial relationship and the microstructure of nonpolar (11−20) ZnO films epitaxially grown on (1−102) R-plane sapphire by molecular beam epitaxy are investigated by transmission electron microscopy. The already-reported epitaxial relationships [1−100]ZnO∥[11−20]sapphire and ⟨0001⟩ZnO∥[−1101]sapphire are confi…
Semiconductor tetrapods are expected to exhibit isotropic optical properties due to their tetrahedral symmetry. We have investigated the optical polarization properties of individual $\mathrm{Cd}\mathrm{Se}∕\mathrm{Cd}\mathrm{S}$ tetrapods of high structural quality. In contrast to the light absorption behavior, a pro…
Many factors influence the shapes of living and manufactured membranes. In addition to boundary conditions, surface tension, and curvature, the ordering of particles embedded in or attached to a membrane can strongly influence its equilibrium shape. As a simple model of such ordering, we consider rodlike particles tha…
The characteristics of chemical vapor sensors constructed from porous Si rugate filters are examined. The peak position of the resonant wavelength exhibits a redshift response upon exposure to ethanol vapors. The filter response scales with the vapor partial pressure; the concentration level is estimated based on theo…
This Communication reports simultaneous tracking of structural and kinetic information for the photoinduced elimination reaction of 1,2-diiodotetrafluoroethane in solution by transient X-ray diffraction. The transient structure of .CF2CF2I is determined to be a classical mixture whereas .CH2CH2I is bridged. Compared w…
First-principles spin-polarized calculations have been conducted to investigate the structural, electronic and magnetic properties of 3d transition metal Mn doping into two typical sites in the upper layer of bilayer graphene with the AB Bernal structure. One of the doping sites is above the center of a carbon hexagon…