Materials Literature
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Recently there has been a great deal of progress in the production of one-dimensional nanostructures with core-sheath structures from a rich variety of materials. Here we highlight the use of electrospinning in the fabrication of polymeric, ceramic, and composite nanofibers with core-sheath, hollow, or porous structur…
ZnO nanowire field-effect transistors (FETs) were fabricated and studied in vacuum and a variety of ambient gases from 5 to 300 K. In air, these n-type nanowire transistors have among the highest mobilities yet reported for ZnO FETs (mu(e) = 13 +/- 5 cm(2) V(-1) s(-1)), with carrier concentrations averaging 5.2 +/- 2.…
High-resolution soft X-ray emission and absorption spectra near the N K-edge of wurtzite GaN are presented. The experimental data are interpreted in terms of band structure based full-potential electronic structure calculations. The absorption spectra, compared with calculations including core hole screening, indicate…
Transport property is investigated in [Ca$_{2}$CoO$_{3-δ}$]$_{0.62}$[CoO$_{2}$] single crystals obtained by varying annealing conditions. The $ρ_{ab}(T)$ exhibits a resistivity minimum, and the temperature corresponding to this minimum increases with the loss of oxygen content, indicative of the enhancement of spin de…
Single crystals of Na$_{0.5}$CoO$_2$ were obtained through a flux method followed by de-intercalation of sodium. The Na$_{0.5}$CoO$_2$ samples were found to be vulnerable to water in the air and a hydration process in which H$_2$O molecules fill oxygen vacancies in CoO$_2$ layers is suggested to be responsible for the…
Polarization-dependent x-ray absorption measurements were performed on a crystalline ZnO three-dimensional array consisting of highly oriented microrods as well as on particulate thin film consisting of monodisperse spherical nanoparticles. Strong anisotropic effects have been observed for the highly oriented ZnO rods…
Giant volume magnetostriction at room temperature is found for the first time in a La(0.7)Ba(0.3)MnO(3) single crystal, achieving 2.54 × 10(-4) in a magnetic field of 8.2 kOe. An even greater value of the volume magnetostriction, equal to 4 × 10(-4) in the same magnetic field, is observed at the Curie point T(C) = 310…
Abstract The dechlorination of polyvinylchloride (PVC) powder initially progressed on an apparent zero order reaction, and proceeded in higher dechlorination range by an apparent first order reaction. The apparent activation energies indicate that the rate of the dehydrochlorination is controlled by the chemical react…
Improved understanding of the plastic deformation of metals during high-strain-rate shock loading is key to predicting their resulting material properties. This paper presents the results of molecular-dynamics simulations which address two fundamental questions related to materials deformation: the stability of supers…
Structural and transport properties of ceramic LaMnO(3+δ) are investigated for δ = 0-0.154. According to x-ray diffraction measurements at room temperature the crystal structure of this compound varies from orthorhombic (Pbnm) for δ = 0 to rhombohedrally distorted cubic (Pm3m) for δ = 0.065-0.112 and to rhombohedral (…
Water-soluble Prussian-blue (PB) analogue transition metal hexacyanoferrate (HCF) nanoparticles FeHCF, CoHCF, NiHCF and CuHCF have been synthesized by using poly(N-vinyl-2-pyrrolidone) as a protective matrix. Transmission electron microscopy (TEM) images of the synthesized PB analogues showed stable and well dispersed…
Ferromagnetism at room temperature, along with a spin-glass-like behaviour at low temperatures, has been observed in laser ablated V-doped ZnO thin films. It is found that V atoms were well substituted for Zn atoms and resulted in a very uniform distribution among the ZnO matrices.
Magnetic properties have been investigated for a zinc ferrite thin film deposited on glass at a substrate temperature close to room temperature using a sputtering method. X-ray diffraction analysis reveals that the thin film consists of nanocrystalline ZnFe(2)O(4) with the size of approximately 10 nm. The magnetizatio…
Non-reversing relaxation enthalpies (ΔH(nr)) at glass transitions T(g)(x) in the P(x)Ge(x)Se(1-2x) ternary display wide, sharp and deep global minima ([Formula: see text]) in the 0.09<x<0.145 range, within which T(g) s become thermally reversing. In this reversibility window, glasses are found not to age, in contrast…
The measurement of optical extinction is used to determine the size of nearly spherical gold nanoparticles suspended in solution, produced by a ‘reverse micelles’ process. The contrast between the maximum and the minimum in the extinction spectra around 450 and 520 nm shows a linear dependence with the mean radius of…
The optical properties of ZnO quantum wells, which have potential application of short-wavelength semiconductor laser utilizing a high-density excitonic effect, were investigated. Stimulated emission of excitons was observed at temperatures well above room temperature due to the adoption of the lattice-matched substra…
Twisting of polymer lamellae manifested by e.g. appearance of concentric bands in polymer spherulites examined in a polarized optical microscope remains a topic of research and controversy. It has been interpreted variously as resulting from phenomena that take place during growth or from structural features of indivi…
Abstract The coordination complexes of the crystalline structure of cellulose ethers/Eu(III) with fluorescence emission, viz CMC/Eu(III), MC/Eu(III), and HEC/Eu(III), were synthesized and characterized. Results showed the emission spectra of Eu 3+ ions in these coordination compounds, which originates from electric di…
Abstract Interpenetrating polymer networks (IPNs) of polyurethane (PU)/polyacrylates have been synthesized by sequential polymerization of castor oil, methylene diisocyanate (MDI), and acrylate monomers such as methyl acrylate (MA), methyl methacrylate (MMA), and ethyl acrylate (EA); with benzoyl peroxide (BPO) and et…
Abstract An optothermomechanical (OTM) device was designed and constructed for fiber characterization with a double‐beam interference microscope. This device enabled us to correlate both the mechanical properties and the thermal properties with the optical properties of fibers. The OTM device consisted of three parts,…