Materials Literature
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Porous yttria‐stabilized ziroconia (YSZ) ceramics were fabricated by freeze casting using aqueous ceramic slurries. Polyvinyl alcohol (PVA) was added to the slurry with the aim of controling the microstructures and properties of the porous YSZ ceramics. The experimental results indicated that the large and nonintercon…
Abstract Poly(lactic acid) (PLA) and its blends with starch and methylenediphenyl diisocyanate (MDI) were extruded in a twin‐screw extruder and compress‐molded in a dog‐bone shaped tensile bars to form test specimens. The thermalgravimetric profile and thermal endurance of these samples were characterized. The effect…
Room temperature ferromagnetism has been observed in ZnO nanorods prepared by hydrothermal method. Saturation magnetization of ∼0.004emu∕g was measured in the nanorods with diameters of ∼10nm and lengths of below 100nm, and the magnetization reduced with the increase of the size. Annealing of the samples at 900°C in a…
The crystal and local structures of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Fe}{\mathrm{O}}_{3\ensuremath{-}\ensuremath{\delta}}$ $(0\ensuremath{\leqslant}x\ensuremath{\leqslant}1)$ samples have been studied by x-ray diffraction and x-ray absorption spectroscopy techniques. The Fe-O bond length decre…
Abstract A novel melt transurethane polycondensation route for polyurethanes under solvent‐free and nonisocyanate condition was developed for soluble and thermally stable aliphatic or aromatic polyurethanes. The new transurethane process was investigated for A + B, A‐A + B, and A‐A + B‐B (A‐urethane and B‐hydroxyl) ‐t…
Magnetically induced reorientation (MIR) is observed in epitaxial orthorhombic Ni-Mn-Ga films. Ni-Mn-Ga films have been grown epitaxially on heated MgO(001) substrates in the cubic austenite state. The unit cell is rotated by 45 relative to the MgO cell. The growth, structure texture and anisotropic magnetic propertie…
Dynamic suspending behavior of microdroplet on fresh lotus leaf is in situ investigated at micro- and nanolevels, by water condensation via environmental scanning electronic microscopy. The observation and analysis reveal that a gradient of wettable micro- and nanostructure is formed along the exterior surface of papi…
Abstract Polyhydroxybutyrate (PHB) is generally considered to be a very uneasy biopolymer to handle because of significant instability during melt processing and some excessive brittleness. This work studied the morphological, thermal, and barrier properties of novel melt‐mixed nanobiocomposites of PHB, poly(ε‐caprola…
Sintered reaction‐bonded silicon nitride (SRBSN) materials were prepared from a high‐purity Si powder doped with Y 2 O 3 and MgO as sintering additives by nitriding at 1400°C for 8 h and subsequently postsintering at 1900°C for various times ranging from 3 to 24 h. Microstructures and phase compositions of the nitride…
Ga-doped ZnO (GZO) transparent conducting films and well-aligned ZnO nanotips were sequentially grown on a glass substrate using metal–organic chemical vapor deposition (MOCVD). The morphology control of ZnO from dense films to nanotips was realized through temperature-modulated growth. The ZnO nanotips/GZO structure…
Clarification of the mechanisms of hydrogen release and uptake in transition-metal-doped sodium alanate, NaAlH(4), a prototypical high-density complex hydride, has fundamental importance for the development of improved hydrogen-storage materials. In this and most other modern hydrogen-storage materials, H(2) release a…
The Peierls Hamiltonian band matrix is developed to investigate magnetoelectronic properties of bilayer Bernal graphene. A uniform perpendicular magnetic field creates many dispersionless Landau levels (LLs) at low and high energies and some oscillatory LLs at moderate energy. State degeneracy of the low LLs is two ti…
We have investigated the absorption spectrum of multilayer graphene in high magnetic fields. The low-energy part of the spectrum of electrons in graphene is well described by the relativistic Dirac equation with a linear dispersion relation. However, at higher energies (>500 meV) a deviation from the ideal behavior of…
In this work, a systematic ab initio study of the influence of doping on electronic structure and local magnetic moments of ferromagnetic MnAs has been carried out. The majority of the considered substitution elements, potentially suitable for modification of MnAs as working material of magnetic refrigerators is shown…
The structural evolution of a nano-powder by repeated dispersion and settling can lead to characteristic fractal substructures. This is shown by numerical simulations of a two-dimensional model agglomerate of adhesive rigid particles. The agglomerate is cut into fragments of a characteristic size l, which then are set…
We present results on the charge dependence of the radiative recombination lifetime, Tau, and the emission energy of excitons confined to single self-assembled InGaAs quantum dots. There are significant dot-to-dot fluctuations in the lifetimes for a particular emission energy. To reach general conclusions, we present…
A study at both the molecular and extended solid level in the framework DFT is carried out for KM[Cr(CN)$_6$] (M = V, Ni). From molecular calculations, the exchange parameters J are obtained, pointing to the expected magnetic ground states, i.e., antiferromagnetic for M = V with J = -296.5 cm$^{-1}$ and ferromagnetic…
The homogeneous nucleation and growth in a simplest two-dimensional phase field model is numerically studied using the cell dynamics method. The whole process from nucleation to growth is simulated and is shown to follow closely the Kolmogorov-Johnson-Mehl-Avrami (KJMA) scenario of phase transformation. Specifically t…
Dielectric constant measurement under magnetic field is an efficient technique to study the coupling between charges and spins in insulating materials. For magnetic oxides, the geometric frustration is known to be a key ingredient to observe such a coupling. Measurements for the triangular Ising-like cobaltite ${\math…
The crystal structure of boron is unique among chemical elements, highly complex, and imperfectly known. Experimentalists report that the $\ensuremath{\beta}$-rhombohedral (black) form is stable over all temperatures from absolute zero to melting. However, early calculations found its energy to be greater than the ene…