Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Abstract This article reports on a comprehensive study of the reaction kinetics, particle morphology development, and polymer properties of impact polypropylene produced in gas phase with a TiCl 4 /MgCl 2 catalyst. Experiments were conducted over a range of copolymerization times, temperatures, monomer compositions, a…
Transport properties of various semiconducting zig-zag carbon nanotube Y junctions are studied for the investigations of rectification and switching. Our results indicate that such junctions, when symmetric, can support both ballistic rectification and/or the ballistic switching operating modes. Although structural sy…
The structural properties of high-quality (0001)ZnO/Al2O3 films grown by plasma-enhanced molecular-beam epitaxy are investigated by x-ray diffraction and transmission electron microscopy. The only defects encountered are threading dislocations with a density of 1010–4×1010 cm−2. Most numerous dislocations are pure-edg…
SrBi 4 Ti 4 O 15 single crystals were grown, and their dielectric and ferroelectric properties were investigated along the a(b) axis and c axis, separately. The dielectric permittivity at 1 MHz was 1900 along the a(b) axis at the Curie temperature of 520 °C. This value was ten times higher than that along the c axis.…
We demonstrate a large-area fabrication of hexagonally ordered metal dot arrays with an area density of ∼1011/cm2. We produced 20 nm dots with a 40 nm period by combining block copolymer nanolithography and a trilayer resist technique. A self-assembled spherical-phase block copolymer top layer spontaneously generated…
Piezoresponse scanning force microscopy measurements performed on lead zirconate titanate mesoscopic structures revealed a negative shift of the initial piezoelectric hysteresis loop. The shift is dependent on the size of the structure and is most probably due to the pinning of ferroelectric domains at the free latera…
In the temperature interval 300–773 K, ac and dc electrical measurements show a phenomenally large enhancement of the electrical conductivity of otherwise excellent insulator Al2O3 crystals when doped with magnesium impurities. The conductivity increases linearly with the concentration of hole-trapped [Mg]0 centers an…
This work deals with the analysis of peculiarities of formation of the hyperfine fields (HFF) at the Fe nuclei in disordered alloys metal- metalloid using the "first-principles" calculations. Some phenomenological models and justification of their usage for the interpretation of the experimental HFF distributions are…
Metamaterials are so-named to recognize and emphasize their purpose, which is to achieve material performance beyond the limitations of conventional composites. The holy grail of conventional composite design is to achieve an optimum combination of the constituent's properties without requiring that they react. Succes…
Abstract Polyfluorenes are an important class of electroactive and photoactive materials. In the last three years this research field has literally exploded because of polyfluorenes' exceptional electrooptical properties for applications in light‐emitting diodes. This is the only family of conjugated polymers that emi…
The configurations of oligomers of polyimide and polyetherketone polycyclic polymers in the melt are predicted by a new hybrid pivot Monte Carlo (PMC)/molecular dynamics (MD) single-chain sampling technique restricted to a limited number of near-neighbor interactions. These are then compared to configurations obtained…
Fully relativistic density functional calculations have been performed for group 8 tetroxides MO4, where M=Ru, Os, and element 108, Hs. The electronic structure analysis has shown HsO4 to be very similar to OsO4, with the covalence and stability increasing from OsO4 to HsO4. Using models of atom-slab interactions, ads…
The energetics and the electronic structure of AlnC clusters (n=3, 4, 5; 11, 12, 13) have been studied by a global optimization of their geometry without any symmetry constraint. The total energies of these clusters both in neutral and charged states are calculated using an all-electron basis and the generalized gradi…
We report high-pressure liquid chromatography (HPLC) and transmission electron microscopy studies of the size-dependent absorbance properties of Au and Ag nanoclusters dispersed in organic solvents. These nanosize metal clusters are synthesized by an inverse micelle synthetic technique at room temperature in inert oil…
Sonochemistry involves focusing acoustic energy through cavitation bubbles to increase chemical activity. The violent bubble collapses lead to temperatures of several thousand kelvin, which drive chemical reactions. In previous work, we gave a detailed computational model of a single bubble collapse, taking into accou…
Resonance Raman intensities of p-nitroaniline, a prototypical “push–pull” chromophore with a large first hyperpolarizability (β), have been measured in dilute solution in five solvents having a wide range of polarities (cyclohexane, 1,4-dioxane, dichloromethane, acetonitrile, and methanol) at excitation wavelengths sp…
We present a comparative study of the structural parameters characterizing thin macromolecular adsorbed films that are obtained from two optical techniques: optical waveguide lightmode spectroscopy (OWLS) and scanning angle reflectometry (SAR). We use polyelectrolyte multilayers and polyelectrolyte multilayers/protein…
CaRuO_3 is perovskite with an orthorhombic distortion and is believed to be close to magnetic ordering. Magnetic studies of single crystal and polycrystalline CaRu_{1-x}Cu_xO_3 (0\le x \le 15 at.%Cu) reveal that spin-glass-like transition develops for x\le 7 at.%Cu and obtained value for effective magnetic moment p_{e…
We consider mesoscopic thermal transport between two bulk dielectrics joined by a narrow wire or weak mechanical link. In the ``tunneling'' regime where the phonon transmission probability through the link is small and the thermal conductance is much less than the value for a single channel, the thermal current is det…
Single molecule confocal microscopy is used to investigate the detailed kinetics of fluorescence intermittency in colloidal II–VI (CdSe) semiconductor quantum dots. Two distinct modes of behavior are observed corresponding to (i) sustained “on” episodes (τon) of rapid laser absorption/fluorescence cycling, followed by…