Materials Literature
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Abstract Polyethylene (PE)–vermiculite (VMT) nanocomposites containing 0.5, 2, 4, 6, and 8 wt % clay loadings were fabricated via direct melt compounding in a twin‐screw extruder. Crystallization kinetics was investigated by means of polarized optical microscopy and differential scanning calorimetry. Moreover, the kin…
Abstract The toughening behavior of polycarbonate modified with core‐shell type particles was investigated. The alloys were found to exhibit maximum impact strength upon addition of a modifier with a poly(butyl acrylate) rubbery core of 0.25 μm diameter. The incorporation of particles with diameter greater than 0.25 μ…
The photophysical properties of L-lysine-based polypeptides bearing porphyrin pendants were investigated. The intramolecular exciton-exciton annihilation resulting from the exciton migration among the porphyrin units deactivates the singlet excited state efficiently. It was revealed that the rate of the exciton migrat…
Zinc stannate (Zn 2 SnO 4 ) thin films were deposited by RF magnetron sputtering on silica substrates at various [O 2 /(Ar+O 2 )] flow ratios. The influences of the [O 2 /(Ar+O 2 )] flow ratio on the crystalline structure, and the optical and electrical properties have been investigated. No sharp X-ray diffraction (XR…
Abstract Differential scanning calorimetry (DSC) does not allow for easy determination of the glass‐transition temperature ( T g ) of the polystyrene (PS) block in styrene–butadiene–styrene (SBS) block copolymers. Modulated DSC (MDSC), which deconvolutes the standard DSC signal into reversing and nonreversing signals,…
Resorcinol-formaldehyde aerogels and carbon aerogels of different mesoporosities have been used as templates for preparing bimodal zeolites of mesopores. Samples were thoroughly characterized with X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, X-ray photoelectron spectrosco…
The design, synthesis, and mesomorphic properties of a new series of homodendrimers consisting of the commercially available poly(propylene imine) (PPI) dendrimers (G = 1-5), PPI-(NH(2))(n)() (n = 4, 8, 16, 32, 64), functionalized with a discotic triphenylene moiety are reported. The liquid crystalline behavior was in…
Mechanical shaft seals used in pumps are critically important to the safe operation of the paper, pulp, and chemical process industry, as well as petroleum and nuclear power plants. Specifically, these seals prevent the leakage of toxic gases and hazardous chemicals to the environment and final products from the rotat…
For binary compound semiconductor nanowires, we find a striking relationship between the nanowire's thermal conductivity ${\ensuremath{\kappa}}_{\mathrm{n}\mathrm{w}\mathrm{i}\mathrm{r}\mathrm{e}}$, the bulk material's thermal conductivity ${\ensuremath{\kappa}}_{\mathrm{b}\mathrm{u}\mathrm{l}\mathrm{k}}$, and the mas…
Differential scanning calorimetry (DSC) was used to study the thermal transitions of smectite organoclays and their dispersions in olefinic systems, which included paraffinic waxes and polyethylene. The organoclays, with treatment on both the basal and edge surfaces, produced nanocscale dispersions without the aid of…
Epitaxial growth of nitride compounds by the metalorganic vapor phase epitaxy (MOVPE) technique is demonstrated for the first time on β-Ga 2 O 3 single crystal substrates, which are near-UV transparent and n-type conductive. High-quality (0 0 0 1) GaN epi-layer with a narrow bandedge luminescence was obtained using a…
Density functional computations show, in contrast to general assumptions, that the reactions at the 7-7 ring fusions of Stone-Wales defects in the sidewalls of armchair (5,5) single-wall carbon nanotubes are much less exothermic than reactions at perfect sites. In addition, the peripheral 5-6 and 6-7 ring fusions of t…
We use small-angle x-ray scattering (SAXS) as a tool to study the binding of proteins to spherical polyelectrolyte brushes (SPB) in situ. The SPB consists of a solid core of approximately 100 nm diam onto which long polyelectrolyte chains [poly(styrene sulfonic acid, PSS) and poly(acrylic acid, PAA)] have been densely…
Singlet molecular oxygen (a(1)Delta(g)) has been produced and optically detected in time-resolved experiments upon nonlinear two-photon excitation of a photosensitizer dissolved in water. For a given sensitizer, specific functional groups that impart water solubility and that give rise to larger two-photon absorption…
Molecular dynamics simulations in three-dimensional copper are performed to quantify the void coalescence process leading to fracture. The correlated growth of the voids during their linking is investigated both in terms of the onset of coalescence and the ensuing dynamical interactions through the rate of reduction o…
X-ray absorption (XAS) and emission (XES) spectroscopy near B K and C K edges have been performed on metallic ($\ensuremath{\sim}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{at.}\phantom{\rule{0.2em}{0ex}}%$ B, B-diamond) and semiconducting ($\ensuremath{\sim}0.03\phantom{\rule{0.3em}{0ex}}\mathrm{at.}\phantom{\rule{0.2em}{0…
A liquid-crystal (LC) lens driven by two voltages is reported. The lens has a focal length that is electrically tunable. The range of the variable focusing power is very wide, covering approximately 0.8-10.7 D. In the entire focal range the LC lens maintains high optical quality. The LC lens can be driven in a simple…
The heat capacity of isotopically enriched 28Si, 29Si, 30Si samples has been measured in the temperature range between 4K and 100K. The heat capacity of Si increases with isotopic mass. The values of the Debye temperature for the three isotopic varieties of silicon have been determined. Good agreement with the theoret…
The structural properties under hydrostatic pressure up to 3 GPa of the layered rare earth carbide halide superconductor Y2C2I2 are studied by neutron powder diffraction at room temperature. The compressibilities are anisotropic, such that the compressibility perpendicular to the layers being approximately twice as la…
The remarkable polarization properties of the synchrotron light have lead to the advent of modern synchrotron-related spectroscopic studies with angular and/or magnetic selectivity. We give here an overview of the prominent aspect of the polarization of the light delivered by a bending magnet, and some dichroic proper…