Materials Literature
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The static dielectric constant of isolated silicon nanocrystals (nc-Si) embedded in a SiO2 thin film synthesized by Si+ implantation has been determined from capacitance measurement based on the Maxwell–Garnett effective medium approximation and the stopping and range of ions in matter simulation. For the nc-Si with a…
A theoretical model is suggested that describes the generation of partial and split dislocations at grain boundaries in nanocrystalline metals. The ranges of parameters (such as grain size and level of external stress) are theoretically revealed at which the formation of partial dislocation semi-loops is energetically…
We examine the dynamics of acid and methylated precursors to sulfonated polystyrene ionomers. Dielectric relaxation spectroscopy was the primary tool used in the investigation of the dynamics, and dynamic mechanical analysis, Fourier transform infrared spectroscopy, and differential scanning calorimetry were employed…
Abstract Well‐defined poly( L ‐lactide)‐ b ‐poly(ethylene oxide) (PLLA‐ b ‐PEO) copolymers with different branch arms were synthesized via the controlled ring‐opening polymerization of L ‐lactide followed by a coupling reaction with carboxyl‐terminated poly(ethylene oxide) (PEO); these copolymers included both star‐sh…
In this letter, a first-principles study of the anisotropic thermal expansion of wurtzite ZnS in the framework of the density-functional theory and the density-functional perturbation theory is reported. The compound in zinc blende structure is also studied for comparison. The curves of the linear and volume thermal e…
We report that measurements of the Raman intensity versus applied voltage are sensitive to filling of the density of states and enable us to measure the second band gap in specific semiconducting single-walled carbon nanotubes (SWNTs). Raman scattering preferentially selects sets of SWNTs whose excitonic transitions a…
The effect of uniaxial compressive pre-stress on the ferroelectric properties of commercial soft PZT ceramics is investigated. The ferroelectric properties under the uniaxial compressive pre-stress of the ceramics are observed at stress up to 24 MPa using a compressometer in conjunction with a modified Sawyer–Tower ci…
A novel class of photochromic materials based on polar azo derivatives containing functionalized biphenyl substituents has been synthesized. Once melt and cooled, these compounds formed amorphous transparent monomeric materials whose glass transition temperatures depend mainly on the bulkiness of the biphenyl substitu…
Pb 2 MnWO 6 has been synthesized and its structure determined by powder x-ray diffraction. This sample undergoes a first order structural phase transition at ∼445 K. This transition is coupled to a change in the electrical properties manifested by a sharp discontinuity of the dielectric permittivity at the phase trans…
X-ray diffraction and differential scanning calorimetric studies were performed on bulk Sn–Sb–Se chalcogenide alloys, which were obtained by the conventional melt quenching technique. The addition of Sn reduces the crystalline nature of Sb20Se80 chalcogenide alloy and amorphous samples are obtained for a-SnxSb20Se80−x…
We report on the growth of uniquely shaped ZnO nanowires with high surface area and patterned over large areas by using a poly(dimethylsiloxane) (PDMS) microfluidic channel technique. The synthesis uses first a patterned seed template fabricated by zinc acetate solution flowing though a microfluidic channel and then g…
Part 1 Fibre, whisker and particulate-reinforced ceramic composites: Fibrous monolithic ceramics Whisker reinforced silicon nitride ceramics Fibre reinforced glass/glass-ceramic matrix composites Particulate composites. Part 2 Graded and layered composites: Functionally-graded ceramic composites SiAlON based functiona…
The influence of shear flow on the temperature evolution of the specific volume and the crystalline morphology of two iPP's, differing in weight-averaged molar mass M̄ w, was investigated at nonisothermal conditions and elevated pressures, using a custom-designed dilatometer. These conditions are typically in the rang…
Abstract The sorption of carbon dioxide in poly(lactic acid) (PLA) was studied by quartz crystal microbalance at high pressures. To address the effect of the D isomer present in the polymer on the gas sorption, measurements were performed in PLA with two different L:D contents, 80:20 and 98:2. New data for the solubil…
Abstract Summary: Multifunctional hyperbranched polyether polyols bearing protective poly(ethylene glycol) (PEG) chains with or without the folate targeting ligand at their end have been prepared. Solubilization in these polymers of a fluorescent probe, pyrene, and an anticancer drug, tamoxifen, was physicochemically…
A series of hybrid organic/inorganic triblock copolymers of polystyrene−butadiene−polystyrene (SBS) grafted with polyhedral oligomeric silsesquioxane (POSS) molecules with different chemical constituents were synthesized by a hydrosilation method. Four POSS macromers, R‘R 7 Si 8 O 12, were designed to contain a single…
Hydrogen-terminated diamond can exhibit a pronounced two-dimensional hole conductivity when it is exposed to appropriate adsorbates. This phenomenon was first encountered in the form of the so-called hydrogen-induced surface conductivity but is meanwhile understood as a novel kind of doping mechanism by which the surf…
FeCo-codoped ZnO nanowires were synthesized by in situ doping with iron and cobalt using a chemical vapor deposition method. Structure and compositional analysis indicated that the as-prepared nanowires were single- crystalline and FeCo codoped. No FeCo clusters and other secondary phases were found in the nanowires.…
To obtain organic nanowire sensors with high sensitivity and rapid response times, based on the inducement effect of surfactants during in situ polymerization, nanostructured polyaniline composites are obtained by using a chemical oxidation method by adding a small amount of surfactant. A casting method is employed on…
Natural biominerals often have exquisite morphologies, where the cells exercise a high degree of crystallographic control through secretion of biological macromolecules and regulation of ion transport. One important example is the sea urchin spine. It has recently been shown to be formed through deposition of a transi…