Materials Literature
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Gold nanoparticles of 5 nm diameter, stabilized by 4-(dimethylamino)pyridine (DMAP), were coated with poly(sodium 4-styrene sulfonate) (PSS) via electrostatic self-assembly. The suspension stability, monitored by the gold surface plasmon band (SPB), was studied by varying the pH, the PSS chain length, and PSS concentr…
We report on microwave operation of top-gated single carbon nanotube transistors. From transmission measurements in the 0.1-1.6 GHz range, we deduce device transconductance gm and gate-nanotube capacitance Cg of micro- and nanometric devices. A large and frequency-independent gm approximately 20 microS is observed on…
The controlled precipitation of a supersaturated Cd2+ solution is used to selectively deposit Cd(OH)2 nanowire bundles on a substrate. As schematically depicted in the figure, when the Cd2+ ionic product exceeds the solubility product, heterogeneous and homogeneous nucleation occur independently on the substrate and i…
Abstract Conductive materials are at the forefront of materials science research because of the large number of applications that have been developed around their interesting and unique properties. This work reports for the first time a correlation between the structural, electrical, and thermal behavior of novel grap…
Mn 2+ -doped II−VI semiconductor quantum dots reveal remarkably intense photoluminescence with a short lifetime associated with the 4 T 1 ( 4 G) → 6 A 1 ( 6 S) transition, which is spin-forbidden and is allowed because of crystal field effects. We explored the photophysical properties of high-quality, narrow-size-dist…
To analyze the thermorheological behavior of various polyethylenes, the relaxation spectra were shifted. Not only linear and short-chain branched PE but also the classical high-pressure LDPE were found to be thermorheologically simple, i.e., the activation energy E a is independent of the relaxation strength or the re…
The influence of the partial substitution of B by Ge on the magnetocaloric response of Fe78Co5Zr6B10Cu1 is studied. Ge addition produces a reduction in the temperature at which the peak entropy change takes place, as well as a slight decrease in the magnitude of the peak, ∣ΔSMpk∣. The refrigerant capacity, RC, and its…
We compute the effect of different isolated defects on the phonon transmission through carbon nanotubes, using an ab initio density functional approach. The problem of translational and rotational invariance fulfillment in the nonperiodic system is solved via a Lagrange-multiplier symmetrization technique. The need fo…
The ultrastructure and mechanical properties of the fusiform, triradiate and ovoid morphotypes of Phaeodactylum tricornutum were investigated using atomic force microscopy. Using topographic imaging, we showed that the surface of the ovoid form is rougher than those of the two other specimens, and coated with an outer…
The electronic properties and stabilities of SnO and $\mathrm{Sn}{\mathrm{O}}_{2}$ bulk materials and their low-index surfaces are investigated by density functional theory. An empirical method has been adopted in this study to account for the van der Waals interactions among the Sn-O layers in the bulk and low-index…
OBJECTIVE: An in vitro model system for pH-triggered release of the antibiotic vancomycin from porous Si films is studied. METHOD: Vancomycin is infused into a mesoporous Si film from a mixed aqueous/acetonitrile solution and trapped by a capping layer containing the protein bovine serum albumin (BSA). The protein eff…
We present real-time, nanoscale temperature mapping using a transmission electron microscope and standard phase transitions in metal islands. Islands are deposited on the reverse side of commercially available silicon nitride membranes, while local thermal gradients are produced by Joule heating in a thin wire on the…
Rare-earth-doped nanocrystalline titania microspheres are prepared using an inexpensive and scalable ultrasonic spray pyrolysis method. Anatase titania nanocrystals distributed inside these microspheres function as sensitizers to absorb light and transfer energy to rare earth ions, which leads to intense and narrow ba…
Abstract The present work describes the synthesis of difluoro‐boradiazaindacenes (Bodipy) functionalized at the central 8‐position by phenylamino moieties easily transformable into phenyl amide scaffoldings. Molecules carrying three linear or branched chains were prepared and characterized. An X‐ray crystal structure…
The irradiation of SrTiO$_3$ single crystals with swift heavy ions leads to modifications of the surface. The details of the morphology of these modifications depends strongly on the angle of incidence and can be characterized by atomic force microscopy. At glancing angles, discontinuous chains of nanosized hillocks a…
Time-resolved X-ray microscopy is used to image the influence of alternating high-density currents on the magnetization dynamics of ferromagnetic vortices. Spin-torque induced vortex gyration is observed in micrometer-sized permalloy squares. The phases of the gyration in structures with different chirality are compar…
Dielectric permittivity spectra of yttrium-doped $\mathrm{Eu}\mathrm{Mn}{\mathrm{O}}_{3}$ in the composition range $0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.5$ have been investigated in the terahertz frequency range. Magnetoelectric contributions to the permittivity were observed in all compositions for ac elec…
We present a general framework to describe the simultaneous para-to-ferromagnetic and semiconductor-to-metal transition in electron-doped EuO. The theory correctly describes detailed experimental features of the conductivity and of the magnetization, in particular, the doping dependence of the Curie temperature. The e…
The ground state energy of current carriers in graphene considered as a zero-gap semiconductor was calculated in the two-band approximation. The condition of the electronic (hole) system stability in graphene was obtained. The possibility of the zero-gap semiconductor-semimetal transition was discussed.
We derive and discuss expressions for the temperature-dependent electrostatic polarizabilities of off-center ions holding good under various experimental conditions. At low temperatures and electric-field strengths, all of them reasonably reduce to values characteristic of phonon-coupled two-level systems. Prospects f…