Materials Literature
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Spherical particles of Lu 2 O 3 : x% Eu, with x varying from 0% to 10% with respect to Lu, were prepared by precipitating hydroxides with urea at 80 °C and subsequently decomposing these hydroxides to oxides at 650 °C. TEM pictures revealed that the spherical particles were very uniform in size and their diameters wer…
Stunning tricolored crystals with distinct regions of green, yellow, and orange luminescence (see picture) are deposited in solutions of potassium hydrogen phthalate that contain proflavin. The dye serves as a fluorescent probe of surface charge while identifying the polar crystallographic axis. Optical probes, common…
Electron paramagnetic resonance (EPR) has been used to characterize three distinct V 4+ centres in undoped Czochralski-grown yttrium orthovanadate (YVO 4 ) crystals. These EPR signals are observed at low temperatures, and their average c -axis splittings between adjacent 51 V hyperfine lines are 40 G, 123 G, and 140 G…
We perform molecular dynamics simulations to study lithium dynamics in a model of ${\mathrm{LiPO}}_{3}$ glass at temperatures below the glass transition. A straightforward analysis of the ionic trajectories shows that lithium diffusion results from jumps between sites, the positions and properties of which are basical…
Guest-induced crystallization of amorphous unoriented syndiotactic polystyrene (s-PS) films can generate oriented clathrate phases with the chain axis of s (2/1)2 helicies nearly perpendicular to the film plane. This perpendicular crystalline phase orientation can be maintained after lower temperature annealing proced…
The bonding environment of boron is usually thought about in terms of localized 2c-2e/3c-2e bonding (as in diborane) or completely delocalized polyhedral bonding (as in B(12)H(12)(2)(-)). Recently, a number of boron compounds having a rhomboidal B(4) framework have been synthesized; these show an amazing variation in…
Explanations for stereoselectivity in the Baeyer-Villiger reaction have relied on the assumption that the antiperiplanar (app) group migrates. However, the magnitude of the preference for app-migration over gauche migration is unknown. To investigate this, the energy differences between the two were estimated from ab…
Poly(p-phenylenevinylene)s with amines and pentafluorophenyl esters on side chains were synthesized and assembled on solid substrates by sequential layer-by-layer (LBL) deposition. This approach enables the creation of robust multilayer thin films via in-situ covalent coupling reactions between successive layers. The…
Abstract The crystalline structure and fibrillar texture of nylon‐6 fibers filled with nanosized particles were investigated using wide‐angle and small‐angle X‐ray scattering. As‐spun fibers filled with organic nanoparticles consisting of aromatic polyamide‐like hyperbranched molecules with amine‐terminating groups ex…
The vibrational properties of single-wall carbon nanotubes have been probed locally with atomic-scale resolution by inelastic electron tunneling spectroscopy with a low-temperature scanning tunneling microscope. The high spatial resolution has allowed the unraveling of changes in the local phonon spectrum related to t…
Most high strength aluminium alloys used in the aircraft industries are susceptible to corrosion. Up to now hexavalent chromium is the conventional corrosion inhibitor. Because chromium in hexavalent state is carcinogenic, it is necessary to develop effective alternative inhibitor systems. We investigated magnetron sp…
This experimental paper deals with phase separations of binary mixtures composed of a continuous liquid crystal phase and an isotropic dispersed phase. In contrast to isotropic binary mixtures, the investigated mixtures do not lead to a full phase separation but to a self-ordering of colloidal particles, as reported e…
We report in situ studies of SiO2 glass under pressure and find that temperature-induced densification takes place in a pressure window. To explain this effect, we study how rigidity of glasses changes under pressure, with rigidity percolation affecting the dynamics of local relaxation events. We link rigidity percola…
We report on the synthesis and characterization of ZnO and Er-doped ZnO nanostructures. ZnO powders were synthesized by the coprecipitation and the combustion techniques. ZnO powders prepared by the coprecipitation method exhibit sheet-like nanostructures. The sheet thickness is found to be less than 100 nm. The struc…
We present detailed results of blinking studies on individual silicon nanocrystals. The experiments show, that similar to II-VI semiconductor nanocrystals, the blinking process obeys a power law statistics. An excitation intensity dependence of the power law exponent is found for the off time probability distribution.…
Dendritic macromers are attractive macromolecules for hydrogel formation since high cross-linking densities at low polymer concentration can be obtained, varied physical properties can be observed based on the macromer structure, and low viscous aqueous solutions can be injected in an in vivo site of irregular shaped…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHighly Functionalized Tetrathiafulvalenes: Riding along the Synthetic Trail from Electrophilic AlkynesAlain Gorgues, Piétrick Hudhomme, and Marc SalléView Author Information Laboratoire de Chimie, Ingénierie Moléculaire et Matériaux d'Angers, UMR CNRS 6200, 2 Boulevard Lavoi…
The electronic structure and (13)C NMR chemical shift of (9,0) single-walled carbon nanotubes (SWNTs) are investigated theoretically. Shielding tensor components are also reported. Density functional calculations were carried out for C(30)-capped and H-capped fragments which serve as model systems for the infinite (9,…
The shape- and phase-controlled synthesis of ZnS nanocrystals (nanorods and nanodots) was realized by the selection of ligand molecules with a simple method of thermolysing single-source precursor zinc ethylxanthate (Zn(exan) 2 ) with octylamine (OA) or trioctylphosphine (TOP) as precursor solvent. The as-prepared nan…
A new approximate method to calculate exchange-correlation contributions in the framework of first-principles tight-binding molecular dynamics methods has been developed. In the proposed scheme on-site (off-site) exchange-correlation matrix elements are expressed as a one-center (two-center) term plus a {\it correctio…