Materials Literature
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The surface of colloidally prepared CdTe nanocrystals capped with thioglycolic acid has been studied by photoelectron spectroscopy with tunable synchrotron radiation excitation. Colloidally prepared CdTe nanocrystals possess photoluminescence properties which depend on the growth conditions. Two samples of the same pa…
The effects of the erbium concentration, crystal size, crystal phase, and different processing temperatures on the upconverted emission of Er 3+ in BaTiO 3 and TiO 2 nanocrystals are reported. A cw diode laser at 975 nm was used as a pump source for resonant sequential excitation of the 4 I 11/2 and 4 F 7/2 levels. Gr…
Low-dielectric-constant nanoporous films (dielectric constant, k = 2.4) with thermal integrity and controllable mechanical strength have been prepared by covalently tethering nanoporous polyhedral oligomeric silsesquioxane (POSS) molecules, 1-nm size, to the side chains of polyimide. The tethered POSS molecules in the…
In this communication, we show that aryldiazonium salts can react efficiently with individual SDS-coated SWNTs in water to form aryl functionalized SWNTs. Remarkably, the resulting SWNTs have up to 1 in 9 carbons along their backbones bearing an organic moiety and they remain unbundled throughout their entire lengths,…
Chiral aluminum isopropoxides based on enantiopure or racemic cyclohexylsalen ligand (Jacobsen ligand) have been prepared and employed for stereoelective/stereoselective ring-opening polymerization of lactide in toluene at 70 degrees C. The kinetics, selectivity of the catalysts, and microstructure of the obtained pol…
The evolution of spin- and orbital-ordered states has been investigated for a series of insulating perovskites $R{\mathrm{MnO}}_{3}$ $(R=\mathrm{L}\mathrm{a},\mathrm{P}\mathrm{r},\mathrm{N}\mathrm{d},\dots{}).$ $R{\mathrm{MnO}}_{3}$ with a large ${\mathrm{GdFeO}}_{3}$-type distortion is regarded as a frustrated spin s…
Abstract A diarylethene dimer connected with a diyne 1 (O–O) was synthesized. Upon irradiation with 350-nm light the colorless hexane solution of 1 (O–O) changed to a dark-blue solution, in which absorption maximum was observed at 574 nm. The color is due to the formation of the isomer having one closed-ring form 1 (O…
It is generally assumed that crystallization begins with a small, crystalline nucleus. For proteins this paradigm may not be valid. Our numerical simulations show that under conditions typically used to produce protein crystals, small clusters of model proteins (particles with short-range, attractive interactions) can…
In this communication, we report on the anisotropy of the superconducting properties of multifilamentary Bi-based tapes experimentally investigated by AC magnetic susceptibility measurements. The susceptibility $χ= χ' - j χ''$ was measured using a commercial system and a couple of orthogonal pick-up coils. The $χ''$ v…
In the investigations of antiferromagnetic (AF)/ ferromagnetic (FM) bilayer samples, often distinct experimental techniques yield different values for the measured exchange anisotropy field (HE). Using a simple microscopic model for representing the AF/FM interface, which incorporates the effect of interface roughness…
We have prepared powder samples of NaxCoO2 x yH2O using a new synthesis route. Superconductivity was observed in Na0.3CoO2 x 1.3H2O between 4 and 5K as indicated by the magnetic susceptibility. The bulk compressibilities of Na0.3CoO2 x 1.3H2O, Na0.3CoO2 x 0.6H2O and Na0.3CoO2 were determined using a diamond anvil cell…
In this Letter the expression for the refractive index of de Broglie wave in the presence of a potential field is obtained and based on this, the physical meanings of negative index of refraction is revealed. We demonstrate that the electromagnetic wave propagation in a left-handed medium with negative refractive inde…
First-principles calculations using density functional theory based on norm-conserving pseudopotentials have been performed to investigate the Mg adsorption on the Si(001) surface for 1/4, 1/2 and 1 monolayer coverages. For both 1/4 and 1/2 ML coverages it has been found that the most favorable site for the Mg adsorpt…
Several experimental techniques have been used in order to characterize the properties of multifilamentary Bi-2223 / Ag tapes. Pristine samples were investigated by electrical resistivity, current-voltage characteristics and DC magnetic moment measurements. Much emphasis is placed on comparing transport (direct) and m…
The basic dissipative particle dynamics (DPD) method is described, and a useful extension to allow many-body interactions is detailed. The application of DPD to problems in materials physics is discussed for polymers, surfactants and self-assembling systems.
Normal-mode relaxation of entangled cis -polyisoprene (PI) confined in porous glass was studied using broadband dielectric spectroscopy. In our designed model systems, geometric confinement effects are much weaker than surface adsorption effects, allowing relaxation dynamics of polymer chains at the surface to be dete…
Tapping mode atomic force microscopy was used to investigate the lamellar morphology of poly(l-lactide) and two poly(l-lactide-co-meso-lactide) random copolymers containing 3% and 6% meso-lactide. Samples were isothermally crystallized at selected temperatures, and qualitative and quantitative analyses of lamellar str…
The adsorption of hydrophobic silica nanoparticles at the poly(dimethylsiloxane) (PDMS) droplet−water interface has been investigated through particle adsorption isotherms, with complementary studies of the adsorbed layer structure by freeze-fracture SEM. The influences of pH and electrolyte concentration as well as d…
A double mutant cycle has been used to evaluate interaction energies between the global stabilizer mutation asparagine 52 --> isoleucine (N52I) in iso-1-cytochrome c and mutations producing single surface histidines at positions 26, 33, 39, 54, 73, 89, and 100. These histidine mutation sites are distributed through th…
The dynamic heterogeneity of the segmental dynamics in miscible polymer blends has been alternatively interpreted in terms of either chain connectivity effects or thermal concentration fluctuations. Taking into account that both phenomena seem to be relevant, in this work we propose a minimal model which combines thes…