Materials Literature
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Multiwalled carbon nanotubes and carbon nanorods were produced through a novel route in the presence of different metallic particle catalysts at the extremely low temperature of 200 °C. In this process, tetrachloroethylene (C 2 Cl 4 ) was used as the carbon feedstock, which can be reduced by metallic potassium to free…
Calculations of the ${A}_{1}$ phonon frequency in photoexcited tellurium are presented. The phonon frequency as a function of photoexcited carrier density and phonon amplitude is determined, including anharmonic effects. The sensitivity of the ${A}_{1}$ mode to photoexcitation is related to the Peierls mechanism for s…
Abstract The thermal degradation of flax was investigated with thermogravimetric analysis. The flax used for these experiments underwent different stages of retting or, in one case, boiling. The most retted type of flax was also chemically treated to obtain elementary fibers. These samples were all tested in dynamic a…
Self-organized long carbon nanotube ribbons consisting of aligned multiwalled carbon nanotubes is fabricated using a simple solvent evaporation technique. The geometry of the ribbons is extraordinarily regular with rectangular cross sections, with dimensions of about 50−100-μm wide, 4−12-μm thick, and 100-mm long. The…
Using density-functional-based methods, we show that the hole-doped Li_{x}BC and Na_{x}BC in P6_{3}/mmc crystal structure and C_{x} in graphite structure are capable of showing superconductivity, possibly with a T_{c} much higher than that of MgB_{2}. We use full-potential methods to obtain the optimized lattice const…
Three different liquid crystal (LC) perylene diimides were investigated with respect to the optical and physical characteristics of their thin films. Films were prepared by spin-coating, vacuum evaporation, and Langmuir−Blodgett (LB) techniques on substrates such as microscope glass, indium−tin oxide-coated glass and…
A tight-binding model is fit to first-principles calculations for copper that include structures distorted according to elastic constants and high-symmetry phonon modes. With the resulting model the first-principles-based phonon dispersion and the free energy are calculated in the quasi-harmonic approximation. The res…
Analytic results for the conductance of a molecular wire attached to mesoscopic tubule leads are obtained. They permit to study linear transport in presence of low dimensional leads in the whole range of parameters. In particular contact effects can be addressed in detail. By focusing on the specificity of the lead-wi…
Surface melting temperature is well-known significantly lower than the bulk melting point. But we find that the interior melting temperature in ultrathin nanowires is lower than that of the surface melting . The thermal stability of helical multi-walled cylindrical gold nanowires is studied using molecular dynamics si…
We consider hypothetical Ga7MnAs8, Ga16MnAs16, and Ga14Mn3As16 crystals with Mn in a substitutional, interstitial, and both positions. Spin-polarized FPLAPW calculations were used to obtain their electronic structure. We show that the interstitial Mn acts as a double donor and compensates the holes created by two Mn a…
The synthesis of a novel fluoroionophore, 5-p-[[4-(10',15',20'-triphenyl-5'-porphinato) phenyloxyl]-1-butyloxyl]phenyl-10,15,20-triphenylporphine (DTPP), and its application for preparation of a Hg(II)-sensitive optical fiber chemical sensor are described. The response of the sensor is based on the fluorescence quench…
The retraction energy of a multiwalled carbon nanotube with an extruded core causes the core to oscillate with respect to its fully retracted position where the van der Waals potential energy is minimized. This phenomenon, together with the available nanotechnology, leads to the creation of nanomechanical systems of o…
L'action inhibitrice du 2-aminothiophénol (ATP) et du 2-aminophényl disulfure (APDS) sur la corrosion du fer dans HCl 1 M est étudiée par détermination de perte de masse et par analyse des courbes de polarisation potentiodynamique. Ces deux composés (ATP, APDS) réduisent la vitesse de corrosion du fer; cependant, l'AP…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
Abstract The structure and thermal properties of polyamide‐1010 (PA1010), treated at 250°C for 30 min under pressures of 0.7–2.5 GPa, were studied with wide‐angle X‐ray diffraction (WAXD), infrared (IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Crystals were formed when the pressu…
Computations, mostly at the RHF level, have been performed on La3+ and Y3+ model complexes of the widely used DOTA ligand [DOTA = 1,4,7,10-tetraaza-1,4,7,10-tetrakis(carboxymethyl)cyclododecane] for the purpose of identifying properties of the transition states of geometrical isomer interconversions, which have been t…
Electrochemical homopolymerization of metanillic acid has been achieved for the first time using a 4:1 acetonitrile-water mixture to get 100% sulfonated polyaniline which is soluble in both organic and aqueous solvents, electrically conducting, and is n-dopable.
Aluminum tetracarboxyphthalocyanine is adsorbed onto silanized silica particles at different dye to particle ratios. Diffuse reflectance spectra are measured and the equilibrium between dye monomers and aggregates is studied. Between 4.0 × 10−8 and 2.0 × 10−6 mol of dye g−1 of support, a simple dimerization equilibriu…
Porous alumina was fabricated by anodization in sulfuric acid and oxalic acid, where a laser dye, rhodamine 6G (RG6), and another luminescent organic molecule 8-hydroxyquinoline aluminum (Alq 3 ) were impregnated. The morphology determined by atomic force microscopy shows that the size of the pores is about 10-15 nm f…
This article reports the first work on the use of silica supported dendritic chiral auxiliaries for the enantioselective addition of diethylzinc to benzaldehyde: the control of dendrimer propagation on the silica surface is of prime importance to obtain enhanced conversion, selectivity, and enantioselectivity.