Materials Literature
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Abstract A series of novel dialdehydes as new monomers, 4,4′‐diformyl‐α,ω‐diphencarbonylalkane, 4,4′‐diformyl‐3,3′‐methoxy‐α,ω‐diphencarbonylalkane, and 4,4′‐diformyl‐3,3′‐ethoxy‐α,ω‐diphencarbonylalkane, was prepared from aliphatic diacid chloride with p ‐hydroxybenzaldehyde, vanillin, and 3‐ethoxy‐4‐hydroxybenzaldeh…
The kinetics of decomposition of formic acid on Ru(001) have been investigated with thermal desorption mass spectrometry following the adsorption of DCOOH and HCOOH at both 130 and 305 K. Formic acid chemisorbs dissociatively on the perfect (001) surface via O–H bond cleavage to form a formate and a hydrogen adatom, a…
Abstract The overall crystallization and crystal melting of one low‐molecular mass poly(ethylene oxide) (PEO) fraction (MW 3000) have been investigated by differential scanning calorimetry (DSC) and in situ small‐angle x‐ray scattering (SAXS). The salient new results indicate that initial transient crystals with nonin…
It is known that polyalkylthiophenes show reversible thermochromism within a well-defined temperature range. The vibrational infrared and Raman spectra are used as structural probes for understanding the structures of polyhexyl and polyoctyl thiophenes at room temperature and their evolution with temperature during th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNear-Infrared Fluorogenic Labels: New Approach to an Old ProblemGabor Patonay and Miquel D. AntoineCite this: Anal. Chem. 1991, 63, 6, 321A–327APublication Date (Print):March 15, 1991Publication History Published online30 May 2012Published inissue 15 March 1991https://pubs.a…
Abstract An investigation of the influence of crystalline microstructure on fatigue crack propagation (FCP) in high‐density polyethylene (HDPE) is reported. Various thermal histories were used to generate samples with the same crystallinity and supermolecular structure for three different molecular weight HDPEs. Estim…
The charge carriers and band structure that evolve upon doping of electrochemically grown poly (3-methylthiophene) (PMeT) films are characterized as a function of film preparation conditions by optical absorption, infrared, and electron spin resonance measurements. Regardless of the solvent (acetonitrile or propylene…
The electronic structure of tetragonal zirconia with ${\mathit{D}}_{4\mathit{h}}^{15}$ symmetry is investigated using density-functional theory. The Kohn-Sham equations are solved by applying the full-potential linearized augmented-plane-wave method. The total energy as a function of the lattice parameters shows that…
We have studied the structural properties of a recently proposed, hypothetical, all-${\mathit{sp}}^{2}$ phase of carbon, using the first-principles pseudopotential total-energy method. Our results are compared with those of an earlier tight-binding calculation. While the two calculations yield equilibrium volumes and…
Abstract Correlations of the linear crystal growth rates with the change in crystal morphology for poly (ethylene oxide) (PEO) (MW 3000) and α,ω‐‐methoxy‐poly (ethylene oxide) (MPEO) (MW 3000) fractions have been established over a wide range of supercooling (Δ T = 25 K). Two linear crystal growth rates were measured,…
Undoped and rare-earth- (Pr, Nd, Eu, and Er) doped transparent Y3Al5O12 ceramics have been prepared, and their optical spectra have been measured. It is found that absorption coefficient of the undoped ceramic Y3Al5O12 is almost independent of wavelength with 0.258 cm−1, which gives transmittance of the undoped cerami…
Abstract New linear and three‐arm star thermoplastic elastomers (TPEs) comprising a rubbery polysobutylene (PIB) midblock flanked by glass polystyrene (PSt) blocks have been synthesized by living carbocationic polymerization in the presence of select additives by sequential monomer addition. First, isobutylene (IB) wa…
The vibrational spectra of a few oligomers of thiophene in the solid and solution are studied with the help of quantum mechanical calculations and of the theory of the effective conjugation coordinate recently developed. The aim of the work is to extract from the spectra structural probes to be used in the understandi…
Abstract Cold‐drawn Nylon‐11 films, which were prepared by stretching the melt‐quenched films to a draw ratio of 2.8: 1 at room temperature, were found to exhibit an electric displacement versus electric field hysteresis loop. The results confirmed that the Nylon‐11 film exhibited ferroelectric behavior at or below ro…
We present the O 1s and V 2p absorption edges of ${\mathrm{VO}}_{2}$ at room temperature and at T=120 \ifmmode^\circ\else\textdegree\fi{}C, i.e., below and above the metal-insulator transition temperature ${\mathit{T}}_{\mathit{c}}$\ensuremath{\approxeq}67 \ifmmode^\circ\else\textdegree\fi{}C. The O 1s spectra show a…
We present a microscopic mechanism of optical nonlinearity in conjugated polymers. It is shown that the bulk of the nonlinearity is determined by only two well-defined channels, even though an infinite number of channels are possible in principle. We are able to explain the complete frequency dependence of the third-h…
The frequency and line shape of the diamond Raman line are examined in detail for a series of microwave-plasma-assisted chemical-vapor-deposition films grown on Si. The Raman lines in the films appear at higher frequency (shifts of up to 3 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$) than that of natural diamond and th…
The temperature-dependent thermal conductivity \ensuremath{\kappa}(T) of amorphous silicon has been calculated from equilibrium molecular-dynamics simulations using the time correlations of the heat flux operator in which anharmonicity is explicitly incorporated. The Stillinger-Weber two- and three-body Si potential a…
Using an all-electron, self-consistent, full-potential, linear muffin-tin-orbitals method within the local-density approximation of density-functional theory, we have studied the structural properties and the elastic constants of Mo and ${\mathrm{MoSi}}_{2}$. The Mo and ${\mathrm{MoSi}}_{2}$ ground-state properties, l…
The electrical conductivity of polymer complexes of bis-2,6-diaminopyridinesulphoxide with CuCl 2 , CuBr 2 and CuI 2 was measured at different frequencies and temperatures. It was found that the conductivity increases as frequency and/or temperature increases. The dielectric constant, dielectric loss and relaxation ti…