Materials Literature
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The dielectric properties of the twist grain boundaries TGB(A) and TGB(C) of liquid crystal phases differ from the smectic-A and smectic-C phase ones: a theoretical model confirmed by experimental results shows that the Goldstone mode of the TGB(C) phase and the soft mode of the TGB(A) phase are strongly reduced. This…
The following flavonoid compounds have been isolated and identified from the flowers of Asclepias svriaca L.: kaempferol, kaempferol 7-O-beta-glucoside, kaempferol 3-O-beta-galactopyranoside, kaempferol 3-O-beta-xylopyranosyl (1-->2)-beta-galactopyranoside, kaempferol 3-O-beta-glucopyranosyl (1-->2)-beta-galactopyrano…
The reduction of Ni(S2C2(CF3)2)2(C7H8) (3) proceeds by an overall two-electron irreversible process through an ECE mechanism. The reduction potential of 3 is about 700 mV negative of that in an earlier report, which is shown to result from contamination of the sample by the monoanion of the olefin-free complex [Ni(S2C…
The (beta alpha)(8)-barrel is the most frequent and most versatile fold among enzymes [Höcker et al., Curr. Opin. Biotechnol. 12 (2001) 376-381; Wierenga, FEBS Lett. 492 (2001) 193-198]. Structural and functional evidence suggests that (beta alpha)(8)-barrels evolved from an ancestral half-barrel, which consisted of f…
A biodegradable block copolymer (PCL-b-PLLA, M(n) = 1.72 x 10(4), M(w)/M(n) = 1.37) of poly(epsilon-caprolactone) (PCL) and poly(L-lactide) (PLLA) with very low crystallinity was obtained by forming the inclusion complex between alpha-cyclodextrin molecules and PCL-b-PLLA followed by coalescence of the guest polymer c…
Abstract Films of poly(ε‐caprolactone) (PCL) blends with α‐chitin and chitosan were prepared as completely biodegradable polyester/polysaccharide composites. DSC thermal analysis revealed that the crystallization of PCL was suppressed by blending with α‐chitin and chitosan. The specific interaction between PCL and pol…
Abstract This work presents a computational material model of flexible woven fabric for finite element impact analysis and simulation. The model is implemented in the non‐linear dynamic explicit finite element code LSDYNA. The material model derivation utilizes the micro‐mechanical approach and the homogenization tech…
A sequence of three metal-catalysed aryl coupling reactions leads to the new ligand 4'-(4-N,N-diphenylaminophenyl)-2,2':6',2"-terpyridine, the intense ICT emission of which undergoes a large red-shift upon binding of zinc ions, providing a unique response over other common metal ions.
The present studies describe the fabrication and characterization of highly porous and interconnected poly(alpha-hydroxy acid) foam scaffolds produced using a phase separation multisolvent system, followed by a sublimation process. Fabrication parameters, including solvent composition, polymer concentration, freezing…
The recent experiments of Crocker et al. [Phys. Rev. Lett. 85, 888 (2000)] suggest that microrheological measurements obtained from the correlated fluctuations of widely-separated probe particles determine the rheological properties of soft, complex materials more accurately than do the more traditional particle autoc…
The acoustic phonon-mediated drag-contribution to the drag current created in the ballistic transport regime in a one-dimensional nanowire by phonons generated by a current-carrying ballistic channel in a nearby nanowire is calculated. The threshold of the phonon-mediated drag current with respect to bias or gate volt…
A numerical scheme for solving the time-evolution of wave functions under the time dependent Kohn-Sham equation has been developed. Since the effective Hamiltonian depends on the wave functions, the wave functions and the effective Hamiltonian should evolve consistently with each other. For this purpose, a self-consis…
Transport in molecular electronic devices is different from that in semiconductor mesoscopic devices in two important aspects: (1) the effect of the electronic structure and (2) the effect of the interface to the external contact. A rigorous treatment of molecular electronic devices will require the inclusion of these…
The doping of the manganese site by iridium (up to 15%) in the small A cation manganites Pr_{1-x}Ca_xMnO_3 (0.4 < x < 0.8), has been investigated as a new method to suppress charge-ordering and induce CMR effects. Ir doping leads to ferromagnetism and to insulator to metal transitions, with high transition temperature…
CO adsorption on the Pt(111) surface is studied using first-principles methods. As found in a recent study [Feibelman, et al., J. Phys. Chem. B 105, 4018 (2001)], we find the preferred adsorption site within density functional theory to be the hollow site, whereas experimentally it is found that the top site is prefer…
Left-handed materials are studied numerically using an improved version of the transfer-matrix method. The transmission, reflection, phase of reflection, and absorption are calculated and compared with experiments for both single split-ring resonators with negative permeability and left-handed materials, which have bo…
A sharp collective charge excitation is predicted in MgB$_2$ at $\sim2.5eV$ for $q$ perpendicular to the boron layers, based on an all-electron analysis of the dynamical density response within time-dependent density functional theory. This novel excitation, consisting of coherent charge fluctuation between Mg and B s…
The recently discovered (1 x 4) reconstruction of the stoichiometric anatase TiO(2)(001) surface is studied via first principles density functional calculations. We propose a new structural model for this reconstruction, which is energetically much more favorable than all the other available models, including the unre…
We review recent advances in experimental methods for high spatial-resolution and high time-resolution thermometry, and the application of these and related methods for measurements of thermal transport in low-dimensional structures. Scanning thermal microscopy (SThM) achieves lateral resolutions of 50 nm and a measur…
The frequency dependence of the shear modulus was studied for cross-linked polyurethane melts and gels at various cross-link densities. The polyurethane used in this study was based on mixtures of bifunctional linear poly(propylene oxide) (PPO) and trifunctional star PPO end-linked with diisocyanate. The connectivity…