Materials Literature
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Photo-cross-linkable side-chain liquid crystalline copolymers comprising a photoreactive 4-(2-cinnamoylethoxy)biphenyl side group and a photoinactive 4-cyanobiphenyl group were synthesized, and thin films of them were irradiated by linearly polarized (LP)-UV light, inducing an alignment of both mesogenic groups with t…
Extended linear complexes of manganese(II) with a bis-chelating nitronyl nitroxide ligand, 2-(2-imidazolato)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-3-oxide-1-oxy (NITIm), have been prepared where metallic and organic spin carriers alternate. Depending on the deprotonating agent, the solvent, and the counteranio…
The morphology of several semicrystalline poly(aryl ether ether ketone) (PEEK) samples with narrow molecular weight distributions and of a commercial sample of PEEK has been investigated by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS). T…
Synthesis of lyotropic mixtures of potassium laurate, 1-decanol, and water is presented, and the phase diagram of this ternary system is investigated in the vicinity of the nematic region. Several phases are identified and the corresponding concentration and temperature-induced phase transitions are studied. To prepar…
The electronic, spectral, and electrochemical characterization of (meso-tetraphenylporphyrinato)zinc(II) complexes bearing between 0 and 8 bromo substituents at the beta-pyrrole positions is reported. The investigated compounds are represented as (TPPBr(x)())Zn where TPPBr(x)() is the dianion of brominated 5,10,15,20-…
The acid−base properties of oxides are well described by the surface complexation model, which superposes a thermodynamic description of acid−base reactions at the oxide surface with a double-layer model of the electrostatics at the solid−solution interface. So far, however, this model has not been extended to include…
Recent reports have shown that cyclic peptides composed of an even number of alternating d - and l -amino acids can adopt flat, disklike conformations and stack through backbone−backbone hydrogen-bonding to form extended nanotubular structures. The present work details a general strategy for limiting this self-assembl…
The coarsening dynamics of three-dimensional islands on a growing film is discussed. It is assumed that the origin of the initial instability of a planar surface is the Ehrlich-Schwoebel step-edge barrier for adatom diffusion. Two mechanisms of coarsening are identified: (i) surface diffusion driven by an uneven distr…
We study the evolution of solidification microstructures using a phase-field model computed on an adaptive, finite element grid. We discuss the details of our algorithm and show that it greatly reduces the computational cost of solving the phase-field model at low undercooling. In particular we show that the computati…
We calculate the free energies of unstable stacking fault (USF) configurations on the glide and shuffle slip planes in silicon as a function of temperature, using the recently developed Environment Dependent Interatomic Potential (EDIP). We employ the molecular dynamics (MD) adiabatic switching method with appropriate…
We discuss how simulations of mechanical properties of materials require descriptions at many different length scales --- from the nanoscale where an atomic description is appropriate, through a mesoscale where dislocation based descriptions may be useful, to macroscopic length scales. In some materials, such as nanoc…
Individual dendrimer molecules of poly(amidoamine) (PAMAM) from generation 10 (G10) to G5 were imaged by conventional transmission electron microscopy (TEM) after staining with aqueous sodium phosphotungstate. The dendrimers were resolved as separate, beam-stable entities, and their sizes and distribution of sizes wer…
Various single layer reflective polarizers are introduced based on cholesteric liquid crystal materials containing one polymeric liquid crystal component and other non-reactive liquid crystals. A non-linear pitch gradient has been created during a process called polymerization induced molecular re-distribution. The po…
We report the results of a density-functional study of the diffusion of Pt dimers on the (111) surface of Pt. The calculated activation energy of 0.37 eV is in {\em exact} agreement with the recent experiment of Kyuno {\em et al.} \protect{[}Surf. Sci. {\bf 397}, 191 (1998)\protect{]}. Our calculations establish that…
This is a response to a recent paper by van Dongen, Uhrig, and E. Müller-Hartmann. We clarify the issues, which the above authors apparently did not fully appreciate, by referring to the microscopic foundations of Landau's Fermi Liquid Theory, its general application to the theory of metals and the theory of local Fer…
The low-temperature DC-transport properties of doped conducting polymers on the metallic side of the metal-insulator transition are analysed with modern localization-interaction theories. The DC conductivity at the lowest temperatures is governed by the 3D electron-electron interaction formula , while the magnetocondu…
Vacancy ordering was directly observed by high resolution transmission electron microscopy (HRTEM) at the heterointerface of GaSe/GaAs(100) grown by molecular beam epitaxy. Ga2Se3 crystalline film forms immediately to the GaAs (100) substrate, acting as an intermediate layer with thickness of 1.6–3.2 nm between the Ga…
We report that the thermally activated conductivity in several fullerene systems obeys the Meyer–Nelder (MN) rule, σ=σ00eΔE/kT0e−ΔE/kT. We found that the MN conductivity σ00 and the characteristic energy kT0 have a strong correlation, which is in good agreement with the prediction of the model proposed by Crandall [R.…
We studied the vibrational modes of H-doped nanocrystalline Pd $\mathrm{H}/\mathrm{Pd}\ensuremath{\le}0.04)$ by neutron spectroscopy, using the small H content as a probe for a separate determination of the vibrations of Pd atoms at surfaces and/or grain boundaries. We find that these atoms are responsible for the add…
Thin film trilayer junction of La0.67Sr0.33MnO3-SrTiO3-La0.67Sr0.33MnO3 shows a factor of 9.7 change in resistance, in a magnetic field around 100 Oe at 14 K. The junction magnetoresistance is bias and temperature dependent. The energy scales associated with bias and temperature dependence are an order of magnitude ap…