Materials Literature
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A series of copolymers of 2,5-dicyano-1,4-phenylenevinylene and 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene were synthesized by Wittig reaction. The HOMO and LUMO energy levels of copolymers can be easily tuned by controlling the feed ratio of co-monomers.
Thermal expansion for ZrW2O8 and ZrMo2O8 is analyzed by a multifrequency Einstein model. Vibrational modes that contribute significantly to the thermal expansion are empirically identified. For ZrW2O8, a negative Grüneisen parameter mode is consistent with the observed Raman spectral peak of 40 cm−1. Experimental conf…
A direct diamond epitaxy on the silicon substrate is demonstrated not only at the interface formed during the growth process but also at the nucleation sites. The small (001) terraces with dimensions of several atomic distances at the site of nucleation are formed due to the roughening of silicon surface and lead to t…
A detailed investigation on the interaction mechanisms between Er ions and Si nanocrystals (nc) is reported. Silicon nc were produced by high-temperature annealing of substoichiometric SiOx thin films grown by plasma-enhanced chemical vapor deposition. Subsequently, some of the samples were implanted by Er. These samp…
Understanding high speed machining processes requires knowledge of the dynamic friction response at the tool-workpiece interface, the high strain rate response of the workpiece material and its fracture mechanisms. In this paper, a novel experimental technique, consisting in the independent application of an axial sta…
Amorphous, partial-crystallized, and epitaxial La0.5Sr0.5MnO3 thin films have been deposited at various temperatures of 200–650 °C on (001) SrTiO3 substrates using pulsed-laser deposition. The x-ray diffraction and high-resolution transmission electron microscopy indicate complete (001) orientation of the crystalline…
Das bemerkenswerte schwammartige Verhalten eines nanoporösen Kristalls, der durch Selbstanordnung von Kupfer(II)-sulfat und 1,3-Bis(4-pyridyl)propan entsteht, beruht auf seiner ungewöhnlichen Topologie, der zwei verschiedene Strukturmotive zugrunde liegen. Die supramolekulare Verkettung führt zur Bildung von aus Ringe…
Two polymetallic iron(III) complexes 1 and 2 have been synthesised from the known corrosion inhibitor 3-(4-methylbenzoyl)-propionic acid HL1 and their crystal structures determined. Coordination geometries extracted from these structures have been used as the basis for molecular modelling onto idealised iron(III) oxid…
We have extended the exploration of microscopic dynamics of supercooled liquids to small wave numbers Q corresponding to the scale of intermediate range order, by developing a new experimental approach for precise data correction for multiple scattering noise in inelastic coherent neutron scattering. Our results in su…
In a struggle between unmatched enantiomers to control the helical sense of a polymer, temperature determines the ratio of the chiral competitors at which the right- and left-handed helical senses are equally populated. Deviation above or below this temperature is detected by the optical activity, which then increases…
A new NLO standard has been set by compound 1 for the substance class of analines: Their second-order polarizability β is two orders of magnitude higher than that of the one-dimensional NLO prototype p-nitroaniline. This is an example of the optimization of nonlinear optical chromophores with a threefold axis of symme…
The total structure factor $S(Q)$ and the radial distribution function $G(r)$ of liquid ${\mathrm{Y}}_{3}{\mathrm{Al}}_{5}{\mathrm{O}}_{12}$ (YAG) were measured at 1770--2230 K by x-ray scattering from samples under containerless conditions in Ar and ${\mathrm{O}}_{2}$. Nominal coordination numbers are 4 for ${\mathrm…
We have investigated the electronic structure of Ti3SiC2 by means of first-principles self-consistent total-energy calculations within the local-density approximation using the full-potential linear-muffin-tin-orbital method. Our calculated volume is in good agreement (within 4%) with experiment. Also, the calculated…
Monodisperse, stabförmige Moleküle 1 aus sich wiederholenden separaten Chromophoreinheiten, die im Grundzustand erheblich miteinander wechselwirken, wurden durch meso-meso-Kupplung von Porphyrinen synthetisiert. Das 128-mer (n=126) ist mit einer Länge von ca. 106 nm das längste derartige System. Die S1-Zustände sind ü…
Structural and dielectric evidences are advanced to show that the ${\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{TiO}}_{3}$ (SCT) system undergoes an antiferroelectric (AFE) phase transition in the composition range $0.18\ensuremath{\le}x\ensuremath{\le}0.40$. Stabilization of the AFE phase, instead of the…
The cyclic hexamer obtained by the condensation of furan and acetone can be used as a convenient starting material for the syntheses of calix[6]pyrrole 1 and of several “hybrid systems” containing both furan and pyrrole units. The solid-state structure of 1 shows a water molecule held inside the cavity by six hydrogen…
Efforts have been made to characterize the mechanical properties of carbon nanotubes. Previous work has concentrated on the tubes' longitudinal properties, and studies of their radial properties have lagged behind. We have used a scanning probe microscope with an indentation/scratch function to investigate the radial…
A model for the transport of nitrogen in austenitic stainless steel at temperatures around 400 °C is presented and discussed. The model considers the diffusion of nitrogen under the influence of trapping and detrapping at trap sites formed by local chromium. Nitrogen depth profiles simulated on the basis of the model…
The underlying physical phenomena behind the increased reflection/diffraction efficiency of holographically formed polymer-dispersed liquid crystal gratings formed from blended oligomers are investigated. Using parameters determined by in situ diffraction measurements during grating formation, a phenomenological diffu…
Optical conductivity data of the intermetallic compounds $({\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}{)}_{3}\mathrm{Al}$ ( $0\ensuremath{\le}x\ensuremath{\le}0.33$) reveal that their density of states around the Fermi energy ( ${E}_{F}$) is strongly reduced as $x$ is increased. In particular, ${\mathrm{Fe}}_{2}\…