Materials Literature
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Abstract Physical aging experiments after a deep quench were performed via an optical photobleaching technique to examine the evolution of the segmental dynamics of a polystyrene melt far below the glass transition temperature ( T g ). Both rotational and translational diffusion measurements of dilute tetracene probes…
Thermodynamisch stabil, aber kinetisch labil sind die M3L2-Käfigverbindungen im hier gezeigten [BF4⊂{Ag3(MsTBim)2}](BF4)2 1 und [{CuI3⊂[Cu3(MsTBim)2]}2][Cu2I4] 2, wobei 2 ein bisher noch nicht beschriebenes Metallkomplex-Wirt/Metallkomplex-Gast-Arrangement aufweist. Größere Anionen wie CF3SO3− oder BPh4− lagern sich a…
The question of localization in a one-dimensional tight-binding model with aperiodicity given by substitutions is discussed. Since the localization properties of the well-known Rudin-Shapiro chain is still far from well understood, partly due to the absence of rigorous analytical results, we introduce a sequence that…
We have investigated the photoinduced optical properties of a new class of chiral methacrylic polymers characterised by the presence in the side chain of an optically active pyrrolidinyl ring linked to a trans-azoaromatic system. The homopolymers are enantiomerically pure and their strong optical activity indicates th…
Highly soluble [(tBu(4)PcM)(2)O] phthalocyanine dimers (M=Ga(III) (3), In(III) (4)) were prepared by the reaction of [tBu(4)PcMCl] (M=Ga(III) (1), In(III) (2)) with excess of concentrated H(2)SO(4) at -20 degrees C. The Mbond;Obond;M linkages in 3 and 4 are not stable against concentrated H(2)SO(4) at room temperature…
An effective method for incorporating cadmium ions into mesoporous silica SBA-15 is demonstrated. One of the novel features is the assembly of CdS nanoparticles inside the mesopores by selectively functionalizing the external surface of SBA-15 in order to avoid the possible adsorption of the cadmium ions onto this sur…
A series of homodinuclear platinum(II) complexes containing bridging chalcogenido ligands, [Pt(2)(mu-E)(2)(P empty set N)(4)] (P empty set N=dppy, E=S (1), Se (2); P empty set N=tBu-dppy, E=S (3)) (dppy=2-(diphenylphosphino)pyridine, tBu-dppy=4-tert-butyl-2-(diphenylphosphino)pyridine) have been synthesized and charac…
The preparation of a new beta-tetrasubstituted porphyrin through a short synthesis with liquid crystalline properties in a wide range of temperatures including room temperature is described.
Polymer electrodes for batteries is one possible application of hybrid polymer films synthesized from pyrrole and polyoxometalates (shown in the graphic). These materials have high specific charges, between 30 and 80 mA h g−1, and the dc conductivities at room temperature are between 20 and 220 S cm−1. The synthesis,…
The efficiency of producing biological damage varies with radiation quality. Conventional explanations rely on spatial differences in the radiation track structure; generally however there are also very large temporal differences in delivery of the radiation at the cellular level. High-LET radiation normally deposits…
ABSTRACT A (high strain) low‐cycle fatigue (LCF) life prediction model of ultrafine‐grained (UFG) metals has been proposed. The microstructure of a UFG metal is treated as a two‐phase ‘composite’ consisting of the ‘soft’ matrix (all the grain interiors) and the ‘hard’ reinforcement (all the grain boundaries). The disl…
Bio-inspired optical systems have the potential to transform the process of image collection and analysis in the future. Through simplicity and dynamics these collection systems may provide multiple functions with an excellent level of reliability. From the graded index of the fish-eye to the hyper-acuity of the compo…
The magnetic and electronic properties of the perovskite system $({\mathrm{La}}_{0.7\ensuremath{-}x}{\mathrm{Gd}}_{x}){\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ $(0<~x<~0.6)$ have been investigated by measurements of magnetization, resistivity and magnetoresistance. The substitution of Gd on La sites not only result…
Without large investments in new clean-room facilities, the nano- and microstructures described here can be achieved by the combination of wet-chemistry with existing conventional lithographic techniques. One of the advantages of the method is that it allows the specific formation of aperiodic patterns, which are of s…
The reaction of Zr(OR)4 (OR = OnBu, OnPr) with methacrylic acid was monitored by extended X-ray absorption fine structure (EXAFS), 1H and 13C NMR, HPLC, and Raman measurements. The study revealed that the initial dimeric zirconium alkoxides react rapidly with the carboxylic acid and form higher aggregated multinuclear…
Enhanced photocurrents are detected in the presence of bipyridinium-modified CdS nanoparticles associated with electrodes. The enhanced photocurrents originate from vectorial electron transfer that retards recombination processes. The Figure shows different architectures for CdS nanoparticles on Au electrodes.
Moieties that can be cross-linked appear to be the necessary feature of dendrimers that can be used to make poled polymers displaying high chromophore density, excellent electrooptic properties, and good thermal and temporal stability. Such materials could find use in optical telecommunications and public networking.
Highly ordered boron nanowire multiple nanojunctions (see Figure) with unilateral feather-like morphology have been created via a simple magnetron sputtering method. These T- and Y-type nanojunctions stand freely in line to form uniform and well-oriented arrays on the substrate surface over areas of up to several tens…
A series of chiral phosphine-functionalized poly(propyleneimine) (PPI) dendrimers was synthesized by the reaction of carboxyl-linked C(2)-chiral pyrphos ligand (pyrphos=3,4-bis(diphenylphosphino)pyrrolidine) with zeroth-fourth generation PPI using ethyl-N,N-dimethylaminopropylcarbodiimide (EDC)/1-hydroxybenzotriazol a…
The mechanism of alkene epoxidation by chromium(v) oxo salen complexes has been studied by DFT and experimental methods. The reaction is compared to the closely related Mn-catalyzed process in an attempt to understand the dramatic difference in selectivity between the two systems. Overall, the studies show that the re…