Materials Literature
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Phytochemical investigation of Semiaquilegia adoxoides was initiated in view of its common usage in traditional Chinese medicine and the scarcity of previous phytochemical studies. Fractionation of an ethanol extract from the roots of this plant led to the isolation and identification of a novel cyanogenic glycoside,…
It is shown that the micro-displacement gradient allows the propagation of two-dimensional localized long nonlinear strain waves in a medium with microstructure. These waves may exist even in the presence of dissipation and energy input in the microstructured medium but with selected values of the wave amplitude and v…
Abstract Poly( p ‐phenylene pyromellitimide) (PMDA‐PDA), poly(oxydiphenylene pyromellitimide) (PMDA‐ODA), and poly(4,4′‐oxydiphenylene p ‐phenylene pyromellitimide) random copolyimide thin films with different p ‐phenylene diamine (PDA) contents were prepared. Nanoindentation was used to characterize the mechanical pr…
Esta pesquisa utilizou materiais reciclados para a produção de compósitos plástico-madeira ou WPC (wood-plastic composites). A madeira utilizada na forma de pó e a serragem foram misturadas ao polietileno de baixa densidade - PEBD reciclado em uma extrusora monorrosca de 75 mm de diâmetro. Foram testadas formulações c…
Acetonitrile has been condensed into porous Vycor glass. The dielectric response in a frequency range from 0.1 Hz to 1 MHz and temperatures between 40 K and 220 K, has been studied for a complete filling and a partial filling of 20%. Thereby the response of the adsorbed layer on the pore walls could be separated from…
The local structure around ${\mathrm{Er}}^{3+}$ ions in Er+O doped silicon has been investigated by extended x-ray absorption spectroscopy. By comparing samples obtained by molecular-beam epitaxy and ion implantation a common structure comes out. Er is linked to five or six O atoms at around 2.24 \AA{} and there is a…
The structure and the associated dynamics have been investigated in melts of hairy-rod macromolecules composed from a poly(p-phenylene) backbone with sulfonate ester and dodecyl side chains. For the structure investigation, polarizing optical microscopy, differential scanning calorimetry, pressure-volume-temperature,…
The aim of this work is to investigate electronic structure, magnetic properties, and electrical resistivity of the ${\mathrm{Fe}}_{2}{\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}\mathrm{Sn}$ Heusler alloys. We report x-ray photoelectron valence-band spectra and compare the results with those obtained from the self…
Field-induced magnetic order has been investigated in detail in the interacting spin 3/2 dimer system Cs3Cr2Br9. Elastic and inelastic neutron scattering measurements were performed up to H=6 T, well above the critical field H(c1) approximately 1.5 T. The ordering displays incommensurabilities and a large hysteresis b…
Chemistry makes the difference between metallic and semiconducting carbon nanotubes. It can also be used to turn metallic nanotubes into semiconducting ones, for example, by the addition of a simple organic fragment. This breakthrough has clear practical implications for nanotechnology. Moreover it begins to reveal th…
The question of why the iron displacement out of the porphyrin plane is enhanced in quintet states of singly ligated iron-porphyrin complexes compared to lower spin states and unligated iron-porphyrin is addressed. The spatial size of the Fe 2+ atom is analyzed with respect to different spin states, and it is shown th…
Guests in an achiral cavity experience asymmetric magnetic environments induced by chiral centers outside the cavity.
Nitrogen substitution reaction in a graphene sheet and carbon nanotubes of different diameter are investigated using the generalized tight-binding molecular dynamics method. The formation of a vacancy in curved graphene sheet or a carbon nanotube is found to cause a curvature dependent local reconstruction of the surf…
In the dithienylethene photochrome series, linking two photochromes together directly, or with an ethynyl spacer, shuts down the photoswitching of one of the photochromes. We report here, that for dihydropyrenes, two photochromes can be linked together without affecting the ability of either to photoswitch. [reaction-…
A series of polyoxometalates (POM)/1,10-decanediamine ultrathin films were fabricated by self-assembly, and their photochromic properties were investigated. It is found that the films fabricated from molybdenum POMs show better photochromic responses than those from tungsten POMs. The photochromic responses of these h…
Synthesis and magnetic studies of annelated macrocyclic polyradicals and a related high-spin polymer with macrocyclic repeat units are described. Polyarylmethyl polyether precursors to the polyradicals and the related polymer are prepared by using Negishi cross-coupling of difunctionalized calix[4]arene-based macrocyc…
The thickness and curvature profiles of partially wetting condensing drops of 2-propanol on a quartz surface were measured using image analyzing interferometry and a new data analysis procedure. The profiles give fundamental insight into the phenomena of phase change, pressure gradient, fluid flow and spreading in a c…
Funktion(alis)iert: Organische Gruppen mit mehreren Alkoxysilansubstituenten werden in der Synthese mesoporöser organisch-anorganischer Hybridmaterialien verwendet (siehe Schema). Die entstehenden Systeme enthalten die organischen Bausteine als integralen Bestandteil der Porenwand. Je nach der Funktionalität der organ…
Time-resolved small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) analyses were used to study the isothermal crystallization and remelting of poly(ethylene isophthalate- co -terephthalate)s containing 0−10 mol % isophthalate unit. For each of the polymers considered, evidence of the formati…
2. Negative-index media 393 3. Wave propagation and refraction in left-handed media 394 4. Negative refraction and the causality principle 395