Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Lightweight magnetic ceramics containing bimetallic (Co–Fe) nanoparticles in an essentially amorphous C/SiC matrix have been prepared from the pyrolysis of a polyferrocenylsilane with pendant cobalt clusters. The Figure shows a TEM image of the ceramic material formed at 600 °C under N 2 . Superparamagnetic or ferroma…
Individual Mn 12 single‐molecule magnets are arranged onto a polymeric film surface using a new, soft, reliable and simple chemical methodology. Polymeric thin films, prepared from a polycarbonate matrix and Mn 12 molecules, are subsequently treated with an organic solvent vapor, resulting in nanocomposite thin films…
Germanium‐filled SiO 2 nanotubes and aligned SiO 2 nanofibers are synthesized via a two‐stage process: thermal evaporation of SiO powder, followed by laser ablation of a Ge target. The nanotubes are either partially filled with Ge nanoparticles/nanorods or completely filled with Ge nanowires, forming Ge/SiO2 nanocable…
Fluoride is a naturally occurring element in many water supplies, and it may cause fluorosis. The hydrotalcite was synthesized and characterized before and after the retention of fluoride ions by x-ray diffraction, electron microscopy, and IR. The thermally treated hydrotalcite was evaluated for the sorption of fluori…
Teilstrukturen in Form einer verdrehten Acht weisen die perfluorierten meso-Aryl-substituierten expandierten Porphyrine auf, die man aus 3,4-Difluorpyrrol und Pentafluorbenzaldehyd unter modifizierten Rothemund-Lindsey-Bedingungen erhält. Das [26]Hexaphyrin enthält zwei nahezu planare Tripyrrol-Untereinheiten, die um…
Copper and silver films are being considered for future multilevel interconnect systems. The reduction of feature size has also demanded the use of different low-dielectric materials (e.g., parylenes) in place of conventional silicon dioxide based layers. Adhesion of these materials with each other is a major hurdle i…
A technique has been developed for the measurement of the K22 twist elastic constant in nematic liquid crystal materials. This involves the measurement of the Freedericksz transition voltages in untwisted linear and π-twist regions in a wedge cell geometry. The method avoids the need for the accurate determination of…
Far-infrared reflectivity spectra of [Pb(Zn1/3Nb2/3)O3]0.92–[PbTiO3]0.08 and [Pb(Mg1/3Nb2/3)O3]0.71–[PbTiO3]0.29 single crystals were investigated between 10 and 530 K, micro-Raman spectra were recorded between 300 and 800 K. No phonon softening was observed near either of the ferroelectric phase transitions. The low-…
A vanadium-substituted polyoxomolybdate ion ([PV2Mo10O40]5−, top right) can activate nitrous oxide to promote the highly selective catalytic oxidation of primary and secondary alcohols to aldehydes and ketones, and the oxidation of various alkylaromatic substrates (see scheme).
The need to develop powerful new catalysts capable of effecting reductions with molecular hydrogen under mild conditions is a pressing one, particularly with the looming importance of the hydrogen economy. We show that nanoparticle (1−1.5-nm diameter) supported bimetallic catalysts, such as Ru−Pd, Ru−Pt, and Ru−Sn, pr…
We propose a new solidification process in crystallizable polymers in which lamellar clustering takes place in the crystallization process under high supercoolings. Clustering of lamellae is a two-step process: the first step is the exclusion process of chain ends from the space of a single Gaussian chain accompanied…
The dc and ac conductivities of Mn-doped ZnO were investigated at temperatures from 10 to 100 K. The temperature dependence of the dc conductivity from 10 to 100 K shows an abrupt change at ∼18 K, manifesting a much lower activation energy for conduction below 18 K. From 10 to 18 K, the ac conductivity, σac(ω), varies…
A model for lattice thermal conductivity in a semiconductor nanowire with a rectangular cross section is investigated. It is based on solving the equations of phonon radiative transfer taking into account interface scattering and modification of the acoustic phonon dispersion. From the numerical calculations, we predi…
Chemically stable LaFe11.6Si1.4Cx (x=0−0.6) interstitial compounds were prepared. The Curie temperatures increases from 195 to 250 K with an increase in X from 0 to 0.6 due to obvious lattice expansion. The maximal magnetic entropy changes |ΔS| with a change in magnetic field of 0–5 T, are 24.8, 24.2, 18.8 and 12.1 J/…
Twisted figure-of-eight structures are found for the perfluorinated meso-aryl-substituted expanded porphyrins synthesized from 3,4-difluoropyrrole and pentafluorobenzaldehyde under modified Rothemund–Lindsey conditions. The crystal structure of the [26]hexaphyrin (see picture) consists of two almost planar tripyrrolic…
An insight into the molecular assembly processes that lead ultimately to the gelation of water by small organic molecules can be gained by the combination of two powerful techniques. Vitrified ice cryo‐transmission electron microscopy (TEM) (see Figure) and X‐ray diffraction, have been applied to evaluate the nanoscal…
Bis(3‐octyl‐2‐thienyl)‐[2.2]paracyclophane is subjected to oxidative polymerization to afford a soluble redox‐active polymer (see Figure) consisting of conjugated tetraarenes held in permanent cofacial stacks by cyclophane linkages. The influence of p‐stacking of the conjugated units along the polymer chain and the ef…
Laser-supported, dipole-assisted self-assembly results in blue-light guiding nanostructures, namely single-crystalline nanofibers of hexaphenyl molecules. The nanofibers are up to 1 mm long, extremely well-aligned to each other and their cross sections can be tuned to span the range from nonguiding to guiding single o…
Abstract Thin films of photoactive Cu 1.8 S have been deposited by atomic layer deposition (ALD) using Cu(thd) 2 and H 2 S as the precursors. This is a first step in the construction of nanoporous heterojunctions of TiO 2 /Cu 1.8 S. The ALD process can be divided into two temperature regimes: below 175 °C, adsorption…
Magnetic circular dichroism (MCD) spectra of a room-temperature ferromagnetic GaN:Mn film show that the film contains Ga1−xMnxN in which the band s,p-electrons interact with the d-electrons of the manganese ions. Both the magnetic field dependence and the temperature dependence of the MCD intensity show that Ga1−xMnxN…