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。
In this letter, we address the effect of grain refinement on room-temperature ductility of copper. Recent experimental results have shown that this material, as well as a number of other single-phase metals that are ductile when coarse grained, lose their ductility with decreasing grain size in the submicrometer range…
An interior of 18 amide groups and a periphery functionalized with 24 dansyl groups forms a light-harvesting dendrimer which features intense absorption bands in the near-UV spectral region and a strong fluorescence band in the visible region. Upon encapsulation of Nd(3+) ions, the fluorescence of the dansyl groups is…
A star is born: Size-selected, end-functionalized single-walled carbon nanotubes react with amine-terminated dendrimers to form star-shaped objects (see schematic representation). Analysis of the nanotube stars by atomic force microscopy and scanning electron microscopy show that they exhibit a peculiar response to el…
We present a simple technique which uses a self-aligned oxide etch to suspend individual single-wall carbon nanotubes between metallic electrodes. This enables one to compare the properties of a particular nanotube before and after suspension, as well as to study transport in suspended tubes. As an example of the util…
C3-symmetric lactams in a tube: Specially designed rigid disc-shaped macrolactams self-assemble as endless tubes by means of backbone–backbone hydrogen bonds and van der Waals contacts (see scheme). All the tubes with very strong dipoles further aggregate in a parallel fashion and all the dipoles are still oriented in…
Moving individual molecules: Up to 250-nm long polystyrene chains with fourth generation dendrons at each repeat unit were synthesized, individualized on highly oriented pyrolytic graphite (HOPG), and manipulated into a stretched linear conformation by a scanning force microscope tip (see images, arrow indicates direc…
256 oligomers make up the quaterthiophene library of compounds 1 which was prepared by a combination of parallel and “mix-and-split” syntheses. An automated screening process for the recording of cyclic voltammetric data and subsequent data analysis allowed the development of structure–property relationships on which…
An unusual bonding mode for a porphyrin ligand is seen in the tellurium porphyrin complex prepared by treatment of TeCl4 with dilithio meso-tetra(p-tolyl)porphyrin [Li2(ttp)]. The structure of [Te(ttp)Cl2] (see picture) has a five-coordinate, square-pyramidal geometry involving a distorted tridentate porphyrin ligand…
A La0.7Ca0.3MnO3−δ single crystal was oxygen-plasma treated at 200 °C. Our electrical and magnetic measurements indicate that the oxygen-plasma treatment can be an effective low temperature method of oxygen stoichiometry modification of colossal magnetoresistance manganites. The oxygen plasma is also shown to introduc…
The effective thermal conductivity of four polymeric thin films with distinct molecular morphologies has been measured as a function of film thickness down to 70 Å using a 3ω technique. Comparing to SiO2, the intrinsic thermal conductivity of polymers is about 5–10 times smaller while the interfacial thermal resistanc…
The present work uses Raman spectra to measure residual stresses in Pb(Zr0.53Ti0.47)O3 thin films. Based on thermodynamic analysis, a linear relationship is found between the stress and the square of the Raman frequency in the A1 [transverse optical3 (TO3)] and E [longitudinal optical3 (LO3)] modes. We calibrate the l…
The results reported in this work show that tightly assembled adducts formed by trisubstituted GdIII complexes and a beta-CD multimer (Poly-beta-CD, d.p. ca. 12) may represent very interesting candidates for novel MRI applications wherein a high number of paramagnetic ions endowed with high relaxivity (per GdIII ion)…
Around 100 porphyrin units have been selectively linked at C(6)-O to a cellulose (Avicel). The properties of the metal-free and zincated porphyrin-celluloses 2 and Zn-2 have been determined by optical and electrochemical methods. Circular dichroism indicates a helical arrangement of the porphyrin units and reveals int…
Abstract 2‐(6‐Oxido‐6H‐dibenzo〈c,e〉〈1,2〉oxa‐phosphorin‐6‐yl)1,4‐benzenediol (ODOPB) and bis(3‐dihydroxyphenyl) phenyl phosphate (BHPP) were successfully synthesized and used as reactive flame retardants in o ‐cresol formaldehyde novolac epoxy resin. Because of the rigid, cyclic, side‐chain structure of ODOPB, the resu…
Acetonitrile might not be an “innocent” solvent after all: The monomeric CuII complex [Cu(dmppy)(en)] (see structure) readily cleaves the C−C bond of acetonitrile under ambient conditions. Previously, heterolytic cleavage of the C−C bond of acetonitrile had only been achieved by phosphane complexes of metals in low ox…
Calorimetric, thermal expansion, resistivity, and magnetization measurements in ${\mathrm{La}}_{2/3}({\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{)}_{1/3}{\mathrm{MnO}}_{3}$ samples evidence the existence of a critical tolerance factor t that determines the relevance of lattice effects in mixed-valence manganites…
A chemical synthesis is described in which ZnSe:Cu particles slowly grow to a final size of ∼3.5 nm radius in 4 h reaction time. During particle growth, samples are extracted to study the luminescence as a function of particle size and temperature. Quantum size effects are observed to influence both the ZnSe and the C…
It has been recently predicted that the co-doping of an acceptor (nitrogen) and a donor (aluminum, gallium, indium) in a 2:1 ratio will dope ZnO p-type due to a reduction in the Madelung energy making the nitrogen acceptor energy level more shallow. We have been growing gallium and nitrogen co-doped ZnO films by radic…
Raman signal enhancements in excess of 10(7) can be achieved at near-infrared wavelengths when mid-nanometer sized gold particles self-organize into close-packed planar arrays. These substrates generate stable surface-enhanced Raman scattering which changes dramatically as a function of periodic structure and excitati…
Structural evolutions of PMN/PT10% $({\mathrm{PbMg}}_{0.3}{\mathrm{Nb}}_{0.6}{\mathrm{Ti}}_{0.1}{\mathrm{O}}_{3})$ and PMN $({\mathrm{PbMg}}_{1/3}{\mathrm{Nb}}_{2/3}{\mathrm{O}}_{3})$ are studied and compared using high-resolution x-ray and neutron diffraction. At high temperature, PMN-like diffuse scattering, associa…