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。
Diacetylene-containing polycarboranylenesiloxane copolymers were prepared by two different methods to yield either alternating or block copolymers with respect to the diacetylene distribution along the backbone. With each method, a set of copolymers was prepared with trisiloxane:carborane:diacetylene molar ratios of 1…
The electronic structure of a monolayer-protected gold cluster, [Au 13 (SCH 3 ) 8 ] 3+, has been investigated by performing density functional calculations. The cluster has a characteristic structure with O h molecular symmetry, and eight (111) facets of a centered cuboctahedral Au 13 core cluster are fully passivated…
Atomically well-defined discrete fully coordinated spherical and elongated nanocages constructed from SiO 2 are shown, via density functional calculations, to be structurally stable. Generally the spherical nanocages are energetically preferred over the elongated nanocages. With increasing size, both types of nanostru…
Photochemical reduction of several 4-picolyl- and N-methyl-4-picolinium esters was examined using product analysis, laser flash photolysis, and fluorescence quenching. It is demonstrated that the radical (anions) formed in these reactions readily fragment to yield a carboxylic acid and a 4-pyridylmethyl radical interm…
Using the Bingel reaction as a model for side-wall functionalization of single-walled carbon nanotubes, we report the discovery of highly regular, long-distance (several nanometer) patterns and examine the conditions for the occurrence of such patterns, possibly due to long-range induced reactivity. Varying periodicit…
Novel quaternary rare-earth copper sulfides EuRCuS3 (R = Y, Gd–Lu excluding Ho, Er) have been investigated by means of x-ray diffraction, magnetic susceptibility, magnetization, and specific heat measurements. These compounds crystallize in the Eu2CuS3-type structure for R = Y, Gd–Dy and in the KZrCuS3-type structure…
A novel donor-bridge-acceptor system has been synthesized by covalently linking a p-phenylene vinylene oligomer (OPV) and a perylene diimid (PERY) at opposite ends of a m-phenylene ethynylene oligomer (FOLD) of twelve phenyl rings, containing nonpolar (S)-3,7-dimethyl-1-octanoxy side chains. For comparison, model comp…
Hybrid organosilica mesoporous materials with pores of ordered three-dimensional hexagonal structure were prepared by the hydrolysis and co-condensation of 1,2-bis(triethoxysilyl)ethane with various concentrations of a surfactant as structure directing agents. The materials had high pore volume of 1-1.5 mL/g and high…
Simultaneous measurements of microscopic infrared (MicIR) dichroism, mesoscale deformation, and macroscopic stress during uniaxial stretching are made to four microphase-separated poly(ether- block -amide) (PEBA) films quenched form melt. Before the onset of microstructural alterations, poly(tetramethylene oxide) (PTM…
A molecular dynamics simulation of ultrathin gold nanowires for tensile behaviour has been carried out. Ultrathin nanowires, unlike the bulk FCC structure, have a multi-shell helical structure. This work compares the mechanical properties of the 7-1 multi-shell helical structure with those of the FCC structure. The re…
Oriented lamellar nanocomposites formed of alternating organic and inorganic layers were prepared by evaporation-induced self-assembly and studied by small-angle X-ray scattering in symmetrical and asymmetrical reflection. Analytical expressions were used for a quantitative fit of the experimental data. The fitting pr…
An increase of the X-ray diffraction line broadening with increasing diffraction angle was observed experimentally in nanocrystalline thin films. Such a change of the line width is usually related to the microstrain in the sample, which, however, contradicts the assumptions that the microstrain is relatively low in na…
Cationic catalysis using simple carboxylic acids to combine the ring-opening polymerization of ε-caprolactone and the regioselective acylation of carbohydrates has been investigated. l -Lactic acid catalyzed the acylation of methyl β- d -glucopyranoside and sucrose with ε-caprolactone in high yield by bulk polymerizat…
We present the microfabrication of silicon nitride membrane supports ('windows') for transmission electron microscopy (TEM) and illustrate their usefulness for direct preparation and studies of nanostructures. These membrane 'windows' enable TEM to be incorporated as an affordable diagnostic tool in nanostructure fabr…
The need for an a priori domain size distribution is one of the main limitations of existing line profile analysis methodologies. A numerical modification of the whole-powder-pattern modelling algorithm is proposed, to allow the refinement of a general domain size distribution from powder diffraction data. The shape o…
The crystallization of the PLLA block within the microphase-separated lamellar microdomain in a poly(styrene)- b -poly( l -lactide) (PS-PLLA) diblock copolymer was carried out from hard confinement (i.e., the crystallization temperature of PLLA ( T c,PLLA ) < the glass transition temperature of PS ( T g,PS )) to soft…
White light emission was obtained from a light-emitting diode prepared from polymer/quantum dot nanocomposites consisting of poly(9,-dihexylfluorene-2,7-divinylene- m-phenylenevinylene-stat-p-phenylenevinylene) (PDHFPPV) and two kinds of CdSe nanoparticles with different particle size. Blue emission from the polymer,…
We review recent experiments on optical detection and manipulation of spin states of impurity centres in a solid. This research topic is of particular interest because of possible applications of the single-spin read-out technique in solid state quantum computing. The experimental background of optical detection of si…
Different nanotubes were prepared from two triblock copolymers. Chemistry was performed on the nanotubes so that one type contained amino terminal groups and the other bore carboxyl terminal groups. The amino and carboxyl groups were reacted by amidization to join the nanotubes head to tail to yield nanotube multibloc…
Certain polyoxometalate anions strongly chemisorb on the surface of carbon black aggregates. Together with an ultrasound treatment, this adsorption constitutes the driving force for the splitting of initially big carbon particles into smaller units. The negative charge generated at the particle surface favors the form…