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。
Abstract The 1,3,5‐triazine derivatives 1 − 4 having styryl or higher oligo(phenylenevinylene) chains in the 2‐, 4‐, and 6‐positions represent star‐shaped push‐pull compounds. Alkoxy or dimethylamino groups on the peripheral benzene rings, which act as electron donors, and the central 1,3,5‐triazine ring, which acts a…
A structuring method capable of producing uniform, large-area cone arrays of diamond films was developed. The technique employs bias-assisted reactive ion etching and is applicable to any structure of diamond films ranging from microcrystalline to nanocrystalline. Variation of the etching conditions enables control of…
We present a novel family of "potentially antiaromatic" alkyl-substituted p-benzoquinonediimine pH-dependent chromophores. It appears from the structural data that these overall 12 pi-electron molecules should be better considered as constituted by two chemically connected but electronically not conjugated 6 pi-electr…
Remarkable doughnut‐shaped micrometer‐sized aragonite particles with mesoporous sponge‐like interiors (see Figure) are spontaneously assembled in water‐in‐oil microemulsions. The structures consist of an interlinked network of complex nanofilaments that arise from the surfactant‐mediated mesoscale transformation and c…
The glass transition temperature Tg of polystyrene spheres in aqueous suspension was investigated by differential scanning calorimetry. Spheres with diameters of 42–548 nm show an unambiguous glass transition very near the Tg of bulk polystyrene. The magnitude of the observed heat capacity jump ΔCp at the transition d…
Optical filters containing resonant waveguide gratings are designed and fabricated using low-loss, robust materials. The double-layer filters contain a silicon dioxide diffractive element on a hafnium dioxide waveguide deposited on a fused silica substrate. Noise-pattern formation is minimized by use of an antireflect…
The polarization reversal in single-crystalline ferroelectric films has been investigated experimentally and theoretically. The hysteresis loops were measured for Pb(Zr0.52Ti0.48)O3 films with thicknesses ranging from 8 to 250 nm. These films were grown epitaxially on SrRuO3 bottom electrodes deposited on SrTiO3 subst…
Layer-by-layer (LbL) assembly has been utilized to fabricate an ultrathin film of polyelectrolytes. The architecture was composed of chitosan and organophosphorus hydrolase polycations along with thioglycolic acid-capped CdSe quantum dots (QDs) as the polyanion. The topography of the films was studied using epifluores…
Thermal decomposition of labile poly(acrylic acid) (PAAc) side chains grafted onto fluorinated polyimide backbones (see Figure) is used to prepare nanoporous ultra‐low‐κ fluorinated polyimide films. The dielectric constant of the nanoporous fluorinated polyimide film can be varied by altering the graft concentration o…
Ultrathin Fe nanowire (about 5 nm in diameter) arrays have been fabricated by electrodeposition using anodic porous alumina templates. These ultrathin nanowires exhibited uniaxial anisotropy and a quite large coercivity (4190 Oe) at 5 K. In addition, the field needed to saturate the magnetization, when the field was a…
We report here the first electrochemical pathway to prepare Au-containing nanocomplexes with the mean diameter of 2 nm in 0.1 N KCl aqueous solutions without addition of any stabilizer. Encouragingly, polypyrrole- (PPy-) coated gold nanocomposites with a core−shell structure and a diameter smaller than 8 nm can be pre…
We report the first direct resonant soft x-ray scattering observations of orbital ordering. We have studied the low temperature phase of ${\mathrm{L}\mathrm{a}}_{0.5}{\mathrm{S}\mathrm{r}}_{1.5}{\mathrm{M}\mathrm{n}\mathrm{O}}_{4}$, a compound that displays charge and orbital ordering. Previous claims of orbital order…
Se@CdSe nanocables and CdSe nanotubes with diameters of around 50 nm (see Figure) can be directly synthesized via a template‐ engaged approach in aqueous solution. The walls of these nanotubes are composed of CdSe nanoparticles 5–10 nm in size. It is believed this approach can be potentially extended to process many o…
The development of ZnO-based semiconductor devices requires band gap engineering. Ternary Zn1−xCdxO allows reduction of the band gap relative to ZnO, which would be necessary for devices emitting visible light. We have analyzed the structural and optical properties of Zn1−xCdxO layers grown by metalorganic vapor-phase…
Well-defined silver chainlike and dendritic nanostructures with fractal features were self-organized via a simple solvothermal method using poly(vinyl pyrrolidone) (PVP) as an adsorption agent and architecture soft template. The branching fractal morphology was reasonably explained by using the Cayley tree model. Ther…
In situ Ga-doped ZnO nanotips were grown on amorphous fused silica substrates using metalorganic chemical vapor deposition. Structural, optical, and electrical properties of as-grown ZnO nanotips are investigated. Despite the amorphous nature of fused silica substrates, Ga-doped ZnO nanotips are found to be single cry…
The directed self-assembly of diblock copolymers offers unique routes for the design and fabrication of well-ordered arrays of nanoscopic structures. However, generating arrays with long-range order and few defects has been a difficult goal to achieve without extended thermal annealing processes. Here, a simple, one-s…
Electromagnetic radiation produced by avalanches in the magnetization reversal of Mn12-Acetate has been measured. Short bursts of radiation have been detected, with intensity significantly exceeding the intensity of the black-body radiation from the sample. The model based upon superradiance from inversely populated s…
We study numerically an atomistic model which is shown to exhibit a one--step crystal--to--amorphous transition upon decompression. The amorphous phase cannot be distinguished from the one obtained by quenching from the melt. For a perfectly crystalline starting sample, the transition occurs at a pressure at which a s…
We present a unifying theory for the observed complex structures of the sp-bonded elements under pressure based on nearly free electron picture (NFE). In the intermediate pressure regime the dominant contribution to crystal structure arises from Fermi-surface Brillouin zone (FSBZ) interactions - structures which allow…