Materials Literature
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The growth mechanism of long and aligned single walled carbon nanotubes using a recently reported “fast heating” chemical vapor deposition (CVD) method is discussed. The effect of heating speed at the initial stage of the CVD process has been systematically studied, and a “kite-mechanism” for the nanotube growth is pr…
Light bends the wrong way in materials where both ε and μ are negative as was pointed out in 1968, but the absence of natural materials with this property led to neglect of the subject until 1999 when it was shown how to make artificial materials, metamaterials, with negative μ. The rapid advance of the subject since…
The chemical solution deposition (CSD) technique as a highly flexible method for the fabrication of electronic oxide thin films is reviewed. Various chemical aspects of different approaches are discussed, including sol–gel, hybrid, and metallo-organic decomposition (MOD) routes, which all have been successfully applie…
A transmission line (TL) approach of left-handed (LH) materials is proposed. The transmission characteristics of an ideal LH-TL are presented, the constitutive parameters of an equivalent LH material are derived and shown to be negative, and some LH-transmission paradoxes are explained. Next, a method to design an art…
Active packaging technologies offer new opportunities for the food industry, in the preservation of foods. Important active packaging systems currently known to date, including oxygen scavengers, carbon dioxide emitters/absorbers, moisture absorbers, ethylene absorbers, ethanol emitters, flavor releasing/absorbing sys…
Nano-graphite films have been deposited on n-Si substrates by microwave plasma chemical vapour deposition. The surface morphology and microstructure of the films were tested by scanning electron microscopy, x-ray diffraction and Raman spectroscopy. In the field emission measurement, a turn-on field of 0.5 V/μm and a h…
Abstract The melting of isothermally crystallized poly(vinylidene fluoride) (PVF 2 ), produced in the intercrystalline spaces of poly(ethylene terephthalate) (PET) from its blends, showed a unique behavior: the melting temperature decreased with the increasing crystallinity of PVF 2 (i.e., with increasing crystallizat…
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…