Materials Literature
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The doping distribution of Tm3+ ions in a transparent oxyfluoride glass ceramic has been investigated. Optical absorption, luminescence, and excitation measurements have been performed in order to determine the environment in which Tm3+ ions and the infrared emissions they give rise to are located. An interesting resu…
Abstract Aqueous chemical growth (ACG) is a low‐temperature approach that is only weakly influenced by the substrate and allows for the growth of ZnO nanopillars on various substrates. ACG is an efficient way to generate wafer‐scale and densely packed arrays of ZnO nanopillars even on polymer materials. Photoluminesce…
Carbon nanotubes, fullerenes, and mesoporous carbon structures constitute a new class of carbon nanomaterials with properties that differ significantly from other forms of carbon such as graphite and diamond.
Micron-scale deformations produced in a chalcogenide glass, As 2 S 3 , by illumination of focused linearly polarized light have been studied comparatively with optical and structural changes. In thin samples (∼2 µm), an anisotropic deformation, which is M-shaped along the electric field of light, grows after appearanc…
Abstract The substitution reaction of poly(vinyl chloride) (PVC) with sodium azide was performed in cyclohexanone. The evolution of unreacted iso‐, hetero‐ and syndiotactic triad contents with the degree of substitution has been followed by 13 C NMR spectroscopy. By quantitatively comparing the microstructure changes…
We report the transmission and reflection characteristics of a two-dimensional (2D) left-handed metamaterial (LHM). A well-defined left-handed (LH) transmission band with a peak value of −9.9 dB is obtained at frequencies where both effective permittivity and permeability are negative. A very sharp dip (−38 dB) at the…
We describe a magnetic field assisted, two-stage secondary electron gas amplification process for low vacuum scanning electron microscopy. The field of an ultrahigh resolution magnetic immersion objective lens and the electric field of an annular electrode configuration partition the amplification volume into two regi…
The processes underlying the synthesis of fibrous carbon nanomaterials via nickel-catalyzed pyrolysis of ethanol vapor are investigated. The IR spectra of the gas released from the reactor during synthesis indicate that, in the initial stages of the process, ethanol molecules decompose into simpler species: CH 4 , CO,…
Conventional magnetic and transport measurements of the melt-grown mixed-valence manganite $({\mathrm{La}}_{0.4}{\mathrm{Eu}}_{0.6}{)}_{0.7}{\mathrm{Pb}}_{0.3}{\mathrm{MnO}}_{3}$ have been supplemented by a magnetic resonance study. The experimental data support the model of two magnetic phases coexisting in the cryst…
Three active filler metals were studied to determine their suitability for joining Si3N4‐TiN composite ceramics. The evolution of the bend strength in the different setups could be explained using microstructural analysis, micro‐hardness measurement and finite element modelling. It was observed that residual stresses…
On a microscopic scale, deformation twinning is carried by the motion of twinning disconnections. A disconnection is an interfacial line defect characterized by a Burgers vector, a line vector, and a step vector. The Burgers vector (dislocation component of the disconnection) carries the deformation while the step vec…
An ultralow refractive index is very advantageous when one designs antireflective coatings. We successfully obtained high-quality MgF2 thin films with ultralow refractive indices from autoclaved sols prepared from magnesium acetate and hydrofluoric acid. The MgF2 films consist of nanosized particles, and they have hig…
Argilas bentoníticas provenientes do Município de Boa Vista/PB foram utilizadas para a produção de argilas organofílicas. As argilas organofílicas foram obtidas a partir da síntese com quatro tipos de sais quaternários de amônio: cloreto de alquil dimetil benzil amônio (Dodigen), cloreto de estearil dimetil amônio (Pr…
Abstract We study the interaction of hydrogen donors and Lithium acceptors in bulk ZnO by electron paramagnetic resonance and photoluminescence. With increasing diffusion temperature the number of hydrogen donors increases whereas the number of deep Li acceptors decreases. In the temperature range between 450 and 600…
A novel plasma atmospheric pressure abnormal glow discharge was used to investigate synthesis gas production from reforming methane and carbon dioxide. Special attentions were paid to the discharge characteristics and CH4, CO2 conversion, H2, CO selectivity, and ratio of H2/CO varied with the changing of discharging p…
[structure: see text] Long chain alkyl-alkyl interactions appears to be the main driving force in hydrogen bond isomerism induced transformation of lamellar architectures to nanotubular constructs in alkylammonium dicarboxylate salts; the syntheses of the nanotubes require no skill for typical organic synthesis, and t…
Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.
The compound R-(+)limonene is available and cheap than its oxidized products. Consequently, the selective oxidation of R(+)limonene has attracted attention as a promising process for the production of compounds with a higher market value, such as cis/trans-1,2-limoneneoxide, cis/trans-carveol and/or carvone. One of th…
The DNA-poly(o-methoxyaniline) (POMA) hybrid is prepared by mixing aqueous solutions of POMA [emeraldine salt (ES), doping level [Cl]/[N] = 0.52] and sodium salt of DNA (Na-DNA) and is then freeze-dried after 4 days. Three different compositions (WDNA = 0.25, 0.5, and 0.75, WDNA is the weight fraction of DNA) of the h…
Single-phase samples of La 1− x Ca x MnO 3 compounds have been synthesized by solid-state reaction. Detailed Rietveld analysis of powder X-ray diffraction data showed that La 1− x Ca x MnO 3 undergoes a structural phase transformation from R -3 c to Pnma at X =0.05–0.075. There is a linear variation of lattice paramet…