Materials Literature
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The inhibitive effect of thiosemicarbazide on the corrosion of cold rolled carbon steel in acidic media has been studied. For this investigation, a standard potentiodynamic polarisation technique was used to determine the corrosion rate and the inhibition efficiency and also to find out which adsorption isotherm gover…
Electrical transport behavior of Ca3MnxCo4−xO9 (0⩽x⩽1.28), prepared by sol-gel process, was investigated at temperatures from 300K down to 5K. The results indicate that dc conductivity σ and carrier concentration decay exponentially with decreasing temperature below ∼75K and ∼100K for Ca3MnxCo4−xO9 with x=0 and 0.03,…
We are continuing an effort to quantitatively measure the influence of processing variables on the structure of polypropylene melt blown webs. In this paper, we report experimental measurements of the influence of die-to-collector distance, primary airflow rate, die temperature, collector speed and resin throughput ra…
The synthesis of ultrafine magnetic material with large saturation magnetisation and high coercivity has received much attention, owing to its wide applications. The reduction of nanocrystalline Fe 2 O 3 into metallic iron was studied. The iron oxide precursor was synthesised by thermal evaporation of iron acetate and…
Sm Co 7 − x Cr x (x=0–0.6) magnets have been synthesized by mechanical alloying and subsequent annealing. A small amount of Cr favors the formation of Th2Ni17-type 2:17 phase and increasing the Cr content can extend the temperature range in which the hexagonal 2:17 phase remains stable. The coercivities of the SmCo7−x…
Films with specific nanoroughness were designed by "virtual coating" to yield ultrahydrophobicity while the light scatter remained below an application-relevant threshold. Examples of coating experiments demonstrate the realization of predicted properties.
This paper describes the first attempt in fabrication of three-dimensional macroporous composites of chitosan and natural coralline material with pore sizes of 300-400 microm, exceeding the upper pore size limit of 250 microm obtained with freeze-dried chitosan-based scaffolds. Natural coral particulates of less than…
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…