Materials Literature
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The dynamics of magnetoelectric RMn 2 O 5 crystals (R=Eu and Gd) was studied in the frequency and temperature ranges 20–300 GHz and 5–50 K, respectively. The crystals possessed magnetic and ferroelectric long-range order and had close transition temperatures, T N, C ≃36 and 30 K for R=Eu and Gd, respectively. Mixed ma…
In this paper a modified version of the RSTRENG 085dL method is proposed. This method, named RPA method or Modified 085dL method, uses two different equations to predict the failure pressure of a corrosion defect: one for short defects (defects in which L { {radical}20 D{sub e} t). The equation for short defects is th…
The possibility of curling hair is attributed to the fact that the mechanical properties of hair fibres depend on time, temperature and humidity. In this study the dependence of the viscoelastic behaviour of human hair fibres on humidity is characterised in a bending deformation. An experimental set-up was used to per…
A poliamida 6 (PA6) é um polímero semicristalino de grande aplicação na engenharia e que apresenta instabilidade no processamento e baixa resistência ao impacto sob entalhe. A incorporação do ABS (acrilonitrila-butadieno-estireno) como modificador de impacto da PA6, pode melhorar estas propriedades. Entretanto, como e…
Abstract In this contribution, we report the design and theoretical analysis, using the INDO/SCI‐SOS quantum chemical formalism, of novel molecular architectures based on planar [N 4 ]‐, (2‐aminobenzylideneiminato)‐ and tetraazamacrocycle‐coordinated nickel( II ) complexes, having second‐order nonlinear optical (NLO)…
Two series of mesogenic compounds having both a perfluorinated substituent and a hydrogen bonding active site were synthesized and their phase behavior investigated. Due to the chemical architecture of these materials exhibiting amphiphilic character, structures of nano-segregation are expected to form. We found a the…
New experimental data illustrating the effect of deep traps on the luminescence properties of anion-defective α-Al 2 O 3 single crystals are presented. It was established that deep traps have electronic nature and their filling occurs through photoionization of F centers and is accompanied by F → F + -center conversio…
Article Kinetic Study of the Bulk Reaction Between TDI and PPG in Prescence of DBTDL and FEAA Catalysts Using Quantitative FTIR Spectroscopy was published on July 1, 2003 in the journal Journal of Polymer Engineering (volume 23, issue 4).
The dry salt layer pollution test method is introduced as a better alternative to the present standardized insulator test method for coastal environments. Comparative tests were performed on an 800 kV composite housed SF/sub 6/ filled bushing, using the salt-fog and dry-salt-layer test methods. The two test methods ar…
Since the 1970s, nothing substantially new has been published in the gas turbine community about the hot corrosion by vanadium and its inhibition, after the “inhibition orthodoxy” based on the formation of magnesium vanadate, was established. However, the experience acquired since the late 1980s with heavy-duty gas tu…
Abstract Structuring multiphase polymer materials to a micrometer scale ( micro‐structuration ) is a facile engineering practice. However, structuring them to a nanometer scale ( nano‐structuration ) is a formidable engineering challenge. In this paper, it is shown first why traditional extruder compounding processes…
Abstract A numerical study was carried out to determine the effects of magnetic fields and thermal conductivity of a crystal on the melt flow in a crystal growth system. Comparisons of computations for the case of no magnetic field and for two types of cusp‐shaped magnetic fields were made. The effect of thermal condu…
Abstract The utilization of Cyclophosphazenes as polymer modifiers is reviewed, with particular concern to their exploitation as versatile chain extenders, possibly for recycle problems, crosslinkers, to enhance mechanical properties of polymeric materials, branchers, to selectively introduce ramifications in linear p…
We report on cylindrical permanent-magnet structures that exploit the image effect in a surrounding circular soft-iron sheath. We present the theory for a general multipole ring, where the polarization direction /spl alpha/ = (n + 1)/spl psi/, n is a positive or negative integer, and /spl psi/ is the angular coordinat…
Abstract Poly(5‐benzyloxy‐trimethylene carbonate) (PBTMC), a new functional polycarbonate was synthesized by enzymatic ring‐opening polymerization in bulk at 150°C using Porcine pancreas lipase (PPL) or Candida rugosa lipase (CL) as catalyst. Influences of different polymerization conditions such as the source of enzy…
The efficiency of major types of cathodoluminescent phosphors has been investigated at high-brightness (up to 30 000 cd/m2) operational conditions using thermionic electron source. The accelerating voltage was varied from 4 to 14 kV and electron beam current density was independently varied from 2 to 50 μA/cm2. Under…
Abstract The room temperature structure ( α -form) of the organic compound p -chlorobenzamide, C 7 H 6 ClNO, can be described as a classical three-dimensional periodic superstructure ( α S ) and also as a commensurately modulated structure ( α M ) in (3 + 1)-dimensional superspace. The diffraction pattern is character…
A surfactant-free method based on power ultrasound was used to emulsify biphasic mixtures of liquid, near-critical carbon dioxide and water ( T = 30 °C, P = 80 bar). When ultrasound above a threshold power density (roughly 0.15 W/cm 3 at 20 kHz) was applied to a biphasic system of carbon dioxide and water, emulsions w…
Field emission from carbon nanotubes can be affected by common carbon- containing residual gases in vacuum systems. In this article, we will show the effects of CO, CO2, CH4, and C2H4 gases on the field-emission currents of patterned multiwalled carbon-nanotube arrays prepared by chemical vapor deposition. Exposure to…
An icosahedral quasicrystalline alloy in the Al-Fe-Cu system has been mechanically milled in a high-energy ball mill (Szegvari attritor) for 1, 3, 6 and 10 h. Samples were characterized by X-ray diffraction and transmission electron microscopy. The evolution of nanosize crystallites of the disordered B2 phase (bcc; a…