Materials Literature
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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…
A novel porous silica matrix has been prepared from Pyrex glass, using hydrothermal treatment under saturated‐steam condition. This process makes it possible to obtain, in one step, a silica support formed of a homogeneously distributed and interconnected macropore microstructure. The new matrix contains silanol group…
Abstract Ruthenium nanoparticles included in alumina membranes have been prepared either by dihydrogen decomposition of the complex Ru(COD)(COT) (COD = 1, 5‐cyclooctadiene; COT = 1, 3, 5‐cyclooctatriene) to give pre‐prepared colloidal solutions which were further used to fill the pores of nanoporous alumina membranes…
Combustibility of polyurethane foam is an important industry issue. Many test methods are in place to characterize foam combustion, and legislation exists to ensure that the foam complies with specified standards. This paper provides a basic understanding of foam combustibility based on the British Standard BS5852 tes…
Optical studies have been conducted as a function of temperature on two (CCH3 and CCH7) of the three odd members of the homologous series of the mesogen trans, trans-4′-alkyl-bicyclohexyl-4-carbonitrite. From birefringence studies the variation of the orientational order parameter ⟨ P2 ⟩ with temperature of the two me…
Sintered α-SiC ceramics containing B4C with various 10B concentrations were neutron-irradiated, and the helium release rate during increasing annealing temperature was observed. The lattice parameter and the macroscopic length changes of the same specimens were also observed. The helium release rate from powdered spec…
Si 3 N 4 /carbon fiber composites were fabricated using several types of fiber. All the composites had higher fracture toughness compared with monolithic Si 3 N 4 ceramics. Tribological properties were investigated by a ball‐on‐disk method under unlubricated conditions. The composite containing fibers with a high orie…
Abstract This paper deals with the numerical simulation of fluid flow and heat transfer in a silicon floating zone (FZ) subjected to axial vibrations. Corresponding experiments were performed under microgravity conditions within the framework of the European sounding rocket Maxus‐4 flight. The study concerns a liquid…
The synthesis and characterization of new hyperbranched organosilicon polymers containing furan or thiophene are described. The air- and moisture-stable polymers were prepared in 78−98% yields by the platinum-catalyzed hydrosilylation polymerization of AB 2 and AB 3 silyl-substituted furans and thiophenes. Complete po…
Cu-based alloys have been used for electric cables for long time. In the field of microelectronics, Al had been used for electrical wiring. However, it became clear that electromigration occurs in Al that causes breaking of wires in minute wirings. Due to this problem, Cu wiring is used in most advanced microprocessor…
Abstract The structure of polypropylene fibers formed by different spinning conditions was studied. The investigations were carried out using wide‐angle X‐ray scattering (WAXS) and small‐angle X‐ray scattering (SAXS) methods. It was stated that in noncolored fibers the mesophase and the monoclinic α forms were formed.…