Materials Literature
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We have studied the influence of antiferromagnetic ordering on the local dielectric moments of the ${\mathrm{MnO}}_{5}$ and ${\mathrm{LuO}}_{7}$ polyhedra by measuring neutron powder-diffraction patterns of ${\mathrm{LuMnO}}_{3}$ at temperatures near ${T}_{N}.$ We show that the coupling is weak, because the magnetic e…
Broadband dielectric spectroscopy was used to investigate the segmental dynamics and ionic conduction in LiClO4/PVME complexes with Li/O from 0.1/100 to 10/100, at temperatures from Tg to approximately Tg + 80 degrees C. Although no microphase separation is observed via DSC, dielectric experiments reveal two segmental…
Abstract Styrene and acrylic acid were impregnated into a series of polyamide products (nylon1212, nylon1010, nylon66, nylon6) using supercritical CO 2 as the additive‐carrier and substrate‐swelling agent. The impregnation efficiency of low molecular weight additives into substrates is attributed to complicated intera…
Abstract In the presence of dicumyl peroxide, the compatibility of thermal plasticized starch/linear low‐density polyethylene (TPS/LLDPE) blends using maleic anhydride (MAH) as compatibilizer was investigated. The thermal plasticization of starch and its compatibilizing modification with LLDPE was accomplished in a si…
We propose a new method of investigating variation of preservation within a parchment sample, which allows a more detailed analysis of alteration of the material structure. X-ray diffraction analysis of parchment typically involves the sample aligned with the plane of the parchment perpendicular to the direction of th…
Abstract In cold climates the correct performance of rubber components such as seismic isolators depends on them maintaining their elastic properties when exposed to prolonged periods at low temperatures. The high damping compounds developed for seismic isolation are normally especially prone to crystallization when e…
In YAlO3 crystals grown in vacuum or reduced by annealing at low oxygen pressure, the luminescence of F centers in the band at 420 nm, with τ=30 ms at 9 K, excited in the bands at 212 and 242 nm, as well as the luminescence of F + centers in the band at 355 nm, with τ=2.7 ns, excited in the main band at 220 nm and wea…
In the reaction crystallization of calcium carbonate using a batch reactor system with aqueous CaCl 2 and Na 2 CO 3 at room temperature, the selective polymorphic control of crystalline calcium carbonate into calcite was achieved by adjusting the operating conditions. The polymorphic ratio of calcite and vaterite nucl…
Using a stroboscopic technique, in which the molecule is repeatedly excited and the structural change is probed more than 5000 times per second immediately after excitation, we performed a 16 K time-resolved single-crystal study of the microsecond lifetime triplet state of the Cu(I)phenanthroline derivative[Cu(I)(dmp)…
In aqueous solution meso-tetrakis(4-phosphonatophenyl)porphyrin shows self-aggregation processes controlled by the "sergeant-soldier rule". After partial protonation of the external phosphonic groups, it is possible (i) to further protonate the inner nitrogen atoms of the molecules or (ii) to allow, over time, the sys…
Abstract The miscibility of different polymer blends was studied with dynamic mechanical thermal analysis (DMTA) in conjunction with differential scanning calorimetry (DSC). The blends were prepared by melt mixing polymers having similar glass transitions such as polyglutarimide (PGI), styrene‐ co ‐maleic anhydride ra…
The effect of molecular weight, composition, and aging temperature on the kinetics of the tetragonal-to-hexagonal polymorphic transformation in isotactic ( it ) 1-butene/ethylene random copolymers has been investigated by differential scanning calorimetry and wide-angle X-ray diffraction. It has been found that, as it…
Abstract In this article, we describe the production of single polymer composites from polyethylene naphthalate (PEN) multifilaments by using the hot compaction process. In this process, developed at Leeds University, highly oriented tapes or fibers are processed at a critical temperature such that a small fraction of…
Homogeneous films of pure single wall carbon nanotubes (SWNTs) sufficiently thin to be optically transparent in the visible range of the spectrum were employed as p-Ohmic contacts on GaN−InGaN quantum-well light-emitting diodes. The specific contact resistance of the SWNT films on the p-GaN was 1.1 × 10 -2 Ω cm 2 afte…
Colloidal crystallization takes advantage of the strong interfacial forces and tunable interactions that organize particles into regular structures at small scales. Thus, colloidal crystallization and patterning provide a powerful and simple method to functionalize planar surfaces with applications to optical, catalyt…
The pyrolysis and gasification of tires was studied in a pilot plant reactor provided with a system for condensation of semivolatile matter. The study comprises experiments at 450, 750, and 1000 degrees C both in nitrogen and 10% oxygen atmospheres. Analysis of all the products obtained (gases, liquids, char, and soot…
We measure the spectrum and efficiency of the infrared light emission from ambipolar carbon nanotube field-effect transistors. The width of the emission peak is strongly device-structure dependent. Long devices (∼50 μm) show narrow spectral peaks that we attribute to relaxed carrier recombination, while short devices…
Eu2O3 nanotubes have been successfully fabricated by an improved sol-gel template method within the nanochannels of porous anodic alumina templates. The morphology, structure, and composition of the nanotubes were characterized by means of X-ray diffraction techniques, scanning electron microscope, transmission electr…
The complex nature of electron-electron correlations is made manifest in the very simple but non-trivial problem of two electrons confined within a sphere. The description of highly non-local correlation and self-interaction effects by widely used local and semi-local exchange-correlation energy density functionals is…
A thermally induced templated synthesis for SiC nanotubes and nanofibers using ammonia or nitrogen as a carrier gas, single wall carbon nanotubes (SWCNT) as templates as well as gaseous Si is presented. The bundles of SWCNT act as both the carbon source and as a nanoframe from which SiC structuctures form. Depending o…