Materials Literature
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Abstract The difference in the glass transition temperatures, T g , of the iso‐ and syndiotactic forms of PMMA has been investigated through molecular dynamics simulations of short duration (110 ps) using an accurate force field, pcff. To correlate with the Gibbs‐DiMarzio theory, which specifies that conformational en…
The field-induced superconductivity-destroying quantum transition in amorphous indium oxide films are investigated at low temperatures down to 30 mK. It is found that, on the high-field side of the transition, the magnetoresistance reaches a maximum and the phase can be insulating as well as metallic. With further inc…
Xenotime‐type RPO 4 (R = Y, Er, Yb, or Lu) powder was dry‐pressed into disks and bars. The disks and bars could be sintered to a relative density of greaterthan equal to98% in air without cracking at 1300° (R = Yb or Lu) or 1500°C (R = Y or Er), depending on the grain size. The linear thermal expansion coefficient (at…
Ultrafine crystalline TiO 2 powders were prepared by just heating and stirring aqueous TiOCl 2 solution with a Ti +4 concentration of 0.5 mol/ l at room temperature to 100°C under one atmosphere. The crystallinity, the phase transformation and the particle shape of ultrafine TiO 2 powders obtained by this simple preci…
All articles of this category functionalized triphenylene - hexakis(pentyloxy)triphenylene - selective ether cleavage - discotic liquid crystals
For iron-rich compositions, reactions among titanite, clinopyroxene, olivine, quartz, magnetite, and ilmenite can constrain the conditions under which common rocks form. Phase equilibrium experiments in the system CaO-FeO-Fe 2 O 3 -TiO 2 -SiO 2 constrain two of these reactions: clinopyroxene + ilmenite = titanite + ol…
Thermogravimetric analysis was used to determine the synthesis conditions for obtaining samples of the Ba-substituted ${\mathrm{LaMnO}}_{3}$ with stoichiometric oxygen content. Single-phase and vacancy-free samples of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ba}}_{x}{\mathrm{MnO}}_{3}$ have been prepared for $x=0.12-…
Abstract Short term flexural creep tests were conducted to investigate the creep behavior of wood‐fiber polypropylene composites. Three experimental parameters were selected: the addition of a wetting agent, temperature, and wood‐fiber concentration. All creep curves are presented in terms of relative creep as a perce…
This work reports the synthesis and characterization of diamantane-based polyimides obtained from 1,6-bis[4-(4-aminophenoxy)phenyl]diamantane and various aromatic tetracarboxylic dianhydrides. This novel polyimide exhibits a low dielectric constant (2.56−2.78), low moisture absorption (<0.292%), good solubility, and h…
Enzymatic ring-opening polymerization of medium-size lactones, ϵ-caprolactone (ϵ-CL) and δ-valerolactone (δ-VL), was performed by using a lipase as a catalyst. For the polymerization of ϵ-CL in bulk, a lipase derived from Pseudomonas fluorescens (lipase PF) showed the highest catalytic activity among the powdery lipas…
▪ Abstract This article reviews the defect chemistry of perovskite ferroelectric oxides such as barium titanate and lead zirconate titanate. Such metal oxides are being considered for a wide range of applications that include nonvolatile memories and dynamic random access memories. Time-dependent degradation of these…
Transient cavitation and shockwave generation produced by pulsed-dye and holmium:YAG laser lithotripters were studied using high-speed photography and acoustic emission measurements. In addition, stone phantoms were used to compare the fragmentation efficiency of various laser and electrohydraulic lithotripters. The p…
Biomaterial-mediated complement activation repeatedly has been invoked as a trigger of phagocyte reactions and inflammation. However, a direct correlation between complement activation and inflammatory responses to biomaterial surfaces has yet to be established. Using an animal implantation model and gold surfaces bea…
To better understand the mechanism of collagen fibrillogenesis, we studied how various sugars and polyols affect the formation and stability of collagen fibers. We combined traditional fiber assembly assays with direct measurement of the interaction between collagen triple helices in fibers by osmotic stress and X-ray…
The hydration of MgAl layered double hydroxides (LDHs) with interlayer terephthalate anions and controlled layer charge is studied. A combination of powder X-ray diffraction (PXRD), thermal gravimmetry (TG), and computer simulation is used to study in detail the effect of layer charge density and interlayer water cont…
One can increase the angular tolerance of resonant grating filters without modifying the spectral bandwidth by adding a second grating component parallel to the first one. The angular tolerance and the filter linewidth can be controlled by the designer in an independent way. Numerical results show that this property p…
The occurrence of hausmannite with an apparent Curie temperature close to 750 K, instead of 41.8 K was recently described from hydrothermally altered manganese ore from the Kalahari manganese field, South Africa. The unusual magnetic properties were related to the substitution of Fe 3+ for Mn in the hausmannite struct…
Ferrimagnetic behavior has been found for the one-dimensional azido-bridged compound [Cu(3-Clpy)2(N3)2]n, in which 3-Clpy is 3-chloropyridine. According to the structural data, this unusual magnetic interaction for an SA = SB system is explained in terms of the topology of the chain: alternating two ferromagnetic with…
Random defects destroy long-range phase coherence, and inhibit the metal-insulator transition in the charge density wave (CDW) system $1T\ensuremath{-}{\mathrm{TaS}}_{2}$. Photoelectron spectroscopy with high resolution reveals corresponding changes in the electronic structure. Core level spectra indicate a temperatur…
Colonization dynamics and metabolism of algal communities on wood (small pieces of Douglas fir) and artificial rock (tiles) substrata were investigated in an open reach in Mack Creek, Cascade Mountain Range, Oregon, for 42 days. Chlorophyll a concentration was not significantly different between the two algal communit…