Materials Literature
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Adhesive strength of Atmospheric Pressure Glow (APG) plasma-treated polypropylene was studied for various gas mixtures by a scratching test. An explanation of the high adhesive strength obtained after He/N2 APG plasma treatment was given. Formation of carbonyl, alcohol, carboxylic and primary amines was investigated b…
In ${\mathrm{Nd}}_{2}{\mathrm{Fe}}_{17\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}{X}_{\ensuremath{\delta}}$ ($X=\mathrm{Al},$ Si, Ti, V, Cr, Mn, Co, Ga, Nb, Mo, W, and $\ensuremath{\delta}=0, 0.5$) the $X$ atoms substitute for Fe without changing the crystal structure. Neutron-diffraction measurements show th…
Dihydrofolate reductase (DHFR) from the hyperthermophilic bacterium Thermotoga maritima was cloned and expressed in Escherichia coli. Sequence determination of the reported dyrA gene was repeated, and a corrected version deposited in the nucleotide sequence databank (accession number Y11021). Ultracentrifugational ana…
Poling of calcium and zirconium modified lead titanate pyroelelectric thin films has been studied. Poling temperature and electrical field were optimized to achieve high figure of merits. It was found that thermal activation is important to obtain highly poled films. Defect-dipole complexes are supposed to play a majo…
Porous silicon (PS) light emitting diodes (LEDs) were fabricated from p + n Si wafers by photoanodization. The maximum external quantum efficiency (η ext ) of electroluminescence (EL) from PS-LED up to 0.8%, which is the highest ever reported for PS-LEDs with solid state contact, was achieved under pulsed operation wi…
The elucidation of the role that injected cations play in the creation of electrochromic (EC) color centers in hydrated films is presented. The electron and cation contributions to the lattice distortion upon film coloration have been evaluated. The evolution of the fundamental absorption edge and vibrational bands of…
Manganese is an inexpensive element and a potent hardenability promoter in ductile iron, but in this role it has the inherent limitations of severe segregation and carbide formation tendencies. In order to use this material in an actual application, attempts must be made to overcome these limitations. In the present w…
Residually compressed thin films are susceptible to spalling from substrates. A prerequisite for this to occur is that a separation develops at the interface large enough to allow buckling. Thereafter, the mechanisms of spalling are well-established. In this article, the mechanics of formation of the initial separatio…
RESUMO: No presente trabalho apresentaremos uma revisão do comportamento dos polímeros quando queimados, procurando enfocar o antagonismo comumente observado entre os aspectos de retardância de chama e emissão de fumaça dos compostos desenvolvidos com vistas à prevenção de incêndio. Apresentaremos também uma breve des…
To simulate the role of sulfurized iron generated by sulfate-reducing bacteria (SRB) in the biocorrosion of steel, ultrathin (50-nm to 200-nm-thick) iron sulfide layers were prepared by metal organic chemical vapor deposition (MOCVD), sulfurization of iron oxides, and spray pyrolysis. After analyzing the morphology of…
Abstract Some hyperbranched aromatic polyamides have been synthesized by direct polycondensation using the modified Higashi's method. Structures of the above polymers have been realized taking in proper account the analogies with amide group sequences of poly( p ‐phenyleneterephthalamide) (PPDT) and poly( p ‐benzamide…
The resistance degradation behavior of Ba0.7Sr0.3TiO3 (BST) and SrTiO3 (ST) thin films is compared to the degradation behavior of titanate single crystals and ceramics with respect to the dependence on parameters such as temperature, thickness of the sample, applied voltage, acceptor dopant concentration and electrode…
A simple and rapid “gelatinization index” can be useful for following thermal treatments and evaluating the effects of different conditions on the sensorial and textural properties of foods. In order to evaluate the degree of gelatinization of thermal-treated starchy products (starches, flours) a method based on the W…
We report here on the results of our continuing effort to study the flame-retardant mechanism of silica gel and potassium carbonate. These additives reduce the flammability of a wide variety of common polymers such as polypropylene, nylon, polymethylmethacrylate, poly(vinyl alcohol), and cellulose. In an effort to det…
The study of “clattering” motion, that occurs when flat objects strike the ground at an oblique angle, is continued. Previously derived equations of motion are solved for values of several clattering quantities (like total number of impacts, maximum velocity jumps in the sequence, time-durations, etc.) for any value o…
The electrostrictive behavior in single crystals of Pb(Mg1/3Nb2/3)O3 (PMN) and 0.93Pb(Mg1/3Nb2/3)O3 - 0.07PbTiO3(PMN-7%PT) was investigated as a function of crystallographic direction. The pseudocubic nature of these materials became highly anisotropic at relatively high electric fields. The observed anisotropy was be…
Ab-initio density functional calculations were performed on the geometric and the electronic structures of coherent cube-on-cube interfaces between spinel (MgAl2O4) and the two metals Al and Ag. The calculations were carried out in the local density approximation (LDA) employing norm-conserving pseudopotentials and a…
The NMR properties of the solid lead (II) halides and the lead (II) hydroxyhalides are reported. The analysis shows extremely wide powder patterns in all cases except the lead (II) iodide. The results indicate that one should be able to distinguish the lead (II) halide from the corresponding lead (II) hydroxyhalide in…
Abstract The focus of this study is to investigate the sintering mechanism of polyethylene. Experiments were conducted to observe the high temperature sintering behaviors of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). It was found that the sintering of polyethylene follows Frenke's mod…
We have made the first calculations of i) the effect of an electric field on the structures corresponding to different phases exhibited by antiferroelectric liquid crystals (using a model proposed by us earlier), ii) the apparent tilt angle corresponding to these field distorted structures and iii) the conoscopic figu…