Materials Literature
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Poly(etherurethane) elastomers are useful materials in medical devices because of their mechanical properties and biocompatibility. However, it is necessary to stabilize these elastomers against the oxidation of their ether soft segments. Synthetic antioxidants such as Santowhite and Irganox are often satisfactory; ho…
A series of Pd–Cu/KL zeolites with varying Pd : Cu ratios have been studied by a combination of FTIR and XANES. XANES indicates that only one PdCu alloy is formed for all samples and that the bulk of the alloy is not modified by extended periods under CO/H2at elevated temperatures. A combination of low temperature ads…
Abstract From neutron powder diffraction intensities it is often problematic to distinguish between centrosymmetry and non-centrosymmetry. X-ray single crystal diffraction may be more accurate. In this paper we compare refinement results of crystal structures on the basis of neutron powder data of orthorhombic NdGaO 3…
In water, the inertial collapse of a bubble is more violent after expansion by a negative acoustic pressure pulse than when directly compressed by a positive pulse of equal amplitude and duration. In tissues, gas bodies may be limited in their ability to expand and, therefore, the relatively strong effectiveness of ne…
The effect of various degrees of deformation was investigated at specific locations in the stress-strain curve under compression on the corrosion resistance of a wrought Ni-Ti alloy with a martensite to austenite transformation peak of 110 degrees C. Two metallurgical conditions were evaluated: 30% cold drawn and anne…
The water absorption properties of a PE-CVD (plasma-enhanced chemical vapor deposition) fluorine-doped SiO 2 film with a low dielectric constant were studied. It was concluded that highly stable F-doped SiO 2 film was obtained at F contents from 2.0% to 4.2% (3.2≤ k ≤3.6) using high-density plasma CVD. However, at F c…
Thermally Stimulated Depolarization Current technique, Differential Scanning Calorimetry, and Dynamic Mechanical Analysis have been applied to amorphous and semicrystalline bisphenol-A polycarbonate with crystallinity degrees up to 21.8%, in a temperature interval covering the α and β relaxations. The secondary β tran…
LaRC ™ -SI (NASA Langley Research Center-Soluble poly Imide) is a wholly aromatic, high-performance thermoplastic with a unique combination of physical, mechanical and adhesive properties. LaRC ™ -SI is synthesized from equimolar amounts of the dianhydrides 4, 4′-oxydiphthalic anhydride (ODPA) and 3, 3′, 4, 4′-bipheny…
The stability of the perovskite phase was studied as a function of sintering temperature. Dielectric, piezoelectric and pyroelectric properties of relaxor ferroelectric in the (1 – x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 solid solution series have been investigated. An important contribution to the dielectric, pyroelectric and pie…
A direct imaging system is introduced to study the oscillations of microbubbles acoustically levitated in water. The bubble is illuminated with a light emitting diode (LED) which is strobed at a frequency different from the driving sound field. This technique slows the moving image of the bubble, allowing one to obser…
The dislocation substructure and the glide activity in cyclically deformed nickel single crystals have been studied using the channelling contrast of backscattered electrons in a scanning electron microscope. Dislocation arrangements which arise in the saturation region after cyclic loading at room temperature and at…
The molecular dynamics of supercooled liquids confined to the mesopores of sol-gel glasses are interpreted in terms of the spatial competition between the average length scale of cooperativity assumed to increase with time and the geometrical confinement on scales between 2.5 and 7.5 nm. Opposed to relating the fast a…
Random packings containing 8192 hard spheres in three dimensions have been built with an efficient computer algorithm for various packing fractions up to $c=0.643$, a value close to the upper limit ${c}_{b}\ensuremath{\simeq}0.649$. Long-range correlations and local order have been investigated via the calculation of…
Abstract Novel perylene‐containing polymers have been synthesized. They exhibit good solubilities in organic solvents and have good film forming properties. A water‐soluble perylene‐containing polyimide was obtained via sulfonation of the corresponding polyimide. Solubilities and spectral characteristics of these poly…
The physicochemical properties of an amyloidogenic mutant human lysozyme (Ile56Thr) were examined in order to elucidate the mechanism of amyloid formation. The crystal structure of the mutant protein was the same as the wild-type structure, except that the hydroxyl group of the introduced Thr56 formed a hydrogen bond…
Raman scattering experiments on metallic ${\mathrm{La}}_{0.7}$${\mathrm{Sr}}_{0.3}$Mn${\mathrm{O}}_{3}$ have been carried out using different excitation wavelengths as a function of temperature from 15 K to 300 K. Our data suggest a Raman mode attributed to electronic excitations centered at 2100 ${\mathrm{cm}}^{\ensu…
In this article, for the necessity of measuring the damping of new materials, a detailed comparison was made between two important free vibration torsion pendulums, that is, the inverted torsion pendulum and the Collette pendulum. Special attention was paid to the strong effect of the torsionally weak suspension in bo…
NOX control employing several combustion modification techniques is studied in batch annealing furnaces and ammonia combustion ovens in steel plants. The fuels of the annealing furnace and ammonia oven are by-product fuel gases and ammonia vapor, respectively, which are generated in the same steelworks. Study of the e…
Hydrogen permeation through thin films of Fe I– Y O on iron and through chemically polished iron were investigated by the sensitive electrochemical technique. The oxide was formed on the exit side of the sample membrane. The hydrogen arriving at the iron/oxide interface is in an atomic or protonic state which renders…
It has been established that phosphate analogues can activate glycogen phosphorylase reconstituted with pyridoxal in place of the natural cofactor pyridoxal 5'-phosphate (Change YC. McCalmont T, Graves DJ. 1983. Biochemistry 22:4987-4993). Pyridoxal phosphorylase b has been studied by kinetic, ultracentrifugation, and…