Materials Literature
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Enzymatic polymerization of alkyl phenols derived from a renewable resource, viz., cashew nut shell, has been carried out in a dioxane-water mixture. The reaction and reaction products have been characterized by a number of spectroscopic, microscopic, and thermometric methods. These monomers have also been copolymeriz…
Intrinsic failure of a knitted Dacron aortic bifurcation graft 19 years after implantation is reported. Failure was due to inability of the dilated and deteriorated left graft limb to hold anastomotic sutures. Numerous transverse cracks and breaks were detected in the Dacron filaments, in addition to small holes throu…
The tensile properties of high- and low-purity Fe–9, –18 and –30Cr alloys irradiated by neutrons up to a dose of 5 × 1024 n/m2 (E >1 MeV) at 613, 673, or 763 K have been examined. The yield strength and the ultimate strength are increased and the elongation is decreased by irradiation. The enhancement of these strengt…
The reported study of charge density waves at low temperatures is based on a microscopic theory. One feature of a charge density wave at low temperatures is a large shift in the chemical potential near its defects, such as solitons, dislocations, and pinning centers, which leads to a higher conductivity of material al…
EPR analysis shows that the anion radical of 2,6-dinitrotoluene (DNT) in liquid ammonia exists with the counterion (either K(+) or Na(+)) associated with one of the two nitro groups. This tight association (-NO(2)(*-)M(+)) persists after solvent removal, and it renders the anion radical very susceptible to loss of met…
DMe-DCNQI forms highly-ordered ultrathin films on various single crystal surfaces. NEXAFS reveals flat lying molecules for all investigated film thicknesses (up to 40 layers) on nearly all substrates under investigation (Ag(111), Ag(100), Cu(100), Cu(111)). The C1s and N1s NEXAFS spectra of these condensed layers show…
The effects of the variations in concentrations of hydrogen (0−480 mol/m 3 ) and 1-butene (0−380 mol/m 3 ) on the gas-phase copolymerization of ethylene and 1-butene over a MgCl 2 /SiO 2 -supported Ti catalyst were investigated using a semibatch reactor operated at 70 °C. Polymers were characterized by size exclusion…
The temperature dependence of transmission loss for IR-transmitting chalcogenide glass fibers of sulfur (S)-based, selenium (Se)-based and tellurium (Te)-containing glasses were investigated above room temperature. The influence of temperature on transmission loss significantly depended upon the kind of chalcogen elem…
The charge-voltage (Q-V) relationship of ferroelectric capacitors experiencing arbitrary applied voltages is investigated both theoretically and experimentally. The complex behavior and history dependence of a ferroelectric capacitor in response to arbitrary voltage patterns can be well described by a parallel-element…
A magnetic study of perovskites RMnO3+x (R = Nd, Eu, Gd, Tb, Dy) is reported. The compounds NdMnO2.99 and EuMnO2.99 are weak ferromagnets with TN=88 and 49 K respectively. It is shown that GdMnO3 undergoes a transition from antiferromagnetic to weak ferromagnetic state upon cooling. The antiferromagnetic ordering of t…
The title compounds were designed as novel electron acceptors and prepared from 4,7-dihalobenzo[1,2,5]chalcogenadiazoles in two steps. Comparisons of X-ray structures indicate that the packing arrangements of the different chalcogenadiazole derivatives are quite different from each other in spite of their similar mole…
It has been known that blends of poly(ε-caprolactone) (PCL) and poly(styrene- co -acrylonitrile) (SAN) show a miscibility window in a relatively narrow range of copolymer composition in SAN. In order to study the interactions in this miscibility window in detail, FTIR and calorimetric measurements were carried out by…
Barium hexaferrites of compositions BaO·(6- x )Fe 2 O 3 · x Bi 2 O 3 with 0 \leqslant x \leqslant0.4 have been synthesized by the ceramic calcination route. The bismuth substituted hexaferrites exhibit dc electrical conductivities more than two orders of magnitude higher than the pure ones. This is believed to arise d…
The amino acid leucine has been shown previously to be transported into a yeast cell by at least three permeases: the general amino acid permease, a high-affinity permease (S1) and a low-affinity permease (S2). We isolated the gene BAP2 as a multicopy suppressor of the YPD- phenotype of aat1leu2 yeast. BAP2 has been i…
In-situ measurements of the motion of special and non-special 〈111〉 tilt grain boundaries in aluminium bicrystals of different purity show that even in very pure aluminium the activation parameters of the grain boundary mobility depend on the content of soluble impurities. The investigations are described in the frame…
We prove a conjecture of A. Hof, O. Knill and B. Simon [Commun. Math. Phys. 174, 149–159 (1995)] by showing that the Rudin-Shapiro sequence is not palindromic, i.e., does not contain arbitrarily long palindromes. We prove actually this property for all paperfolding sequences and all Rudin-Shapiro sequences deduced fro…
Becker and Mott have provided different formulae for the thermal activation energy of a process that occurs under stress. As the applied stress tends towards the critical stress, Becker's formula requires the smaller activation energy. We argue that, while the Mott formula represents the energy required for the system…
The first polarized low-temperature absorption and luminescence spectra of manganese-doped crystals of BaSO(4) containing essentially MnO(4)(2)(-) are reported. By using a flux composed of NaCl, KCl, and CsCl we were able to grow BaSO(4):Mn(6+) crystals below 620 degrees C. This prevents the simultaneous presence of M…
The values for Young's modulus of porous single-crystal Ni in the [100] and [111] directions are computed using the embedded-atom method (EAM). Both pore volume fraction and pore size (defined by ratio S/R of the flaw size to pore radius) are varied. A reduction in Young's modulus with increasing pore volume fraction…
Abstract A high molecular weight, linear aromatic poly(ether ketone ether ketone ketone) (PEKEKK) has been synthesized by electrophilic Friedel‐Crafts acylation condensation of 1,4‐diphenoxybenzophenone with terephthaloyl chloride. The syntheses were performed as precipitation polycondensations, and the polyketones we…