Materials Literature
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Permeabilities for a series of gases through free-standing films of the conjugated polymer polyaniline are reported. A remarkable selectivity has been achieved for important gas pairs incuding hydrogen-nitrogen, oxygen-nitrogen, and carbon dioxide-methane. The selectivity values of 3590 for H(2)/N(2), 30 for O(2)/N(2)…
The reaction of bis(benzene)vanadium with tetracyanoethylene, TCNE, affords an insoluble amorphous black solid that exhibits field-dependent magnetization and hysteresis at room temperature. The critical temperature could not be estimated as it exceeds 350 kelvin, the thermal decomposition temperature of the sample. T…
Abstract An elongational flow method established in polymer physics was applied to study dynamic structure and properties of biopolymers in solution. Type I collagen solutions in the dilute to semidilute region are studied in elongational flow fields, generated in a Taylor four‐roll mill, for temperatures from 20°C th…
Abstract The aggregative stability of natural rubber (NR) latex stabilized by nonionic, fatty alcohol ethylene oxide condensate surfactant (Verol S‐15) was studied in the presence of formic acid. Natural rubber latex having an additional 3–5 phr surfactant is stable at pH 2 when acidified by formic acid and can be suc…
Abstract Graft copolymerization of vinyl compounds onto chitin was studied, and an efficient and reproducible procedure has been established, cerium (IV) being used as the initiator. The reactions with acrylamide and acrylic acid onto powdery chitin were carried out under various conditions to elucidate the polymeriza…
57 Fe Mossbauer spectra have been obtained at room temperature and at 15 K for R 2 Fe 17 and R 2 Fe 1 7 N 3- delta ( delta approximately=0.4) with R identical to Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu and Y. The easy direction of magnetization of the R 2 Fe 17 compounds can be identified by analysis of the hyperfi…
High resistivities associated with a reduced density of states and a very low effective number of carriers are measured in high-structural-quality AlCuFe icosahedral phases. These properties vary strongly with composition close to ${\mathrm{Al}}_{63}$${\mathrm{Cu}}_{25}$${\mathrm{Fe}}_{12}$ and suggest that insulating…
The magnetic susceptibility of phases with block type structures in the Nb 2 O 5-2x system, with 0<or=x<or=0.083, has been determined by the Faraday method in the temperature region 77-400 K. The samples consisted of crystals of composition Nb 28 O 70 (Nb 2 O 5 ), Nb 53 O 132 (NbO 2.491 ), Nb 25 O 62 (NbO 2.480 ), Nb…
A polarization insensitive, electrically tunable Fabry–Perot structure is demonstrated. The polarization insensitivity is realized by using a twisted structure of a nematic liquid crystal such that the molecules at one surface are orthogonal to those at the other surface. In the high-field regime, this configuration c…
Previous experimental work has revealed an anomalous increase of thermal conductivity lambda in solid UO 2 above about 2000 K, which has been attributed to the effect of electronic excitations. The present molecular dynamics simulations of UO 2 and the closely related material CaF 2 are designed to test this explanati…
The seeding for large-area mosaic diamond films approaching single-crystal quality is described. The technique includes patterned etching of relief structures in Si substrates, deposition from a slurry and orientation of macroscopic diamond seed crystals in the structures, and chemical vapor deposition overgrowth of t…
High precision electron probe microanalysis (EPMA) has been used to measure the correlation of oxygen deficiency with carrier concentration in thin films of amorphous indium oxide. This has shown that there are ten times as many oxygen vacancies as would be expected from the carrier concentration measurements, giving…
A new relationship between the relative surface free energy and the surface structure of a cubic material with terrace, step, and kink structures based upon the application of the information theory is presented. Any surface of a face centered cubic crystal exists as combinations of (111), (100), and (110) microfacets…
The combined effect of uniaxial mechanical compression and gradient heating on the pyroelectric properties and domain structure realignment processes in gadolinium molybdate single crystals has been studied. It is shown that the application of mechanical stresses under the condition of gradient heating results in a st…
Abstract A series of thermally stable, tough, linear polyimides containing amide linkages was prepared. The new polyamide‐imides were synthesized by reacting a group of isomers of diaminobenzanilide (DABA) with various dianhydrides, such as 4,4′‐oxydiphthalic anhydride (ODPA), 3,3′,4,4′‐biphenyltetracarboxylic dianhyd…
Crystallization of Li‐Al‐Si‐O‐N oxynitride glasses based on the β‐spodumene composition and the properties of the resultant glass‐ceramics have been studied. The onset of the precipitation of metastable high‐quartz solid solution and its transformation to β‐spodumene shift to higher temperatures with increasing nitrog…
series of samples of the system Co-xnxFe2O4 (x = 0.0, 0.3, 0.4, 0.5 and 0.8) have been prepared by the usual ceramic technique. X-ray analysis shows that they are cubic spinel (single phase). The lattice parameter a and the bulk density D are measured for the samples. The substitution experiments replacing Coe+ by n2+…
The tilt angle behavior of the smectic C phase was studied in several binary systems. The concentration dependence of the tilt angle deviated from the linear relationship. The degree of the deviation was influenced by the difference in the molecular structure between the two components. The tilt angles were found to c…
Abstract The toughening effect of the separate phases of ethylene/propylene block copolymers and their blends was studied by scanning electron microscopy (SEM). The results obtained show that the interfacial adhesion between separate phases and the isotactic polypropene (iPP) matrix in ethylene/propylene block copolym…
A method for retrieving the magnetization curve of a nonlinear coil is described. The parameters of a piecewise-linear or a third-order polynomial approximation can be obtained. A simple bridge RL-multivibrator, which includes an operational amplifier and this coil, is used. The coil parameters are calculated observin…