Materials Literature
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Tantalum single crystals of the four orientations (100), (110), (111), and (112) have been irradiated with electrons in the energy range 1.0-1.7 MeV. A special irradiation procedure has been used which enables us to distinguish between subthreshold and intrinsic defects. The threshold energy for atomic displacement is…
The oscillatory magnetothermal effect has been used to study the Fermi surface of niobium-doped strontium titanate at low temperatures. Several de Haas-van Alphen frequencies were identified in the (011) crystallographic plane and compared with the predictions of various theoretical models of the conduction band. The…
Abstract Melt blends of polycarbonate with Kodel, a homopolyester formed from 1,4‐cyclohexanedimethanol and terephthalic acid, and with Kodar, a copolyester formed by replacing some of the terephthalic acid with isophthalic acid, were prepared and their transitional behavior were examined by thermal analysis and dynam…
Abstract Polycarbonate blends with poly(ε‐caprolactone) were prepared by both melt‐blending and solution‐blending techniques, and the properties of these blends were studied by thermal analytical and dynamic mechanical testing methods. Each blend composition was found to have a single glass transition temperature, and…
Coherent acoustic echoes are generated in fused silica glass at very low temperatures by a sequence of short acoustic pulses that interact with the intrinsic two-level configurational systems of the glass. Coherent effects are observable below $T\ensuremath{\approx}100$ mK, where the two-level-system phase memory time…
Single crystals of $n$-${\mathrm{Bi}}_{2}$${\mathrm{Se}}_{3}$ were prepared with free-carrier concentration $N$ in the range $5\ifmmode\times\else\texttimes\fi{}{10}^{18}<N<2\ifmmode\times\else\texttimes\fi{}{10}^{20}$ ${\mathrm{cm}}^{\ensuremath{-}3}$. Results of the measurements of infrared reflectance, Seebec…
We show that a suitable electron paramagnetic resonance experiment can discriminate sufficiently against the predominantly harmonic fluctuations characterizing a system undergoing a displacive phase transition, that a cluster-induced order-disorder component of the local behavior is exposed. We find evidence that, at…
The dissolution of iron from carbon steel in aqueous H 2 S solutions has been studied as a function of time and temperature at 0.1 MPa H 2 S pressure using the rotating disc technique. The iron sulfide film formed on the disc surface has been identified by X-ray diffraction analysis. The solubility and dissolution rat…
The random-network model for amorphous alloys proposed by White has been developed for some Se-based amorphous semiconductors (Ge-Se, As-Se, and Se-As-Ge) annealed or irradiated with light. The model suggests that the photobleaching and the photodarkening in these systems may be due to change in the number of bonds. A…
The results of Raman scattering and infrared reflectivity studies of the mixed-valence ternary sulphide ${\mathrm{Sn}}^{\mathrm{II}}$${\mathrm{Sn}}^{\mathrm{IV}}$${\mathrm{S}}_{3}$ are presented. The infrared-active phonon frequencies and the dielectric constants for all the principal directions have been determined.…
The near-band-edge optical properties of a series of 15 crystals including the two binary compounds GaSe and GaTe have been investigated in great detail at 300, 77, and 1.6\ifmmode^\circ\else\textdegree\fi{}K. The absorption spectra at 77 and 1.6\ifmmode^\circ\else\textdegree\fi{} K show well-resolved excitonic struct…
Abstract The influence of shearing history on the viscoelastic properties of low‐density polyethylene (LDPE) is investigated. Swelling of extrudates from a melt indexer is measured for monitoring the variation in viscoelasticity. Continuous shearing of molten LDPE reduces the swelling ratio. The reduction is not due t…
Abstract A low molecular weight poly(ester urea), poly(L‐phenylalanine/ethylene glycol/1,6‐diisocyanatohexane), and a model diester diurea, dimethyldiphenylalaninehexamethylenediruea, were synthesized and found to be hydrolyzed by α‐chymotrypsin solutions at pH 7.8. After ten‐day exposure to 0.1 mg/ml enzyme solution…
Spectral, kinetic, and relative quantum intensity measurements are reported for a series of ${\mathrm{Y}}_{3}$${\mathrm{Al}}_{5}$${\mathrm{O}}_{12}$ (YAlG) crystals, both nominally undoped and activated by ${\mathrm{Ce}}^{3+}$ and ${\mathrm{Tb}}^{3+}$. The undoped crystal shows a complex emission band in the near uv w…
A new electromagnetic transducer configuration is described for generating horizontally polarized shear (SH) waves in ferromagnetic materials. The transducer consists of a meander coil and static bias magnetic field parallel to the coil elements. This configuration generates no ultrasonic waves in a nonmagnetic metal…
Single-crystal samples of $\ensuremath{\alpha}$-${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$ have been studied that were colored during growth. The samples initially contained a single absorption band at 6.1 eV with a half-width of 0.68 eV. The sample had to be heated to a over 1400\ifmmode^\circ\else\textdegree\fi{}C to rem…
Abstract The adsorption abilities of chitin and its congeners with two series of degrees of deacetylation prepared by two different deacetylation procedures were compared. Among the polysaccharides obtained by the heterogeneous method, those with higher amino group content had higher adsorption ability. Plots of colle…
Measurements are presented of the optical properties of the radical cation TT${\mathrm{F}}^{+}$ (tetrathiafulvalenium) in a variety of different conditions: as TT${\mathrm{F}}^{+}$ monomers in solution, as ${(\mathrm{T}\mathrm{T}{\mathrm{F}}^{+})}_{2}$ dimers in solution, in the monovalence (TTF)${\mathrm{Br}}_{1.0}$…
The fine structure in the angle-resolved secondary electron emission (SEE) spectra can be interpreted fully in terms of the electronic structure of the semi-infinite crystal. A large number of elements of structure can be related to the bulk band structure. In addition, extra features are unambiguously interpreted in…
Abstract The polymerization of 1‐vinylindole ( 1a ) induced by free radical and cationic initiators is studied and the structure of the resulting polymers is elucidated by 13 C NMR spectroscopy. Also 2‐methyl‐1‐vinylindole ( 1b ), 3‐methyl‐1‐vinylindole ( 1c ), and 2,3‐dimethyl‐1‐vinylindole ( 1d ) are polymerized in…