Materials Literature
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The excitation energies of impurities in semiconductors, as well as their donor and acceptor ionization energies, represent a combination of one-electron and many-electron multiplet effects, where the latter contribution becomes increasingly significant as localized states are formed. Analysis of the absorption and io…
We report self-consistent density-functional calculations of the energy and enthalpy of silicon and carbon in the fully relaxed complex B-8 structure (bcc with 8 atoms per cell). We find B-8 to be unstable in Si, with enthalpy slightly higher than the diamond and $\ensuremath{\beta}$-tin phases. B-8 is found to be a s…
Films of pure and Sn-doped semiconducting ${\mathrm{In}}_{2}$${\mathrm{O}}_{3}$ were prepared by reactive $e$-beam evaporation. The spectral absorption coefficient was evaluated by spectrophotometry in the (2-6)-eV range. The extracted band gap increases with electron density (${n}_{e}$) approximately as ${n}_{e}^{\fr…
The description of polymer collapse is presented both in conformational space and field theoretic forms along the same lines as we have provided for treating the theta point (tricritical) region for polymers. This enables the problem to be considered in terms of the same measurable parameters which are used in the the…
Recently it was proved that the Majumdar-Ghosh chain with the Hamiltonian H=4 Sigma j=1 2N S j .S j+1 +2 Sigma j=1 2N S j .S j+2 , S i+2N identical to S i , S i = 1 / 2 , has at least two ground states, in which the spins are arranged in nearest-neighbour singlet pairs. In this work it is shown that these two states a…
An elastic Ginzburg-Landau theory which includes strain and strain-gradient contributions is formulated for inhomogeneous strain fields associated with interface boundaries, heterophase inclusions, and transformation precursors. For proper purely ferroelastic materials of ${D}_{4h}$ symmetry, an explicit kink-type sol…
Abstract Two popular electrochemical methods for the investigation of the permeability of metal membranes to atomic hydrogen are critically discussed. In the potentiostatic (P) method, hydrogen is generated at constant potential at the entrance face; in the galvanostatic (G) method, it is generated at constant current…
Classification of potential energy minima-mechanically stable molecular packings-offers a unifying principle for understanding condensed phase properties. This approach permits identification of an inherent structure in liquids that is normally obscured by thermal motions. Melting and freezing occur through characteri…
The kinetics of polaron recombination into bipolarons in polypyrrole has been studied by optical-absorption spectroscopy on films doped in situ in an electrochemical cell. ESR studies confirm that the metastable states possess spin, while the stable states do not. The data reveal a slow evolution, consistent with pola…
A class of models for relaxation in strongly interacting glassy materials is suggested. Degrees of freedom are divided into a sequence of levels such that those in level $n+1$ are locked except when some of those in level $n$ find the right combination to release them, this representing the hierarchy of constraints in…
Reflection spectra were measured with oblique incident σ and π polarized light in a chiral smectic C liquid crystal. For the first-order diffraction, with σ -polarized incident light, the reflectionl light is π -polarized and vice versa.
The structures of three [OOl] coincidence twist grain boundaries were calculated for NiO. The symmetry of the structures enables the probable low‐energy configurations for a series of such boundaries to be deduced. The interfaces have a reduced density of ions in the boundary plane and achieve a maximum amount of undi…
The reactivities of calcined magnesites for industrial use and of magnesium oxides prepared from basic magnesium carbonate were assessed by using potentiometry to monitor pH changes in aqueous suspensions following step wise acid additions. The results were compared with those obtained by calorimetric measurements per…
The stress-strain properties of a NSSC-fluting medium plasticized with various amounts of ethylene glycol have been measured over a temperature range up to 250°C. By comparison with delignified and hemicellulose-extracted samples it is concluded that the major softening is to a large extent caused by the lignin. It is…
Abstract Chemical shift and scalar coupling constant data have been obtained for the 1 H, 13 C and 29 Si nuclei in allyl, methally, cis ‐ and trans ‐crotyl, cis ‐2‐methyl‐2‐butenyl and 3‐methyl‐2‐butenyl derivatives of trimethylsilane.
Four permanent magnet specimens of the form Sm1-xErx(Co,Fe,Cu,Zr)7.22have been investigated with regard to coercivity, remanence, energy product, and temperature coefficients of remanence and energy product at temperatures ranging from 200K to 800K. The results are compared with previously measured SmCo5and SmCo17type…
The deposition of the hexagonal ferrite films hopeful for high density recording has been attempted by means of Targets-Facing Type(TFT) of sputtering apparatus. The sputtering conditions and the concentration of sputtered films were investigated. The difference in composition between targets and deposited film become…
The nucleophilic substitution reactions between dimethylgalliumchloride (1) and the silyl sulfides (CH 3 ) 3 SiSR (R = CH 3 , C 2 H 5 , n-C 3 H 7, i-C 3 H 7 , Ph and CH 2 Ph) (2-7) in benzene result in the formation of the moisture-sensitive dimethyl(alkylthio)- and dimethyl(phenylthio)gallanes (CH 3 ) 2 GaSR (R = CH…
The time dependence of the rates of permeation of hydrogen through annealed and as-rolled nickel foils was measured in the temperature ranges 120–430°C and 80–200°C, respectively. Annealed specimens exhibited permeabilities, diffusivities and solubilities that were in fairly good agreement with previous results, while…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpecific formation of a polymer containing five-membered oxalactone rings in the main chain in the cationic ring-opening polymerization of 6,8-dioxabicyclo[3.2.1]octan-7-oneMasahiko Okada, Hiroshi Sumitomo, and Miharu AtsumiCite this: Macromolecules 1984, 17, 9, 1840–1843Pub…