Materials Literature
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The lamellar semiconductors GaSe and InSe have been studied with k-resolved inverse-photoemission spectroscopy along two major symmetry directions (\ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{} K\ifmmode\bar\else\textasciimacron\fi{} and \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{} M\ifmmode\b…
In order to optimize the magnetic properties of die-upset Pr-Fe-B magnets, we have systematically altered alloy compositions, including partial substitution of cobalt and neodymium, and low-level additions of gallium. In general, the remanences of Pr-Fe-B die-upset magnets were lower by ∼1 kG, and coercivities were hi…
Abstract The glass transition and melting behavior of poly(ether‐ester) multiblock copolymers with poly(tetramethylene isophthalate) (PTMI) hard segments and poly(tetramethylene oxide) (PTMO) soft segments are studied by differential scanning calorimetry (DSC) and small‐ and wide‐angle x‐ray scattering (SAXS and WAXS)…
Abstract New polyarylates and aromatic polyethers were synthesized from 1,2‐bis(4‐hydroxyphenyl)‐1,2‐diphenylethylene, and aromatic dicarboxylic acid chlorides and aromatic dihalides, respectively. The polyarylates having inherent viscosities of 0.28–1.05 dL/g were synthesized by either the two‐phase method or the hig…
We have calculated the contribution of the lowest-order vertex-correction diagram to the direct gap of silicon at the \ensuremath{\Gamma} point, taking into account the dynamic screening of the electron-electron interaction. Our best calculation yields a contribution of 0.12 eV. This result supports the assumption of…
Abstract The reaction of the alternating ethylene–carbon monoxide copolymer with Lawesson's reagent resulted in the conversion of 75% of the carbonyl groups to thiophene units. A few thioketone groups were also present in the derived polymer. A polymer with furan units in the backbone was formed upon treatment of the…
We have performed infrared absorption, continuous-wave photoluminescence, and nanosecond photoluminescence decay measurements to characterize stain-etched porous silicon. Stain-etched porous silicon samples were prepared by etching boron-doped crystalline silicon wafers in a solution of HF:${\mathrm{HNO}}_{3}$:${\math…
Abstract A new simulation model for the kinetics of long‐chain branching formed via chain transfer to polymer and terminal double‐bond polymerization is proposed. This model is based on the branching density distribution of the primary polymer molecules. The theory of branching density distribution is that each primar…
Accurate measurements of the polarized reflectance spectra of the series of isostructural organic conductors (TMTSF${)}_{2}$${\mathrm{ClO}}_{4}$, (TMTSF${)}_{2}$${\mathrm{PF}}_{6}$, (TMTTF${)}_{2}$Br, and (TMTSF${)}_{2}$${\mathrm{PF}}_{6}$ (where TMTSF denotes tetra-methy tetraselenafulvalene and TMTIF denotes tetra m…
Classical trajectory calculations were employed to study oxygenated (100) diamond surfaces. Atomic forces were computed from two types of potential energy functions, a quantum mechanical potential based on the semiempirical PM3 (parametric method number 3) Hamiltonian which was used to describe the central code core o…
The tight-binding method is used to calculate the electronic densities of states of various models of a-C. Both models generated using Tersoff's potential and quantum mechanically derived forces show \ensuremath{\pi} and ${\mathrm{\ensuremath{\pi}}}^{\mathrm{*}}$ states in the \ensuremath{\sigma} gap in agreement with…
Borosilicate glass films nominally containing up to 40 wt% ZnSe semiconductor crystallites have been successfully prepared on silica glass substrates by the sol-gel process. The influence of heat treatment on optical absorption, emission, and excitation properties was studied. On heating the films at temperatures from…
The anisotropy of the magnetoresistance has been measured systematically by changing the current and field direction with respect to the crystallographic axes in the quasi-two-dimensional organic conductor \ensuremath{\alpha}-(BEDT-TTF${)}_{2}$KHg(SCN${)}_{4}$, where BEDT-TTF denotes bis(ethylenedithio)tetrathiafulval…
A detailed surface chemistry mechanism is proposed for chemical vapor deposition of diamond films, which extends the growth-by-methyl mechanism proposed by Harris to treat any CHm radical, m=0–3, as a growth monomer. Numerical computations were performed in which the mechanism was coupled to a model for the boundary l…
The meta-antimonates, MSb 2 O 6 , M=Ca, Sr and Ba, have been prepared, and their crystal structures refined from powder X-ray diffraction data. The interatomic distances have been determined to reasonable accuracy and the preferred space group was found to be P31m, not the previously identified P312 (a subgroup of P31…
Polycrystalline samples of Ba2(ZnxFe1−x)2Fe28O46 [(ZnxFe1−x)2−X, 0≤×≤1] X-type hexaferrites were prepared by the ceramic method. Magnetization, magnetic moment, and Curie temperature were investigated. With increasing Zn content the magnetization and magnetic moment increase linearly, but the Curie temperature decreas…
The M 2 p core-level XPS peaks of doped elements in Ni 1- x M x S are observed at the binding energies of M in "M 2 S 3 " rather than those of "MS" below and above the nonmetal-metal transition temperature ( T t ), indicating that the M atom are ionized to M 3+ and acts as shallow donor impuritites. Below T t the T 1/…
Abstract Polyether‐based polyurethane/poly (methyl methacrylate‐co‐ethyleneglycol dimethacrylate) interpenetrating polymer networks [PU/P (MMA–co–EGDMA)‐IPNs] were synthesized and used as adhesives to adhere vulcanized natural rubber (NR) and soft polyvinyl chloride (PVC). The structure and morphology of the IPN adhes…
Chemical composition, core-level line shape, and electron affinity measurements are performed on the Se-terminated (2\ifmmode\times\else\texttimes\fi{}1) and Zn-terminated c(2\ifmmode\times\else\texttimes\fi{}2) ZnSe(100) surfaces. The (2\ifmmode\times\else\texttimes\fi{}1) reconstruction corresponds to a complete mon…
We study the recombination mechanism of the visible photoluminescence (PL) S-band in p-doped porous Si layers by time-resolved photoluminescence. From the observed ‘‘stretched-exponential’’ PL decays we present a simple yet accurate evaluation method for lifetime distributions G(τ) and average recombination lifetimes…