Materials Literature
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[C 16 H 36 N] 2 °Mo 6 O 19 ] M r =1364.6, monoclinic, C2/c, a=16.280 (3), b=17.204 (3), c=17.738 (4) A, β=101.42 (2) o , V=4869.3 (17) A 3 , Z=4, D x =1.861 g cm -3 , λ(Mo Kα) = 0.71073 A, μ=15.66 cm -1 , F(000)=2728, T=298 K, R=0.0633 for 2857 observed reflections and 269 least-squares parameters. The six Mo atoms fo…
Beryllium calcium diborate, CaBeB 2 O 5 , M r =150.71, monoclinic, P2 1 /n, a=5.167 (2), b=3.756 (2), c=17.160 (2) A, β=98. 12 (2) o , V=329.7 (2) A 3 , Z=4, D x =3.036 g cm -3 , λ(Mo Kα)= 0.71069 A, μ=17.38 cm -1 , F(000)=296, T=298 K, R=0.039 for 508 reflections having F o 2 ≥3σ(F o 2 )
The electrical conductivity and thermoelectric power have been measured to investigate the semiconductor-metal transition in liquid Ge 15 Te 85 . It has been found that the activation energy of the electrical conductivity has a marked peak definitely below the temperature where the specific heat, compressibility and t…
Two competing theories of the optical absorption edge of intrinsic crystalline silicon, the indirect transition theory, and the recent disorder (Urbach edge) theory, are assessed critically. The assessment of the indirect transition theory includes an attempt to predict, by the use of the luminescence spectrum and the…
Gas-gun reverse-ballistic experiments have been performed in which Ti6Al4V alloy disks were impacted onto smaller diameter, hardened steel rods to push out shear plugs from the disk material. The range of disk velocities was 219–456 m/s. For each experiment, the disk, plug, and rod were soft recovered after impact. Be…
Control over the switching times of polymer dispersed liquid crystal (PDLC) displays is an area of technological importance. We found that the switching times of a PDLC cell can be effectively controlled by using a dual frequency addressable liquid crystal mixture and driving it with appropriate electric fields. The d…
The electronic bands of BaB2O4 (BBO) and LiB3O5 (LBO) have been computed from first principles using the ab initio pseudofunction method. Optical conductivities and densities of states in good agreement with optical measurements and x-ray photoemission are obtained. The gap in BBO results from the borate group to the…
We have studied the effects of expansion of the lattice on band-edge levels in Si, Ge, Sn, and SiSn. The variation in the gap in the Si\ensuremath{\rightarrow}Ge\ensuremath{\rightarrow}Sn series can be explained as moving along a universal curve of the variation of band-edge levels with the combined effect of volume a…
Epitaxial thin films of naphthalocyanines (Nc’s) were prepared on the (001) surface of alkali halide (AX) by a vacuum-deposition technique. Two types of molecular stacking and orientation were found depending on the molecular structure. Metal-free Nc(H2Nc) and divalent zinc Nc(ZnNc) took the face-to-face, eclipsed sta…
The structural and electronic properties of iron clusters ${\mathrm{Fe}}_{\mathit{n}}$ (n\ensuremath{\le}5) are studied using a Gaussian orbital local (nonlocal) spin-density method. Starting from n=2 and 3 with localized multiple d bonds and short equilibrium bond lengths, ${\mathit{R}}_{\mathit{e}}$\ensuremath{\sime…
The defects in ${\mathit{p}}^{+}$ porous silicon of low and high porosity have been studied by using electron-paramagnetic-resonance (EPR) spectroscopy and compared with an impurity analysis obtained from nuclear reaction analysis (NRA). The EPR measurements show, in both high- and low-porosity samples, the same domin…
We present the results of time-resolved luminescence studies of poly[2-methoxy, 5-(2′-ethyl-hexyloxy)-p-phenylene-vinylene] (MEH-PPV), as a pure film, in solution, in a gel formed by a network of ultrahigh molecular weight polyethylene (UHMW-PE), and in a blend with UHMW-PE. The luminescence has a characteristic lifet…
Abstract It has been discovered that a combination of heat and high‐power ultrasound can be used to initiate ring‐opening polymerization in cyclic bisphenol A polycarbonate oligomers. The polymerization can be conducted with or without the use of added chemical initiators. The use of ultrasound was extended to prepare…
Abstract Blends of propylene–ethylene block copolymer (PEB) and propylene homopolymer (PP) were prepared to give various rubber contents (4–20 wt %). By diluting the PEB with PP with molecular weight equal to that of the PEB matrix, molecular characteristics of all the blends were kept constant. The rubber particle si…
The spectra of optical constants of α-Al 2 O 3 single crystals at 297 K and 10 K are presented over the range of photon energies from 6 eV to 120 eV for the electric fields of incident light parallel to optic axis < c > and normal to it. The optical constants include the complex index of refraction, conductivity, comp…
Tatsumisago, Angell, and Martin [J. Chem. Phys. 97, 6968 (1992)] have compared conductivity relaxation data and 7Li nuclear spin lattice relaxation (SLR) data measured on a lithium chloroborate glass and found pronounced differences in the most probable relaxation times. The electrical conductivity relaxation (ECR) ti…
The bead-spring model pioneered by Rouse is generally considered to be the basis of polymer physics. We show generally that it breaks down dramatically near the glass transition temperature by shear creep measurements on several polymers with very different backbone structures. The physical origin of this breakdown is…
A model for a multichain polymer system in three-dimensional continuous space is studied by link cell Monte Carlo methods, using systems up to chain length N=64 and up to 16 384 monomers. The chains consist of beads with a hard core connected by rather stiff harmonic bonds, with a repulsive Lennard-Jones-type interact…
Experiments with local gas feeds of methane or acetylene indicate that both ${\mathrm{C}}_{2}$${\mathrm{H}}_{2}$ and ${\mathrm{CH}}_{3}$ contribute to the growth of (111) surfaces, whereas only ${\mathrm{CH}}_{3}$ contributes to that of the (100) surface. High-resolution electron-energy-loss spectroscopy has been used…
We outline a method for the calculation of nonlinear properties such as dynamic hyperpolarizabilities for self-consistent-field (SCF) wave functions. In this method, two-electron integrals are only addressed in the evaluation of Fock matrices and Fock matrices with one-index transformed integrals. These matrices are d…