Materials Literature
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Abstract Microcellular semicrystalline polymers such as poly(ethylene terephthalate) show great promise for engineering applications because of their unique properties, particularly at higher densities. Recent studies have shown that some high density microcellular polymers have longer fatigue lives and/or equivalent…
The ferroic phase‐transition behavior of two (Na 1/2 Bi 1/2 )TiO 3 (NBT) crystals grown by flux and by the Czochralski method has been investigated in the present study. Although both the tetragonal and the rhombohedral phases of NBT are expected to be ferroelastic, these crystals exhibit different ferroelastic behavi…
Two new diglycidyl ester compounds containing preformed imide rings for better thermal stability were prepared to be used as chain extenders for PET and PBT. The preparation of these compounds was carried out in two steps. In the first step, diimidodiacids were prepared from pyromellitic anhydride and 3-aminopropanoic…
An efficient expression system for recombinant collagens would have numerous scientific and practical applications. Nevertheless, most recombinant systems are not suitable for this purpose, as they do not have sufficient amounts of prolyl 4-hydroxylase activity. Pro-alpha 1 chains of human type III collagen expressed…
The majority of molecules which form liquid crystals are elongated in shape. However, disk shaped molecules have also been shown to exhibit liquid crystalline phases. In this paper we report a series of constant pressure Monte Carlo simulations of model discotic molecules. We have used the Gay–Berne potential, which i…
Under mildly oxidizing ultrahigh vacuum conditions, it is possible to form on top of CoO(100) single crystal substrates, thin films that have higher oxygen content but that preserve the overall symmetry of the CoO(100) low-energy electron diffraction pattern. X-ray photoelectron spectroscopy (XPS) and high-resolution…
Highly transparent and conductive In2O3–ZnO films have been prepared by rf magnetron sputtering using targets composed of In2O3 and ZnO. Polycrystalline Zn2In2O5 films were deposited at a substrate temperature of 350 °C using targets with a Zn content [Zn/(Zn+In)] of about 10–60 at. %. A uniform spatial resistivity di…
Optical emission spectra (OES) from CH4/N2 rf plasmas, which are used for the deposition of nitrogen-containing hydrogenated amorphous carbon (a-C:H:N) thin films, have been characterized. Previously unidentified spectral lines have been assigned to atomic N. Further identified species include CH, H, H2, N2, N+2, N, a…
Previous simulation studies of localized low-frequency vibrational modes in a soft sphere glass are extended to larger samples. We find a boson peak in the spectral density and a maximum in the specific heat divided by ${\mathit{T}}^{3}$ similar to experiment. These maxima are caused by (quasi)localized vibrations. Fo…
Ultrafine crystalline spinel powder has been prepared using flame spray pyrolysis of alcoholic solutions of a novel double alkoxide precursor. The particles produced are spherical, dense, single crystals with diameters of 10–100 nm and specific surface areas ranging from 40 to 60 m 2 /g. Powder production rates of 50–…
This work investigated the barrier properties of metalorganic chemical-vapor-deposited (CVD) tantalum nitride (TaN) and physical-vapor-deposited (PVD) TaN between Cu and Si. The CVD TaN film had a preferred orientation (200) with a grain size of around 60 nm, while the PVD TaN had a (111) preferred orientation with a…
The first dendritic liquid crystalline polymer (DLCP) , consisting of a flexible, second‐generation dendritic carbosilane scaffold substituted with 36 rid cyanobiphenyl groups (see Figure), has been prepared. The synthesis and characterization of the mesophase are reported as an initial approach to determining how the…
It was observed that the dielectric permittivity of ${\mathrm{PbMg}}_{1/3}$${\mathrm{Nb}}_{2/3}$${\mathrm{O}}_{3}$ (PMN) relaxor ceramics increases with increasing amplitude of the applied ac field. A strong nonlinearity occurs at temperatures where the frequency dispersion of the dielectric response is observed. A si…
Abstract The electrical resistivity and morphology of polypropylene/nylon (PP/Ny) immiscible blends incorporated with carbon black (CB) were studied. CB was found to be preferentially located in the Ny phase or upon the Ny/PP interface. Blends with a co‐continuous phase morphology depicted especially low resistivity v…
The fabrication of gated diamond field-emission cathodes is described and a theory of their operation is discussed. These cathodes are made using commercial diamond grit with the addition of Ni and Cs salts to enhance emission. The resulting structure resembles a field-emission Spindt cathode with the internal metal c…
peer reviewed
Substrate‐type planar solid oxide fuel cells with an effective electrode area of 10 cm 2 and reference electrodes were fabricated and run for 211 and 1015 h to investigate Ni‐YSZ anode degradation. An Ni‐YSZ anode degradation of 14 μV/h at a current density of 0.3 A/cm 2 was determined by impedance analysis. Mercury p…
The macroscopic dielectric function in the random-phase-approximation without local field effect has been implemented using the local density approximation with an all electron, full-potential linear muffin-tin orbital basis-set. This method is used to investigate the optical properties of the semiconductors Si, Ge, a…
A minimal model is constructed for two-dimensional fracture propagation. The heterogeneous process zone is presumed to suppress stress relaxation rate, leading to non-quasistatic behavior. Using the Yoffe solution, I construct and solve a dynamical equation for the tip stress. I discuss a generic tip velocity response…
Ca2+ compartments, Ca2+ transport and the calcification process were studied by using 45Ca as a tracer. The biological model used was clones of Stylophora pistillata developed into microcolonies whose skeleton is entirely covered by tissues, thus avoiding direct radioisotope exchange between the sea water and the skel…