Materials Literature
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BACKGROUND: This study compared the therapeutic effects of doxorubicin hydrochloride in saline and in sterically stabilized, long-circulating liposomes composed of hydrogenated soy phosphatidylcholine/cholesterol/polyethylene glycol-distearoyl-phosphatidyl-ethanolamine (Doxil). METHODS: The drug formulations were inje…
Abstract Polymer morphology is controlled over a continuum from microspheres to interconnected bicontinuous networks to fibers with a versatile new process: precipitation with a compressed fluid antisolvent. The results are explained qualitatively as a function of phase behavior, mass‐transfer pathways, and the format…
The quasiparticle electronic band structure of ${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$ carbon nitride in the \ensuremath{\beta}-${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ structure is calculated using the GW approximation. The indirect band gap is predicted to be 6.4\ifmmode\pm\else\textpm\fi{}0.5 eV and the minimum direct ga…
Diamond (111) and (100) surfaces have been investigated by low-energy electron diffraction and high-resolution electron-energy-loss spectroscopy (HREELS). Samples were boron-doped semiconducting diamond surfaces grown homoepitaxially on natural diamond by microwave-plasma-assisted chemical-vapor deposition. A dipole-a…
β Dicalcium diphosphate is composed of eclipsed P 2 O 7 groups linked through Ca 2+ cations. The P-Ob bonds involving the bridging O atoms arelonger [average 1.620 (5) A] than the others [average 1.517 (5) A]. As the «O 4 » tetrahedra are almost regular the displacement of the P atoms involves two sets of O-P-O angles…
Raman spectroscopy is found to be a powerful tool to determine the structural phase boundary between cubic (Fm3m) and tetragonal (P42/nmc) phase in arc-melted Zr1−XYXO2−X/2 (0.08≤X≤0.24) solid solution. The Raman peak intensity characteristic of the tetragonal phase at about 470 cm−1 decreases with the YO1.5 content X…
Abstract Electrical and magnetic properties of composite materials prepared by incorporating various nickel‐based fillers of different shapes into polyethylene were investigated. The fillers used were nickel powders, nickel filamentary powders, nickel flakes, and nickel‐coated graphite fibers. The particle‐size distri…
Spall strength measurements for commerical grade molybdenum and molybdenum single crystals were made in a wide range of load durations (∼10−9 s – 10−6 s) and intensities (∼5 – 100 GPa). Resistance to fracture of pure single crystals was found to exceed two times the spall strength of polycrystalline molybdenum and to…
Lithium yttrium tetrafluoride, LiYF 4 , M r =171.8, tetragonal, I4 4 /a, a=5.164 (1), c=10.741 (2) A, V=286.5 (1) A 3 , Z=4, D x = 3.99 g cm -3 , λ(Mo Kα)=0.7107 A, μ=204 cm -1 , F(000)=312, T=295 K, R=0.015 for 156 unique observed [F>4σ(F)] reflections. The scheelite (CaWO 4 ) structure is confirmed. Lithium is locat…
Critical behavior of the electrical conductivity near the disorder-induced metal-insulator (MI) transition has been observed in polyaniline (PANI) doped with camphor sulfonic acid (CSA). The temperature dependence of the resistivity (\ensuremath{\rho}) depends on the degree of disorder present in the PANI-CSA films. I…
An experimental study of the luminescence time decay in porous silicon as a function of temperature, excitation, and observation energies is reported. The decay line shape is well described by a stretched exponential for a variety of experimental conditions. A hierarchy of waiting times for carrier hopping, of intersi…
Successful control of the conductivity of tetrahedrally bonded amorphous carbon (ta-C) by incorporation of N during film growth is reported. N is introduced into the films during growth by injecting ${\mathrm{N}}_{2}$ gas into a plasma stream formed by a carbon cathodic vacuum arc. X-ray-photoemission-spectroscopy stu…
Powder-x-ray-diffraction measurements on siloxene and calculations of the diffraction patterns for the three commonly proposed structures of siloxene (${\mathrm{Si}}_{6}$${\mathrm{H}}_{6}$${\mathrm{O}}_{3}$) clearly show that only a structure with silicon layers is ever observed. The formation of siloxene from ${\math…
We observed by scanning tunneling microscopy (STM) a hexagonal superlattice on graphite with a period of 66 \AA{}. Direct measurement of the angle between lattice vectors confirmed that the superlattice is a Moir\'e pattern caused by a 2.1\ifmmode^\circ\else\textdegree\fi{} rotation of the topmost (0001) plane with re…
The optical study of trivalent 3d transition-metal-oxide compounds (RM${\mathrm{O}}_{3}$) with the perovskitelike structure has revealed the variation of their electronic structure with the 3d element (M) as well as the A-site rare-earth element (R). The crossover of the gap nature from the Mott type to charge-transfe…
The damping of collective electron resonances in clusters which develop into plasmon polaritons at larger sizes is investigated for free, supported, and embedded neutral metal clusters. Embedding of free 2 nm Ag clusters of 2-nm diameter into a ${\mathrm{SiO}}_{2}$ matrix leads to an increase of the width of the reson…
Electron backscattering (EBS) and secondary electron emission (SEE) yield have been measured for bulk carbon with a density of 1.8 g cm -3 , for primary electron energies in the range from 100 to 500 eV and from 12 to 1000 eV respectively. The backscattering results were in agreement with an empirical formula to withi…
Thermoluminescence in LiF:Mg,Ti is frequently described with the Randall-Wilkins model which assumes first-order kinetics. This model fits a measured single glow curve (light output as a function of temperature during heating up the sample) very well. If this model describes the thermoluminescence phenomenon correctly…
The significance of permanent electric dipoles in second harmonic generation is considered with regard to their role in both the non-linear susceptibility and also in the orientation of polar molecules. Under conditions of near-resonance with the first electronic excited state, the susceptibility is dominated by a two…
The crystal structures of the stable, closed complexes of chicken mitochondrial aspartate aminotransferase with the natural substrates L-aspartate and L-glutamate have been solved and refined at 2.4- and 2.3-A resolution, respectively. In both cases, clear electron density at the substrate-coenzyme binding site unequi…