Materials Literature
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This article presents the main core lines and the valence band x-ray photoelectron (XPS) spectra obtained for a commercial gamma-alumina (γ-Al2O3) powder. The electronic record includes the Al 2p, Al 2s, O 1s, O 2s, C 1s, and valence band spectra. Although it is usually difficult to distinguish among the various forms…
Supercooled m-tricresyl phosphate has been studied by different nuclear magnetic resonance (NMR) methods using the 31P spin probe (180–400 K). Combining measurements of the spin-lattice relaxation at two Larmor frequencies, of the line shape and of the stimulated echo decay, a reorientational correlation function F2(t…
Extensive interlamellar spacing measurements on directionally solidified Al–CuAl2 eutectic alloys show that in this system the eutectic exhibits a limited range of spacings rather than a unique spacing during steady state growth at a constant velocity. The minimum spacing observed corresponds to the extremum spacing p…
The D-glucose/D-galactose-binding protein (M(r) = 33,000) found in the periplasm of bacterial cells serves as the primary high-affinity receptor of active transport for and chemotaxis toward both sugar epimers. This protein from Escherichia coli binds D-glucose with a Kd of 2 x 10(-7) M, which is about 2 times tighter…
The connective tissue of the skin is composed mostly of collagen and elastin. Collagen makes up 70-80% of the dry weight of the skin and gives the dermis its mechanical and structural integrity. Elastin is a minor component of the dermis, but it has an important function in providing the elasticity of the skin. During…
XPS data have been obtained from a pressed Ag2O powder obtained from AESAR. The Ag2O sample was annealed in vacuum at 300°C for 30 min. This resulted in a surface primarily composed of Ag2O with a small amount of Ag metal present also. The anneal temperature is above that which results in the decomposition of AgO to A…
The effect of grain boundaries on the electrical resistivity of bulk nickel with a nanocrystalline structure has been investigated. For this study, nanocrystalline nickel was produced using a pulse plating technique that yields equiaxed nanostructures with negligible porosity. Using the four probe technique, resistivi…
Zinc aluminate (ZnAl4O4, also known as zinc aluminum oxide) is a material that has applications as a catalyst and catalyst support. This paper presents the XPS spectra of the major Zn, Al, and O photoelectron lines, and the major x-ray induced Zn LMM Auger lines for ZnAl2O4.
Densely packed monolayers of spherical polymer particles are expected to show interesting materials properties, e.g. a high permeability. It is demonstrated that relatively close‐packed Langmuir films of monodisperse 0.5 μm particles—with a hydrophilic shell and hydrophobic core—can be formed at the air‐water interfac…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLewis Acid-Assisted Anionic Ring-Opening Polymerization of Epoxide by the Aluminum Complexes of Porphyrin, Phthalocyanine, Tetraazaannulene, and Schiff Base as InitiatorsHiroshi Sugimoto, Chikara Kawamura, Masakatsu Kuroki, Takuzo Aida, and Shohei InoueCite this: Macromolecu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnsheathing a Polyoxometalate: Convenient Systematic Introduction of Organoimido Ligands at Terminal Oxo Sites in [Mo6O19]2-Joseph B. Strong, Robert Ostrander, Arnold L. Rheingold, and Eric A. MaattaCite this: J. Am. Chem. Soc. 1994, 116, 8, 3601–3602Publication Date (Print)…
For antitumor agents introduced directly into the intracranial space, the extent of penetration into tissue, and hence the effectiveness of therapy, depends on the rate of drug elimination from the tissue. To test the hypothesis that slowly eliminated agents would penetrate further through tissues, methotrexate (MTX)-…
ABSTRACT: Peroxy radicals, when generated in the presence of hindered-amine light stabilizers (HALS), oxidized HALS to produce nitroxides. This reaction, in addition to the scavenging of alkyl radicals by nitroxides, forms a cycle describing HALS as a class of excellent polymer stabilizers. As model systems for the me…
The lattice constants of diamond crystals consisting of an isotopic mixture of $^{13}\mathrm{C}_{\mathit{x}}^{12}$${\mathrm{C}}_{(1\mathrm{\ensuremath{-}}\mathit{x})}$ were measured as a function of the isotopic composition by single-crystal diffractometry using the synchrotron x-ray radiation. The isotope ratio of th…
Abstract Polyurethane foam formation involves both polymerization and expansion processes. The dynamics of the water and R‐11 blown foams depend on the rates of chemical and physical blowing processes, along with the rate of viscosity increase of the reacting mixture. Experiments were carried out to study the dynamics…
In this paper we report a time-resolved investigation of transients derived from curcumin, which may be intimately involved in the processes leading to its biological activity. Fluorescence and triplet quantum yields are respectively 0.06 and 0.11. The high percentage of internal conversion is proposed to proceed via…
Pressureless sintering of monolithic ceramics results in substantial shrinkage as the void space in the initially porous starting material is eliminated. Introduction of fibers or platelets inhibits sintering. Thus, when ceramic composites are made, processes other than sintering are used to achieve dense structures o…
Abstract Poly(propylene)s with narrow molecular weight distributions were prepared with various methylaluminoxane‐activated metallocene‐based Ziegler‐Natta catalysts to study the influence of randomly incorporated regio‐ and stereoirregularities on the crystallization behavior. As a function of the metallocene type an…
We describe here the experimental conditions under which the photoelectrochemical etching (PEC‐etching) of n‐type silicon in HF induces the formation of porous silicon. Two types of porous silicon are formed underneath an etch crater: a layer of nanoporous material with pores in the nanometer range on top of a macropo…
Pure Ta has been cold rolled and annealed at various temperatures. The crystallographic textures were studied by measuring X-ray pole figures and subsequently calculating the orientation distribution function. The microstructure was investigated via optical microscopy. The rolling textures were explained by dislocatio…