Materials Literature
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The dislocation structure of a typical low-angle boundary associated with a kink band in a sample of Ti3SiC2 deformed at room temperature was studied by high-resolution transmission electron microscopy. The boundary had both tilt and twist components. To account for both, the boundary was interpreted to be composed of…
Abstract In order to verify the possibility of manufacturing good quality articles by recycled polypropylene (PP), a study on the effect of many recycling operations on the rheological and mechanical properties of PP was conducted. The amount of degradation occurring during the reprocessing was estimated in the melt s…
The electrochemical behavior of chemically prepared α‐phase Al‐substituted was investigated in relation to its crystallinity. α‐Phase samples with 5–20% Al were prepared by precipitation, and the crystallinity was tailored by changing the metal/alkali ratio or the aging temperature. A highly crystallized sample was ob…
Diamond-like-carbon (DLC) thin films have been deposited at room temperature on Si substrates by ablation of a graphite target using a KrF excimer laser at intensities ranging from 0.9×108 W/cm2 to 6.0×109 W/cm2. The microstructure of the films was studied by x-ray photoelectron spectroscopy (XPS) and Raman spectrosco…
The octahydrochloride salt of octa(3-aminopropyl)octasilsesquioxane can be isolated in 30% yields by controlled hydrolytic condensation of 3-aminopropyltriethoxysilane in strongly acidic methanol. The analytically pure product can be filtered from the reaction solution. The product was characterized by standard analyt…
The separation of global and local motion for [Gd(DTPA−BA)−(CH2)n]x copolymers (see diagram) shows that, contrary to usual linear polymers, the global rotation can strongly contribute to proton relaxivity. The rate and mechanism of water exchange is not influenced by polymerization. The collective results for these th…
We have fabricated semiconducting oxide p-i-n diodes in order to explore minority carrier injection effects in oxide materials. The diodes comprised p -La 0.85 Sr 0.15 MnO 3 / i -SrTiO 3 / n -La 0.05 Sr 0.95 TiO 3 . All oxide layers were grown epitaxially by the eclipse pulsed laser deposition method on (100) SrTiO 3…
Titanium silicon carbide (Ti3SiC2) is a damage tolerance material that is expected to be used in a number of high temperature applications. In this work, the microstructure and damage tolerance mechanism of Ti3SiC2 was investigated. The result demonstrated that the Ti3SiC2 ceramics prepared by the in-situ hot pressing…
We have developed a high energy resolution electron energy-loss spectroscopy (EELS) microscope, which can take spectra from specified small specimen areas and specified small reciprocal space areas to investigate detailed electronic structures. The EELS microscope is equipped with retarding Wien filters as the monochr…
The concept of the inductive effect is defined in terms of thermodynamics and its quantitative estimation is reviewed. The electrostatic (through-space) and sigma-inductive (through-bond) theories are confronted and experimental proofs evaluated, with the result that both theories are very approximate and neither is i…
Novel silane based metal pretreatments have been developed as cost effective alternatives to the chromating process. The new process is a simple solution dip process, is non-carcinogenic, and has outperformed chromated systems under different test conditions. The system provides superior corrosion and adhesion per for…
Zinc-meso-tetrasulfonatophenyl-porphyrin (ZnTPPS 4- ) spontaneously forms a complex with methyl viologen (MV 2+ ) in aqueous solutions. Both the free porphyrin and its complex with viologen were studied by pump−probe spectroscopy. Excitation in the porphyrin Soret band with a short laser pulse (fwhm = 200 fs) populate…
To understand the complex mechanisms of reaction, solvation, and diffusion that determine the chemistry of silica in solution, it is necessary to study first the silicate clusters that participate in these processes. We have investigated, by ab initio density functional methods, all silica-based clusters of the form S…
This study compared surface characteristics and dissolution behavior of well-crystallized (KGa-1b) and poorly crystallized (KGa-2) kaolinite standards. Atomic force microscopy (AFM) revealed that particles of KGa-1b generally have nicely hexagonal micromorphology and crystallographically controlled microtopographic fe…
A binary poly(L-lactide)/poly(ε-caprolactone) (PLLA/PCL) (70/30 w/w) blend and a ternary PLLA/PCL/PLLA-PCL-PLLA blend of the same composition which contains 4 wt.-% of a triblock PLLA-PCL-PLLA copolyester as compatibilizing agent were prepared by melt mixing at 200°C. Investigation of the thermal and mechanical proper…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesis and Characterization of Stable Stoichiometric Clathrates of Silicon and Germanium: Cs8Na16Si136 and Cs8Na16Ge136Svilen Bobev and Slavi C. SevovView Author Information Department of Chemistry and Biochemistry University of Notre Dame, Notre Dame, Indiana 46556…
A vertex-sharing double square pyramid of cobalt(II) ions (see picture) is present in the nonanuclear complex 1, obtained by treating cobalt acetate with 0.5 equivalents of (py2)CO. The corresponding 1:1 reaction gave 2, which has a central core with a cubane structure. py=pyridine.
A simple method of producing aligned carbon nanotube films and a mechanism for their formation are described. The alignment method is based on the self-organization by surface decomposition of a SiC wafer in a vacuum at a temperature between 1500 and 1700°C. From the results of cross-sectional observations by high-res…
The adsorption of benzotriazole (BTAH) on copper in aqueous electrolytes is examined by means of a vibrational analysis utilizing surface-enhanced Raman spectroscopy (SERS) as a function of solvent deuteration, pH, and electrode potential in order to examine adsorbate speciation, surface bonding, and the potential-dep…
OBJECTIVE: Currently used valve substitutes for valve replacement have certain disadvantages that limit their long-term benefits such as poor durability, risks of infection, thromboembolism or rejection. A tissue engineered autologous valve composed of living tissue is expected to overcome these shortcomings with natu…