Materials Literature
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Alumina specimens with small amounts of CaO and TiO 2 were prepared and their microstructural evolution during sintering was investigated. Because of the appearance of a liquid phase during sintering, a duplex microstructure of a few abnormal grains and fine matrix grains was obtained when the CaO + TiO 2 content was…
Abstract Recent results are presented demonstrating the application of cross‐sectional analytical transmission electron microscopy (ATEM) to corrosion and cracking in high‐temperature water environments. Microstructural, chemical and crystallographic characterization of buried interfaces at near‐atomic resolutions is…
The magnetic and structural properties of FeCoB thin films as a function of boron content have been investigated for applications requiring soft, high moment materials. The films were either co-sputtered from separate FeCo-35 and B targets or from a (Fe/sub 65/Co/sub 35/)/sub 90/B/sub 10/ alloy target. A peak in the c…
Successful net‐shape sintering offers a significant advantage for producing large or complicated products. Porous Si 3 N 4 ceramics with very low shrinkage were developed, in the present investigation, by the addition of a small amount of carbon. Carbon powders (1–5 vol%) of two types, with different mean particle siz…
The intercalation of a cationic azobenzene derivative into the interlayer space of magadiite has been achieved. The spectral properties as well as the X-ray diffraction results reveal that the adsorbed azo cations form head-to-head aggregates in the interlayer space. The basal spacing of the intercalation compound cha…
Developing cotton (Gossypium hirsutum) fibers, cultured in vitro with their associated ovules, were used to compare the effects of two herbicides that inhibit cellulose synthesis: 2,6-dichlorobenzonitrile (DCB) and an experimental thiatriazine-based herbicide, CGA 325'615. CGA 325'615 in nanomolar concentrations or DC…
Spark plasma sintering (SPS) was applied for preparing dense Ca2.75Gd0.25Co4O9 ceramics, and their thermoelectric properties were investigated from room temperature to 700 °C in air. The SPS process was effective in obtaining dense Ca2.75Gd0.25Co4O9 ceramics, typically 98% of the theoretical x-ray density, with lower…
We consider a model for phase separation of a multi-component alloy with non-smooth free energy and a degenerate mobility matrix. In addition to showing well-posedness and stability bounds for our approximation, we prove convergence in one space dimension. Furthermore an iterative scheme for solving the resulting nonl…
Based on the processing strategy of improving the mechanical properties of liquid‐phase‐sintered materials by modifying the secondary phase chemistry, four rare‐earth oxides (RE 2 O 3 , RE = La, Nd, Y, and Yb), in combination with alumina, were used as sintering aids for a submicrometer‐size β‐SiC powder. Doped with 5…
In this work we investigated the influence of formamide on the acid-catalyzed sol-gel process by Fourier transform infrared spectroscopy (FTIR). Three silica sols were studied: Sol catalyzed with nitric acid without formamide, sol catalyzed with nitric acid containing formamide and sol catalyzed with a mixture of nitr…
Inrush currents are frequently encountered during the switching process of transformers. The purpose of this paper is to present an investigation of forces that appear as a result of inrush currents. While both short circuit and inrush transformer situations might seem identical, they vary significantly from the core…
Cobalt–nickel oxide films of nominal 100 nm thickness, and resistivity on the order of 10−2 Ω cm have been deposited by spin casting from both aqueous and organic precursor solutions followed by annealing at 450 °C in air. Films deposited on sapphire substrates exhibit a refractive index of about 1.7 and are relativel…
The synthesis of ultrafine cerium dioxide (CeO 2 ) powders via mechanochemical reaction and subsequent calcination was studied. Anhydrous CeCl 3 and NaOH powders, along with NaCl diluent, were mechanically milled. A solid‐state displacement reaction—CeCl 3 + 3NaOH → Ce(OH) 3 + 3NaCl—was induced during milling in a ste…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSurface-Initiated Polymerization of l-Lactide: Coating of Solid Substrates with a Biodegradable PolymerInsung S. Choi and Robert LangerView Author Information Department of Chemical Engineering, Massachusetts Institute of Technology…
Noise suppression in downsized circuits utilizing magnetic granular films is demonstrated. Films of Fe-Al-O with thickness of 2 /spl mu/m which exhibit very high /spl mu/" dispersion in the quasimicrowave band were found to work as noise suppressors. The films were attached onto a micro-strip line and the transmission…
Full atomistic molecular dynamics (MD) simulations on five polymers with different chain backbone (C—C, Si—O, and C—O) and different side groups (—H, one —CH3, and two —CH3) are performed to study the effects of chain flexibility and side groups on the glass transition of polymers. Molecular dynamics simulations of NP…
Poly(L-lactide) (PLLA) films having different crystallinities (Xc's) and crystalline thicknesses (Lc's) were prepared by annealing at different temperatures (Ta's) from the melt and their high-temperature hydrolysis was investigated at 97°C in phosphate-buffered solution. The changes in remaining weight, molecular wei…
Polymacromonomers with a main chain much larger than the side-chain length adopt the form of cylindrical brush polymers the contour length per main-chain monomer of which depends on the side-chain length. In the present investigation it is demonstrated that the length per monomer also depends on the solvent quality, i…
The synthesis, processing, and electrical properties of SrZrO 3 and SrTiO 3 materials have been examined. Phase‐pure powders of SrZrO 3 and SrTiO 3 materials were synthesized using the Pechini method. Powder processing routes that used water and 2‐propanol as carrier fluids were developed to achieve high green densiti…
Here we report the first synthesis of a forsterite (Mg 2 SiO 4 ) composition glass as an essentially phase‐pure bulk material. Under containerless conditions, with heterogeneous nucleation sites minimized, glass forms by cooling ca. 1 mm liquid Mg 2 SiO 4 droplets in oxygen at 700 K/s. 29 Si NMR spectroscopic data ind…