Materials Literature
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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…
We investigate the electronic structure of Ca 1 − x Sr x VO 3 using photoemission spectroscopy. Core level spectra establish an electronic phase separation at the surface, leading to a distinctly different surface electronic structure compared to the bulk. Analysis of the photoemission spectra of this system allowed u…
Photostable quantum dot (QD)-glasses for use in optical devices can be prepared by solution-phase synthesis of the luminescent material followed by sol-gel processing, to embed the semiconductor particles in silica. Prevention of surface reactions that slowly quench the luminescence and degrade the QD is a key problem…
Coarse-grained molecular dynamics simulation of a bead–spring polymer model has been conducted for polymer melt confined between two solid walls. The wall effect was studied by changing the distance between the walls and the wall–polymer interaction. It was observed that the polymers near the walls are compressed towa…
When a Cu surface is exposed to a clean room ambient, a surface layer containing Cu2O, CuO, Cu(OH)2, and CuCO3 is formed. Thermal treatment in a vacuum combined with hydrogen plasma can remove this layer. Water and carbon dioxide desorb during the thermal treatment and the hydrogen plasma reduces the remaining Cu oxid…
Electrodes can impact the device performance of ferroelectric capacitors in several ways. The present controlled studies on Pb (Nb, Zr, Ti)O3 with Pt, (La, Sr)CoO3 and SrRuO3 is a clear demonstration of the role of electrodes in impacting the leakage current mechanism of the ferroelectric capacitors and their reliabil…