Electrochemical sensors for Volatile Organic Compound (VOCs) based on commercial YSZ layers were fabricated using Pt and SmFeO3 perovskite oxide as electrodes, both exposed to the same gas environment. Pt was sputtere...
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Metal inclusions in polymeric composites exhibit different fracture patterns under a process of calendering, i.e. cold rolling and folding. Combinations of NiTi and Ti inclusions were used in polypropylene, polycarbon...
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materials used in handheld consumer electronic devices (CEDs), such as cell phones or PDAs, create environmental risks both during procurement and disposal. The increasing global demand for CEDs and recent legislative...
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ISBN:
(纸本)0873396456
materials used in handheld consumer electronic devices (CEDs), such as cell phones or PDAs, create environmental risks both during procurement and disposal. The increasing global demand for CEDs and recent legislative pressure motivate our review of alternative materials that could make CEDs more environmentally friendly. Hazardous materials considered include brominated flame retardants, lead-based solders, hexavalent chromium, copper, and ceramic materials. We survey recent research in the development of environmentally benign replacement materials, provide a brief assessment of the potential environmental, industrial, and economic consequences of their substitution, and assess progress in their industrial application. Identifying appropriate environmentally benign replacement materials provides a starting point for developing environmentally friendly CED prototypes.
Impurities at heterointerfaces can alter the interfacial structure resulting in changes in physical, electrical and optical properties. We present a study of the interfacial roughness of GaAs/A1xGa1-xAs superlattices ...
Impurities at heterointerfaces can alter the interfacial structure resulting in changes in physical, electrical and optical properties. We present a study of the interfacial roughness of GaAs/A1xGa1-xAs superlattices which were grown using controlled addition of oxygen at the interface. The interfacial properties were characterized by x-ray diffraction. The morphology of the surface was determined by Atomic Force Microscopy (AFM). X-ray diffraction measurements, both θ-2θ and rocking curves, were used to analyze the correlated and uncorrelated component of the interfacial roughness. A strong difference in the interfacial roughness was observed depending on whether the intentional oxygen incorporation occurred at the GaAs-to-A1GaAs interface or at both interfaces. When oxygen is incorporated at both interfaces, the x- ray reflectivity of the superlattice is decreased considerably resulting from a much higher interfacial roughness. The substrate miscut has a significant effect on RMS roughness, correlated roughness and its correlation length when oxygen is incorporated at the GaAs-to-A1xGa1-xAs interface.
This work reports the synthesis of apatite-type lanthanum silicate powders with nominal composition La10Si6O27 by an innovative chemical route which combines co-precipitation and sol-gel approaches. The herein propose...
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The surface morphology and structure of AIN deposited by metal organic vapor phase epitaxy (MOVPE) on Si (111) at growth temperatures ranging from 825 to 1175°C was investigated. Transmission electron microscopy ...
The surface morphology and structure of AIN deposited by metal organic vapor phase epitaxy (MOVPE) on Si (111) at growth temperatures ranging from 825 to 1175°C was investigated. Transmission electron microscopy (TEM), reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), and secondary ion mass spectrometry (SIMS) techniques were used to study the resulting film structure. Growth at high temperatures but less than ≈1100°C, resulted in a wire texture with some degree of in-plane alignment with (0001)AIN //(111)si, <101¯0>AIN //<2¯11>si, and <112¯0>AIN. // <1¯10>si. Deposition at temperatures greater than 1100°C results in single crystal films consisting of domains 60 nm across with an aspect ratio near unity. Growth below 1100°C leads to degraded crystal quality with the grains developing random rotational misalignments around the AIN [0001] axis. Growth at lower temperatures produces islands elongated along the [112¯0] direction. At the growth temperature of 825°C, the aspect ratio of the islands increased to 3 and a width of 25 nm. Cross -sectional TEM reveals that these islands are faceted due to slow growth on the {11¯01} planes.
The microstructure of epitaxial InAs thin films grown by MOCVD on mask-patterned "LEO" (lateral epitaxial overgrowth) GaAs and on unpatterned GaAs substrates was studied using double-crystal x-ray diffractio...
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The microstructure of epitaxial InAs thin films grown by MOCVD on mask-patterned "LEO" (lateral epitaxial overgrowth) GaAs and on unpatterned GaAs substrates was studied using double-crystal x-ray diffraction, scanning electron microscopy and cross-sectional transmission electron microscopy. This paper describes the improvement in crystal quality (factor of 20 reduction in x-ray rocking curve width), the order of magnitude reduction in dislocation density, and the rearrangement of the remaining extended defects that were observed in the LEO material when compared to the film grown on the unpatterned wafer.
Electrochemical sensors for Volatile Organic Compound (VOCs) based on commercial YSZ layers were fabricated using Pt as reference electrode and SmFeO3 perovskite oxide as a sensing electrode, both exposed to the same ...
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Electrochemical sensors for Volatile Organic Compound (VOCs) based on commercial YSZ layers were fabricated using Pt as reference electrode and SmFeO3 perovskite oxide as a sensing electrode, both exposed to the same gas environment. Pt was sputtered on YSZ layers while SmFeO3 p-type semiconducting oxide was deposited by electrophoretic deposition (EPD). Nanometric SmFeO3 oxide powders were selected because they have already shown good sensing performance in semiconducting sensors for oxidizing gases such as NO2 and ozone, and reducing gases, such as VOCs. Potentiometric measurements were performed under exposure to different concentrations of VOCs such as: methyl ethyl ketone (MEK), ethanol (EtOH) and acetic acid (AA). The best gas sensing response was obtained at 400°C.
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