Search results for "Wire"
showing 10 items of 1383 documents
Structural studies of nano/micrometric semiconducting GaInP wires grown by MOCVD
2004
Abstract 3D (Ga,In)/GaInP structures were grown on polycrystalline InP substrates by the MOCVD technique. The growth temperature was varied from 600 to 700 °C. Trimethyl-gallium and N 2 were, respectively, used as the Ga source and the carrier gas. These newly presented 3D structures have a scepter-like shape and are composed of a long GaInP internal support (rods of tens of μm long and tens of nm diameter) capped by a micrometer size metallic (Ga,In) structure. These structures were characterized by the SEM, EDX and TEM techniques. High-resolution TEM shows that the support rods present a GaInP single crystal structure. A preliminary discussion about the growth step mechanism, based on the…
Structural and electronic properties of InN nanowire network grown by vapor-liquid-solid method
2015
Growth of InN nanowires have been carried out on quartz substrates at different temperatures by vapor-liquid-solid (VLS) technique using different thicknesses of Au catalyst layer. It has been found that a narrow window of Au layer thickness and growth temperature leads to multi-nucleation, in which each site acts as the origin of several nanowires. In this multi-nucleation regime, several tens of micrometer long wires with diameter as small as 20 nm are found to grow along [ 11 2 ̄ 0 ] direction (a-plane) to form a dense network. Structural and electronic properties of these wires are studied. As grown nanowires show degenerate n-type behavior. Furthermore, x-ray photoemission study reveal…
Analysis of static friction and elastic forces in a nanowire bent on a flat surface: A comparative study
2014
ZnO nanowires bent to a complex shape and held in place by static friction force from supporting flat surface are investigated experimentally and theoretically. The complex shapes are obtained by bending the nanowires inside a scanning electron microscope with a sharp tip attached to a nanopositioner. Several methods previously described in the literature are applied along with author's original method to calculate the distributed friction force and stored elastic energy in the nanowires from the bending profile. This comparative study evidences the importance of the usage of appropriate models for accurate analysis of the nanowires profile. It is demonstrated that incomplete models can lea…
Wavelength multiplexed hydrogen sensor based on palladium-coated fibre-taper and Bragg grating
2004
A novel configuration of a wavelength multiplexed hydrogen sensor based on a palladium-coated tapered fibre and a fibre Bragg grating is presented. This scheme allows cascading several sensors along a single fibre, which increases the capability of implementing multipoint sensor networks for volumetric detection. Moreover, in this configuration the light interacts twice with the palladium layer, thus enhancing the sensitivity of the sensor.
CNT-based RFID passive gas sensor
2011
Summary form only given, as follows. Single-wall carbon nanotube (CNT) is examined for the design of a passive and maintenance-free wireless RFID sensor. CNT buckypaper is characterized from a dielectric and a sensitivity point of view, using an indirect way, by using antenna measurement and simulations in a controlled medium. A CNT-based prototype RFID tag is then described as the featured maintenance free sensor and experimentally verified for its applicability and sensitivity towards NH3.
Ultrasonic phased array inspection of wire plus arc additive manufacture samples using conventional and total focusing method imaging approaches
2019
In this study, three aluminium samples produced by wire + arc additive manufacture (WAAM) are inspected using ultrasonic phased array technology. Artificial defects are machined using a centre drill, ø 3 mm, and electrical discharge machining (EDM), ø 0.5-1 mm, in a cylindrical through-hole topology. The samples are first inspected using a single-element wheel probe mounted on a KUKA robot in order to investigate the feasibility of using a conventional ultrasonic transducer approach. Unfortunately, the wheel probe is found to be unsuitable for scanning the WAAM specimens and ultrasonic phased arrays are employed next. The set-up includes 5 MHz and 10 MHz arrays (128 elements) in direct cont…
Wireless partial discharge tracking on cross-linked polyethylene MV and HV cables
2018
Medium voltage (MV)/high voltage (HV) cable lines are high-value assets and require substantial costs for their installation or replacement. For this reason, the capability to assess the condition of cable lengths and accessories on site is of great importance. Cross-linked polyethylene (XLPE) insulation is extensively used for MV, HV, and extra-high voltage (EHV) class cables [1] thanks to its excellent voltage-endurance and thermomechanical properties. In particular, XLPE-insulated cables feature substantially lower losses, easier manufacturing and jointing procedures, better environmental compatibility, and higher operating temperature compared with impregnated paper cables, which lead t…
Gold Nanowired: A Linear (Au25)n Polymer from Au25 Molecular Clusters
2014
Au25(SR)18 has provided fundamental insights into the properties of clusters protected by monolayers of thiolated ligands (SR). Because of its ultrasmall core, 1 nm, Au25(SR)18 displays molecular behavior. We prepared a Au25 cluster capped by n-butanethiolates (SBu), obtained its structure by single-crystal X-ray crystallography, and studied its properties both experimentally and theoretically. Whereas in solution Au25(SBu)18(0) is a paramagnetic molecule, in the crystal it becomes a linear polymer of Au25 clusters connected via single Au-Au bonds and stabilized by proper orientation of clusters and interdigitation of ligands. At low temperature, [Au25(SBu)18(0)]n has a nonmagnetic ground s…
Colloidal lithography and Metal-Organic Chemical Vapor Deposition process integration to fabricate ZnO nanohole arrays
2010
A complete set up of optimal process conditions for an effective colloidal lithography/catalyst assisted MOCVD process integration is presented. It mainly focuses on the determination of the deposition temperature threshold for ZnO Metal-Organic Chemical Vapour Deposition (MOCVD) as well as the concentration of metal-organic silver (Ag) catalyst. Indeed, the optimization of such process parameters allows to tailor the ZnO film morphology in order to make the colloidal lithography/catalyst assisted MOCVD approach a valuable bottom up method to fabricate bi-dimensional ordered ZnO nanohole arrays. (C) 2010 Elsevier B.V. All rights reserved.
An Iterative Method for Bifurcation-Free Resonant Inductive Power Transfer System Design
2021
The development of electric mobility makes the charging systems one of the main discussed topic. Among the different technologies, Resonant Inductive Power Transfer (RIPT) systems are in deep study. Several aspects, including the choice of coils, the compensation network and the bifurcation phenomenon are necessary for a proper design of the system. In this paper an iterative method for bifurcation-free RIPT system design is provided as a valid solution to the need of accurate models requiring low computational efforts.