117,349 research outputs found
Temperature-dependent dielectric properties of a thermoplastic gelatin
No full textThe frequency and the temperature dependence of the dielectric properties of a thermoplastic gelatin based bio-material have been investigated. At lower frequencies the dielectric response is strongly affected by charge carrier accumulation at the electrodes which modifies the dominating hopping conduction mechanism. The variation of the ac conductivity with frequency obeys a Jonscher type power law except for a small deviation in the low frequency range due to the electrode polarization effect. The master curve of the ac conductivity data shows that the conductivity relaxation of the gelatin is temperature independent
New biodegradable nano-composites for transient electronics devices
No full textA comparison between transient energy storage systems based on a gelatin composite with graphene flakes and graphene oxide layers has been done. Energy storage devices, based on the proposed new materials have higher values of the surface capacitance than those measured for energy storage devices based on activated carbon. As evidenced, both the composites enable the realization of energy sources that can supply a stable bias voltage in time. The biopolymer acts both as solid electrolyte and as binder for holding together the filler and the water-glycerol molecules. In addition, the use of the graphene oxide as filler within the gelatin matrix leads to a major increase of the mechanical stability of the prepared blends
Epoxy/MWCNT Composite Based Temperature Sensor With Linear Characteristics
No full textAn ultra-low cost temperature sensor has been developed that uses as active sensing material an epoxy layer, mixed with a small concentration of multi-walled carbon nanotubes. A stable NTC characteristics has been measured during temperature cycling. Under Joule heating conditions, a linear current-temperature characteristics has been obtained
Measurement Setup for In-Situ Quantum Yield Characterization of Solar Cells during High Energy Particle Irradiation
No full textAn extremely simple on-line quantum yield measurement tool was developed, that permits to measure the photocurrent spectra of solar cells under harsh measurement conditions without the need of optical windows or moving parts. The small photocurrent, induced by the sequential illumination by a series of LEDs with different emission wavelengths, distributed within the responsivity range of the tested solar cell, is converted to a proportional frequency and then monitored using the audio-card of a personal computer and an appropriate Labview-based Software. Subsequently the quantum yield measurements were performed in-situ during the irradiation of a conventional crystalline Silicon solar cell with 1.7 MeV protons in the spectral range between 400 nm and 880 nm. In this case the complete photocurrent spectrum can been monitored continuously with good temporal resolution
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Anomalous photoresponse behaviour and reliability of InGaAs/InP based avalanche photodiodes
No full textApplication of epoxy/carbon nanotube composites as microwave absorber at frequencies up to 25 GHz
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