Search results for "Capacitance"
showing 10 items of 112 documents
Pressure sensor development based on Dielectric Electro Active Polymers
2012
The Dielectric Electro Active Polymer's (DEAP's) sensing capabilities is one of the main trio-characteristics of the material applicable area's, the trio-formations as applicable use are actuator, transducer and last but not least sensor. It is noted here that one of the main value propositions whenever DEAP material is used is the dual characteristics as the sensing/actuating capability.
A Comparative Performance Study of a 1200 V Si and SiC MOSFET Intrinsic Diode on an Induction Heating Inverter
2014
This paper presents a comparison of the behavior of the intrinsic diode of silicon (Si) and silicon carbide (SiC) MOSFETs. The study was done for 1200 V Si and SiC MOSFETs. The data sheet from manufacturers shows the characteristics of MOSFET' intrinsic diode when gate source voltage (VGS) is 0 V. There are applications where the MOSFET' intrinsic diode is used while VGS is different than 0 V. One of these applications is induction heating, where depending on the load and the regulation system, the diode can conduct a significant part of the inverter current. In most applications which use the MOSFET' intrinsic diode, the turn ON of the intrinsic diode happens at VGS = 0 V. After a blanking…
Performance of sensl C-Series SiPM with high photoelectron resolution at cryogenic temperatures
2016
The C-Series of silicon photomultipliers (SiPM) from SensL provides devices with a fast response and high performance at low cost. The device's ability to detect light at temperatures of liquid nitrogen (77K) and liquid helium (4 K) with high photoelectron resolution was demonstrated. Results include relative photon detection efficiency (PDE), gain, microcell capacitance, and cross-talk probability at different over-voltages, both at room and at cryogenic temperatures. At 77K the SiPM demonstrated significantly improved operating characteristics while at 4K the observed increase in break-down voltage, the reduction of PDE by a factor of 2-3, and the extensively dropped microcell capacitance…
Band unpinning and photovoltaic model for P3HT:PCBM organic bulk heterojunctions under illumination
2008
Capacitance analysis of P3HT:PCBM bulk heterojunction solar cells, in dark and under illumination, shows a linear Mott-Schottky characteristic at moderate reverse bias, indicating p-doping of the organic blend. The flatband potential under illumination is displaced negatively about 0.6 V with respect to dark conditions. A basic photovoltaic model is developed to explain this, in terms of electron transfer via surface states at the metal/organic interface. Surface states with a slow exchange kinetics, become charged under illumination, unpinning the band and decreasing the depletion layer at the electron extraction contact. This becomes a major factor limiting the performance of bulk heteroj…
Imaging of photonic nanopatterns by scanning near-field optical microscopy
2002
We define photonic nanopatterns of a sample as images recorded by scanning near-field optical microscopy with a locally excited electric dipole as a probe. This photonic nanopattern can be calculated by use of the Green’s dyadic technique. Here, we show that scanning near-field optical microscopy images of well-defined gold triangles taken with the tetrahedral tip as a probe show a close similarity to the photonic nanopattern of this nanostructure with an electric dipole at a distance of 15 nm to the sample and tilted 45° with respect to the scanning plane.
Noise and Microwave Properties of Set-Transistors
2002
Electron tunneling through a small tunnel junction with capacitance C 0 is suppressed by the so-called Coulomb blockade if the charging energy E c = e 2/2C∑ is larger than the thermal energy k B T 1. This effect is observed in a single electron tunneling transistor (SETT), which is a nano-meter size three-terminal device in which two leads connect to a small metallic island through two tunnel junctions. The excess charge on the island is regulated by the potential of the capacitively coupled gate electrode. The SETT is a very sensitive electrometer, noise levels of 10−5e/√Hz have been reached.2,3 A similar device, the electron pump, is made by connecting two or more islands in series throug…
Extended gate electrode arrays for extracellular signal recordings
2000
Abstract We have fabricated arrays of planar gold electrodes arranged in a matrix of 8×8 with active areas ranging from 6 to 30 μm in diameter. An electronic amplification circuitry based on commercial junction field-effect transistors was used where the gold sensor fields act as extended gate electrodes (EGE) of the transistors, which leads to a new approach for long-term extracellular recording systems in vitro. The high input resistance of the amplification circuitry allows the use of small planar bare gold electrodes without further modification which therefore extends the frequency range of the measuring set-up down to the DC-level. The performance of our recording system has been test…
Characterization of LiFePO4/C Composite Thin Films Using Electrochemical Impedance Spectroscopy
2012
The composite LiFePO4/C thin films were prepared on steel substrate by radio frequency (RF) magnetron sputtering. Electrochemical properties of the obtained thin films were investigated by cyclic voltammetry charge-discharge measurements and electrochemical impedance spectroscopy (EIS). The films annealed at 550 °C exhibited a couple of redox peaks at 3.45 V vs. Li/Li + characteristic for the electrochemical lithium insertion/extraction in LiFePO4. At low current rate such composite thin film showed a discharge capacity of over 110 mAh g -1 . The dependence of charge transfer resistance, double layer capacitance and lithium diffusion coefficients on applied electrode potential were calculat…
Small-pore driven high capacitance in a hierarchical carbon via carbonization of Ni-MOF-74 at low temperatures
2016
A hierarchical porous carbon prepared via direct carbonization of Ni-MOF-74 loaded with furfuryl alcohol at 450 °C displays high specific capacitance in comparison with other MOF-derived carbons as a result of the formation of micropores smaller than 1 nm.
Eddy covariance and sap flow measurement of energy and mass exchange of woody crops in a Mediterranean environment
2012
Evapotranspiration estimation by micrometeorological techniques through the assessment of mass and energy exchanges in the soil-plant-atmosphere continuum (SPAC) is a very active research area, involving both well-known and novel measurement techniques. A crucial aspect in validating experimental results is the integration of independent measurements of mass and energy exchanges in the SPAC. To this aim, the development and validation of an integrated approach in major tree crop species, involving different independent techniques, are presented. Eddy covariance estimates of ET fluxes were compared to up-scaled sap flow measurements in olive, orange and grapevine, three important Mediterrane…