Global ETD Search
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Showing 1 to 20 of 28 for “"AC impedance"”.
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Analysis of Electrode Geometric Parameters on AC Impedance Response
<p>Electrochemical Impedance Spectroscopy (EIS) is a powerful and proven tool for analyzing AC impedance response. A conventional three electrode EIS method was used to perform the investigation in the present study. Saturated potassium chloride solution was used as the electrolyte, and three …
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Investigation on thermal conductivity and AC impedance of graphite suspension
… conductivity enhancement of our suspensions achieved record high thermal conductivity values in different base fluids including water, engine oil, and ethylene glycol. This thesis investigates the effect of graphite flake preparation methods such as microwave and ultrasonic on the thermal …
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Theoretical and experimental study of solid oxide fuel cell (SOFC) using impedance spectra
… Little is known about the complex interfacial electrochemistry and thermochemistry, and it is also difficult to diagnose problems and optimize cell performance. Therefore, physics-based models are needed to better understand the underlying mechanisms of SOFCs. This research work addressed …
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Power Electronics- based Photovoltaics Panel Fault Detection using Online Impedance Measurement Technique
… systems. PV researchers today explore factors such as reducing utility energy bills and CO2 emissions, grid voltage stability, peak demand shaving, supply of electric power off-grid areas, and many more. The technology discussed is easy to incorporate, requires no additional hardware, …
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Synthesis and Characterization of Polymer Composite Materials For Lithium Battery Cathodes and Capacitors
… dissertation discusses the synthesis and characterization of polymer composite materials used in lithium primary batteries and capacitors. The objective of the first part of the dissertation is to develop cathode materials based on silver vanadium oxide (SVO) coated with polypyrrole (PPy) …
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Properties and sensor performance of zinc oxide thin films
Reactively sputtered ZnO thin film gas sensors were fabricated onto Si wafers. The atmosphere dependent electrical response of the ZnO micro arrays was examined. The effects of processing conditions on the properties and sensor performance of ZnO films were investigated. Using AFM, SEM, XRD and …
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Design and Evaluation of a Photovoltaic Inverter with Grid-Tracking and Grid-Forming Controls
… applies the concept of a virtual-synchronous-machine- (VSM-) based control to a conventional 250-kW utility-scale photovoltaic (PV) inverter. VSM is a recently-developed control scheme which offers an alternative grid-synchronization method to the conventional grid-tracking control scheme, …
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Polymer Electrolytes For lontophoretic Drug Delivery
… in which the transport of ions of soluble salts across skin is facilitated by an externally applied potential difference. This technique is novel in providing an external stimulus to ionic drugs in their passage across a skin. Hence, a positively charged drug may be delivered across the skin, by …
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Transient and steady state electrochemical studies of transport dynamics and equilibria in thin polymer films containing redox centers
… (QPVP) modified electrodes in contact with potassium nitrate (KNO$\sb3$) solution. The goal was to intercompare the electron diffusion coefficient (D$\sb{\rm E}$) of the system obtained by transient and steady state electrochemical methods and to evaluate the effect of equilibrium …
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Preparation and Application of Conducting Polymer-Carbon Nanotube Composite.
… of the quinone/hydroquinone redox reaction. Voltammetry, bulk electrolysis with coulometry, AC impedance, and EQCM techniques have been used to elucidate the preparation, ion transport, and intermolecular interaction processes within these composites.</p>
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Structural Characterization of Sulfur-Based Monomolecular Thin Films: I. Langmuir-Blodgett Films Derived From Multisulfur Heterocycles. II. Second Harmonic Generation Studies of Alkanethiolates on Ag and Au
… (SHG) has been used as a very sensitive surface probe to study metal-electrolyte interfaces at potentials within the double layer charging region. In this work, the potential dependence of second harmonic (SH) signal from metal/thin film/electrolyte systems have been studied. Self-assembled …
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An electrochemical study on the ionic conductivity of ceramic electrolyte La1-2SrxCo3-yMyO3-sigma oxide and its Pd/Ag compsites
… conductivity, which was obtained by applying AC impedance method. Among these factors, temperature has the most significant impact on the ionic conductivity, for instance La0.2Sr0.8CoO3-d (LSCO) exhibits O2- conductivity of 2.56 A' 10-3 S/cm at 900A?C but of only 1.23 A' 10-7S/cm at 400A?C. …
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Synthesis and properties of some doped lithium transition-metal phosphates
… and Li₃V₂(PO₄)₃, were synthesised, characterised and evaluated as potential cathode materials for lithium secondary batteries. The materials were synthesized using mainly solid-state techniques. Structural characterisation was performed using powder XRD with Rietveld refinement and Raman …
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Studies of the corrosion of materials for bipolar plates in fuel cells
… of corrosion. The medium chosen was phosphoric acid pH 2 at 353 K and a potential of + 100 mV was considered in order to mimic the conditions at an oxygen cathode in a fuel cell. Stainless steel showed good corrosion resistance but was considered too expensive. Mild steel corroded rapidly and …
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The low-temperature formation of mixed-metal oxides
… in air at room temperature. X-ray powder diffraction data show that the formation of highly crystalline Li₂MoO₄ is largely complete after 10 min, and that this product crystallises with the phenacite structuretype. This structure is the same as that derived from an X-ray diffraction study of a …
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Erosion-corrosion mitigation using chemicals
… becoming a major mechanism of material attack. Its understanding, prediction and control are key challenges to sound facilities design. The use of carbon steel in conjunction with corrosion inhibitors in preventing erosioncorrosion has been observed as an economically viable solution for …
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Aqueous hydrogen sulphide corrosion of iron, iron/chromium and iron/nickle alloys.
Aqueous corrosion reactions, which are electrochemical, occur at the metal/liquid interphase. In anaerobic acidic environments the rate of corrosion is frequently controlled by a charge-transfer reaction rather than by the rate of diffusion of reactant to (or from) the interphase. These …
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DEVELOPMENT OF NANO-STRUCTURED METAL OXIDES/GRAPHENE FOR ENERGY APPLICATIONS
… using in operando high-energy x-ray diffraction (HEXRD) and in operando x-ray adsorption near edge spectroscopy (XANES). The HEXRD results clearly show that V2O5 undergoes phase transformations during the first Li+ ion intercalation (i.e. discharge) process. The analysis of the XANES data …
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DEVELOPMENT OF NANO-STRUCTURED METAL OXIDES/GRAPHENE FOR ENERGY APPLICATIONS
… using in operando high-energy x-ray diffraction (HEXRD) and in operando x-ray adsorption near edge spectroscopy (XANES). The HEXRD results clearly show that V2O5 undergoes phase transformations during the first Li+ ion intercalation (i.e. discharge) process. The analysis of the XANES data …
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Electro-chemo-mechanical Studies of Perovskite-Structured Mixed Ionic-Electronic Conducting SrSni-₁₋xFexO₃₋x/₂₊[epsilon]
… make solid oxide fuel cells (SOFCs) attractive. However, when operating at reduced temperatures, there is significant loss in efficiency, of which slow surface reaction kinetics at the cathode are most responsible. Previously, the mixed ionic and electronic conducting (MIEC) …
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