Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 45 for “"pyroelectric"”.
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Pyroelectric crystal-based X-ray diffractometer
We investigate the use of an Amptek Cool-X X-ray Generator for an instructional tool in the physics of x-rays, as well as a source for x-rays for crystal diffraction experiments. The x-ray source is a solid-state two-phase air-cooled source with a time-varying photon output. Two detectors are used …
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Power Converters for Piezoelectric and Pyroelectric Materials
… V to 1.5 kV, regulated output voltage is 5 V. Pyroelectric effect is a cross-coupling between thermal property and electrical property in some dielectrics. It is also reversible. The pyroelectric effect refers to the polarization change caused by temperature change, while the reversed …
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Compressive gait biometric with wireless distributed pyroelectric sensors
… of previously established centralized pyroelectric sensor system. Our final goal is to provide wireless distributed pyroelectric sensor nodes as an alternative to the centralized infrared video sensors, with lower cost, lower detectability, lower power consumption and computation, and …
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INFRARED PHASE-SHIFTING INTERFEROMETRY USING A PYROELECTRIC VIDICON
… and experimentally of the feasibility of using a pyroelectric vidicon for infrared phase-shifting interferometry, (2) the design and fabrication of a prototype next-generation optical shop infrared phase-shifting interferometric system, and (3) the definition and quantification of the fundamental …
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Secondary pyroelectric and electrocaloric effects in thin films
The pyroelectric and electrocaloric effect play an important role in many applications such as energy harvesting and solid-state cooling. This dissertation focuses on the characterization of the pyroelectric and electric coefficient in thin film using novel laser-based technique. The implementation …
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Nanometer-thick oxide films for pyroelectric energy conversion
Pyroelectric energy conversion utilizes the temperature dependence of spontaneous polarization in crystalline materials to convert waste heat into electricity. High-power-density thermal-to-electrical energy conversion is possible using pyroelectric thin films which allow fast thermal cycling and …
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Pyroelectric emission from PbZr20Ti80O3 emitter coupled on silicon heater
This thesis reports pyroelectric emission from high frequency epitaxial 60 nm thick PbZr20Ti80O3 (PZT) film emitters coupled on silicon heater. The silicon heater is designed for generating joule heating on heater regions using low dosage ion implantation, while bridging electric connection on leg …
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Dielectric and pyroelectric susceptibilities of epitaxial ferroelectric thin films
The dielectric and pyroelectric properties of ferroelectrics have been utilized extensively in a variety of applications such as memories, transducers, and sensors. Traditionally, such applications have utilized bulk or single crystal versions of ferroelectrics but modern electronic devices …
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Design of a Multiloop Pyroelectric Neutron Generator Control System
Pyroelectric neutron generators are compact, low power systems which may be capable of producing short intense pulses of neutrons from D-D fusion reactions. Initial analysis of pyrofusion dynamics has indicated the potential to manipulate the pulse characteristics through system control. This …
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New pyroelectric phenomena from graded ferroelectric barium strontium titanate thin films
… of graded ferroelectric thin films in uncooled pyroelectric detectors. We built a magnetron sputter system, and developed a method of deposited compositional graded ferroelectric thin films using rf magnetron sputtering, a silicon compatible thin film fabrication process. By obtaining giant …
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Preparation and Characterization of Ferroelectric Thin Films for Tunable and Pyroelectric Applications
… studied for their wide applications in pyroelectric detectors and tunable devices. In the present work, pulsed laser deposition (PLD) technique has been employed to deposit ferroelectric Ba(Ti0.85Sn0.15)O3 (BTS) thin films and heterostructures. BTS thin films have been successfully …
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Microstructure, Tunable and Pyroelectric Properties of Laser-Ablated Ba (Zr0.25 Ti0.75) O3 Thin Films
… in infrared sensors is based on the induced pyroelectric effect, while the use of ferroelectric thin films in tunable devices is to take advantage of the dependence of dielectric constant on applied electric field. This research focuses on studying the variations of microstructures and their …
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Development and characterization of a hydrogen peroxide sensor using catalase immobilized on a pyroelectric poly(vinylidene fluoride) film
… and results of a simple, inexpensive, rugged, pyroelectric heat-of-reaction detector that can be made in many configurations. The measured heat of reaction results from the reaction of a substrate on an enzyme. The enzyme is immobilized in a flow channel with a pyroelectric polymer film, …
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Responsive temperature and pressure sensor design for in-situ prosthesis monitoring applications based on the piezoelectric and pyroelectric effects in lead zirconate titanate
… the development of a sensor based on the pyroelectric and piezoelectric effects that can be used to measure both temperature and/or axial stress for specific use within a prosthetic socket, and more generally as a responsive temperature sensor capable of detecting high frequency skin …
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An Examination of the ThermopiezoelectricEffect in Piezoelectric Actuators Via Finite Elements
… fields have to be considered, including the pyroelectric (change in the electric potential due to the presence of a thermal field) and electrocaloric (change in the temperature when an electric field is applied) effects. This thesis presents an examination of how these coupled effects can …
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Effective properties of magneto-electro-elastic two-dimensional cellular solids
… elastic, piezoelectric, piezomagnetic, thermal, pyroelectric and pyromagnetic effective properties as a function of the relative density. Results obtained for purely elastic properties were compared with results from other studies and showed good agreement. Varying microstructures of the cellular …
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Graded ferroelectric devices: the dielectric analogues of semiconductor diode junctions
This study demonstrates that a new pyroelectric device can be created from ferroelectrics with gradient in composition, and that the field dependence of the observed hysteresis offset is as predicted from theory. Homogeneous thin films of BaxSr1-xTiO3 (x=0.7, 0.8, 0.9, and 1.0) were prepared by …
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Characterization of Novel Pyroelectrics
… due to a change of temperature is known as the pyroelectric effect and is restricted to crystalline, non-centrosymmetric and polar matter. Its main application is the utilization in infrared radiation sensors, but usage for waste heat energy harvesting or chemical catalysis is also possible. A …
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Microstructure and Electrical Properties of Mocvd-Derived Perovskite Lead Zirconium(x) Titanium(1-X) Oxygen(3) and Lead (Scandium Tantalum)(1-X) Titanium(x) Oxygen(3) Thin Films on Lanthanum Nickel Oxide Electrode-Buffered Silicon
… the current theories of relaxor ferroelectrics. Pyroelectric properties of the PSTT thin films were also demonstrated.
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New modalities of strain-based engineering of ferroelectrics: domain structure and properties of PbZr1-xTixO3 thin films
… ultimately the dielectric, ferroelectric, and pyroelectric responses of ferroelectric thin-films for a wide variety of applications including memories, transducers, energy harvesters, sensors, and many more. Traditionally, the ability to engineer materials using epitaxial strain has been …
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