Дисертації з теми "High energy deposition"
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Savoy, Steven Michael. "Molecular thin film/high temperature superconductor heterostructures : deposition, characterization and energy transfer /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Повний текст джерелаMcCrea, Ian William. "Radar observations of energy deposition and dissipation in the high-latitude ionosphere." Thesis, University of Leicester, 1989. http://hdl.handle.net/2381/35729.
Повний текст джерелаRohweder, Matthew Flynn. "A numerical investigation of flowfield modification in high-speed airbreathing inlets using energy deposition." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2010. http://scholarsmine.mst.edu/thesis/pdf/Rohweder_09007dcc80722a47.pdf.
Повний текст джерелаVita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed Jan. 5, 2010). Includes bibliographical references (p. 52-53).
Hansen, Steven Richard. "Vaporizing Foil Actuator Process Parameters: Input Characteristics, Energy Deposition, and Pressure Output." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1514997723443633.
Повний текст джерелаPoint, Guillaume. "Energy deposition in air from femtosecond laser filamentation for the control of high voltage spark discharges." Palaiseau, Ecole polytechnique, 2015. https://tel.archives-ouvertes.fr/tel-01202982/document.
Повний текст джерелаLaser filamentation is a spectacular optical propagation regime appearing for pulses of which peak power exceeds a few GW in air. Filament forms due to the optical Kerr effect, which tends to self-focus the beam until intensity reaches the medium ionization threshold by multiphoton absorption. A complex dynamic competition is then established between the Kerr effect on the one hand, and diffraction, nonlinear absorption and plasma defocusing effect on the other hand. This results in a reorganization of the beam profile, characterized by a thin (100 µm) and intense (10^18 W/m²) core able to propagate over a distance much longer than the Rayleigh length. When the initial pulse peak power largely exceeds filamentation threshold, several co-propagating filaments are formed in the same beam, with each of these multifilaments sharing physical properties of isolated single filaments. While propagating in air, filaments transfer a portion of the laser energy to the medium, mainly through Raman rotational excitation of air molecules, ionization and inverse Bremsstrahlung in the plasma. This energy is redistributed in one nanosecond and almost entirely converted into air molecule translational energy, that is heat. The medium reacts to this rapid heating by launching a cylindrical pressure wave that brings the system back to pressure equilibrium by ejecting matter from the center. This results in the formation of a hot underdense air channel, which slowly resorbs by diffusion at timescales > 1 ms. My work as a Ph. D. Student first focused on the study and the optimization of laser energy deposition in air by filamentation. Thus, I investigated the influence of laser parameters such as pulse energy, focusing strength or pulse duration on deposited energy. To this purpose, I used several complementary diagnostics: study of pressure waves using microphones, characterization of the filamentation plasma by means of spectroscopy and time resolved study of underdense air channels using interferometry. I demonstrated in the single filamentation regime that above a given pulse energy, energy deposition becomes so important that the medium generates a shock wave instead of a sound wave, and that underdense channels can last for more than 100 ms. I also studied and characterized the high energy multifilamentation regime, showing that moderately focusing the pulse leads to a reorganization of filaments in the focal zone, generating large structures with a resulting plasma ten times denser than filaments. Filamentation-induced hydrodynamic effects lead to a transient reduction of the air breakdown voltage along the path of the laser pulse, enabling one to trigger and guide electric discharges. The second part of my thesis focused on the study and the optimization of such guided discharges for the design of a radio-frequency plasma antenna, contactless high-voltage switches or a laser lightning rod. To this purpose I developed and built an interferometric plasma diagnostic, allowing to measure the lifetime of generated plasmas. I also contributed to the proof of principle for a filament induced plasma antenna emitting RF signal. Finally, I took part to prospective experimental studies for the development of a laser lightning rod
Van, Meveren Mayme Marie. "Graphene-Based ‘Hybrids’ as High-Performance Electrodes with Tailored Interfaces for Alternative Energy Applications: Synthesis, Structure and Electrochemical Properties." TopSCHOLAR®, 2017. https://digitalcommons.wku.edu/theses/2048.
Повний текст джерелаHe, Chao [Verfasser], Reinhart Akademischer Betreuer] Poprawe, and Thomas [Akademischer Betreuer] [Bergs. "High-precision and complex geometry helical drilling by adapted energy deposition / Chao He ; Reinhart Poprawe, Thomas Bergs." Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1233316028/34.
Повний текст джерелаMedvedev, Nikita A. [Verfasser], and Baerbel [Akademischer Betreuer] Rethfeld. "Excitation and relaxation of the electronic subsystem in solids after high energy deposition / Nikita Medvedev. Betreuer: Baerbel Rethfeld." Kaiserslautern : Universitätsbibliothek Kaiserslautern, 2011. http://d-nb.info/1015869106/34.
Повний текст джерелаEaton, Ammon Nephi. "Multi-Fidelity Model Predictive Control of Upstream Energy Production Processes." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6376.
Повний текст джерелаJones, Jessica C. "Atomic Layer Deposition of H-BN(0001) on Transition Metal Substrates, and In Situ XPS Study of Carbonate Removal from Lithium Garnet Surfaces." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1703333/.
Повний текст джерелаAl, Ibrahim Ali Abdullah H. "Development of CexSm1-xO2-δ as an Insulation Barrier via Chemical Deposition of Aerosol Nanoparticles for Applications for High Temperature Superconductor Power Cables in Sustainable and Renewable Energy". Thesis, Griffith University, 2016. http://hdl.handle.net/10072/365828.
Повний текст джерелаThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
Full Text
Boukezzata, Messaoud. "Mecanismes d'oxydation des si-lpcvd fortement dopes au bore." Toulouse 3, 1988. http://www.theses.fr/1988TOU30183.
Повний текст джерелаChen, Chun-Liang, and 陳俊良. "The Applications of Chemical Vapor Deposition Diamond Films for High Energy Radiation Dose Measurements." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/41172489947124753204.
Повний текст джерела國立清華大學
原子科學系
92
Recently, high energy radiation has been used for medical diagnosis and treatment, and the standard dosimetry is defined as air kerma and absorbed dose to water. Because human’s body contains 70% water, so it can be assumed that body is water equivalent. To measure the absorbed dose to water in medical radiation oncology, an ion chamber calibrated with colbat-60 irradiation is used together with a phantom to measure the electric charge after being exposed to high energy radiation, and then according to AAPM No.21 or No.51,the human’s body dose can be calculated. Many research workers have investigated the glow curve and dynamic of CVD diamond film fabricated with chemical vapour deposition methods(CVD method), and they have also used computer code for glow curve fitting and identification of the light source interference from radiation. In practice, the glow curve must be analyzed by computer, in order to obtain the dose. This work is to study CVD diamond as a tool for radiation dosimetry, and to find the reading modular similar to TLD which can then be used in laboratories. The main component of CVD diamond film is carbon, its atomic number is 6 which is close the mean atomic number of 7.4 for water, it can be used as a tissue equivalent material, and is convenient to measure absorbed dose to water. Results of experiment show that the difference between absolute dose measured and dose profile obtained is about ±10%. The CVD diamond is a practical material for high-energy radiation measurements.
Harari, Berkan. "Development of High Capacitance Films for Electrical Energy Storage Using Electrophoretic Deposition of BaTiO3 on Ultrasonically Etched Ni." Thesis, 2012. http://hdl.handle.net/1974/7590.
Повний текст джерелаThesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2012-10-12 00:54:53.915
Wei, Yiying. "Graphene and metal oxide nanomaterials for high-performance supercapacitors." Thesis, 2015. http://hdl.handle.net/10453/116211.
Повний текст джерелаEnergy storage systems (ESSs) play a critical role in plenty of applications including renewable energy systems, power systems for electric vehicles (EVs) and hybrid electric vehicles (HEVs), and electrical power grids for improving reliability and overall use of the entire system. Currently, there are several types ESSs dominated the energy storage. Each kind of ESSs has their own operation mechanism, energy efficiency, energy density, power density, cycle life, charge and discharge capability, cost efficiency, operating temperature. The common ESS is based on lead acid battery which stores electrical energy in the form of chemical energy. However, if the batteries are overdischarged or kept at a discharged state, its capability will be irreversibly undermined because the sulfate crystals become larger and more difficult to break up during recharge. Since the first NiCd battery was created by Waldemar Jungner in 1899, even though NiCd battery technologies have experienced a series of evolutionary developments, its demerits are obvious including 1) shorter life cycle; 2) memory effect; 3) toxicity of Cd; 4) lower energy density; and 5) limited negative temperature coefficient. Based on the development of NiCd battery technology, nickel metal hydride (NiMH) batteries was proposed by researchers which possess better performance than NiCd batteries in cycle life, energy density and charge&discharge rates. Lithium ion is the preferred chemistry, having a superior specific energy and power density to nickel metal hydride. More lithium per gram stored in the electrodes contributes to higher energy density and power density. In addition to chemical battery system, researchers recently proposed some new sorts of ESSs including flywheel, compressed air energy storage (CAES), superconductive magnetic energy storage (SMES), etc. All of them can provide super energy density and power density. But they are more or less blocked ether in complex mechanical construction or cooling device. Supercapacitor has emerged to be an exciting energy storage device, which is able to provide high specific power, charge and discharge up to million times, have long lifetime and broad range of working temperature. Even though supercapacitor has been widely seen as a promising energy storage candidate to replace the traditional chemical batteries, it also suffer its drawback that the low energy density (the energy stored in per unit of volume and weight), high equivalent series resistance (ESR) and its high cost associated with its performance. Therefore, this PHD thesis project aims to address these drawbacks of supercapacitor by designing different nanotechnologies and fabrication methods to synthesize advance materials with better performance than that of conventional supercapacitor. A Series of designed structures and materials were fabricated by designed methods. All the materials were also investigated by using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) observation techniques, Brunauer–Emmett–Teller (BET) surface area measurement and electrochemical testing. A facile and effective hydrothermal treatment that is able to control the condensation speeds of precursors in the solution along the <010>, <100> and <001> directions was designed to fabricate vanadium oxide nanoribbon used for the electrode of supercapacitor. It was achieved by controlling the hydrothermal reaction time and the weight ratio to synthesize the ultralong vanadium oxide nanoribbon with controlled width. It has high specific capacitance of 453 F g⁻¹ at the scam rate of 2 mV s⁻¹ in 2 M NaCl electrolyte, and it still maintained a high capacitance of 201 F g⁻¹ at a higher scan rate of 50 mV s⁻¹, attributing to the easy ion insertion and electronic transport along the a-b plane rather through the layers of the c-axis. Vanadium oxide nanotubes were synthesized by a revised hydrothermal treatment with high-speed stirring. The preparation involved dissolution of V₂O₅ into H₂O₂ and high-speed stirring (10000 r/min) with hexadecylamine. The product was characterized by scanning electron microscopy, transmission electron microscope, X-ray diffraction and thermogravimetric analysis. The electrochemical properties of the materials as electrodes for electrochemical capacitors were evaluated by cyclic voltammetry in a three electrode system consisting of a saturated calomel electrode as reference electrode, platinum as a counter electrode and the active materials as the working electrode. A high capacitance of 148.5 F g⁻¹ was obtained at a scan rate of 2 mV s⁻¹ in 2M KCl. The electrode maintained a high capacitance of 105 F g⁻¹ at a higher scan rate of 50 mV s⁻¹ in 2M KCl electrolyte. 3D mesoporous hybrid NiCo₂O₄@graphene nanoarchitectures were successfully synthesized by a combination of freeze drying and hydrothermal reaction. Field-emission scanning electron microscopy (FESEM) and TEM analyses revealed that NiCo₂O₄@graphene nanostructures consist of a hierarchical mesoporous sheet-on-sheet nanoarchitecture with a high specific surface area of 194 m² g⁻¹. Ultrathin NiCo₂O₄ nanosheets, with a thickness of a few nanometers and mesopores ranging from 2 to 5 nm, were wrapped in graphene nanosheets and formed hybrid nanoarchitectures. When applied as electrode materials in supercapacitors, hybrid NiCo₂O₄@graphene nanosheets exhibited a high capacitance of 778 F g⁻¹ at the current density of 1 A g⁻¹, and an excellent cycling performance extending to 10000 cycles at the high current density of 10 A g⁻¹. We also presented a rational, large-scale and general method, called controllable freeze casting (CFC), to fabricate a high-densely assembled and aligned free-standing NiCo₂O₄@graphene 3D foam by vacuum filtration and air compress pressure assembly method. In the designed method, the amount of water is controllable, therefore controlling the size and the shape of the ice when the material was introduced into freeze drying system, finally achieving controllable pore size and aligned structure. This free-standing foam retains the intrinsic properties of graphene sheet, such as high surface area and high electrical conductivity. In the foam, the graphene sheets build the high conductive skeletons. And the skeletons with high surface areas support the uniform distribution of NiCo₂O₄ nanoparticles on the graphene sheets. By controlling the amount of water in the precursor, it is possible to fabricate 3D NiCo₂O₄@graphene foams with a wide range of thickness and pore size. This dense NiCo₂O₄@graphene material exhibited a high capacitance of 790 F g⁻¹ at a current density of 2 A g⁻¹, and an excellent cycling performance at a high current density of 10 A g⁻¹. The compression test revealed that the 3D NiCo₂O₄@graphene foam exhibited strong mechanical property which is able to support 20,000 times its own weight without structure collapsing. The novel synthesis method of such 3D foam with excellent properties paves the way to explore the application of lamellar materials like graphene in a self-supporting, metal oxide deposition and 3D foam.
Brewer, Rhett Ty. "Quantitative Biaxial Texture Analysis with Reflection High-Energy Electron Diffraction for Ion Beam-Assisted Deposition of MgO and Heteroepitaxy of Perovskite Ferroelectrics." Thesis, 2004. https://thesis.library.caltech.edu/3160/1/ThesisFinalDefended.pdf.
Повний текст джерелаTo facilitate ferroelectric-based actuator integration with silicon electronics fabrication technology, we have developed a route to produce biaxially textured ferroelectrics on amorphous layers by using biaxially textured MgO templates.
Using a kinematical electron scattering model, we show that the RHEED pattern from a biaxially textured polycrystalline film can be calculated from an analytic solution to the electron scattering probability. We found that diffraction spot shapes are sensitive to out-of-plane orientation distributions and in-plane RHEED rocking curves are sensitive to the in-plane orientation distribution. Using information from the simulation, a RHEED-based experimental technique was developed for in situ measurement of MgO biaxial texture. The accuracy of this technique was confirmed by comparing RHEED measurements of in-plane and out-of-plane orientation distribution with synchrotron x-ray rocking curve measurements.
Biaxially textured MgO was grown on amorphous Si3N4 by ion beam-assisted deposition (IBAD). MgO was e-beam evaporated onto the amorphous substrate with a simultaneous 750-1200 eV Ar⁺ ion bombardment at 45° from normal incidence. We observed a previously unseen, dramatic texture evolution in IBAD MgO using transmission electron microscopy (TEM) and RHEED-based quantitative texture measurements of MgO. The first layers of IBAD MgO are diffraction amorphous until the film is about 3.5 nm thick. During the next 1 nm of additional growth, we observed rapid biaxial texture evolution. RHEED and TEM studies indicate that biaxially textured MgO film results from a solid phase crystallization of biaxially textured MgO crystals in an amorphous matrix.
Biaxially textured perovskite ferroelectrics were grown on biaxially textured MgO templates using sol-gel, metallorganic chemical vapor deposition (MOCVD), and molecular beam epitaxy (MBE). Through RHEED-based biaxial texture analysis we observed that the heteroepitaxial ferroelectric in-plane orientation distribution, deposited using ex situ techniques (not performed in the same high vacuum growth environment where the MgO was deposited), narrowed significantly with respect to the in-plane orientation distribution of its MgO template (from 11° to 6° FWHM). Evidence from cross section TEM and RHEED suggest that atmospheric moisture degrades the crystallinity of highly defective, misaligned MgO grains and that heteroepitaxially grown ferroelectrics preferentially nucleate on well-aligned grains and over grow misaligned regions of MgO.
Νικολάου, Νικόλαος. "Διατάξεις παγίδευσης φορτίου (Memories) με τη χρήση νέων υλικών υψηλής διηλεκτρικής σταθεράς". Thesis, 2014. http://hdl.handle.net/10889/8504.
Повний текст джерелаThis thesis studies the functionality of high-k oxides as blocking oxide layers in SONOS type charge-trap memory devices. The oxide materials that were examined were the HfO2, the ZrO2 and the Al2O3. All these blocking oxide layers were deposited by atomic layer deposition technique (ALD). The electrical performance of the trilayer stacks was examined using Pt-gate MOS-type capacitors. The properties of the memory structures were examined as a function of: (a) precursor chemistry of HfO2 and ZrO2 deposition, (b) the deposition oxidizing agent in the case of Al2O3 and (c) subsequent high temperature annealing steps. The HfO2 films were deposited on SiO2/Si3N4 bilayer stacks using: (a) hafnium alkylamide (TEMAH) and O3 at 275 oC, and (b) hafnium cyclopentadienyl (HfD-04) and O3 at 350 oC. Similarly the ZrO2 films were deposited by (a) zirconium alkylamide (TEMAZ) and O3 at 275 oC, and (b) zirconium cyclopentadienyl (ZrD-04) and O3 at 350 oC The structural characterization of the HfO2 showed that the crystallinity of the deposited high-k material depends on the precursor choice and the post deposition annealing step (600 °C, 2 min). On the contrary ZrO2 is deposited in a crystalline phase independent of the deposition conditions and the choice of the precursors. The electrical characterization of Si/SiO2/Si3N4/high-k/Pt capacitors showed that all fabricated structures operate well as memory elements, despite the absence of an energy barrier between the trapping layer and control oxide. The trapping efficiency and the performance of structures with HfO2 or ZrO2 blocking layers do not revealed a dependence upon the precursor chemistry. However, endurance testing using continuous write/erase pulses showed that both structures deposited by cyclopentadienyl precursors cannot sustain the resulting electrical stress. The Al2O3 layers were deposited using the TMA molecule while three different oxidizing agents were used: (a) H2O, (b) O3 and (c) oxygen plasma. Electrical testing of the resulting Pt-gate trilayer capacitors showed that in the deposited condition all three samples were characterized by gate electrode induced electron leakage currents in the negative bias regime, which completely masked the substrate hole injection effects. This effect limits the performance and the functionality of the memory stacks. After a high temperature annealing step (850 or 1050 oC, 15 min) this leakage current is reduced significantly and the stacks can function as memory elements. The results point to suggest that after annealing the best performance is exhibited by the TMA/H2O and TMA/Plasma O2 samples. The effect of gate induced electron leakage current is attributed to hydrogen related contamination, which has been verified by ToF-ERDA in depth profile measurements, at least for the case of TMA/H2O samples. The modification of the memory properties of the SiO2/Si3N4/Al2O3 stacks was also investigated using low energy and high fluence nitrogen implantation into Al2O3 layer. The concentration and the chemical bonding of the implanted nitrogen is a function of annealing temperature. The memory properties of the stack depend therefore on the chemical bonding and the concentration of the remaining nitrogen in the modified Al2O3. The high temperature annealing (1050 oC, 15 min) appears to provide the structures with improved memory properties in terms of retention and fast erase performance.
Niedermayer, Graeme. "Investigations of calorimeter clustering in ATLAS using machine learning." Thesis, 2017. https://dspace.library.uvic.ca//handle/1828/8970.
Повний текст джерелаGraduate