Dissertations / Theses on the topic '621.365.5'
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Leach, Mark. "A new method for holographic measurement of microwave antenna radiation patterns." Thesis, Northumbria University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416351.
Full textTalukdar, Sumanta. "Microstereolithography implemented via visible light digital holography." Thesis, University of Sussex, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404209.
Full textPayne, Doug. "Simulating perceived 3D images replayed by computer generated holograms." Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/355.
Full textKim, Jong Man. "Holographic optical elements recorded in silver halide sensitized gelatin." Thesis, De Montfort University, 2002. http://hdl.handle.net/2086/4128.
Full textDong, Hongpai. "Applications and developments of digital holography." Thesis, University of Aberdeen, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430382.
Full textDarakis, Emmanouil. "Advanced digital holographic data compression methods." Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438460.
Full textZhang, Yanfeng. "Diamond and GaN waveguides and microstructures for integrated quantum photonics." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=16937.
Full textAthanasiou, Giorgos S. "The fabrication of chalcogenide glass fibre photonic components." Thesis, University of Nottingham, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606721.
Full textMilosevic, Milan. "Silicon waveguide technology for emerging applications." Thesis, University of Surrey, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590803.
Full textTaylor, David Maurice. "Shallow Junction Single Photon Detection Technology for Quantum Information." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504229.
Full textPeruzzo, Alberto. "Quantum information science in integrated photonics technology." Thesis, University of Bristol, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.573139.
Full textGray, Stephen James. "Construction of DNA-based photonic wire assemblies by programmable polyamides." Thesis, University of Leicester, 2012. http://hdl.handle.net/2381/10810.
Full textGris, Sanchez Itandehui. "Fabrication and applications of low OH photonic crystal fibres." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577736.
Full textAndreakou, Peristera. "Hybrid nanomaterials for novel photonic devices." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/347152/.
Full textHueting, Nikolai Alexander. "Nanophotonic sensors based on 1D and 2D photonic crystals in gallium nitride." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.689692.
Full textLi, Hang. "Structural and optoelectronic properties of rare earth doped silicon photonic materials." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/structural-and-optoelectronic-properties-of-rare-earth-doped-silicon-photonic-materials(f877ad6a-2ea0-4ed6-b05c-defa12709f88).html.
Full textБілянін, Роман Володимирович. "Тепловий контроль технічного стану індукційних установок для виробництва мідної катанки." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41338.
Full textThe thesis for a Candidate of Engineering Sciences degree by specialty 05.11.13 – devices and methods of control and determination of composition of substances. – National technical university "Kharkov polytechnic institute", Kharkiv, 2019. The thesis solves the important scientific task to improve methods of control of the technical condition of induction installations for the production of high-quality copper rod using the mathematical modeling of electrothermal processes in copper melt and multi-layer thermal insulation, with taking into account its degradation and temperature distribution on the installation surface, which is essential for the development of cable industry. A new method of non-destructive control of the technical condition of induction installations for the production of copper rod for power cables of energy value is developed, in which in addition to measuring the reactive and active resistances of the inductor and the reduction of the water temperature in the cooling system, the degree of degradation of multilayer thermal insulation is additionally determined by comparing the calculated distribution of the current temperature in the volume of melt and insulation on a three-dimensional mathematical model of the installation with practical measurement of temperature in local areas (in the work they were 72) of the surface of the furnace casing. This makes it possible to more accurately predict the furnace's profile and to detect the modes of its operation in a timely manner close to the emergency. A new technical solution for improving the multilayer thermoinsulation of induction installations has been developed in order to reduce their energy consumption and increase the resource. It consists in applying instead of the third thermal insulation layer of light-weight brick of three layers: monolithic refractory concrete, lightweight brick and refractory paper, with the preservation of the overall thickness of the insulation. The implementa-tion of the developed lining structure improvement at PJSC " YUZHCABLE WORKS" in the UPCAST US20X-10 induction installation for copper rod in the cable industry in Ukraine has yielded positive results in a 20°C decrease in the temperature of the furnace casing, a reduction of 5-15% of the specific cost Electricity for 1 ton of production and improvement of quality of copper rod, by reducing the percentage of foreign impurities and ensuring copper content in it 99,99%.
Білянін, Роман Володимирович. "Тепловий контроль технічного стану індукційних установок для виробництва мідної катанки." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41340.
Full textThe thesis for a Candidate of Engineering Sciences degree by specialty 05.11.13 – devices and methods of control and determination of composition of substances. – National technical university "Kharkov polytechnic institute", Kharkiv, 2019. The thesis solves the important scientific task to improve methods of control of the technical condition of induction installations for the production of high-quality copper rod using the mathematical modeling of electrothermal processes in copper melt and multi-layer thermal insulation, with taking into account its degradation and temperature distribution on the installation surface, which is essential for the development of cable industry. A new method of non-destructive control of the technical condition of induction installations for the production of copper rod for power cables of energy value is developed, in which in addition to measuring the reactive and active resistances of the inductor and the reduction of the water temperature in the cooling system, the degree of degradation of multilayer thermal insulation is additionally determined by comparing the calculated distribution of the current temperature in the volume of melt and insulation on a three-dimensional mathematical model of the installation with practical measurement of temperature in local areas (in the work they were 72) of the surface of the furnace casing. This makes it possible to more accurately predict the furnace's profile and to detect the modes of its operation in a timely manner close to the emergency. A new technical solution for improving the multilayer thermoinsulation of induction installations has been developed in order to reduce their energy consumption and increase the resource. It consists in applying instead of the third thermal insulation layer of light-weight brick of three layers: monolithic refractory concrete, lightweight brick and refractory paper, with the preservation of the overall thickness of the insulation. The implementa-tion of the developed lining structure improvement at PJSC " YUZHCABLE WORKS" in the UPCAST US20X-10 induction installation for copper rod in the cable industry in Ukraine has yielded positive results in a 20°C decrease in the temperature of the furnace casing, a reduction of 5-15% of the specific cost Electricity for 1 ton of production and improvement of quality of copper rod, by reducing the percentage of foreign impurities and ensuring copper content in it 99,99%.
Head, Christopher Robin. "Optical trapping and optical sources for nanophotonics." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/359888/.
Full textDedman, Emma Ruth. "Characterisation of photonic crystals fabricated by holographic lithography." Thesis, University of Oxford, 2004. http://ora.ox.ac.uk/objects/uuid:35f8c1da-fca7-4086-aab3-fdda5ce346c6.
Full textMd, Zain Ahmad Rifqi. "One-dimensional photonic crystal / photonic wire cavities based on silicon-on-insulator (SOI)." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/996/.
Full textLeung, David. "Characterisation of silicon photonics devices." Thesis, City University London, 2013. http://openaccess.city.ac.uk/2135/.
Full textUthman, Muhammad. "Finite element characterisation of photonic crystal fibres." Thesis, City University London, 2013. http://openaccess.city.ac.uk/3012/.
Full textGenevrier, Kévin. "Sources laser de forte énergie à base d'YbCaF2." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLO006/document.
Full textThis PHD work is aiming at the development of a pump source for the nanosecond OPCPA of the 10 PW laser Apollon.First, we present the characteristics of the multipetawatt systems and the interest of OPCPA architecture for this type of systems. After detailing its characteristics, we then justify the choice of Yb:CaF2 as active media for the development of the nanosecond OPCPA pump source. We finally end the first chapter by the preliminary design of the pump source which is adapted to the specificities of the Yb:CaF2 crystal.The second chapter begins by the study of thermal lenses and thermal induced depolarization under high-power pumping in function of polarization or crystal orientation. The results allow us to validate the choice of [111] orientation for active media in the frame of high power laser systems. We then focus on ceramics because their mechanical isotropy appears to be interesting for high power systems. We study the ceramics made by wet route synthesis and highlight a strong heating, restricting their utilization. Several hypothesis are then investigated to explain this effect.In the last chapter we finished the design of the pump source with simulations of absorption, gain and energy extraction. We finally detailed the experimental results for two different architectures (regenerative and multipass), using Yb:CaF2 crystals in active mirror configuration
Li, Yan. "Digital holography and optical contouring." Thesis, Liverpool John Moores University, 2009. http://researchonline.ljmu.ac.uk/4539/.
Full textPan, Yi. "Terahertz time-domain spectroscopy and near-field imaging of microstructured waveguides." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607613.
Full textThomas-Peter, Nicholas. "Quantum enhanced precision measurement and information processing with integrated photonics." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:7bd47582-d32f-4d07-9e90-4978c32cf14e.
Full textMilicevic, Marijana. "Manipulation of Dirac Cones and Edge states in Polariton Honeycomb Lattices." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS515.
Full textExciton polaritons are mixed light-matter particles arising from strong coupling of quantum well excitons and cavity photons in semiconductor microcavities. They prove to be an extraordinary platform to emulate 1D and 2D Hamiltonians. This is due to the single site control when fabricating polariton lattices as well as to the possibility to directly visualize dispersion, spatial eigenfunctions and propagation of polaritons in photoluminescence experiments. By etching GaAs-based microcavity a honeycomb lattice for polaritons has been fabricated. The lowest two bands of this structure emulate for photons the π and π* bands of graphene. Remarkably, the system also permits exploring orbital degrees of freedom, inaccessible in actual graphene. In the first part of this thesis polariton emulator is used to address the physics of edge states in honeycomb lattice. New edge states, with flat and dispersive character have been discovered and visualised in orbital graphene. In the second part of the thesis we demonstrate experimentally a method to tailor the Dirac dispersion for photons. By implementing uni-axial strain in the honeycomb lattice Dirac photons that combine zero, finite and infinite effective masses are created. Presented results open new perspectives for the engineering of interfaces between various types of Dirac dispersions. Furthermore, the excitonic part of polaritons assures sensitivity to the magnetic field, creating the possibility to break the time reversal symmetry of the system and study photonic topological edge states in exotic Dirac cones. Finally, nonlinear Dirac physics can be probed in this system owing to polariton-polariton interactions
Грицан, Іван Іванович, and Ivan Hrytsan. "Розробка системи електротеплоакумуляційного обігріву навчального корпусу №5 ТНТУ ім. І. Пулюя." Bachelor's thesis, Тернопільський національний технічний університет імені Івана Пулюя, 2021. http://elartu.tntu.edu.ua/handle/lib/35524.
Full textМетою роботи є розробка системи електротеплоакумуляційного електрообігріву навчального корпусу для забезпечення споживачів теплом та гарячою водою. Основним технічним рішенням роботи є впровадження енергоефективного облад-нання, а також технологічні особливості роботи системи електротеплоакумуляційного обігріву навчального корпусу, яка буде працювати за диференційованими тарифами на електроенергію. Аналіз актуальності проблемної ситуації, полягає у вирішенні питання, що може суттєво розширити масштаби розповсюдження електрообігріву в Україні. Одним з перспективних шляхів підвищення енергоефективності електрообігріву є перехід до електротеплоакумуляційних технологій. Тобто, заміна традиційних котелень на електроопалювальні акумуляційні комплекси з переведенням їх у режим споживання електроенергії тільки вночі з багатотарифним обліком електроенергії є одним з найдоцільніших засобів підвищення енергоефективності.
The aim of the work is to develop a system of electro-heat-accumulating electric heating of the educational building to provide consumers with heat and hot water. The main technical solution is the introduction of energy-efficient equipment, as well as technological features of the electric heating system of the educational building, which will operate at differentiated tariffs for electricity. Analysis of the urgency of the problem situation is to address the issue, which can significantly expand the distribution of electric heating in Ukraine. One of the promising ways to increase the energy efficiency of electric heating is the transition to electro-heat storage technologies. That is, the replacement of traditional boilers with electric heating storage complexes with their transfer to the mode of electricity consumption only at night with multi-tariff metering of electricity is one of the most appropriate means of improving energy efficiency.
ПEPEЛIК УМOВНИХ CКOPOЧEНЬ 6 ВCТУП 7 1 AНAЛIТИЧНИЙ POЗДIЛ 9 1.1 Oцiнкa мoжливocтeй впpoвaджeння eлeктpoтeплoaкумуляцiйних тeхнoлoгiй в Укpaїнi 9 1.2 Пpoблeми eлeктpoaкумуляцiйнoгo oбiгpiву 17 1.3 Пocтaнoвкa зaдaчi дo пpoeктувaння 20 2 ПPOEКТНO-КOНCТPУКТOPCЬКИЙ POЗДIЛ 21 2.1 Тeплoтeхнiчнa чacтинa 21 2.2 Eлeктpoтeхнiчнa чacтинa 28 2.3 Виcнoвки дo poздiлу 2 35 3 POЗPAХУНКOВO-ДOCЛIДНИЦЬКИЙ POЗДIЛ 36 3.1 Poзpaхунoк тeплoтeхнiчних пoкaзникiв нaвчaльнoгo кopпуcу №5 36 3.2 Poзpaхунoк тeплoвих втpaт, тa тeплoвoї пoтужнocтi пpoeктoвaнoї кoтeльнi 43 3.3 Тeхнiкo-eкoнoмiчнi poзpaхунки зaпpoвaджeння cиcтeми oпaлeння нaвчaль нoгo кopпуcу №5 50 3.4 Виcнoвки дo poздiлу 3 53 4 БEЗПEКA ЖИТТЄДIЯЛЬНOCТI ТA OCНOВИ OХOPOНИ ПPAЦI 54 4.1 Пpaвилa бeзпeки пpи eкcплуaтaцiї eлeктpoтeплoaкумуляцiйних cиcтeм 54 4.2 Poзpaхунoк зaхиcнoгo зaнулeння cиcтeми eлeктpoтeплoaкумуляцiйнoгo oбiгpiву 55 4.3 Бeзпeкa пpи гaciннi eлeктpoуcтaнoвoк 59 ЗAГAЛЬНI ВИCНOВКИ 61 ПEPEЛIК ПOCИЛAНЬ 63
Иванов, Владимир Михайлович. "Усовершенствование высоковольтных импульсных трансформаторов с полупроводниковыми коммутаторами для электротехнологических установок." Thesis, НТУ "ХПИ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/18954.
Full textDissertation for competition a technical science candidate degree. Speciality 05.09.13. "High electric and magnetic field engineering". National Technical University "Kharkov Polytechnical Institute", Kharkov, 2015. In this work the scientific and practical problem of improvement of high-voltage pulsed transformers with using semiconductor switches for electrophysical plants has been solved which enabled to modernize existing and to create new electrotechnological plants that generate strong pulsed electric and magnetic fields. It was found that improvement of high-voltage transformers, which consist in that the parts of the secondary and primary windings are separated and placed not at one common core but at four crosswise situated parts of split core of magnetic circuit, enabled to reduce a resulting leakage inductance of the transformers. Using them in two-stage circuit of voltage pulse generator enabled to create a compact pulsed voltage source with pulse rise time 250 ns at a capacitive load about 1 nF and voltage of 1 MV. Accident-free rational operation modes of pulsed transformers with semiconductor switches in generators for creating PCD with high pulse repetition frequency have been investigated. For the first time in the factory conditions a plant on the basis of pulsed transformers with semiconductor switches in the circuit of the generator of voltage pulses for steam reforming of methane as part of coke-oven gas into synthesis gas with help of high-voltage pulsed volumetric discharges: corona and barrier discharge with nickel catalyst in the reactor, has been successfully test-operated.
Alem, Nour. "Développement de l'émetteur hyperfréquence d'un système Lidar-Radar pour des applications optiques marines." Thesis, Brest, 2019. http://www.theses.fr/2019BRES0013/document.
Full textThe Lidar Radar technique is commonly used for submerged target detection in shallow waters less than a few tens of meters. This technique is based on sending a modulated signal, associated with a bandpass filter around the modulation frequency after detection. This technique requires an intense blue-green optical signal modulated at radar frequencies. We present in this thesis new modulator architectures perfectly adapted to this technique. The first architecture consists of an external cavity with an intracavity SHG stage. This architecture is coupled to an infrared picosecond laser source (1064 nm). The results showed that this modulator makes it possible to generate a green signal (532 nm), intense (5 mJ) and stable in frequency. Thanks to the source used, the signal modulated at the output of the transmitter (laser source and modulator) lasts only a few nanoseconds. This makes it possible to use the "range-gating" method to precisely locate the target.Nevertheless, this device has the disadvantage of a fixed bandwidth. We have therefore developed a second architecture of the modulator, allowing to easily tune the bandwidth of the transmitted signal. This configuration is based on the polarimetric behavior of the optical components in order to change the bandwidth of the signal. We have shown that this modulator can deliver , an intense signal (up to 2.9 mJ), short (a few nanoseconds), at 532 nm, modulated at mirowave frequencies, stable in frequency and tunable in bandwidth
Іванов, Володимир Михайлович. "Удосконалення високовольтних імпульсних трансформаторів з напівпровідниковими комутаторами для електротехнологічних установок." Thesis, Стиль Издат, 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/18951.
Full textDissertation for competition a technical science candidate degree. Speciality 05.09.13. "High electric and magnetic field engineering". National Technical University "Kharkov Polytechnical Institute", Kharkov, 2015. In this work the scientific and practical problem of improvement of high-voltage pulsed transformers with using semiconductor switches for electrophysical plants has been solved which enabled to modernize existing and to create new electrotechnological plants that generate strong pulsed electric and magnetic fields. It was found that improvement of high-voltage transformers, which consist in that the parts of the secondary and primary windings are separated and placed not at one common core but at four crosswise situated parts of split core of magnetic circuit, enabled to reduce a resulting leakage inductance of the transformers. Using them in two-stage circuit of voltage pulse generator enabled to create a compact pulsed voltage source with pulse rise time 250 ns at a capacitive load about 1 nF and voltage of 1 MV. Accident-free rational operation modes of pulsed transformers with semiconductor switches in generators for creating PCD with high pulse repetition frequency have been investigated. For the first time in the factory conditions a plant on the basis of pulsed transformers with semiconductor switches in the circuit of the generator of voltage pulses for steam reforming of methane as part of coke-oven gas into synthesis gas with help of high-voltage pulsed volumetric discharges: corona and barrier discharge with nickel catalyst in the reactor, has been successfully test-operated.
Сокола, Дмитро Ярославович, and Dmytro Sokola. "Обгрунтування методу використання системи антиобледеніння антени." Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, 2020. http://elartu.tntu.edu.ua/handle/lib/33929.
Full textIn the master's thesis research of antenna anti-icing systems. The use and reliable operation of terrestrial infrastructure of data reception and transmission systems, which will be located around the globe, in different climatic zones, should be based on such principles as: reliability, innovation, thermal stabilization of systems, noise protection, electromagnetic compatibility, manufacturability, stability. At present, many satellite-based ground-based systems operate reliably, serving several thousand satellites in various Earth orbits, but the introduction of new high-speed data transmission technologies 4G, 5G and later 6G imposes additional requirements on manufacturers and operators, especially climatic and mechanical (wind load) aspects. Given the increase in various climatic cataclysms, it is necessary to ensure maximum thermal stabilization of the antenna system. Mirror parabolic antennas or their modifications are mainly used in such systems. There are international companies that deal with anti-icing systems for antennas. One of the disadvantages of such methods is that the systems are not universal and do not have the ability to thermostabilize individual components of the antenna system (reflector, irradiated, antenna-wave system, subreflector, amplifier, converter, rotary actuators for Az and El) as in negative - (0 - 45) ° C and at positive temperatures + (25 - 55) ° C, as well as during the daily variable temperature cycle, especially in the desert.
ВСТУП. РОЗДІЛ 1 АНАЛІТИЧНА ЧАСТИНА 1.1 Впливи обледеніння на конструкції антен 1.2 Види обмерзання антен 1.3 Топографічні впливи на конструкції антен.. 1.4 Теоретичне моделювання обледеніння 1.5 Інтенсивність осадження 1.6 Висновок до розділу 1. РОЗДІЛ 2 ОСНОВНА ЧАСТИНА. 2.1 Системи антиобледеніння серій IF-P. 2.2 Системи антиобледеніння серій IF-K 2.3 Системи антиобледеніння серій IF-С 2.4 Система антиобледеніння антенного поста 2,4 м 2.5 Пристрій протиобмерзання і термостабілізації антенних контрукцій…... 2.6 Висновки до розділу 2 РОЗДІЛ 3 НАУКОВО-ДОСЛІДНА ЧАСТИНА 3.1 Система антиобледенніння антен Environmenta Technology 3.2 Максимізація тривалості роботи супутникової мережі AdWavez Marketing 3.3 Усунення погіршення сигналу діапазону Ka 3.4 Висновки до розділу 3. РОЗДІЛ 4 ОХОРОНА ПРАЦІ БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ….. 4.1 Забезпечення безпеки життєдіяльності підприємств радіотехнічної галузі у воєнний час 4.2 Проведення державного нагляду за охороною праці. Види та основні параметри проведення наглядових заходів 4.3 Висновок до розділу ВИСНОВКИ СПИСОК ВИКОРИСТАНИХ ДЖЕРЕЛ.. ДОДАТКИ
Alhajj, Assaf Salim. "Innovative nanostructured textiles for thermal comfort." Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1I012.
Full textFor the past ten years, photonic nanostructures have represented a paradigm for the control of thermal radiations, offering a panel of exciting properties for energy applications. Because of their abilities to control and manage electromagnetic waves at the Mid-Infrared (Mid-IR) wavelength scale, photonic nanostructures demonstrate their ability to manage thermal radiations properties in a way drastically different from conventional thermal emitters. The fundamental advances in controlling thermal radiation led to different applications in the energy domain, as thermo photovoltaic devices or through the concept of daytime radiative cooling to passively decrease the temperature of terrestrial structures. Recently, another field of application has appeared in the thermal radiation control, with the introduction of photonic nanostructures in textiles for personal thermoregulation. The goal of the thesis is to study different passive photonic membranes that modulate the human body optical radiations in the Mid-IR for personal thermoregulation. We have investigated the optical properties of different polymer membranes, considering the effect of their structuration. We showed that a photonic crystal membrane is able to modulate the transmission coefficient by 28% in benefit or deficit of both the absorption and reflection. We analyzed the thermal balance between the human body and the indoor environment through the photonic membrane, considering the radiation, convection and conduction mechanisms. We found that the temperature of the skin is almost 2°C higher when the human body is clothed with a structured membrane. The study was carried out on analytical calculations and numerical simulation with the help of the finite element method (FEM). The numerical study was supported by experiments in fabrication in the IEMN cleaning room and in characterization by infrared spectroscopy (FTIR) at the HEI engineering school
Soun, Léna. "Exaltation d’effets non linéaires dans des métasurfaces à multi-résonances accordées." Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX066.
Full textNano-antennas are nanostructured componentscapable of concentrating light in subwavelengthvolumes, exalting the electric field by severalorders of magnitude. This is particularly interestingfor the generation of nonlinear effects, which dependon the powers of the incident electric field. Actually,the second order non-linear effects, which allowfrequency conversion phenomena, such as secondharmonic generation (SHG), or difference frequencygeneration (DFG), depend on the square of the electricfield. Thus, if we include a nonlinear crystal in anano-antenna, we can significantly enhance these effects.The objective of this thesis is thus to designnano-antennas that can efficiently generate secondorder nonlinear effects. Such devices could be appliedto the creation of new sources for infrared spectroscopy.The thesis work ranges from electromagnetic modellingof nonlinear effects in nanostructures to experimentaldemonstration. The modelling of nonlinear polarizationgenerated along the optical axis has beendeveloped using a B-Spline modal method for linearcalculations. This model has allowed to simulate thenonlinear effects related to this polarization, to refinethe understanding of physical phenomena in multiresonantnanostructures, and to optimize a structurewith an efficiency of 0.1W/W² in difference frequencygeneration in the infrared. The design of a sample allowedthe validation of the resonant properties, as wellas an experimental demonstration of second harmonicgeneration
James, Jemy. "Refractive index engineering using polymer nanocomposites Surface engineering of polystyrene–cerium oxide nanocomposite thin films for refractive index enhancement." Thesis, Lorient, 2019. http://www.theses.fr/2019LORIS552.
Full textHistorically, light was a centre of interest for numerous inquisitive people: the philosophers who were interested in its nature and the scientists who wanted to interpret its associated phenomena. Optics is playing a pivotal role in many of our day to day applications.The refractive index is one of the most significant parameters in photonics. An increase in the efficiency of the photonic devices, like Light Emitting Diodes, Solar Cells, etc., can be achieved by reducing the refractive index mismatch of materials used in the optical devices.This thesis throws some light into the tailoring the refractive index of materials, by giving detailed aspects of refractive index and engineering of the refractive index using polymer nanocomposite. This introductory chapter evolves into a wider discussion on the refractive index and the types of refractive index and the potential leverage that can be obtained by engineering the refractive index. Polymer thin films were prepared and the nanoparticles were introduced so as to modify the refractive index. Similarly, thick polymer films were prepared using PMMA and Polystyrene and these were utilized to optically and morphologically characterize the prepared samples. Multiple methods have been utilized to prepare the polymer films. Ultra thin polymer films were also prepared using the spin coating technique and later the thickness of the polystyrene film was changed so as to understand its impact on the refractive index. There were multiple challenges to overcome while carrying out the research like the preparation of ultra pure substrate, uniformity in the prepared polymer thin film, adherence of the polymer thin film on to the substrates after solvent casting etc. All the challenges were overcome using the innovations, which are detailed in the thesis
Addoum, Ahmad. "Caractérisation de tissus biologiques par diffusion de la lumière : application au diagnostic du cancer." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0013/document.
Full textDiffuse Optical Tomography (DOT) is a new medical imaging technique used to reconstruct the optical properties of biological tissues in order to detect cancerous tumors. However, this is an ill-posed and under-determined inverse problem. The work of this thesis deals with the resolution of this problem using the radiative transfer equation as a forward model of light propagation. The sensitivity analysis showed that the anisotropy factor g of the Henyey-Greenstein phase function is the most sensitive parameter of the forward model followed by the scattering coefficient µs and then the absorption coefficient µa. In a first step, a Gauss-Newton algorithm was implemented using the sensitivity functions. However, this algorithm allows to estimate a very limited number of the optical parameters (assumed to be constant in space). In a second step, a Quasi-Newton algorithm was developed to reconstruct the spatial distributions of the optical properties. The gradient of the objective function was efficiently computed by the adjoint method through the Lagrangian formalism with a Multi-frequency approach. The reconstructed images were obtained from simulated boundary data. The g factor was reconstructed as a new optical contrast agent in DOT and the crosstalk problem between this factor and µs has been studied. The results showed that the algorithm is efficient to reconstruct in 2D and 3D one or several tumor inclusions having different shapes. The quality of the reconstructed images was examined according to several parameters: the number of frequencies, the crosstalk, the contrast and the noise levels
Schoenauer, Mathilde. "Enhancing perovskite solar cells through upconversion nanoparticles insertion." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS369.
Full textRenewable energies represent nowadays one of the keys that can tackle at the same time energy supply needs and a sustainable environmental behavior. Photovoltaic devices convert the energy of sunlight into electricity, and solar energy remains one of the most common renewable energy sources. In the search for cost-effective solar cells, the recently discovered solution-processable hybrid organic-inorganic perovskites are considered as one of the most important candidates. They belong to the category of thin-film technologies and require much less and as abundant resource than Si. One limiting parameter of such photovoltaic devices is however the absorption of low-energy photons (wavelength over 800 nm, the near-infrared range). In order to address this specific loss of sub bandgap photons’ absorption, this PhD thesis aims to develop plasmonic-enhanced upconversion approaches to extend the spectral sensitivity of organo-metal halide perovskite solar cells to the near-IR spectrum. Near-infrared-to-visible up-conversion fluorescent materials can be used to widen the part of the spectrum used for electric current generation. Two low-energy photons are added up in order to give a higher energy photon. However, this effect has a rather small efficiency. This effect being quite inefficient, the idea is to combine those particles with metallic nanoparticles, that have the property to enhance electromagnetic field intensity at a certain wavelength (this is called plasmonic effect). By combining both types of particles, we thus enhance the activity of up-conversion materials (higher emission). Once implemented in a perovskite solar cell, this increases its efficiency
Боянівський, Владислав Петрович. "Підвищення ефективності печей для переплавки алюмінієвого брухту." Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/24376.
Full textMaster's dissertation on "Improving the efficiency of furnaces for aluminum scrap remelting": 104 p., 35 f., 12 tables, 4 applications, 15 sources. The object of the study is an oven for aluminum scrap remelting. The purpose of the work is to increase energy efficiency and improve the design of furnaces for aluminum scrap remelting. Analyzed the main ways of improving energy efficiency. Presented the results of calculations of the energy efficiency of a 6-ton capacity kiln with a capacity of 600 kW for the remelting of aluminum scrap. It is shown that due to reduction of the opening time of the firebox, the cost of the supplied heat in the furnace decreased by 45% and due to the change of the thermal insulation layers - by 21%. Selected gas-fired devices - burners type GPP-5 and the scheme of their placement in the side of the front wall of the furnace. The calculations of the energy and economic efficiency of the furnace conversion from the electric heating to the gas have been performed, while for the gas heating the costs of the supplied heat are reduced by 9 - 10% in comparison with the electric one. Calculations have shown that the use of gas heating compared to electric is economically more efficient, since the cost of natural gas in the melt cycle for a 600 kV upgraded furnace decreases by about 10%. Developed the furnace design with an inclined vault for which the average melting time decreases by 11% compared to the traditional one, and the efficiency increases by 7%. For utilization of flue gases heat was chosen one-sided-needle metal recuperator for heating of blown air with the area of the heating surface 12 m2. As a result of the installation of the recuperator, the temperature of the flue gases is reduced from 800 °C to 390 °C, while the ambient air temperature rises from 20 ° C to 350 C. The amount of fuel savings is 16.9 %. Based on the Solid Works software, constructed geometric models of the multilayer walls of the furnace and obtained the results of the distribution of temperature fields along the thickness of the enclosing structures. The presented results are comparable to the experimental data obtained on real furnaces. Made provision for safe and comfortable work in the premises of a research laboratory and fire and safety measures in emergencies. A startup project based on the Business Model Canvas template has been developed.
Магистерская диссертация на тему «Повышение эффективности печей для переплавки алюминиевого лома» 104 с., 35 рис., 12 табл., 4 приложения, 15 источников. Объект исследования - печь для переплавки алюминиевого лома. Цель работы - повышение энергетической эффективности и совершенствование конструкции печей для переплавки алюминиевого лома. Проанализированы основные способы повышения энергетической эффективности. Приведены результаты расчетов энергетической эффективности печи вместимостью 6 т, мощностью 600 кВт, для переплавки алюминиевого лома. Показано, что за счет уменьшения срока открытия форкамер снизились расходы подведенной теплоты в печи на 45%, а за счет изменения теплоизоляционных слоев - на 21%. Выбраны газосжигающие устройства - горелки типа ГПП-5 и приведена схема их размещения в боковой передней стенке печи. Выполнены расчеты энергетической и экономической эффективности перевода печи с электрического нагрева на газовый, при этом для газового нагрева расходы подведенной теплоты уменьшаются на 9 - 10% по сравнению с электрическим. Расчетами установлено, что использование газового нагрева по сравнению с электрическим экономически более эффективно, поскольку затраты на природный газ в цикле плавки для модернизированной печи мощностью 600 кВт уменьшаются примерно на 10%. Разработана конструкция печи с наклонным сводом, для которой по сравнению с традиционным уменьшается срок плавки в среднем на 11%, а КПД повышается на 7%. Для утилизации теплоты дымовых газов выбран односторонне-игольчатый металлический рекуператор для подогрева дутьевого воздуха с площадью поверхности нагрева 12 м2. В результате установки рекуператора температура дымовых газов снижается от 800 °С до 390 °С, при этом температура дутьевого воздуха повышается от 20 °С до 350 °С. Величина экономии топлива составляет 16,9%. На базе программного обеспечения Solid Works построены геометрические модели многослойных стенок печи и получены результаты распределения температурных полей по толщине ограждающих конструкций. Приведены результаты сопоставимы с экспериментальными данными полученными на реальных печах. Предусмотрены меры по безопасной и комфортной работе в помещении научно-исследовательской лаборатории. Разработан стартап-проект по шаблону Business Model Canvas.
Barbier, Margaux. "Génération de paires de photons corrélés par mélange à quatre ondes spontané dans des fibres microstructurées à coeur liquide." Thesis, Palaiseau, Institut d'optique théorique et appliquée, 2014. http://www.theses.fr/2014IOTA0011/document.
Full textQuantum telecommunication technologies rely on correlated photon pair sources, which are often based on the third-order nonlinear process of spontaneous four-wave mixing in silica-core photonic crystal fibres. A fibred architecture is advantageous because it minimizes the coupling losses between the optical source and the other components of quantum communication networks. Moreover, using a photonic crystal fibre rather than a conventional silica fibre offers the possibility of improving the photon generation (thanks to a small effective core area) and extending the wavelength coverage (thanks to dispersion management through the microstructuration design). However, the performances of silica-core photonic crystal fibre sources are limited in terms of quantum purity, because of the ubiquitous spontaneous Raman scattering process, which is a source of uncorrelated broadband noise photons in silica. We propose an original solution to this Raman problem by replacing the silica core by a liquid core, thanks to a hollow-core photonic crystal fibre filled with a nonlinear liquid. We actually performed the first experimental demonstration of the generation of correlated photon pairs in a liquid-core fibre, and demonstrated that, thanks to the specific Raman properties of liquids (which usually exhibit thin-line Raman spectra), it is possible to reduce the Raman noise level by several orders of magnitude. This work opens the way for the development of high quantum quality correlated photon pair fibred sources
Сімейко, Костянтин Віталійович. "Науково-технологічні основи високотемпературних процесів у електротермічному псевдозрідженому шарі." Diss., Інститут газу Національної Академії Наук України, 2021. https://ena.lpnu.ua/handle/ntb/56157.
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