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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Development of Light Emitting Electroluminescent Device by Means of Material Printing / Development of Light Emitting Electroluminescent Device by Means of Material Printing

Hrabal, Michal January 2019 (has links)
Cílem této práce je vývoj světelného zdroje založeného na technologii tlustostěnného elektroluminiscenčního panelu napájeného střídavým napětím (ACPEL). V současné době se jedná se o jedinou technologii založenou na metodách materiálového tisku vhodnou pro přípravu velkoplošných, flexibilních a vzorovaných zdrojů světla. Důraz je v této práci kladen na představení, prozkoumání a odstranění typických problémů, které jsou spojovány s touto technologií. Tyto problémy jsou omezený odstín barvy emitovaného světla a dlouhodobá stabilita elektroluminiscenčního prvku, který je vystaven vlivům prostředí. Rešeršní část dizertační práce je zaměřena na představení a identifikaci depozičních technik, vhodných pro reprodukovatelnou přípravu ACPEL panelů. Dalším cílem je identifikace fyzikálních parametrů, vhodných pro charakterizaci velkoplošných zdrojů světla. Praktickým cílem práce je nalezení vhodné metodologie pro popis a charakterizaci panelů, jakožto plošných světelných zdrojů. Fotometrická veličina jas L a spotřeba elektrické energie P byly vyhodnoceny jako vhodné parametry, určující aplikaci ACPEL panelů. Na modrém panelu bylo dosaženo maximální hodnoty jasu L = 133 cd•m2 při napětí Upp = 500 V a frekvenci f = 1000 Hz. Hodnoty spotřeby elektrické energie, vztažené na jednotkovou plochu panelů zkoumaných v této práci, jsou (7±3) mW. Tyto dosažené hodnoty dělají ze světelných zdrojů založených na ACPEL technologii zajímavé kandidáty pro různé aplikace. Vlivu rostoucí amplitudy a frekvence budícího napětí na dlouhodobou stabilitu panelů je důležitým cílem této práce. Pro popis stability byly zavedeny parametry L50 and L75. Bylo zjištěno, že rostoucí frekvence budícího napětí zkracuje životnost panelů. Laminovaný panel napájený napětím s přibližně trojnásobně vyšší frekvencí vykazoval přibližně třetinové hodnoty parametrů L50 a L75. Nejvyšších hodnot stabilitních parametrů dosahoval panel enkapsulován mezi skleněné pláty – přibližně sedminásobnou hodnotu oproti laminovanému panelu s trojnásobnou frekvencí. Optimální stability panelů lze dosáhnout při nastavení frekvence v rozmezí 400–800 Hz a zapouzdřením mezi sklo. Úzká paleta odstínů barev emitovaného světla je jeden z typických problémů, který dále zkoumán v dizertační práci. Tato práce zkoumá nadějnou metodu, přídavek vhodného materiálu pro konverzi barvy (CCM). Nový derivát diketopyrrolopyrrolu (DPP), absorbující v modré oblasti, byl přidán k modrému fosforu a byl pozorován sedminásobný narůst hodnot absolutního spektrálního ozáření v oblasti vlnových délek odpovídajících maximální emisi CCM materiálu. Jednoduchost přípravy vyvinutých zdrojů světla spolu s velmi nízkou spotřebou a vysokou dobou života dělají z ACPEL panelů zajímavé kandidáty pro podsvícení prvků například v automobilovém průmyslu, pro dekorativní osvětlení, pro „branding“ – zvýraznění reklamních značek.
62

Využití moderních inteligentních elektroinstalací pro osvětlení budov / Use of modern inteligent wiring for building lighting

Hlinecký, Tomáš January 2009 (has links)
This diploma thesis concerns with problematic of modern intelligent wiring systems in buildings, meanwhile presents their advantages against old classical wiring systems. Also deals with utilization and properties of modern components for regulation, switching and light controlling. The first part deals with light sources and possible ways how to control the power of individual luminary sources. The second part discuss about utilization of radio-frequency systems in new buildings and also in reconstructions. In the next part is described a possibility of bus system for controlling building illumination scope with focusing to control system Nikobus. The last part is concerned on technical-economical evaluation of intelligent wiring systems by various manufacturers according to specific requirements.
63

Stanovení spotřeby elektrické energie pro veřejné osvětlení / Analysis of Electric Power Consumption of Public Lighting

Varmuža, Jan January 2011 (has links)
The thesis deals with analysis of the public lighting system from the point of view of light sources and luminaries. It focuses on the specifics of the lighting systems such as lighting for pedestrian crossings or decorative lighting. It analyzes the energy consumption depending on daylight and how it manifests a shift sunrise and sunset on the consumption of electricity. The work clarifies how the model can be simplified sunrise, sunset for the entire Czech Republic. Based on the distribution of municipalities with population over 10,000 and modeling of sunrise and sunset calculation is carried out power consumption of lighting systems and compared to the total consumption of the Czech Republic. Simplification is an estimate of the consumption of electricity to villages to 10 000 people on the basis of the estimate, the final consumption of electricity for public lighting for the entire Czech Republic.
64

Svítidla a aplikace s Power LED zdroji / Luminaires and Applications with Power LEDs

Vaňko, Adam January 2011 (has links)
Progress in development of modern LEDs, their long lifetime and high luminous efficacy predetermine them for usage in lighting systems. This master's thesis examines possibilities of application of LEDs in luminaires, parameters of diodes and problems, which can appear in construction of luminaire with LED lighting source. In the practical part of this thesis a luminaire is designed, capable of illuminating traffic signs, vertical surfaces, billboards and fasades. By standards required parameters of a lighting system and adaptability of application must be considered in complex predesign. Simulations of lighting scene, created in special computer software, measurements of optical point’s parameters and construction of real luminaire model using high quality CREE LEDs, are included in analysis of the problem. Parameters of the luminaire were proved by measurements of product’s attributes at light laboratory. There are also some suggestions for improvement and further development of the product.
65

Fotobiologická bezpečnost světelných zdrojů a osvětlovacích soustav / Photobiological safety of light sources and lighting systems

Štěpánek, Jaroslav January 2014 (has links)
The thesis deals with the problems of the photobiological lamp and lamps systems safety. It is divided into theoretical and practical parts. The theoretical part touches the basic knowledge concerning the eye and vision, eye and skin diseases caused by excessive exposure to non-ionizing radiation. And besides that there are described the sources of light causing the possible exposure and further more it includes the methodology of measurement and evaluation of photobiological safety. The practical part investigates a measurement of the spectrum of light sources. The measured data are evaluated according to the methods mentioned in the theoretical part.
66

Optimalizace uložení projektorové čočky / Placement Optimization of Projector Lens

Bezděk, Matěj January 2014 (has links)
This diploma thesis deals with the creation of engineering design of holder of projector lens. The thesis is created in cooperation with department of development in Varroc Lighting Systems, s.r.o. Initial part provides a brief description of the development of lighting technology used in car´s headlamps. The following part describes solutions currently used in clamping the lens in holder. The main part of the thesis focuses on the design of holder of projector lens itself. Projector lenses testing provide critical values of cohesive failure of the lens material, which cannot be exceed during the process of lens fitting and its subsequent clamping. In the final part the engineering design is verified and optimized using finite element analysis.
67

Using plasmonic nanostructures to control electrically excited light emission / Nanostructures plasmoniques pour le contrôle de l'émission de lumière excitée électriquement

Cao, Shuiyan 16 February 2018 (has links)
Dans cette thèse, nous utilisons différentes nanostructures plasmoniques pour contrôler l'émission de lumière excitée électriquement. Notre émission électrique provient d'une "nanosource STM" qui utilise le courant tunnel inélastique entre la pointe d'un microscope à effet tunnel (STM) et un échantillon métallique, pour exciter localement les plasmons polaritons de surface localisés et propagatifs. L’interaction de notre nanosource STM et d'une lentille plasmonique circulaire (une série de fentes concentriques gravées dans un film d'or épais) produit une microsource radialement polarisée de faible dispersion angulaire (≈ ± 4 °). L'influence des paramètres structuraux sur la propagation angulaire de la microsource résultante est également étudiée. En outre, une faible dispersion angulaire (<± 7 °) pour une grande plage de longueurs d'onde (650-850 nm) est obtenue. Ainsi, cette microsource électrique de lumière presque collimatée a une réponse spectrale large et est optimale sur une large plage d'énergie, en particulier en comparaison avec d'autres structures plasmoniques résonantes telles que les nanoantennes Yagi-Uda. L'interaction de notre nanosource STM et d'une lentille plasmonique elliptique (une seule fente elliptique gravée dans un film d'or épais) est également étudiée. Lorsque l'excitation STM est située au point focal de la lentille plasmonique elliptique, un faisceau lumineux directionnel à faible divergence est acquis. De plus, expérimentalement, nous trouvons qu'en changeant l'excentricité de la lentille plasmique elliptique, l'angle d'émission varie. On constate que plus l'excentricité de la lentille elliptique est grande, plus l'angle d'émission est élevé. Cette étude permet de mieux comprendre comment les nanostructures plasmoniques façonnent l'émission de lumière. L'interaction de SPP excités par STM et d'une structure de pile multicouche planaire plasmonique est également étudiée. Il est démontré qu'en utilisant l'excitation STM, nous pouvons sonder la structure de bande optique de la pile Au-SiO₂-Au. Nous trouvons que l'épaisseur du diélectrique joue un rôle important dans la modification du couplage entre les modes. Nous comparons également les résultats obtenus par excitation laser et STM de la même structure de pile. Les résultats indiquent que la technique STM est supérieure en sensibilité. Ces résultats mettent en évidence le potentiel de la STM en tant que technique de nanoscopie optique sensible pour sonder les bandes optiques des nanostructures plasmoniques. Enfin, l'interaction d'une nanosource STM et d'une plaque triangulaire individuelle est également étudiée. Nous trouvons que lorsque l'excitation STM est centrée sur la plaque triangulaire, il n'y a pas d'émission de lumière directionnelle. Cependant, lorsque la nanosource STM est située sur le bord du triangle, on obtient une émission de lumière directionnelle. Cette étude nous fournit une nouvelle voie pour atteindre l'émission de lumière directionnelle. Nous étudions également l'exploration du LDOS optique du triangle avec la nanosource STM. Ainsi, nos résultats montrent que la manipulation de la lumière est réalisée par des interactions SPP-matière. En utilisant des nanostructures plasmoniques, nous contrôlons la collimation, la polarisation et la direction de la lumière provenant de la nanosource STM. / In this thesis, we use different plasmonic nanostructures to control the emission of electrically-excited light. Our electrical emission is from an “STM-nanosource” which uses the inelastic tunnel current between the tip of a scanning tunneling microscope (STM) and a metallic sample, to locally excite both localized and propagating surface plasmon polaritons. The interaction of our STM-nanosource and a circular plasmonic lens (a series of concentric slits etched in a thick gold film) produces a radially polarized microsource of low angular spread (≈±4°). The influence of the structural parameters on the angular spread of the resulting microsource is also investigated. In addition, a low angular spread (<±7°) for a large wavelength range (650-850 nm) is achieved. Thus this electrically-driven microsource of nearly collimated light has a broad spectral response and is optimal over a wide energy range, especially in comparison with other resonant plasmonic structures such as Yagi-Uda nanoantennas. The interaction of our STM-nanosource and an elliptical plasmonic lens (a single elliptical slit etched in a thick gold film) is also studied. When the STM excitation is located at the focal point position of the elliptical plasmonic lens, a directional light beam of low angular spread is acquired. Moreover, in the experiment we find that by changing the eccentricity of the elliptical plasmonic lens, the emission angle is varied. It is found that the larger the eccentricity of the elliptical lens, the higher the emission angle. This study provides a better understanding of how plasmonic nanostructures shape the emission of light. The interaction of STM-excited SPPs and a planar plasmonic multi-layer stack structure is also investigated. It is demonstrated that using STM excitation we can probe the optical band structure of the Au-SiO₂-Au stack. We find that the thickness of the dielectric plays an important role in changing the coupling between the modes. We also compare the results obtained by both laser and STM excitation of the same stack structure. The results indicate that the STM technique is superior in sensitivity. These findings highlight the potential of the STM as a sensitive optical nanoscopic technique to probe the optical bands of plasmonic nanostructures. Finally, the interaction of an STM-nanosource and an individual triangular plate is also studied. We find that when the STM excitation is centered on the triangular plate, there is no directional light emission. However, when the STM-nanosource is located on the edge of the triangle, directional light emission is obtained. This study provides us a novel avenue to achieve directional light emission. We also study probing the optical LDOS of the triangle with the STM-nanosource. Thus, our results show that the manipulation of light is achieved through SPP-matter interactions. Using plasmonic nanostructures, we control the collimation, polarization, and direction of the light originating from the STM-nanosource.
68

Development of a method to overcome the power threshold during supercontinuum generation based on an Yb-doped photonic crystal fiber

Baselt, Tobias, Taudt, Christopher, Nelsen, Bryan, Lasagni, Andrés Fabián, Hartmann, Peter 16 September 2019 (has links)
Optical coherence tomography benefits from the high brightness and bandwidth, as well as the spatial coherence of supercontinuum (SC) sources. The increase of spectral power density (SPD) over conventional light sources leads to shorter measuring times and higher resolutions. For some applications, only a portion of the broad spectral range can be used. Therefore, an increase of the SPD in specific limited spectral regions would provide a clear advantage over spectral filtering. This study describes a method to increase the SPD of SC sources by amplifying the excitation wavelength inside of a nonlinear photonic crystal fiber (PCF). An ytterbium-doped PCF was manufactured by a nanopowder process and used in a fiber amplifier setup as the nonlinear fiber medium. The performance of the fiber was compared with a conventional PCF that possesses comparable parameters. Finally, the system as a whole was characterized in reference to common solid-state laser-based photonic SC light sources. An order-of-magnitude improvement of the power density was observed between the wavelengths from 1100 to 1350 nm.
69

Applications of X-ray Hydroxyl Radical Protein Footprinting

Asuru, Awuri P. January 2019 (has links)
No description available.
70

Tvorba znalostní databáze pro světelnou techniku s možností expertního zpracování dotazů / Creation of Knowledge Database for Lighting Technology with the Possibility of Expert Query Processing

Krbal, Michal January 2014 (has links)
This presented thesis is focused on the complex description of creation the database system for the lighting. The important static and dynamic parameters of light sources and luminaires are listed in the first part of thesis. These parameters are complemented by the measured values and their relationships. The next chapters of thesis are focused to description of obtained parameters, structural design, historical and expected development of individual representatives of light sources. In the following sections are described current state of used data formats of luminaires and the possibilities for describing of light sources. The database systems are created as a result of this thesis. These databases are used for collecting, sorting, searching and sophisticate comparison of the parameters of light sources and luminaires.

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