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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.
111

Design of a full-sized NFC Desktop Keyboard for Smart Devices

Castrup, Stefan January 2015 (has links)
The master´s thesis project was performed in collaboration with the design and engineering company Eker Design from Fredrikstad in Norway, who is designing and developing flip cover NFC keyboards for smartphones. The new product idea is the full-sized NFC desktop keyboard for public institutions to offer to pupils, students or business people for instance. The thesis project is examining how such a product can be designed and should be designed in order to fit into its market and environment to meet the target group´s interest in order to be successful. With a human-centered design approach the project work was starting by the user and the market. The work consisted of analyzing and emphasizing with the market which mainly included the users, the competitors and the trends within a market analysis and a survey research. From the findings and insights of the research phase a design strategy and a business model for the new keyboard was created and communicated via a design brief. Different ideas and concepts were created, tested and presented via concept sketches along with mock-ups. The final concepts were evaluated via a concept evaluation in relation to the requirements of the business and user value. The final concept was developed and designed via the CAD software SolidWorks and the rendering software Keyshot. The design and development phase was focusing on functionality, usability, materials, surfaces, textures and the mechanical and technical solutions for the design. The result of this thesis project is named TRANSIT and is presenting how a collapsible desktop keyboard which is offering a NFC connection could look like and work to offer to people in public places such as libraries or universities and be as well be suitable for people to use at home. The TRANSIT keyboard is a simple and robust concept of a full-sized tactile keyboard which is offering a NFC connection as well as a Bluetooth connection for devices which do not support NFC yet. The design is aimed for smartphones and tablets and is offering a support which consists of an automated stand and a back plate which angle is adjustable step-less. The design allows to collapse stand, keyboard and back plate into a compact package which makes it easy to store and transport. Furthermore the design is providing a charging option for the smart device via energy harvesting or cable and has therefore internal batteries.   The project is ending with the final presentation of the physical model in scale 1:1. / Detta examensarbete genomfördes i samarbete med design och ingenjörsföretaget Eker design från Fredriksstad i Norge, som designar och utvecklar flipcover NFC tangentbord till smartphones. Den nya produktidén är ett fullstort stationärt NFC tangentbord för offentliga institutioner, tänkt att användas av till exempel elever, studenter eller affärsmänniskor. Detta examensarbete undersöker hur ovan nämnda produkt kan och bör designas för att passa dess målmarknad och möta målgruppens intresse för att bli framgångsrik. Med en Human-centered design approach, började projektet med att utgå från användaren och marknaden. Arbetet bestod i att analysera och empatisera med marknaden som huvudsakligen bestod av användare och konkurrenterna, samt att undersöka trender genom en marknadsundersökning. Med utgångspunkt från de insikter som uppkom genom projektets utforskningsfas, skapades en design strategi och en affärsmodell för det nya tangentbordet i form av en design brief. Olika idéer och koncept skapades, testades och presenterades via koncept skisser och mock-ups. Det slutgiltiga konceptet utvecklades och designades med hjälp av CAD programvaran SolidWorks och renderingsprogrammet Keyshot. Design och utvecklingsfasen fokuserade på funktionalitet, användbarhet, material, ytor, texturer och mekaniska och tekniska lösningar för designen. Den slutgiltiga produkten heter TRANSIT och visar på hur ett hopfällbart stationärt tangentbord som erbjuder en NFC-anslutning skulle kunna se ut och fungera för människor som arbetar på olika platser i det publika rummet, som på bibliotek eller universitet. Men även för privat användning i hem. TRANSIT tangentbordet är ett enkelt och robust koncept av ett fullstort taktilt tangentbord som erbjuder en NFC-koppling såväl som Bluetooth for enheter som ännu inte stöder NFC. Designen, som är riktad mot smartphones och tablets, har ett ställ som består av ett automatiskt stöd och en bakplatta med steglös justering. Designen gör att tangentbordet, stödet och bakplattan går att fälla ihop till ett kompakt paket som är enkelt att transportera och förvara. Dessutom erbjuds möjligheter att ladda smart-enheter via energi-skördning eller kabel då enheten har inbyggda batterier. Projektet avslutades med en slutpresentation av en fysisk modell i skala 1:1.
112

Atomic Force Microscope Based Near-field Imaging for Probing Cell Surface Interactions

Amini, Sina 03 October 2013 (has links)
Near-membrane and trans-membrane proteins and their interactions with the extracellular matrix (ECM) can yield valuable information about cell dynamics. However, advances in the field of nanoscale cellular processes have been hindered, in part, due to limits imposed by current technology. In this work, a novel evanescent field (EF) imaging technique is designed, modeled, created and tested for near-field imaging in the apical surface of cells. This technique and Förster resonance energy transfer (FRET) were used to investigate interactions between integrins on the cell surface and the ECM protein, fibronectin. The goal was to monitor changes in the integrin density at the cell surface as a function of clustering after binding to fibronectin on the microsphere surface. For the EF technique, quantum dot (QD)-embedded polystyrene microspheres were used to couple light into whispering gallery modes (WGMs) inside the microspheres; the resulting EF at the surface of the microsphere was used as a near-field excitation source with ~50 nm axial resolution for exciting fluorescently-labeled integrins. For FRET measurements (~10 nm axial resolution), QDs (donors) were coated on the surface of microspheres and energy transfer to red fluorescent protein (RFP)-integrin constructs (acceptors) studied. In both techniques, the QD-modified microspheres were mounted on atomic force microscope (AFM) cantilevers, functionalized with fibronectin, and brought into contact with fluorescently-labeled HeLa or vascular smooth muscle (VSM) cells. The results obtained from both methods show the clustering and activity of the integrins and are in good agreement with each other. Amsterdam discrete dipole approximation (ADDA) was used to study the effects of inhomogeneous surrounding refractive index on the quality factor and position of the WGMs due to the attachment of a microsphere to an AFM cantilever. WGMs of various QD-embedded microspheres mounted on AFM cantilevers were experimentally measured and shown to be consistent with the model.
113

Nano-focusing of light electromagnetic analysis and simulation /

Čajko, František. January 2009 (has links)
Dissertation (Ph. D.)--University of Akron, Dept. of Electrical and Computer Engineering, 2009. / "August, 2009." Title from electronic dissertation title page (viewed 9/23/2009) Advisor, Igor Tsukerman; Committee members, Nathan Ida, Iqbal Husain, Ernian Pan; Department Chair, Alex De Abreu Garcia, Dmitry Golovaty; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
114

The effect of nonlinear propagation on near-field acoustical holography /

Shepherd, Micah Raymond, January 2007 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Physics and Astronomy, 2007. / Includes bibliographical references (p. 99-106).
115

A low cost planar near-field / far-field antenna measurement system /

Yan, Bing, January 1997 (has links)
Thesis (M. Eng.), Memorial University of Newfoundland, 1998. / Bibliography: leaves 74-76.
116

Investigation of the Iterative Fourier Technique for Phaseless Planar Near-Field Antenna Measurements

Li, Xiang 11 January 2016 (has links)
This thesis focuses on the use of phaseless (magnitude-only) planar near-field antenna measurements for the far-field characterization of an antenna under test (AUT). This is important since the use of phaseless data only requires power measurements, thus, removing the need of using expensive instruments, such as vector network analyzers which can measure both magnitude and phase. In addition, as opposed to far-field measurement techniques, performing measurements in the near-field zone of an AUT makes the measurement system more compact. / February 2016
117

Microscopia de campo próximo aplicada ao estudo dos domínios ferroelásticos / Ferroelastic domains studied by near field microscopy

Dantas, Saulo Maia January 2011 (has links)
DANTAS, Saulo Maia. Microscopia de campo próximo aplicada ao estudo dos domínios ferroelásticos. 2011. 116 f. Dissertação (Mestrado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2011. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-10-16T20:43:18Z No. of bitstreams: 1 2011_dis_smdantas.pdf: 2227981 bytes, checksum: 19c007c3550b22fce922a346d6f4508f (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-10-21T20:37:21Z (GMT) No. of bitstreams: 1 2011_dis_smdantas.pdf: 2227981 bytes, checksum: 19c007c3550b22fce922a346d6f4508f (MD5) / Made available in DSpace on 2015-10-21T20:37:21Z (GMT). No. of bitstreams: 1 2011_dis_smdantas.pdf: 2227981 bytes, checksum: 19c007c3550b22fce922a346d6f4508f (MD5) Previous issue date: 2011 / A significant part of the nowadays scientific research is based on the synthesis, characterization and application of the nanostructured materials. In order to make possible a further understanding of the intriguing properties of these materials, many techniques with nanometric and even subnanometric resolution have been created during the last 50 years and are passing through a process of continuous improvement. In spite of the great scientific and technical development on the available instrumentation, the optical characterization with nanometric resolution of these materials remains a challenge for researchers from all over the world. In this context, techniques based on near field radiation have emerged as a great alternative for the diffraction limit break which is a nature imposed limit for conventional optical instruments. Besides this, contact near field microscopy in illumination mode acquires optical and topographical information of the material simultaneously. This capability permits the distinction between the real and topographic induced nanometric optical features. The domain phenomenon in crystals has been a subject of interest for crystallographers since crystallography started to develop as a scientific branch. The obvious reasons are the beauty of some domain patterns as well as evident and challenging symmetry relations between their constituents. The ferroelastic domains are one of the important kinds of domains presented by crystals. They have, sometimes, very small dimensions without inducing any topographic element on the sample. On the other side the optical behavior of different domains under almost the same measurement condition may be very dissimilar. Such characteristics make then an ideal class of materials for contact near field microscopy in illumination mode based studies. Ferroelastic domains images, using near-field optical microscopy in illumination and contact mode, were obtained with a nanometric resolution. Such images, in general, presented very little relation with the topographical structure of the material, revealing optical and structural features such as occurrence of the waveguide effect in the domains, domain´s dimensions and presence of dislocations on the crystalline structure. / Uma parcela significativa da pesquisa científica hodierna baseia-se na síntese, caracterização ou aplicação de materiais nanoestruturados. No intuito de possibilitar um maior entendimento das intrigantes propriedades destes materiais, muitas técnicas com resolução nanométrica e até subnanométrica foram criadas nos últimos 50 anos e têm passado por um processo de contínuo aprimoramento. Apesar do grande desenvolvimento técnico e científico da instrumentação disponível, a caracterização ótica com resolução nanométrica destes materiais tem se mostrado um desafio para pesquisadores do mundo inteiro. Nesse contexto, as técnicas baseadas em radiação de campo próximo têm despontado como uma boa alternativa para quebra do limite de difração, que constitui um limite natural para os instrumentos óticos convencionais. Além disso, a microscopia de campo próximo em modo de iluminação e contato adquire simultaneamente informações óticas e topográficas do material, o que permite fazer uma distinção entre as propriedades óticas nanométricas reais e as induzidas por topografia. O fenômeno de domínios cristalográficos tem sido um assunto de interesse da cristalografia desde que ela começou a se desenvolver como ciência. As razões óbvias para isso são a beleza de formas externas de algumas estruturas de domínios, assim como as evidentes e desafiantes relações de simetria entre os seus constituintes. Os domínios ferroelásticos são um dos importantes tipos de domínios apresentados por cristais. Tais domínios apresentam, algumas vezes, dimensões muito reduzidas sem manifestar uma considerável alteração na estrutura topográfica da amostra. Por outro lado, o comportamento ótico de domínios distintos pode ser bem diferente quando sujeitos a uma mesma condição de medida. Tais características tornam esta classe de materiais ideais para um estudo baseado na microscopia de campo próximo em modo de iluminação e contato. Imagens de domínios ferroelásticos, utilizando microscopia de campo próximo em modo de iluminação e contato, foram obtidas com resolução nanométrica. Tais imagens, em geral, apresentaram pouquíssima relação com a estrutura topográfica do material, revelando importantes características óticas (ocorrência do efeito de guias de onda nos domínios) e estruturais (dimensões dos domínios ferroelásticos, presença de defeitos de deslocamento na rede cristalina).
118

Skin Tissue Terahertz Imaging for Fingerprint Biometrics

January 2017 (has links)
abstract: Fingerprints have been widely used as a practical method of biometrics authentication or identification with a significant level of security. However, several spoofing methods have been used in the last few years to bypass fingerprint scanners, thus compromising data security. The most common attacks occur by the use of fake fingerprint during image capturing. Imposters can build a fake fingerprint from a latent fingerprint left on items such as glasses, doorknobs, glossy paper, etc. Current mobile fingerprint scanning technology is incapable of differentiating real from artificial fingers made from gelatin molds and other materials. In this work, the adequacy of terahertz imaging was studied as an alternative fingerprint scanning technique that will enhance biometrics security by identifying superficial skin traits. Terahertz waves (0.1 – 10 THz) are a non-ionizing radiation with significant penetration depth in several non-metallic materials. Several finger skin features, such as valley depth and sweat ducts, can possibly be imaged by employing the necessary imaging topology. As such, two imaging approaches 1) using quasi-optical components and 2) using near-field probing were investigated. The numerical study is accomplished using a commercial Finite Element Method tool (ANSYS, HFSS) and several laboratory experiments are conducted to evaluate the imaging performance of the topologies. The study has shown that terahertz waves can provide high spatial resolution images of the skin undulations (valleys and ridges) and under certain conditions identify the sweat duct pattern. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2017
119

Localized surface plasmon and phonon polaritons investigated by mid-infrared spectroscopy and near-field nanoscopy / Etude de modes de surface localisés phononiques et plasmoniques par spectroscopie-IR et champ proche optique

Al Mohtar, Abeer 08 June 2015 (has links)
Longtemps cantonnées au visible et au proche IR, des nanostructures résonantes sont à présent réalisées dans l’IR, notamment en vue d'applications spectroscopiques. Pour étudier la réponse de ces nanostructures des moyens de caractérisation spécifiques doivent être mise en œuvre. Nous considérons la réponse IR de nano-structures et développons des outils à même de les caractériser. Nous nous sommes intéressés à des échantillons pouvant présenter des modes localisés de surface associés à des Plasmons Polaritons au sein de semiconducteurs fortement dopés ou des Phonons Polaritons dans des matériaux semiconducteurs polaires comme SiC. Cette étude a été menée d’abord en champ lointain (Spectroscopie à Transformée de Fourier et analyse Kramers-Kronig) pour étudier la réponse collective des nanostructures. Nous montrons que la fonction diélectrique de l’échantillon structuré peut être représentée par un oscillateur de Lorentz amortit modifié. Une permittivité effective est aussi déterminée par l’emploi de matrices de transfert pour rendre compte de la réflectivité complexe. L’étude en champ proche permet ensuite d’obtenir une réponse individuelle des structures. Nous développons ici une méthode d’extraction novatrice de l’amplitude et de la phase du signal avec un rapport signal à bruit optimum. Après avoir théoriquement et expérimentalement démontré la pertinence de l’approche, la signature de SPP localisés a pu être observée par des cartographies de champ complexe en fonction de la longueur d’onde. Les images obtenues sont confrontées à des simulations électromagnétiques et discutées / We studied the response of a nano-structured material to an IR electromagnetic excitation. For a given geometry, this response is dictated by the dielectric function to which phonons and free carriers contribute. In case of defect-free semiconductors the phonon response is the dominant term; however when we consider doped semi-conductors the plasmon response plays a major role. In both case, the permittivity functions can be negative with small losses which permits a resonant coupling between the surface modes and the electromagnetic excitation. Our work focuses on the development of experimental tools to analyze both SPP and SPhP. This study was conducted in the far-field regime to see a collective response and in the near-field regime to study nano-structures individually. In far-field, the experimental spectroscopic response of the material was conducted by Fourier Transform Infrared Reflectivity and Kramers-Kronig analysis. Quantitative information on the dielectric function was extracted using a modified Lorentz damped oscillator to fit the reflectivity. An effective permittivity is also retrieved using a transfer matrix method. The near-field study was done in a two-step procedure. The first step was the development of an innovative detection technique with optimum signal to noise ratio. The second step was the implementation of this technique to NSOM after proving its success. LSPP were detected using the developed NSOM. A spectroscopic study was performed as well. Experimental results were compared to theoretical ones obtained with electromagnetic simulations
120

Advanced x-ray multilayer waveguide optics

Zhong, Qi 11 August 2017 (has links)
No description available.

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