The work deals with design of the converter digital to analog on transistor level. Requirements converter a minimum resolution of 10 bits, short conversion time, low power and small chip area. For the realization of the converter is selected technology I3T25

The thesis deals with the analysis of the usual time and frequency of vehicle mirrors and dashboard observation. Within the theoretical part are summarized the current knowledge of the visual distraction of the driver, or circumstances which affect the conduct and behavior of the driver while driving. Furthermore there is a closer approximation and characterization of devices for recording the driver's eye movement, which is used during the measurement of the usual time of observation. This data is used in the experimental part of the thesis. The results were processed and statistically analyzed to determine the usual time of mirrors and dashboard observation. Conclusions done from the measurement results are contained in the last chapter, which also evaluates contribution of this work to practical use in the field of analysis of road accidents and to improve safety on our roads.

Structural and morphological characterization of a Si(110) film heteroepitaxied on 3C-SiC(001)/ Si(001) on-axis template by chemical vapor deposition has been performed. An antiphase domain (APD) free 3C-SiC layer was used showing a roughness limited to 1 nm. This leads to a smooth Si film with a roughness of only 3 nm for a film thickness of 400 nm. The number of rotation domains in the Si(110) epilayer was found to be two on this APD-free 3C-SiC surface. This is attributed to the in-plane azimuthal misalignment of the mirror planes between the two involved materials. We prove that fundamentally no further reduction of the number of domains can be expected for the given substrate. We suggest the necessity to use off-axis substrates to eventually favor a single domain growth.

No description available.

Understanding of material migration and its impact on the formation of co-deposited mixed material layers on plasma-facing components is essential for the development of fusion reactors. This thesis focuses on this topic. It is based on experiments performed at JET and TEXTOR tokamaks. The major objectives were to determine: (i) fuel and impurity removal from plasma-facing components by ICWC in different gas mixtures, (ii) fuel and impurity transport connected to ICWC operation, (iii) plasma impact on diagnostic mirrors. All these issues are in line with the ITER needs: mitigation of co-deposition and fuel inventory, and the performance of first mirrors in long-term operation. The novelty in research is demonstrated by several elements. In wall conditioning studies, tracer techniques based on injection of rare isotopes (N-15, O-18) were used to determine conclusively the impact of respective gases. Also, a new approach to ICWC was developed by combining global gas balance studies based on mass spectrometry and the use of multiple surface probes exposed to discharges and then studied ex-situ with accelerator-based techniques. Impact of plasma on diagnostic mirrors was determined after exposure to the entire first experimental campaign in JET-ILW. / <p>QC 20141103</p>

With the availability of high reflectivity multilayer mirrors and zone plate lenses, the EUV region (5nm - 40nm) of the electromagnetic spectrum is currently being explored for applications of nanoscale printing and imaging. Advances made in this area have consequences for many areas of science. Research for producing a compact, bright EUV source for laboratory use has gained momentum in recent years. For this study, EUV radiation is produced by irradiating target materials using a focused laser beam. Focused laser beam ionizes the target to create a hot, dense, pulsed plasma source, where emission is a result of the relaxation of excited levels. Spectroscopy is used as the main diagnostic to obtain the spectral signature of the plasma. Spectral characteristics are used to deduce the physical state of plasma, thus enabling the tuning of laser irradiance conditions to maximize the needed emission bandwidth. Various target materials are studied, as well as different target geometries, with spectroscopy below 200 nm on pulsed micro-plasmas being a particularly daunting task. Total range spectroscopy from 1 nm to greater than 1 micron is completed for tin-doped spherical droplet plasma source. Reliable plasma diagnostics require both accurate measurements and solid theoretical support in order to interpret the experimental results. Using existing 1D-hydrocode, temperature and density characteristics of the expanding plasma is simulated for any set of experimental conditions. Existing atomic codes written for calculating one-electron radial wavefunctions with LS-coupling scheme via Hartree-Fock method is used in order to gain details of the ion stages, populations, transitions, etc, contributing to the spectral data.

A part of the Ph.D. project focused on growth and characterization of metal multilayers is presented in this licentiate thesis. The main interest in carrying out this research is to develop highly reflective normal-incidence condenser mirrors for soft X-ray microscopy studies in the water window (λ=2.4-4.2 nm) wavelength regime. Transition metals like Sc, Ti V, etc. have been considered because of the presence of their 2p-absorption edges within the water window. An anomalous dispersion at absorption edges has been utilized to get enhanced reflectance of soft X-rays. Since a single surface exhibits a very poor X-ray reflectivity, Cr/Sc, Cr/Ti, and Ni/V multilayers were grown in order to coherently add many reflections from several interfaces. The selection of Cr and Ni, as spacer layer, was made on the basis of their X-ray optical contrasts with the above-mentioned transition metals. The multilayer design, i.e., the individual layer thicknesses and the total number of bilayers, directly influences the resultant reflectance and careful determination was therefore made with the aid of computer simulations. All multilayers were grown on chemically cleaned Si substrates by ion-assisted dual target magnetron sputtering under high vacuum (~10-7 Torr) conditions. The effect of low and high ion-flux bombardment of low energy (&lt;50 eV) Ar ions, on growing surfaces was studied for all material systems. Furthermore, a two-stage deposition of each individual layer with modulated ion-energies was applied in order to obtain smooth and abrupt interfaces with as small intermixing as possible. Ion-surface interactions were also theoretically considered for estimating an appropriate ion-flux and ion-energy range desired for sufficient ad-atom mobilities. X-ray reflectivity and transmission electron microscopy have been the main probes for multilayer characterization in this work. For the Cr/Ti multilayer designed for normal incidence and grown with optimized two-stage ion-energy modulation, a peak reflectance of 2.1% was achieved at the Ti-2p absorption edge (λ=2.74 nm). For a multilayer mirror designed for the Brewster angle a maximum reflectance of 4.3% was accomplished. These measurements were made at the synchrotron radiation source BESSY in Berlin. Specular reflectivity and diffuse scattering scans were utilized for quantitative and qualitative analysis of the vertical and lateral structure of the multilayers. At-wavelength measurements of a series of Cr/Ti multilayers revealed the accumulation of roughness with increasing number of bilayers (N&gt;100) for this material system. Hard X-ray reflectivity and diffractometry were used for quality checks of the multilayers for rapid feedback to the deposition. In-situ annealing using hard X-ray reflectivity was also performed to assess the thermal stability of Cr/Ti multilayers. It was found that probably due to a strong thermal diffusion the degradation of multilayers (with bilayer period of 1.37 nm) in this material system occurs just above the growth temperature (~40°C). The accumulation of a low spatial frequency "waviness" with increasing number of layers in Cr/Ti multilayers was investigated by transmission electron microscopy. The influence of process conditions on multilayer structure with different periodicities was investigated by TEM analyses of a series of three samples for each of the above-mentioned material system. The Cr/Sc multilayers have shown the most flat and abrupt interface structure without any significant roughness evolution when grown with optimum process parameters. / <p>Report code: LiU-TEK-LIC-2005:48. On the day of the defence data the status of article I was: Accepted.</p>

The tensile behavior of two ceramic matrix composites (CMC's) was observed. The materials of interest in this study were a glass-ceramic matrix composite (GCMC) reinforced with Nicalon fibers and a Blackglas™ composite also reinforced with Nicalon fibers. Both had a symmetric cross-ply layup. Initial observations of the composites showed significant porosity and some cracking in the Blackglas™ samples. The GCMC samples showed considerably less damage. From the observed tensile behavior of the cross-ply composites, a 'back-out' factor for determining the 0° ply data of the composite was calculated using Classical Lamination Theory (CLT). The predicted behavior of the 0° ply was then compared to actual data supplied by McDonnell Douglas Corporation. While the Blackglas™ material showed good correlation, the GCMC did not. Analysis indicates that the applicability of this technique is strongly influenced by the initial microstructure of the composite, i.e., porosity, cracking. Fracture mirror measurements were also observed to determine the in-situ strength of the Nicalon fibers. Resulting characteristic strength and Weibull modulus values combined with measured fiber pullout lengths were then used to determine material parameters such as the ultimate tensile strength, strain to failure, work of pullout, sliding distance at the characteristic strength, and interfacial shear stress. Comparisons of measured and calculated ultimate tensile strengths and strains to failure showed good agreement. This research was sponsored by the Naval Surface Warfare Center (NSWC) in Dahlgren VA. / Master of Science

Die Nutzbarmachung des in den Köpfen von Mitarbeitern und Kunden schlummernden, disruptiven Ideenpotenzials stellt Unternehmen weiterhin vor eine große Herausforderung. Der Ansatz des Idea Mirrors verfolgt in diesem Zusammenhang das Ziel, die Möglichkeiten großer Wandbildschirme zu nutzen, um das kreative Ideenpotenzial von Unternehmen insbesondere in den frühen Phasen des Innovationsprozesses besser sichtbar zu machen und so die Motivation zur Ideengenerierung, zur kommunikativen Ideenvernetzung und zur späteren gemeinschaftlichen Ideennutzung zu fördern. Die Einbettung der Benutzungsschnittstelle in den normalen Geschäftsalltag an halböffentlichen Orten wie Empfangshallen, Cafeterien oder in Gruppenräumen soll die Hemmschwelle zur Interaktion herabsetzen und gleichzeitig die Wahrnehmung der dargestellten Inhalte durch eine breite Nutzerbasis garantieren.

Future generations of space-based telescopes will require increasingly large primary reflectors, with very tight optical-quality tolerances. However, as their size grow, it becomes more and more difficult to meet the requirements, due to the manufacturing complexity and the associated costs. Chapters 2 and 3 propose two concepts of Adaptive Optics deformable mirrors, intended to be used as secondary corrector to compensate for manufacturing errors, gravity release and thermal distortion of large lightweight primary mirrors of space telescopes: (i) A scalable segmented bimorph mirror, based on independent PZT patches glued on Silicon wafers, providing a large number of degrees of freedom, a low mass while overcoming the problem of a low resonance mode; and (ii) A monolithic bimorph mirror, controlled by an array of independent electrodes, done by laser ablation on a single PZT patch. The modelling, the control strategy and the technological aspects are described. The performances of the manufactured prototypes are demonstrated experimentally. These prototypes have been developed in the framework of the ESA project, Bimorph Adaptive Large Optical Mirror Demonstrator (BIALOM). Chapter 4 introduces alternative designs, allowing to face the thermal distortion inherent to the bimorph architecture. They are compared in terms of stroke, voltage budget and first resonance frequency. These designs are required to be controlled in both directions using only positive voltages. Finally, the last chapter explores the feasibility of the shape control of a small size active thin shell reflector (with double curvature). The prototype is intended to be a technology demonstrator of a future large and very light active primary reflector. The behavior of the shell is studied through numerical simulations, and a preliminary design is proposed. This investigation is carried out in the framework of the ESA project: Multilayer Adaptive Thin Shell Reflectors (MATS). / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished