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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.
21

The optical properties of high-T(c) superconductors grown by pulsed laser deposition.

Hughes, Robert Alan. Timusk, T. Unknown Date (has links)
Thesis (Ph.D.)--McMaster University (Canada), 1993. / Source: Dissertation Abstracts International, Volume: 54-12, Section: B, page: 6277. Adviser: T. Timusk.
22

Instrumentation requirements for TREE Effects Data Collection at the Naval Postgraduate School Flash X-ray facility

Galarowicz, Dale. January 1990 (has links) (PDF)
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 1990. / Thesis Advisor(s): Maruyama, X.K. Second Reader: Michael, S.N. "June 1990." Description based on title screen as viewed on March 24, 2010. DTIC Descriptor(s): Data Acquisition, Electronics, Facilities, Instrumentation, Integrated Systems, Noise (Electrical And Electromagnetic), Photons, Pulse Generators, Pulses, Radiation, Requirements, Scale, Transient Radiation Effects, Transients, Trees, Wafers, X Rays. DTIC Identifier(s): Transient radiation effects, Data acquisition, X ray apparatus, Electromagnetic pulses, Theses. Author(s) subject terms: EMP, IEMP, Flash X-Ray Instrumentation. Includes bibliographical references (p. 105-106). Also available in print.
23

Skakeling met transistors in die lawinegebied (Afrikaans)

Taute, Willem Jacobus 12 June 2013 (has links)
Skakeling met diffusie-transistors by höe kollektorspannings word ontleed. Die gebied waar vermenigvuldiging verkry word en skakelsnelheid aansienlik verhoog word, is ondersoek met behulp van 'n relaksasie-ossillator. Lawineskakeling soos veral benut in pulsgenerators, is hier ter sake. Met behulp van 'n ladingsmodel is dit moontlik om uitdrukkings vir stygtyd, piekstroom en daaltyd in terme van transistorparameters te kry. Hierdie waardes is getoets met 2N414-transistors. Die invloed van eksterne komponente en toevoer word beskou. ENGLISH : Switching with transistors (diffusion flow type) in the high voltage region is analysed. The high Switching speed in this multiplication region is investigated by means of a relaxation oscillator. Avalanche mode switching as is relevant here, is mostly used in pulse generators. Expressions for rise time, peak current and fall time are obtained by means of a charge control model in terms of transistor parameters. 2N414 transistors were used to verify the theory experimentally. The influence of external components and supplies are also considered. / Dissertation (MEng)--University of Pretoria, 1969. / Electrical, Electronic and Computer Engineering / unrestricted
24

Applications of Electroporation in Microorganism Inactivation and Pain Remediation

Emily Fay Downing (14231846) 08 December 2022 (has links)
<p>  </p> <p>Electroporation uses puled electric fields to permeabilize cell membranes to either introduce exogeneous molecules into cells through normally impermeable membranes or completely lysing cells to induce cell death. This thesis examines electroporation in combination with a natural product for microorganism inactivation and pulsed magnetic fields for inducing pain remediation. Motivated by previous studies using curcumin with pulsed electric fields for cancer treatment, we hypothesized that this combined treatment modality could also enhance microorganism inactivation. The experiments did not indicate any synergistic benefit from combining curcumin and pulsed electric fields for microorganism inactivation. We also hypothesized that a pulsed magnetic field treatment could permeabilize neuron membranes to block action potentials to reduce pain without requiring drugs or direct intervention with the electric pulses. This thesis explored Sim4Life, a commercial software that coupled electromagnetic solvers with models of organisms to assess the interaction of pulsed magnetic fields with tissues. We designed and simulated a device for generating a pulsed magnetic field with different geometries to assess electric and magnetic field generation. These studies only considered pulsed magnetic fields and not specifically time-dependent currents or DC magnetic fields that could be benchmarked to standard analytic solutions. The process outlined here will enable future benchmarking for Multiphysics, multiscale simulations of pulsed magnetic fields, AC magnetic fields, or novel electromagnetic waveforms. The results for this thesis provide a starting point for future experiments coupling electroporation with natural products for microorganism inactivation and for assessing in vivo effects of external electromagnetic fields. </p>
25

Millimetre wave quasi-optical signal processing systems

Webb, M. R. January 1993 (has links)
The development of spatial signal processing techniques at millimetre wavelengths represents an area of science and technology that is new. At optical wavelengths, spatial signal processing techniques are well developed and are being applied to a variety of situations. In particular they are being used in pattern recognition systems with a great deal of success. At millimetre wavelengths, the kind of technology used for signal transport and processing is typically either waveguide based or quasi-optically based, or some hybrid of the two. It is the use of quasi-optical methods that opens up the possibility of applying some of the spatial signal processing techiques that up to the present time have almost exclusively been used at optical wavelengths. A generic device that opens up this dimension of spatial signal processing to millimetre wave quasi-optical systems is at the heart of the work described within this thesis. The device could be suitably called a millimetre wave quasi-optical spatial light modulator (8LM), and is identical in operation to the spatial light modulators used in many optical signal processing systems. Within this thesis both a theoretical and an experimental analysis of a specific millimetre wave quasi-optical spatial light modulator is undertaken. This thesis thus represents an attempt to open up this new area of research and development, and to establish for it, a helpful theoretical and experimental foundation. It is an area that involves a heterogeneous mix of various technologies, and it is an area that is full of potential. The development of the experimental method for measuring the beam patterns produced by millimetre wave quasi-optical spatial light modulators involved the separate development of two other components. Firstly, a sensitive, low-cost millimetre wave pyroelectric detector has been developed and characterised. And secondly, a high performance quasi-optical Faraday rotator (a polarisation rotator) has been developed and characterised. The polarisation state of a quasi-optical beam is the parameter most often exploited for signal processing applications in millimetre wave quasi-optical systems, and thus a high performance polarisation rotator has readily found many opportunities for use.
26

Estudo dos mecanismos de geracao de pulsos ultracurtos em lasers de neodimio com bombeamento continuo longitudinal

MALDONADO, EDISON P. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:40:45Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:47Z (GMT). No. of bitstreams: 1 02749.pdf: 9285161 bytes, checksum: dfb17ccf35fc0cce66c71d0904ccb146 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
27

Estudo dos mecanismos de geracao de pulsos ultracurtos em lasers de neodimio com bombeamento continuo longitudinal

MALDONADO, EDISON P. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:40:45Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:47Z (GMT). No. of bitstreams: 1 02749.pdf: 9285161 bytes, checksum: dfb17ccf35fc0cce66c71d0904ccb146 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
28

Uma Analise no dominio espectral do mecanismo de travamento de modos

WETTER, NIKLAUS U. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:38:06Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:53Z (GMT). No. of bitstreams: 1 05639.pdf: 6476184 bytes, checksum: 3037d7c0ce96c51e46c15baa5bdd114c (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:92/01672-4
29

Uma Analise no dominio espectral do mecanismo de travamento de modos

WETTER, NIKLAUS U. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:38:06Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:53Z (GMT). No. of bitstreams: 1 05639.pdf: 6476184 bytes, checksum: 3037d7c0ce96c51e46c15baa5bdd114c (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:92/01672-4
30

Estudo da acao laser de matrizes de fluoretos (LiSrAlF sub (6), Lu:LiYF sub (4)) dopadas com Cr sup (3+) e Nd sup (3+)

BARBOSA, EDUARDO A. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:45:36Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:38Z (GMT). No. of bitstreams: 1 07309.pdf: 6512485 bytes, checksum: da19e05a16a320b11188314140f1865c (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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