• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 77
  • 13
  • 13
  • 5
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 137
  • 137
  • 66
  • 55
  • 38
  • 18
  • 16
  • 14
  • 13
  • 10
  • 10
  • 9
  • 8
  • 8
  • 8
  • 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.
31

Design of a Monitoring System for a Plasma Cleaning Machine

Fooks, Terry M. (Terry Max) 05 1900 (has links)
Plasma cleaning is the most effective dry process to remove surface contaminates from a SAW (Surface Acoustical Wave) device. Consistent gas pressures, flows, and good electrical connections between the chamber shelves are necessary for the process to function predictably. In addition, operation of the monitoring system must be transparent to the plasma cleaning unit. This thesis describes a simple solution to the complex problem of monitoring a plasma cleaning system. The monitoring system uses the LabVIEW® G programming language and hardware, both products of National Instruments, Inc.®, to monitor critical parameters necessary to achieve a consistent process when cleaning these devices.
32

Terahertz Surface Plasmon Polariton-like Surface Waves for Sensing Applications

Arbabi, Amir January 2009 (has links)
Surface plasmon polaritons are electromagnetic surface waves coupled to electron plasma oscillation of metals at a metal-dielectric interface. At optical frequencies, these modes are of great interest because of their high confinement to a metal-dielectric interface. Due to the field enhancement at the interface, they have been used in different applications such as sensors, second harmonic generation and enhanced Raman scattering. Surface plasmon resonance based sensors are being used for detection of molecular adsorption such as DNA and proteins. These sensors are known to be highly sensitive and have successfully become commercialized. Terahertz (THz) frequency band of electromagnetic spectrum has attracted researchers in the last few years mostly because of sensing and imaging applications. Many important chemical and biological molecules have their vibrational and rotational resonance frequencies in the THz range that makes the THz sensing one of the most important applications of THz technology. Considering above mentioned facts, extending the concept of surface plasmon sensors to THz frequencies can result in sensitive sensors. In this work the possibility of this extension has been investigated. After reviewing optical surface plasmon polariton waves and a basic sensor configuration, surface plasmon polariton waves propagating on at metallic and doped semiconductor surfaces have been examined for this purpose. It has been shown that these waves on metallic surfaces are loosely confined to the metal-dielectric interface and doped semiconductors are also too lossy and cannot meet the requirements for sensing applications. Afterwards, it is shown that periodically patterned metallic surfaces can guide surface waves that resemble surface plasmon polariton waves. A periodically patterned metallic surface is used to guide THz surface plasmon polariton-like surface waves and a highly sensitive sensor is proposed based on that. The quasi-optical continuous wave (CW) THz radiation is coupled to this structure using the Otto's attenuated total reflection (ATR) configuration and the sensitivity of the device is discussed. A general scattering parameter based model for prism coupling has been proposed and verified. It is shown that a critical coupling condition can happen by changing the gap size between the prim and periodic surface. Details of fabrication of the periodic structure and experimental setup have also been presented.
33

Terahertz Surface Plasmon Polariton-like Surface Waves for Sensing Applications

Arbabi, Amir January 2009 (has links)
Surface plasmon polaritons are electromagnetic surface waves coupled to electron plasma oscillation of metals at a metal-dielectric interface. At optical frequencies, these modes are of great interest because of their high confinement to a metal-dielectric interface. Due to the field enhancement at the interface, they have been used in different applications such as sensors, second harmonic generation and enhanced Raman scattering. Surface plasmon resonance based sensors are being used for detection of molecular adsorption such as DNA and proteins. These sensors are known to be highly sensitive and have successfully become commercialized. Terahertz (THz) frequency band of electromagnetic spectrum has attracted researchers in the last few years mostly because of sensing and imaging applications. Many important chemical and biological molecules have their vibrational and rotational resonance frequencies in the THz range that makes the THz sensing one of the most important applications of THz technology. Considering above mentioned facts, extending the concept of surface plasmon sensors to THz frequencies can result in sensitive sensors. In this work the possibility of this extension has been investigated. After reviewing optical surface plasmon polariton waves and a basic sensor configuration, surface plasmon polariton waves propagating on at metallic and doped semiconductor surfaces have been examined for this purpose. It has been shown that these waves on metallic surfaces are loosely confined to the metal-dielectric interface and doped semiconductors are also too lossy and cannot meet the requirements for sensing applications. Afterwards, it is shown that periodically patterned metallic surfaces can guide surface waves that resemble surface plasmon polariton waves. A periodically patterned metallic surface is used to guide THz surface plasmon polariton-like surface waves and a highly sensitive sensor is proposed based on that. The quasi-optical continuous wave (CW) THz radiation is coupled to this structure using the Otto's attenuated total reflection (ATR) configuration and the sensitivity of the device is discussed. A general scattering parameter based model for prism coupling has been proposed and verified. It is shown that a critical coupling condition can happen by changing the gap size between the prim and periodic surface. Details of fabrication of the periodic structure and experimental setup have also been presented.
34

Modeling heterostructure acoustic charge transport devics for perfomance and manufacturability

Kenney, James Stevenson 12 1900 (has links)
No description available.
35

Magnetically programmable surface acoustic wave devices for RFID applications /

Chin, Matthew January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 118-123). Also available on the World Wide Web.
36

Acoustic wave induced convection and transport in gases under normal and micro-gravity conditions /

Lin, Yiqiang. Farouk, Bakhtier. January 2007 (has links)
Thesis (Ph. D.)--Drexel University, 2007. / Includes abstract and vita. Includes bibliographical references (leaf 195).
37

Design and Synthesis of Acoustic Surface Wave Filters (Part A)

Donnison, William R. 04 1900 (has links)
One of two Project Reports / <p> This report describes the basic physical properties of surface wave devices and design procedures necessary to realize filter functions from such devices. The mathematical form of the surface wave is presented. Filter models based on this wave are reviewed and the strong relationship between device geometry and resultant transfer functions is developed. </p> <p> Design and experimental procedures adopted for the synthesis of a surface-wave filter used for colour T.V. I.F. strips are given. Two such filters are actually made in the laboratory and experimental-theoretical results are compared. Results obtained indicate good agreement between theory and experiment, and clearly demonstrate the superiority of surface wave filters over conventional L-C filters in high frequency applications. </p> / Thesis / Master of Engineering (ME)
38

Spectral methods for the estimation of acoustic intensity, energy density, and surface velocity using a multimicrophone probe.

Steyer, Glen C. January 1984 (has links)
No description available.
39

Non-Iterative Finite Impulse Response Design Techniques

Bishop, Carlton D. 01 January 1984 (has links) (PDF)
A general, non-iterative design technique for low shapefactor, transversal filters is presented. This design approach uses two cosine series to specify appropriate eigenfunctions. An infinite set of such eigenfunctions are defined and the method for choosing the coefficients is discussed. The total filter response is specified as the product of two individual frequency responses. The impulse response of each is then determined by applying the superposition of appropriate eigenfunctions. The criteria for choosing the appropriate eigenfunctions is discussed. A synthesis procedure for designing surface acoustic wave filters is presented. The effects of truncating the impulse response are also explored. A design example is shown for a filter with 10 percent fractional bandwidth and a shapefactor of 1.15.
40

Saw Draw: An Interactive Graphical Layout System for Surface Acoustic Wave Devices

Abbott, Jeffrey Blair 01 January 1988 (has links) (PDF)
This thesis introduces a solution to the problem of time and memory space requirements associated with the manipulation/creation of solid state device layout. Through the use of a hierarchical organization of data and a tailored indexing technique, the software described here, referred to as Saw Draw, is capable of manipulating huge amounts of data in a short period of time. This program was written for surface acoustic wave (SAW) device layout but works for a broad range of devices to include semiconductors, microstrip and others. Due to the large number of details which must be stored for each SAW structure, simply displaying a typical SAW device can become exceedingly tedious. When an entire mask of devices is organized, disk storage requirements can become prohibitive. This software has been designed to minimize both of these critical problems. This work describes the capabilities, structure and special algorithms used in Saw Draw. Included is an example of how a SAW device might be created and a listing of the program code in the Appendix.

Page generated in 0.0343 seconds