• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 933
  • 243
  • 145
  • 110
  • 77
  • 31
  • 25
  • 22
  • 11
  • 7
  • 6
  • 6
  • 5
  • 5
  • 4
  • Tagged with
  • 1897
  • 253
  • 230
  • 182
  • 172
  • 140
  • 128
  • 125
  • 111
  • 95
  • 95
  • 94
  • 91
  • 90
  • 83
  • 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

Tensor polarization of deuterons scattered from He⁴

McIntyre, Laurence Cook, January 1965 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. Abstracted in Dissertation abstracts, v. 25 (1965) no. 10, p. 6015. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 180-183).
22

THE INFLUENCE OF INDUCED POLARIZATION IN INDUCTIVE METHODS OF ELECTRICAL PROSPECTING.

Debroux, Patrick Serge, 1957- January 1985 (has links)
No description available.
23

Enhanced high resolution '1'2'9Xe NMR via spin exchange with optically pumped Rb

Davies, Gareth Reynold January 1993 (has links)
No description available.
24

Solid-state NMR studies of compatibilised polymer blends

Oliver, Sarah Louise January 1999 (has links)
No description available.
25

Tracking antenna architectures based on an integrated mixer microstrip patch array

Gupta, Sanjeev January 1997 (has links)
No description available.
26

Variable Polarization Ferrite Antenna

Dunn, Daniel S., Telep, Matthew S., Augustin, Eugene P. 10 1900 (has links)
International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / This paper describes a ferrite antenna that can produce any polarization on the Poincaré sphere over the frequency range of 9.0 to 11.4 GHz by utilizing Faraday rotation and a quarter-wavelength phase shifter. All possible polarizations of the electromagnetic wave are achievable with this antenna which includes linear, circular and elliptical polarizations. Any tilt angle of elliptical polarization and any orientation of the linear polarization can be achieved as well. The polarization of the ferrite antenna can be electronically switched to a different polarization instantly without the use of moving parts. An automatic data acquisition system was designed and built to fully analyze the antenna' s characteristics.
27

Polarization dOTF: on-sky focal plane wavefront sensing

Brooks, Keira J., Catala, Laure, Kenworthy, Matthew A., Crawford, Steven M., Codona, Johanan L. 22 July 2016 (has links)
The differential Optical Transfer Function (dOTF) is a focal plane wavefront sensing method that uses a diversity in the pupil plane to generate two different focal plane images. The difference of their Fourier transforms recovers the complex amplitude of the pupil down to the spatial scale of the diversity. We produce two simultaneous PSF images with diversity using a polarizing filter at the edge of the telescope pupil, and a polarization camera to simultaneously record the two images. Here we present the first on-sky demonstration of polarization dOTF at the 1.0m South African Astronomical Observatory telescope in Sutherland, and our attempt to validate it with simultaneous Shack-Hartmann wavefront sensor images.
28

The Dielectric Constant of Galvinoxyl

Mizell, Michael E. 05 1900 (has links)
The molecules in many substances are know to undergo at characteristic temperatures a change in their rotational freedom in the solid state, signifying either a change in structure of the material of the onset of limited rotation of the molecule about some symmetry axis. The purpose of this research was to determine from dielectric constant measurements over the 100°K-420°K temperature range whether or not the organic free radical galvinoxyl and its diamagnetic parent molecule, dihydroxydiphenylmethane, undergo any such transitions.
29

Theoretical investigation of nonlinear optical responses in neutral and charged conjugated chains. / CUHK electronic theses & dissertations collection

January 2000 (has links)
An Zhong. / "November 30, 2000." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (p. [167]-173). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
30

Multiferrocity in bismuth layer structured materials

Li, Zheng January 2016 (has links)
Multiferroics (MF) have attracted much research attention due to the coexistence of ferroelectric and magnetic ordering as well as magnetoelectric (ME) coupling. At present there are very few room temperature single phase MF except BiFeO3. Multiferroic properties of Aurivillius compound Bi5FeTi3O15 were reported at 80 K. The at 80 K. The at 80 K. The at 80 K. The at 80 K. The magnetization of Bi5FeTi3O15 was significantly improved by substituting parts of Fe cations by Co cations. Bi5FeTi3O15 showed ferromagnetic order above room temperature. The magnetic cations Fe/Co in B-site contribute to the both ferroelectric and ferromagnetic properties, which could possibly induce strong magnetoelectric effect. Aurivillius materials are layered structured materials with formula (Bi (Bi2O2)2+ (A m-1BmO3m+1 )2-. The polarization of Aurivillius materials is mainly in a-b plane . High dense and textured ceramics were fabricated by a two-step spark plasma sintering (SPS) method to improve the polarization of ceramics. The multiferroic properties of of Aurivillius materials with different octahedral layers (m=2, 3, 4 and 5) were investigated. All these materials showed ferroelectric and ferromagnetic order at room temperature except Bi 3Nb 1.1251.1251.1251.1251.125Fe 0.1250.1250.1250.1250.125Co 0.1250.1250.1250.1250.125Ti 0.750.750.750.75O9 (m = 2). (m = 2). (m = 2). (m = 2). (m = 2). Bi 3.253.253.253.25La 0.750.750.750.75Nb 0.250.250.250.25Fe 0.1250.1250.1250.1250.125Co 0.1250.1250.1250.1250.125Ti 2.52.52.5O12 (m = 3) was identified to be single phase. (m = 3) was identified to be single phase. Although a small amount of secondary phase (CoFe (CoFe2O4/Co /Co2FeOFeOFeO4) were found in Bi 4.254.254.254.25La 0.750.750.750.75Fe 0.50.50.5Co 0.50.50.5Ti 3O15 (m = 4) and Bi 5.25.25.25La 0.750.750.750.75FeCoTiFeCoTiFeCoTiFeCoTi FeCoTi3O18 (m = 5), ), the intrinsic multiferroicity of the main Aurivillius phase was confirmed by the magnetic controlled ferroelectric domain switching. Clear ME couplings were observed in these materials.

Page generated in 0.0982 seconds