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Ion injection into radio frequency quadrupole field devicesGulick, Sidney Luther. January 1986 (has links)
No description available.
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Electromagnetic diffraction by a planar array of dielectric cylinders.Barkley, Lorne. January 1971 (has links)
No description available.
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Vectorial finite element analysis of E-plane waveguide junctionsKanellopoulos, Vassilios N. January 1987 (has links)
No description available.
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Dynamics of ions in radiofrequency quadrupole trapsLunney, Matthew David Norwood January 1986 (has links)
No description available.
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Plane wave scattering by thin linear dielectric-coated wires and dielectric strips : a moment method approach with physical basis functions /Kent, William J. January 1985 (has links)
No description available.
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Small oscillations of a beam-column with finite electrical conductivity in a constant transverse magnetic fieldPeddieson, John January 1966 (has links)
Small oscillations of a beam-column with finite electrical conductivity in a transverse magnetic field are examined under the assumption that the vibration of the bar causes only a weak perturbation in the electromagnetic-field. The frequency equation is derived for a column and reduced to that for free vibration of a beam by equating the end load to zero. The roots of this equation are obtained approximately and the effect of the magnetic field on the frequencies is noted. In addition, the elastic stability of a conducting column and beam-column are investigated. The effect of the magnetic field on the buckling load is determined. Numerical results are presented which indicate that the effect of the dynamic electromagnetic forces is negligible except at extremely high frequencies of vibration. / M.S.
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Second-Surface Mirror Effects in Thin-Film Absorber LayersDobarco-Otero, Jose 11 October 2000 (has links)
The Thermal Radiation Group at Virginia Polytechnic Institute and State University has been developing analytical and numerical heat transfer models for NASA's Langley Research Center for more than 25 years. Recent versions of these models are being used in the design of the next-generation thermal radiation detectors intended for Earth radiation budget campaigns. The current investigation presents three models for the absorption of electromagnetic radiation in thin films. The first assumes a surface heating boundary condition. The second model, derived from electromagnetic theory, is an analytical volumetric heat generation model. This model can be applied to a semi-infinite medium or to a thin-film absorber layers behaving as a second-surface mirror; that is, a semi-transparent coating deposited on top of a reflective surface. The third model is a statistical volumetric heat generation model that is derived using the Monte Carlo ray-trace (MCRT) method. These models are compared by using them to predict the transient temperature response of a generic thermal radiation detector. Results are presented for absorber layers in which the index of refraction is equal to the extinction coefficient. It was found that both of the volumetric heat generation models produce identical results. It was also found that the response of the detector due to shorter wavelengths deviates less from the surface absorption model than at longer wavelengths. A second-surface mirror reflection model for the absorber layer of the thermal radiation detector is also presented in this thesis. / Master of Science
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Modeling of nonlinear active and passive devices in three-dimensional TLM networksCascio, Lucia 07 June 2017 (has links)
The increase in clock rate and integration density in modem IC technology leads to
complex interactions among different parts of the circuit. These interactions are poorly
represented with traditional lumped circuit design methodologies. Traditional CAD tools,
such as SPICE, provide very accurate models for a large variety of active devices, but
their description of the passive part of the circuit is progressively becoming insuffcient,
as the frequencies of the signals increase. Problems such as dispersion, crosstalk and
package effects require a full electromagnetic approach in order to predict their impact
on the final response of the circuit. On the other hand, the application of a full-wave
numerical method for the analysis of a complete device containing nonlinear elements is
not sustainable with the present computer capabilities. The spatial and time discretization
steps required to accurately model the nonlinear part of the device are much smaller than
those necessary to describe the distributed part of the circuit.
In the present thesis, the possibility of modeling nonlinear devices with the three-dimensional
TLM method has been explored; a new procedure has been successfully
developed and implemented, linking the equivalent circuit representation of the nonlinear
device to the transmission line model of the electromagnetic fields in the TLM network.
No restrictions are applied on the size of the device, which can thus occupy more
than a TLM cell. In order to model devices embedded in heterogenous media, a modification
of the TLM node and relative scattering matrix has also been proposed. In view of
linking the TLM field solver with a lumped element circuit CAD tool, the modified TLM
scattering algorithm has remained independent of the specific device connected to the
mesh.
The general methodology shown in this thesis appears to be a promising approach
to solve a large variety of electromagnetic problems containing nonlinear elements. / Graduate
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Determination of the ratio of magnetic dipole to electric-quadrupole radiation in the atomic spectral line 6647A(D5/2-D3/2) of HgIIRettig, Terrence W. 03 June 2011 (has links)
This thesis has involved an attempt to determine the ratio of electric-quadrupole radiation to magnetic-dipole radiation for the forbidden transition 6647A(2D5/2-2D3/2) of ionized mercury. The high resolution needed for this type of work was obtained by using a 14mm Fabry-Perot etalon and a three prism glass spectrograph, The mercury source was a heated eleotrodeless quartz discharge tube excited by an rf oscillator. A large electromagnet was used to obtain the Zeeman effect. This is the first time that the 6647A transition has been analyzed. The experimental results for the longitudinal view show agreement with predictions for the Zeeman components giving complete verification of the identity of the line but the intensity patterns show a possible disagreement with theoretical predictions for the ratio of magnetic-dipole to electric-quadrupole radiation.Ball State UniversityMuncie, IN 47306
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Diffraction and scattering of high frequency wavesFozard, John Andrew January 2005 (has links)
This thesis examines certain aspects of diffraction and scattering of high frequency waves, utilising and extending upon the Geometrical Theory of Diffraction (GTD). The first problem considered is that of scattering of electromagnetic plane waves by a perfectly conducting thin body, of aspect ratio O(k^1/2), where k is the dimensionless wavenumber. The edges of such a body have a radius of curvature which is comparable to the wavelength of the incident field, which lies inbetween the sharp and blunt cases traditionally treated by the GTD. The local problem of scattering by such an edge is that of a parabolic cylinder with the appropriate radius of curvature at the edge. The far field of the integral solution to this problem is examined using the method of steepest descents, extending the recent work of Tew [44]; in particular the behaviour of the field in the vicinity of the shadow boundaries is determined. These are fatter than those in the sharp or blunt cases, with a novel transition function. The second problem considered is that of scattering by thin shells of dielectric material. Under the assumption that the refractive index of the dielectric is large, approximate transition conditions for a layer of half a wavelength in thickness are formulated which account for the effects of curvature of the layer. Using these transition conditions the directivity of the fields scattered by a tightly curved tip region is determined, provided certain conditions are met by the tip curvature. In addition, creeping ray and whispering gallery modes outside such a curved layer are examined in the context of the GTD, and their initiation at a point of tangential incidence upon the layer is studied. The final problem considered concerns the scattering matrix of a closed convex body. A straightforward and explicit discussion of scattering theory is presented. Then the approximations of the GTD are used to find the first two terms in the asymptotic behaviour of the scattering phase, and the connection between the external scattering problem and the internal eigenvalue problem is discussed.
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