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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.
291

The Black Mountain phase occupation at Old Town : an examination of social and technological organization in the Mimbres Valley of southwestern New Mexico, ca. A.D 1150 - 1300

Taliaferro, Matthew Stuart 15 September 2014 (has links)
The Black Mountain phase of the Mimbres Mogollon cultural tradition, dating from around A.D. 1150 through A.D. 1300, is perhaps the most poorly understood time period of the entire Mimbres sequence. During that time, people inhabiting the Mimbres Valley of southwestern New Mexico adopted new ceramic sequences, ceased producing Black-on-white pottery, adopted new architectural styles, and possibly changed mortuary patterns. These changes have been interpreted in a multitude of ways that can be reduced to models of continuity and discontinuity. Unfortunately, these models and interpretations rest on a very limited set of data that comes largely from three moderately tested Black Mountain phase sites in the Mimbres Valley proper: Montoya, Old Town, and Walsh. Thus, arguments for or against either model based on the presence of absence of particular traits are necessarily limited by the modest data from these three sites. It was in this context of opposing interpretations that other aspects of the life ways of Black Mountain phase peoples were analyzed. Specifically, I look at the ways lithic and ceramic technologies were organized to assess if the changes that occurred during the Black Mountain phase also represent changes in the ways social systems were organized. I believe that while certain aspects of material culture such as shifts in ceramic or architectural style are easily changed whereas the social mechanisms responsible for their production are more resistant. The results of these analyses demonstrate that there are more similarities than differences with respect to the manner in which technologies were organized during the time periods traditionally accepted as representing “Mimbres” manifestations and the Black Mountain phase. Thus, the social mechanisms dictating the processes of production, distribution, transmission, and reproduction appear to be similar from the Pithouse periods through the Black Mountain phase. This research adds to the growing body of evidence that suggests continuity between the Classic period inhabitants of the Mimbres area and later Black Mountain phase peoples. / text
292

Analysis of MIMO Relay Chains

Manning, David Patrick January 2011 (has links)
This thesis is split into two parts: first a statistical analysis of multi-hop MIMO relay networks, followed by a simulation of the perfomance of a P25 SISO multi-hop relay network. The basis of the MIMO section is the developement of an end to end statistical model of the multiple relay channel. This end to end model simplifies the statistics involved, making the analysis of systems with large numbers of relays and antennas more practical. A partial system model is obtained. This is exact for a multiple input single output network and can be used to describe the received signal at a single antenna in a multiple output system. We go on to look at the relationship between end to end system parameters and the paramters of individual inter-relay channels. The SISO section contains a characterisation of BER for P25 relay chains. The effect of the SNR at each relay node, the nature of the channel and the number of relay hops on the BER is determined. Furthermore, the performance trends are compared for a range of common relaying protocols, including amplify and forward and two types of decode and forward.
293

LIF studies of simple radicals

Derbyshire, David Wyn January 1987 (has links)
No description available.
294

Properties of texturally equilibrated two-phase aggregates

Cheadle, Michael John January 1989 (has links)
No description available.
295

Immiscible flow behaviour in porous media

Schechter, David S. January 1988 (has links)
No description available.
296

The synthesis of c-glycopeptides and hydroxylamine reagents

Pearce, Alan James January 1998 (has links)
No description available.
297

Scanning tunnelling microscopy studies of liquid crystals

Rivera-Hernandez, Margarita January 1997 (has links)
No description available.
298

Frequency hopping spread spectrum multiplexing for interferometric optical fibre sensor networks

Radi, Haidar M. January 1997 (has links)
No description available.
299

Phase measurement accuracy limitation in phase shifting interferometry.

Ai, Chiayu. January 1987 (has links)
In phase shift interferometry (PSI), several factors affect measurement accuracy, such as piezoelectric transducer (PZT) calibration (i.e. PZT slope error) and PZT nonlinearity, vibration, spurious reflection, source bandwidth, detector nonlinearity, and detector noise. The effects of these error sources on several algorithms to solve the phase of the wavefront are studied. When the simple arctangent formula is used, if the PZT slope is properly adjusted, the error due to the PZT quadratic nonlinearity can be tremendously reduced. An exact solution is derived to remove the error when the PZT quadratic nonlinearity is large. Although Carre's formula is insensitive to PZT slope, this formula is more sensitive to the detector nonlinearity than the simple arctangent formula. For most error sources, the error of the phase solved has a double-frequency characteristic. Thus, averaging two measured phases of two runs, which have a ninety degree phase shift related to each other, can effectively reduce the error. For a small vibration, the phase error has a very simple relation to the vibration amplitude, and a very complex relation to the vibration frequency. Although the error caused by vibration has this double-frequency characteristic, the averaging technique does not apply. The error caused by spurious reflection does not have such a characteristic. A new algorithm is proposed to eliminate the phase error caused by certain types of spurious reflection. When detector noise is concerned, the phase error is inversely proportional to the modulation of the intensity times the square root of the number of steps/buckets. For the shot noise, the phase error is inversely proportional to the fringe contrast times the square root of the total number of photons. In practice, the shot noise is very much smaller than the detector noise. In a practical environment, PZT calibration, vibration, and spurious reflection have much more prominent effects on the PSI than the source bandwidth, detector nonlinearity, and detector noise. When spurious reflection and vibration are under control, and the signal-to-noise ratio is about 20, the PSI has an accuracy of 2 degrees, i.e. 3.3nm at 633nm. Because vibration and detector noise are random error sources, the errors caused by them can be reduced by averaging many measurements. However, the error caused by the other discussed sources cannot be reduced by averaging many measurements.
300

QUANTUM THEORY OF MULTIWAVE MIXING (RESONANCE FLUORESCENCE, SATURATION SPECTROSCOPY, MODULATION, PHASE CONJUGATION, QUANTUM NOISE).

HOLM, DAVID ALLEN. January 1985 (has links)
This dissertation formulates and applies a theory describing how one or two strong classical waves and one or two weak quantum mechanical waves interact in a two-level medium. The theory unifies many topics in quantum optics, such as resonance fluorescence, saturation spectroscopy, modulation spectroscopy, the build up of laser and optical bistability instabilities, and phase conjugation. The theory is based on a quantum population pulsation approach that resembles the semiclassical theories, but is substantially more detailed. Calculations are performed to include the effects of inhomogeneous broadening, spatial hole burning, and Gaussian transverse variations. The resonance fluorescence spectrum in a high finesse optical cavity is analyzed in detail, demonstrating how stimulated emission and multiwave processes alter the spectrum from the usual three peaks. The effects of quantum noise during the propagation of weak signal and conjugate fields in phase conjugation and modulation spectroscopy are studied. Our analysis demonstrates that quantum noise affects not only the intensities of the signal and conjugate, but also their relative phase, and in particular we determine a quantum limit to the semiclassical theory of FM modulation spectroscopy. Finally, we derive the corresponding theory for the two-photon, two-level medium. This yields the first calculation of the two-photon resonance fluorescence spectrum. Because of the greater number of possible interactions in the two-photon two-level model, the theoretical formalism is considerably more complex, and many effects arise that are absent in the one-photon problem. We discuss the role of the Stark shifts on the emission spectrum and show how the Rayleigh scattering is markedly different.

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