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In order to fully understand the role methane (CH₄) plays in the microwave emission spectra of the deep atmospheres of the outer planets, over 280 laboratory measurements of the opacity of ammonia in a methane environment have been made in the 5-20 cm wavelength range. All opacity measurements were made with either 100 or 200 mbars of ammonia and with 1 to 3 bars of added methane in the 330-450K temperature range. A formalism for the absorptivity of ammonia broadened by methane has now been developed and had been applied to the Hanley et al. (Icarus, v. 202, 2009) model for the opacity of ammonia. Due to methane's relatively low abundance at Jupiter (~0.2% by volume), its effect on the microwave spectrum which will be observed by the Juno MWR (Microwave Radiometer) will be minimal. However, these experimental results will significantly improve the understanding of the microwave emission spectrum of Uranus and Neptune where methane plays a more dominant role.

Thesis (M.S.); Submitted to the University of California, Berkeley, 210 Hearst Mining Memorial Bldg., Berkeley, CA 94720 (US); 15 Dec 2003. / Published through the Information Bridge: DOE Scientific and Technical Information. "LBNL--54116" Li, Sonny X. USDOE Director. Office of Science. Basic Energy Sciences (US) 12/15/2003. Report is also available in paper and microfiche from NTIS.

Thesis; Thesis information not provided; 1 Feb 2003. / Published through the Information Bridge: DOE Scientific and Technical Information. "JLAB-PHY-03-39" "DOE/ER/40150-2763" Silvia Niccolai. 02/01/2003. Report is also available in paper and microfiche from NTIS.

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A complex environment causes strong distortion of the field, inhibiting tasks such as imaging and communications in both the optical and radio-frequency (RF) region. In the optical regime, strong modal dispersion in highly multimode fiber (MMF) results in a scrambled output field in both space (intensity speckles) and time (spectral and temporal speckles). Taking advantage of the pulse shaping technique, spatial and temporal focusing has been achieved in this thesis, offering potential opportunities for nonlinear microscopy and imaging or space-division multiplexed optical communication through MMF. In the RF regime, multipath effect in wireless RF channel gives multiple echoes with random delay and amplitude attenuation at the receiver end. Static channel sounding and compensation with ultra-broadband spread spectrum technique resolves the issue by generating a peaking signal at the receiver, significantly improving the signal-to-noise/interference performance. However, the limited communication speed in the static approach makes it challenging for sounding and compensation in a dynamic channel. Here, we achieve real-time channel sounding and compensation for dynamic wireless multipath channel with 40 micro-seconds refresh rate by using a fast processing field programmable gate array (FPGA) unit, providing potential opportunities for mobile communications in indoor, urban, and other complex environments. Furthermore, by combining broadband photonics and RF radar technologies, a high depth and transverse resolution wide bandwidth (15 GHz) W-band (75 - 110 GHz) photonic monopulse-like radar system for remote target sensing is demonstrated, offering prospects for millimeter wave 3-D sensing and imaging.

New radio telescopes under development, will significantly enhance the capabilities of radio astronomy in the Southern Hemisphere. South Africa, in particular, is actively involved in the development of a new array (MeerKAT) as well as in the expansion of existing very long baseline interferometer arrays in the south. Participation in these new developments demands a thorough understanding of radio astronomy techniques, and data analysis, and this thesis focusses on two projects with the aim of gaining such experience. The Southern Hemisphere very long baselines array is not well served with calibrator sources and there are significant gaps in the present calibrator distribution on the sky. An adequately dense, well distributed, set of strong, compact calibrator or reference sources is needed. With this in mind, observations using the Southern Hemisphere long baseline array were conducted to investigate a sample of candidate calibrator sources. The compactness of the sources was investigated and new potential calibrators have been identified. Single antenna radio spectroscopy of OH masers has identified sources of 1720 MHz emission associated with supernova remnants at the shock interface between the expanding supernova remnant and a molecular cloud. Models indicate that these masers are shock excited and can only be produced under tight physical constraints. Out ows from newly-formed stars create nebulous regions known as Herbig-Haro objects when they interact with the surrounding medium, and these regions are potentially similar to those seen in supernova remnants. If conditions behind the shock fronts of Herbig-Haro objects are able to support 1720-MHz OH masers they could be a useful diagnostic tool for star formation. A survey toward Herbig-Haro objects using a single-dish radio telescope did detect 1720-MHz OH lines in emission, but neither their spectral signature nor follow-up observations with the Very Large Array showed evidence of maser emission. / Mathematical Sciences / Ph.D. (Astronomy)

Les méthodes optiques passives de mesures de température comme la thermographie ou la pyrométrie optique sont intéressantes car elles permettent une mesure non intrusive de l’objet cible à condition de connaître le facteur d’émission. La connaissance de ce facteur est critique pour déterminer la température de surface par le rayonnement thermique émis dans un domaine spectral. Le pyromètre bichromatique impulsionnel permet de surmonter la connaissance de ce paramètre à condition que le choix des valeurs de longueurs d’onde soit fait avec précautions. Lorsque l’objet à mesurer est situé dans un environnement industriel, de telles méthodes optiques sont fortement perturbées par la présence d’un milieu optiquement absorbant. C’est également le cas pour des objets situés dans des environnements très chauds qui émettent d’intenses radiations interférentes. Dans cette thèse, nous présentons une méthode radiométrique active bichromatique pour mesurer la température d’une surface en milieu industriel. Cette méthode est basée sur une excitation locale par une source laser modulée dans l’infrarouge. La détection de la température qui est corrélé avec l’excitation permet d’extraire par détection synchrone le signal modulé noyé dans un bruit jusqu’à un million de fois supérieur. Travailler à courtes longueurs d’onde (domaine visible et proche infrarouge) offre une grande dynamique et minimise l’erreur induite par les variations d’émissivité avec la longueur d’onde. Ce système collecte le rayonnement émis par l’objet à distance, de quelques mètres à plusieurs dizaines de mètres selon la configuration du système optique. Le principe de la méthode de mesure, le système optique et l’appareillage sont présentés dans ce rapport ainsi que les études théoriques et expérimentales sur la sensibilité, sa calibration et les résultats obtenus sur différents sites industriels. / Optical passive methods of temperature measurements such as thermography or optical pyrometry are very interesting because they allow a non-intrusive measurement with the target object provided to know the emission factor. The knowledge of this factor is critical for determining the actual temperature of a surface from the thermal radiation emitted in a wavelength band. The bichromatic pulsed pyrometer allows to overcome the knowledge of this parameter provided that precautions are taken in the choice of the values of wavelengths. When the object to be measured is placed in industrial environments, such passive optical methods are greatly disturbed by the presence of an optically absorbing medium. It is also distorted for objects located in very hot environments emitting intense interfering radiation. In this thesis, we present an active bichromatic radiometric method for measuring the temperature of a surface in harsh environments. The method is based on a localized excitation by a modulated laser source in the infrared range. Detecting the temperature range which is correlated with the excitation allows a synchronous detection to extract the signal embedded in a noise up to 106 times superior. Working at short wavelengths (visible range and near infrared range) offers a large dynamic range and minimizes the error due to variations in emissivity with the wavelength. This system collects the radiation emitted by the object at a distance from a few meters up to dozens of meters depending on the configuration of the optical system. The principle of the measurement method, the optical wavelength separation system and the telemetry apparatus are presented in this report as well as the theoretical and experimental study of the sensitivity of the device, its calibration and the results obtained in different industrial sites.

La détection sensible et sélective des métaux lourds, en particulier les métaux detransition, est d’une grande importance pour la santé publique ainsi que pour la surveillancede l’environnement. Les méthodes actuelles de référence, de par leur non portabilité, limitentla possibilité de disposer de mesures à haute résolution spatiale et temporelle. Lesmicrocapteurs optiques offrent un moyen attrayant et pratique pour surmonter ces limitationsde coût global et de temps d’analyse, en permettant la mesure en temps réel sur site.Pour démontrer ce potentiel, ces travaux de thèse sont orientés sur la détermination duchrome hexavalent Cr(VI) en solution à l’aide d’une réaction colorimétrique avec le 1,5-diphénylcarbazide (DPC), permettant de créer un complexe présentant un maximumd’absorption dans le domaine du visible. Ces travaux s’inscrivent dans la volonté dedévelopper un véritable laboratoire sur puce, intégrant la fonction fluidique parélectromouillage sur diélectrique pour créer la réaction colorimétrique, ainsi que la fonctionde mesure par intégration d’un capteur optique dédié à la mesure d’absorption dans desmicrovolumes (< μL). Pour la mesure d'absorption sur de si faibles volumes, l'utilisation demicrorésonateurs vise à augmenter de façon importante le chemin optique effectif et ainsi lasensibilité du capteur.Nous décrivons nos travaux sur la conception, la fabrication de la plateformemicrofluidique digitale ainsi que du résonateur optique en anneaux à des dimensionssubmicroniques par photolithographie par projection. Les matériaux polymères sontprivilégiés pour une intégration totale bas coût à terme, ainsi qu’un substrat verre, dont lespropriétés sont particulièrement adaptées aux applications optiques dans le domaine duvisible. / The selective and sensitive detection of heavy metals, such as transition metals, is ofparamount importance for health and safety an environmental monitoring. Current referencemethods, due to their lack of portability, are limiting factors to obtain high-resolution spatialand temporal data. Optical sensors offer an attractive and convenient way to overcome theselimitations of cost and time per analysis by offering real time, on-site measurementcapabilities.In order to demonstrate this potential, this thesis is focused on the detection and quantificationof hexavalent chromium Cr(VI) in water samples by a colorimetric reaction based on areaction with the 1,5-diphenylcarbazide (DPC), that produces a complex possessing anabsorption maximum in the visible range. This works endorse the goal of creating a true labon-chip, integrating both the fluidic function based on ElectroWetting on Dielectric (EWOD)to create the colorimetric reaction, and the sensing function based on the integration of anoptical sensor able to measure absorption variations in micro-volumes (< μL). In order toobtain sufficient sensitivity on such small volumes, optical microring resonators are used inthis work, due to their ability to enhance the effective optical path length by constructiveinterferences.This thesis describes the conception and fabrication of the EWOD microfluidic platform, aswell as the conception, simulation and fabrication of submicronic microring resonators usingstepper lithography. Polymer materials and glass substrates are selected, due to their greatoptical properties in the visible range, their compatibility with the EWOD platform, and theirintegrability at a reasonable cost.