Dissertationen zum Thema „High Spectral Resolution“
Um die anderen Arten von Veröffentlichungen zu diesem Thema anzuzeigen, folgen Sie diesem Link: High Spectral Resolution.
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Machen Sie sich mit Top-50 Dissertationen für die Forschung zum Thema "High Spectral Resolution" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Sehen Sie die Dissertationen für verschiedene Spezialgebieten durch und erstellen Sie Ihre Bibliographie auf korrekte Weise.
1
Brierley, Mita Leela. „High Resolution Spectral Models for Globular Clusters“. Thesis, University of Canterbury. Physics and Astronomy, 2010. http://hdl.handle.net/10092/4963.
Annotation:
This thesis covers the development of high-resolution model spectra of simple-stellar-populations (SSP) to be used in the measurement of the ages, metallicities and chemical abundances of unresolved extragalactic globular clusters (GCs). The models are compared to low- and high-resolution spectra of GCs in the Milky Way and M31 galaxies, whose properties are already known, to establish the effectiveness of both the SSP spectral grid and of the direct spectral fitting procedure employed in this work.
The model SSP spectra were created using Dotter et al. (2007) isochrones, populated using the flux derived from a grid of stellar spectra, weighted by the Kroupa (2001) mass function. Models with varying mass loss from the red giant branch and varying numbers of He-burning stars were generated. The spectral grid currently covers a parameter range of 2 to 15 Gyrs in age, and -2.5 to 0 dex in [Fe/H] at an [alpha/Fe] of +0.4 dex. Metallicities derived for Milky Way GCs from Lick index comparisons to the model grid are in good agreement with values in the literature.
The stellar spectral grid, from which the GC spectra are generated, has been created using ATLAS9 and SYNTHE. The spectra are at a resolution of R = 100,000 and cover a wavelength range from 3000 - 9000 Angstroms. Extensive work was undertaken in creating appropriate lists of atomic and molecular transition oscillator strength (log gf) values for this spectral grid. An automated program was created to alter the strengths of millions of atomic transition lines in the Kurucz atomic line lists to fit a model spectrum of appropriate parameters to that of the red-giant star Arcturus and to the Solar spectrum at shorter wavelengths (3000 - 3727 Angstroms). Comparisons to these observed spectra were made manually for several molecular lines and band-heads, and log gf values changed en-mass for all the lines of a given molecular species.
The SSP spectra were compared to low-resolution spectra of Milky Way GCs. Integrated-light spectra of a large number of Galactic GCs were obtained from three sources: the Schiavon et al. (2005) Library of Integrated Spectra of Galactic Globular Clusters, taken using the Ritchey-Chretien spectrograph on the Blanco 4m telescope at Cerro Tololo Inter-American Observatory; spectra obtained through private communication with M. Bessell using the Double Beam Spectrograph on the 2.3m telescope at Siding Springs Observatory; and spectra obtained using the Robert Stobie Spectrograph on the 11m diameter Southern African Large Telescope. With resolutions of 1500 to 2800, abundances of individual elements could not be determined, but overall ages and metallicities were derived. The model spectra were fitted to the observed spectra using a Chi^2 minimisation procedure over large wavelength regions to fully utilise the information available in the spectra. Derived metallicity values were in agreement with literature values. However, age determinations were not consistent with those derived from photometric methods and had large associated uncertainties. The lack of age information in the spectra at such resolutions is a similar result to that found by other studies using the Schiavon data (eg. Mendel et al., 2007; Koleva et al., 2008).
The SSP spectral grid was used to determine ages, metallicities and individual elemental abundances of three clusters (GCM06, GC5 and GC10) in the outer halo of M31. High-resolution spectra from Keck-HIRES were obtained through private communication with D. Forbes. Age and metallicity determinations were made simultaneously by fitting un-blended FeI lines and the H-beta and H-gamma lines. Diagnostic analysis (such as that done by Colucci et al., 2009) and simultaneous fitting of the FeI lines alone gave unrealistic age values that tended towards the lower limits (2 Gyrs) of the age grid. The age and metallicities derived in this work for these clusters are consistent with those found by Alves-Brito et al. (2009) using the same data.
Abundances of a number of elements were derived from the high-resolution spectra. An overall enhancement of alpha-elements (from measurements of Ca, Si and Ti) was seen in all three clusters ([alpha/Fe] = 0.67 +/- 0.2, 0.63 +/- 0.2 and 0.5 +/- 0.2 dex for clusters GCM06, GC5 and GC10 respectively) which is greater than that found for other M31 GCs (Puzia et al., 2005; Colucci et al., 2009). A depletion in Mg compared to the other alpha-elements is seen, in accordance with patterns seen in both Milky Way and M31 GCs (Gratton et al., 2004; Colucci et al., 2009). All three clusters show varying levels of enhancements and depletion in the other measured elements (C, Sc, V, Cr, Mn, Ni, Ba), none of which follow the trends seen in Milky Way clusters. Comparisons to high-resolution spectra of Milky Way GCs, for which abundance ratios are known from the measurement of individual stars, need to be made to establish the accuracy of this elemental-abundance analysis.
Overall, the system presented in this thesis is well designed to be used in the analysis of integrated-light spectra from distant, unresolved GCs. The uncertainties in the derived ages are still larger than desired, but the metallicity determination is very consistent when tested against clusters of known metallicities.
2
Dawsey, Martha Wallis. „Investigation into High Spectral Resolution Lidar Technologies“. Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/306986.
Annotation:
The Intergovernmental Panel on Climate Change (IPCC) found in their 2007 report that aerosol radiative forcing contributed larger uncertainties to estimates affecting future climate change than any other radiative forcing factor. Lidar is a tool with which this uncertainty can be reduced, increasing our understanding of the impact of aerosols on climate change. Lidar, or laser radar, is a monostatic active remote sensing technique used to measure aerosols and particulates in the atmosphere, with accuracies comparable to in-situ measurements (Russell 2002). High Spectral Resolution Lidar (HSRL) systems use a narrow band filter to spectrally separate Doppler broadened aerosol and molecular back-scattered return signals, which allows for range resolved profiles of aerosol extinction and backscatter. The narrow band filter is a key component, for which two novel approaches are currently being used: NASA Langley Research Center has implemented a wide-angle Michelson interferometer in the second version of their airborne HSRL, and Montana State University is using a spherical Fabry-Perot interferometer in a ground based HSRL. In this research, a comprehensive comparative analysis of these two interferometric filters is performed, the result of which is a methodology for the design of narrow band filters for HSRL systems. The techniques presented identify the critical components and analyze the performance of each filter based on the spectral and angular properties, as well as the efficiency.
3
Hoffman, David Swick. „Confocal Fabry-Perot interferometer based high spectral resolution LIDAR“. Diss., Montana State University, 2012. http://etd.lib.montana.edu/etd/2012/hoffman/HoffmanD1212.pdf.
Annotation:
A high spectral resolution lidar (HSRL), which has been developed at Montana State University, utilizes a confocal Fabry-Perot interferometer (CFP) to separate aerosol and molecular lidar returns for the purpose of atmospheric aerosol observation. The CFP is actively frequency locked to the laser-transmitter via a novel frequency modulation based technique. 532 nm second harmonic light from a frequency doubled Nd:YAG injectionseeded, pulsed laser is directed vertically into the atmosphere. Light backscattered by the atmosphere is collected using a commercial Schmidt-Cassegrain telescope. The secondharmonic return signal is mode matched into a tunable CFP interferometer with a free spectral range of 7.5 GHz and a finesse of 50.7 (312) at 532 nm (1064 nm) placed in the optical receiver for spectrally filtering the molecular and aerosol return signals. The light transmitted through the CFP is used to monitor the aerosol return signal while the light reflected by the CFP is used to monitor the molecular return signal. Data collected with the HSRL are presented and inversion results are compared to those from a co-located solar radiometer, demonstrating the successful operation of the instrument. The HSRL presented in this dissertation provides an important means to study atmospheric aerosols, which are the largest source of uncertainty in current global climate models. Additionally, the novel frequency locking technique allows for the future development of multi-wavelength HSRL instruments, and the robustness of the frequency locked optical filter allows for the deployment of future air and space based HSRL instruments.
4
FARINELLO, PAOLO. „Solid-State Lasers for High Spectral Resolution Lidar Applications“. Doctoral thesis, Università degli studi di Pavia, 2017. http://hdl.handle.net/11571/1203268.
5
Cohen, Jacob Arthur. „Measuring the electric field of picosecond to nanosecond pulses with high spectral resolution and high temporal resolution“. Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37179.
Annotation:
We demonstrate four experimentally simple methods for measuring very complex ultrashort light pulses. Although each method is comprised of only a few optical elements, they permit the measurement of extremely complex pulses with time-bandwidth products greater than 65,000. First, we demonstrate an extremely simple frequency-resolved-optical gating (GRENOUILLE) device for measuring the intensity and phase of pulses up to ~20ps in length. In order to achieve the required high spectral resolution and large temporal range, it uses a few-cm-thick second harmonic-generation crystal in the shape of a pentagon. This has the additional advantage of reducing the device's total number of components to three. Secondly, we introduce a variation of spectral interferometry (SI) using a virtually imaged phased array and grating spectrometer for measuring long complex ultrashort pulses up to 80 ps in length. Next, we introduce a SI technique for measuring the complete intensity and phase of relatively long and very complex ultrashort pulses. It involves making multiple measurements using SI (in its SEA TADPOLE variation) at numerous delays, measuring many temporal pulselets within the pulse, and concatenating the resulting pulselets. Its spectral resolution is the inverse delay range--many times higher than that of the spectrometer used. The waveforms were measured with ~ fs temporal resolution over a temporal range of ~ns and had time-bandwidth products exceeding 65,000, which to our knowledge is the largest time-bandwidth product ever measured with ~fs temporal resolution. Finally, we demonstrate a single-shot measurement technique that temporally interleaves hundreds of measurements with ~fs temporal resolution. It is another variation of SI for measuring the complete intensity and phase of relatively long and complex ultrashort pulses in a single shot. It uses a grating to introduce a transverse time delay into a reference pulse which gates the unknown pulse by interfering it at the image plane of an imaging spectrometer. It provided ~125 fs temporal resolution and a temporal range of 70 ps using a low-resolution spectrometer.
6
Appadoo, Dominique R. T. (Dominique Rupert Thierry) 1964. „Spectral simplification techniques for high resolution fourier transform spectroscopic studies“. Monash University, School of Chemistry, 2002. http://arrow.monash.edu.au/hdl/1959.1/7746.
7
Karaman, Ersin. „Road Network Extraction From High-resolution Multi-spectral Satellite Images“. Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615362/index.pdf.
Annotation:
In this thesis, an automatic road extraction algorithm for multi-spectral images is developed. The developed model extracts elongated structures from images by using edge detection, segmentation and clustering techniques. The study also extracts non-road regions like vegetative fields, bare soils and water bodies to obtain more accurate road map. The model is constructed in a modular approach that aims to extract roads with different characteristics. Each module output is combined to create a road score map. The developed algorithm is tested on 8-band WorldView-2 satellite images. It is observed that, the proposed road extraction algorithm yields 47 % precision and 70 % recall. The approach is also tested on the lower spectral resolution images with four-band, RGB and gray level. It is observed that the additional four bands provide an improvement of 12 % for precision and 3 % for recall.
Road type analysis is also in the scope of this study. Roads are classified into asphalt, concrete and unpaved using Gaussian Mixture Models. Other linear objects such as railroads and water canals may also be extracted by this process. An algorithm that classifies drive roads and railroads for very high resolution images is also investigated. It is based on the Fourier descriptors that identify the presence of railroad sleepers. Water canals are also extracted in multi-spectral images by using spectral ratios that employ the near infrared bands. Structural properties are used to distinguish water canals from other water bodies in the image.
8
Polehampton, Edward. „The ISO LWS high resolution spectral survey towards Sagittarius B2“. Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249161.
9
Martinazzo, Michele. „Cloud optical properties parameterizations for infrared high spectral resolution fast codes“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21747/.
Annotation:
Lo scopo principale di questo lavoro di tesi è quello di produrre un set di parametrizzazioni analitiche per le proprietà ottiche delle nubi e degli aerosoli, utili per essere implementate in un codice veloce di trasferimento radiativo. Il codice veloce da noi preso in considerazione è sigma-IASI-as. Allo stato attuale, questo modello incorpora delle routines di Mie, le quali vengono sfruttate per il calcolo dello spessore ottico in presenza di nubi o aerosoli. Inoltre il codice sfrutta l'approssimazione di Chou allo scopo di tener conto dello scattering della radiazione infrarossa da parte delle particelle di nube o aerosol. La parametrizzazione prodotta potrà essere sfruttata allo scopo di creare un set di tabelle consultabili dal codice,
che potranno essere usate per sostituire le routine di Mie. Lo studio sugli effetti indotti dalla implementazione della approssimazione di Chou è stata investigata considerando diversi scenari atmosferici. Il modello sfruttato per calcolare le radianze è LBLDIS. Per ogni scenario sono quindi calcolate e confrontate le due soluzioni, implementando o non implementando l’approssimazione di Chou. Una parametrizzazione in funzione del raggio della distribuzione è trovata per: l’efficienza di estinzione, l’albedo si singolo scattering, il parametro di asimmetria, e il parametro di backscattering di Chou. L’impatto e le differenze nelle radianze introdotte dall'utilizzo dell’approssimazione di Chou e della parametrizzazione delle proprietà ottiche, è valutato per diversi scenari atmosferici.
10
Matthews, Alison Mary. „High resolution spectral remote sensing of phytoplankton in the coastal zone“. Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241275.
11
Milner, Christian Rigby. „High spectral resolution remote sensing of foliar chemistry in forest ecosystems“. Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621793.
12
Prakash, Vindhiya. „Narrowband photon pairs for atoms: high resolution spectral engineering and characterisation“. Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/673390.
Annotation:
This thesis describes experimental work to generate and characterise single photons and photon pairs, with frequency content suitable for controlled interaction with cold rubidium atoms. We describe a photon-pair source, consisting of a cavity-enhanced spontaneous parametric down-conversion (CE-SPDC) system, followed by Fabry-Perot interferometer (FPI) filters, that produces narrowband photon pairs that have a bandwidth of ˜ 5 MHz. Both photons from the photon-pair source are matched to the D1 line in atomic rubidium. Type-II phase matching, a tuneable-birefringence resonator and MHz-resolution pump tuning are used to achieve independent frequency control over each photon in the pair with MHz precision, enabling them to excite different hyperfine transitions in rubidium. We have designed and implemented tuneable FPI, also with ~ MHz control over their resonance frequencies, to isolate a single frequency mode-pair from the CE-SPDC source. The filters have ~ 90 % on-resonance transmission and extinguish unwanted frequency components by over 20 dB. The thesis includes predictions of the two-photon spectra at the output of the CE-SPDC source, and also after the filters, based on existing theoretical models of CE-SPDC. We measure the two-photon linewidth, the number of modes in an emission cluster and the spacing between clusters, the second-order cross-correlation and heralded autocorrelation functions, and find good agreement with predictions. We demonstrate independent tuneability of the signal and idler frequencies by atomic absorption spectroscopy with the filtered CE-SPDC output as the light source.
We also report a technique to resolve narrow frequency differences between photons with a high frequency resolution. The technique, which we call autoheterodyne characterisation, can measure the photon-pair joint spectra by detecting the time-correlation beat-note when nondegenerate photon-pairs interfere at a beamsplitter. It implements a temporal analog of the Ghosh-Mandel effect with one photon counter and a time-resolved Hong-Ou-Mandel interference with two. We provide a complete theoretical description of the process and show how the distribution of sum and difference frequencies in the photon-pair spectrum can be obtained from measured correlation functions. Through a power spectral analysis of the correlation measurements, the strengths, linewidths and relative frequencies of the spectral content in the two-photon state is obtained. With this, it is possible to quantify the contribution of undesired frequency modes when a single mode output is required. We analyse the application of this technique to photon-pairs that are produced by narrowband pumping and are strongly anti-correlated in frequency, and to pairs with reduced frequency correlations produced by broadband pumping. Experimentally, we demonstrate this technique using photon-pairs from the filtered CE-SPDC source described in the previous paragraph, that have a frequency separation of ~ 200 MHz. From the results, we quantify the performance of the filters and verify the accuracy of our model for the two-photon joint spectra from this source.Esta tesis describe trabajos de laboratorio, que tienen como objetivo generar y caracterizar fotones individuales y pares de fotones, aptos para interactuar con átomos fríos. Para este fin, el espectro conjunto o contenido en frecuencia de los fotones pares es de particular interés. El átomo considerado en la tesis es rubidio. Primero describimos una fuente de pares de fotones, basada en el proceso de conversión paramétrica descendente espontánea (spontaneous parametric down-conversion, SPDC por sus siglas en inglés), aumentada por un resonador óptico (cavity-enhanced SPDC, o CE-SPDC). Este proceso genera pares de fotones de banda estrecha, con un ancho de banda de ≈5MHz Ambos fotones producidos por la fuente concuerdan en frecuencia con la línea D1 del rubidio atómico. La coincidencia de fases (phase matching) de tipo dos, un resonador de birrefringencia ajustable, y una bomba de frecuencia ajustable con resolución de unos MHz, son usados para conseguir control independiente sobre la frecuencia de cada fotón del par, con precisión de MHz, permitiendo que exciten diferentes transiciones hiperfinas del rubidio. Diseñamos e implementamos filtros Fabry-Perot sintonizables, también con una precisión de control de _ MHz en su frecuencia de resonancia. Con dichos filtros, demostramos la selección de pares de fotones que provienen, cada uno, de un solo modo del resonador, y por lo tanto con un ancho de banda definido por dicho modo. Los filtros tienen una transmisión del .̴ 90% en resonancia y extinguen componentes fuera de banda en 20 dB. Calculamos el espectro conjunto de los pares de fotones producidos, tanto a la salida de la fuente, como después de lo filtros, a base de modelos teóricos de CE-SPDC. Medimos el ancho de banda de ambos fotones, el número de modos de emisión en un cúmulo, el espaciado espectral entre grupos de modos cuasi-resonantes, y las funciones de correlación cruzada de segundo orden y de autocorrelación anunciada, y resultan estar en buen acuerdo con las predicciones. Demostramos un ajuste independiente de la frecuencia del fotón signal y del fotón idler mediante espectroscopía de absorción con la salida del CE-SPDC como fuente de luz. También presentamos una técnica para distinguir diferencias estrechas de frecuencia entre fotones con una gran resolución en frecuencia. Esta técnica, a la que llamamos caracterización autoheterodina, permite medir el espectro conjunto de un par de fotones mediante la detección de la correlación en tiempo de su batido (beat-note) cuando el par de fotones no-degenerados interfiere en un divisor de haz. Esta técnica implementa un análogo temporal al efecto Ghosh-Mandel con un contador de fotones y una interferencia Hong-Ou-Mandel con resolución temporal con dos. Proporcionamos una descripción teórica completa del proceso y mostramos como la distribución de la suma y diferencia de frecuencias en el espectro del par de fotones puede obtenerse a partir de las medidas de las funciones de correlación. Mediante el análisis del espectro de las medidas de correlación, se obtienen las amplitudes, anchos de línea y frecuencias relativas del contenido espectral del estado conjunto de los dos fotones. Con esto, es posible cuantificar la presencia de modos indeseados de frecuencia cuando se requiere una salida monomodo. Analizamos la aplicación de esta técnica a pares de fotones producidos por bombeo de banda estrecha y fuertemente anti-correlacionados en frecuencia, y a pares con correlaciones de frecuencia reducidas producidos por bombeo de banda ancha. Experimentalmente, demostramos esta técnica usando pares de fotones generados por la fuente descrita en el párrafo anterior, con una separación en frecuencia de .̴ 200MHz. A partir de los resultados, cuantificamos el desempeño de los filtros y verificamos la exactitud de nuestro modelo para el espectro conjunto de los dos fotones provenientes de la fuente CE-SPDC con filtros.
Fotònica
13
Kim, Jijoong. „A new recursive high-resolution parametric method for power spectral density estimation /“. Title page, table of contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09ENS/09ensk49.pdf.
14
Cossich, Marcial de Farias William <1987>. „Analysis of far-infrared (FIR) high spectral resolution data for cloud studies“. Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9487/1/Tesi_WilliamCossich.pdf.
Annotation:
The Far-Infrared Outgoing Radiation Understanding and Monitoring (FORUM) mission has recently been selected by the European Satellite Agency (ESA) as 9 th Earth Explorer mission. FORUM mission aims at studying the water vapor and clouds by filling the long-standing gap in Far-Infrared (FIR) spectral observations from space. In the framework of the FORUM mission, this thesis analyses FIR measurements to characterize the spectral signatures of radiance in presence of ice clouds. At this purpose, a cloud identification and classification code (named CIC) is implemented. CIC is an innovative machine learning algorithm, based on principal component analysis, able to perform cloud detection and scene multi-class classification. CIC is easily adaptable to different datasets and type of spectral sensors. It is firstly tested against a synthetic dataset comprising simulated measurements of the FORUM mission. Subsequently, CIC is applied to airborne interferometric data and finally it is used for the analysis of measured downwelling radiances collected in very dry conditions on the Antarctic Plateau. Provided the excellent performances of the algorithm, especially in the identification of thin cirrus clouds, CIC is adopted as the classificator in the official ESA FORUM End-to-End simulator (FE2ES). The FE2ES is a complex chain of codes used to simulate the entire FORUM mission from satellite orbit and geometry to level 2 product analysis. An extensive use of CIC is performed on ground-based radiances collected in Antarctica. The dataset is exploited to test and to optimize the CIC algorithm and for the developing of punctual statistic of cloud occurrence in the Antarctic Plateau. Meteorological conditions from this region are also analysed and correlated with the presence of clouds. The studies presented in this work showed the potentiality and the importance of the exploitation of spectral radiance measurements in the FIR for cloud identification and classification.
15
Repaka, Sunil Reddy. „Comparing spectral-object based approaches for extracting and classifying transportation features using high resolution multi-spectral satellite imagery“. Master's thesis, Mississippi State : Mississippi State University, 2004. http://library.msstate.edu/etd/show.asp?etd=etd-11082004-231712.
16
Otwell, Dwight Woodard. „Conifer Discrimination in the Sandhills of North Carolina Using High Spectral Resolution Data“. NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-07102008-165201/.
Annotation:
We investigated techniques to discriminate long leaf pine (Pinus palustris) and loblolly pine (Pinus taeda) in 126 band HyMap imagery with a 4 meter spatial resolution. Field assessment provided stand composition information, and crowns of known species were selected in the imagery to represent species types for model construction. A Quadratic Discriminant Analysis used with a likelihood ratio test was able to identify southern yellow pine with a producerâs accuracy of 98% and a userâs accuracy of 96%. The same test identified loblolly pine with a producerâs accuracy of 80% and a userâs accuracy of 49%. Longleaf pine identification had a producerâs accuracy of 60% and a userâs accuracy of 76%. Price of image acquisition, the relatively low accuracy of discrimination between longleaf and loblolly pine crowns, and inherent bias in the approach make this particular method unreliable as an option for targeting potential sites for RCW habitat restoration.
17
Myers, Richard Michael. „High spectral resolution gamma ray astronomy in the energy region 50keV to l0MeV“. Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6413/.
Annotation:
Observations of the Crab nebula region and of the unusual active galaxy NGC1275 made during a balloon flight of the Durham high spectral resolution gamma ray telescope are described. From the Crab, spectral line fluxes were detected at 79 keV (transient), 405 keV, and at 1050 keV. The first two are possible confirmation of previous results. From NGC1275, evidence of two-photon electron-positron annihilation radiation with the expected redshifted energy of 502 keV was observed. Possible interpretations are suggested.
18
Hassan-Esfahani, Leila. „High Resolution Multi-Spectral Imagery and Learning Machines in Precision Irrigation Water Management“. DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4480.
Annotation:
The current study has been conducted in response to the growing problem of water scarcity and the need for more effective methods of irrigation water management. Remote sensing techniques have been used to match spatially and temporally distributed crop water demand to water application rates. Remote sensing approaches using Landsat imagery have been applied to estimate the components of a soil water balance model for an agricultural field by determining daily values of surface/root-zone soil moisture, evapotranspiration rates, and losses and by developing a forecasting model to generate optimal irrigation application information on a daily basis. Incompatibility of coarse resolution Landsat imagery (30m by 30m) with heterogeneities within the agricultural field and potential underestimation of field variations led the study to its main objective, which was to develop models capable of representing spatial and temporal variations within the agricultural field at a compatible resolution with farming management activities. These models support establishing real-time management of irrigation water scheduling and application. The
AggieAirTM Minion autonomous aircraft is a remote sensing platform developed by the Utah Water Research Laboratory at Utah State University. It is a completely autonomous airborne platform that captures high-resolution multi-spectral images in the visual, near infrared, and thermal infrared bands at 15cm resolution. AggieAir flew over the study area on four dates in 2013 that were coincident with Landsat overflights and provided similar remotely sensed data at much finer resolution. These data, in concert with state-of-the-art supervised learning machine techniques and field measurements, have been used to model surface and root zone soil volumetric water content at 15cm resolution. The information provided by this study has the potential to give farmers greater precision in irrigation water allocation and scheduling.
19
Zara, Stephen John. „A high spectral resolution study of vegetation reflectance in the red and near infrared“. Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38204.
20
Akasheh, Osama Zaki. „Hydrological Characterization of A Riparian Vegetation Zone Using High Resolution Multi-Spectral Airborne Imagery“. DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/172.
Annotation:
The Middle Rio Grande River (MRGR) is the main source of fresh water for the state of New Mexico. Located in an arid area with scarce local water resources, this has led to extensive diversions of river water to supply the high demand from municipalities and irrigated agricultural activities. The extensive water diversions over the last few decades have affected the composition of the native riparian vegetation by decreasing the area of cottonwood and coyote willow and increasing the spread of invasive species such as Tamarisk and Russian Olives, harmful to the river system, due to their high transpiration rates, which affect the river aquatic system. The need to study the river hydrological processes and their relation with its health is important to preserve the river ecosystem.
To be able to do that a detailed vegetation map was produced using a Utah State University airborne remote sensing system for 286 km of river reach. Also a groundwater model was built in ArcGIS environment which has the ability to estimate soil water potential in the root zone and above the modeled water table. The Modified Penman- Monteith empirical equation was used in the ArcGIS environment to estimate riparian vegetation ET, taking advantage of the detailed vegetation map and spatial soil water potential layers. Vegetation water use per linear river reach was estimated to help decision makers to better manage and release the amount of water that keeps a sound river ecosystem and to support agricultural activities.
21
Cinar, Umut. „Road Extraction From High Resolution Satellite Images Using Adaptive Boosting With Multi-resolution Analysis“. Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614650/index.pdf.
Annotation:
Road extraction from satellite or aerial imagery is a popular topic in remote sensing, and there are many road extraction algorithms suggested by various researches. However, the need of reliable remotely sensed road information still persists as there is no sufficiently robust road extraction algorithm yet. In this study, we explore the road extraction problem taking advantage of the multi-resolution analysis and adaptive boosting based classifiers. That is, we propose a new road extraction algorithm exploiting both spectral and structural features of the high resolution multi-spectral satellite images. The proposed model is composed of three major componentsfeature extraction, classification and road detection. Well-known spectral band ratios are utilized to represent reflectance properties of the data whereas a segmentation operation followed by an elongatedness scoring technique renders structural evaluation of the road parts within the multi-resolution analysis framework. The extracted features are fed into Adaptive Boosting (Adaboost) learning procedure, and the learning method iteratively combines decision trees to acquire a classifier with a high accuracy. The road network is identified from the probability map constructed by the classifier suggested by Adaboost. The algorithm is designed to be modular in the sense of its extensibility, that is
new road descriptor features can be easily integrated into the existing model. The empirical evaluation of the proposed algorithm suggests that the algorithm is capable of extracting majority of the road network, and it poses promising performance results.
22
Jay, Steven Charles. „Detection of leafy spurge (Euphorbia esula) using affordable high spatial, spectral and temporal resolution imagery“. Thesis, Montana State University, 2010. http://etd.lib.montana.edu/etd/2010/jay/JayS0510.pdf.
Annotation:
Leafy spurge is a designated noxious weed. Accurate mapping and monitoring of this species are needed to understand leafy spurge's extent and spread. Current methods are based on ground crews who survey patches. Development of an affordable technique to map and monitor leafy spurge would contribute to the control of this species. High spatial, temporal, and spectral resolution imagery was used to classify the amount of leafy spurge present with ground and aerial-based imagery. A proof of concept study was performed in 2008 using ground-based images of an area infested with leafy spurge. This proof of concept project guided the development of the methods to be used for the 2009 aerial portion of the study. Thirty-five randomly selected reference points were selected in a range area in southwest Montana. These reference points were ground surveyed to record the density of leafy spurge in a 0.5-m radius area around the reference point. Images were captured approximately 108-m from the study area and classified using random forest classification. Multiple images were collected throughout the summer in order to determine at which time period leafy spurge is most easily detected. A classification using multiple image dates was also performed to determine if a time series of images improves classification. Single date accuracies were highest late in the summer with the highest single date classification achieving 83% accuracy. The multiple date classification significantly increased overall accuracy. Several aerial images were acquired in southwest Montana over the 2009 summer. Fifty randomly selected 2-m x 2-m reference areas were surveyed for percent cover of leafy spurge as well as several other variables. Aerial images were collected at flight elevations between 300-m to 460-m. Classifications were performed using random forest classifier, and both single date and multiple date classifications were performed. Leafy spurge was most accurately detected early and late in the growing season, and significant classification accuracy increases were observed with the multiple date classification. Single date accuracies achieved 90% accuracy in early June, while multiple date classifications achieved over 96% accuracy.
23
Brooks, Donald Ray. „Development of Specialized Laser Doppler Velocimeters for High Resolution Flow Profile and Turbulence Spectral Measurements“. Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/78089.
Annotation:
Fluid dynamicists are always in need of innovative instruments for flow velocity measurements. An ideal instrument would be non-intrusive, have a very fine spatial resolution as well as a very fine temporal resolution, be able to measure three-components of velocity, and be compact. Through recent advancements, laser Doppler velocimetry can now meet all of those requirements making it an important part of aerodynamicist's research toolbox.
The first paper presented in this manuscript style thesis explains the development of an advanced three-velocity component, spatially-resolving laser-Doppler velocimetry (LDV) system for highly resolved velocity measurements in situations with limited optical access. The new instrument, a next generation version of the previously developed 'comprehensive' LDV technology, enables measurements of three components of velocity and particle position in the axial direction all through a single transceiving lens. Described here is the design process and the final design for the 'compact, comprehensive' LDV (Comp²LDV). The probe was designed to achieve ± 10 micron root-mean-square uncertainties in axial particle position, which combined with the long measurement volume, allow researchers to obtain a three-velocity-component velocity statistics profiles over a span of approximately 1.5mm without the need for traversing. Results from measurements in a flat plate turbulent boundary layer very near the wall have compared favorably to data from previous studies.
The second paper focuses on the motion and evolution of coherent structures in supersonic jet flows and how that relates to the intense noise the flows generate. As a preliminary study to experimentally address these relationships, novel non-intrusive measurements using two-component laser Doppler velocimetry (LDV) have been conducted at exceptionally high data rates to lend insight into the statistical behavior of noise-generating flow structures. A new heated supersonic jet facility has been constructed to provide supersonic flow at total temperatures ratios (T₀/Tₐ) up to 3. In the present work, the instrumentation is validated via comparison of LDV measurements along the centerline of a screeching cold jet with microphone and high-speed shadowgraph results. Reynolds stress spectra are presented for an over-expanded case (nozzle pressure ratio of 3.2) of a design Mach number 1.65 nozzle operated cold (T₀/Tₐ = 1). A preliminary study was then conducted in the near-nozzle shear layer, up to x/d = 4.0, at design nozzle pressure ratio (4.58) and total temperature ratio of 2.0. Results are presented for Reynolds stress time-delay correlations and power spectra at Re_d = 1.1M for this case. The stream-wise Reynolds normal stress spectra are compared with published spectral behavior reported by other researchers, indicating a similar spectral shape in the downstream stations as previously measured with LDV and hot wire anemometry for cold jets, but which differ in shape from density-based techniques.Master of Science
24
Lee, Jong Yeol. „Integrating spatial and spectral information for automatic feature identification in high resolution remotely sensed images“. Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1600.
Annotation:
Thesis (Ph. D.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains x, 132 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 124-132).
25
McPherson, Christopher. „Refinement of CALIPSO Aerosol Retrieval Models Through Analysis of Airborne High Spectral Resolution Lidar Data“. Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/145281.
Annotation:
The deepening of scientific understanding of atmospheric aerosols figures substan¬tially into stated goals for climate change research and a variety of internationally col¬laborative earth observation missions. One such mission is the joint NASA/Centre Na¬tional d’Études Spatiales (CNES) Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission, whose primary instrument is the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP), a spaceborne two-wavelength, elastic-scatter li¬dar, which has been making continuous, global observations of atmospheric aerosols and clouds since June of 2006, shortly after its launch in April of the same year. The work presented in this dissertation consists of the development of an aerosol retrieval strategy to improve aerosol retrievals from lidar data from the CALIPSO mission, as well as a comprehensive formulation of accompanying aerosol models based on a thor¬ough analysis of data from an airborne High Spectral Resolution Lidar (HSRL) instrument. The retrieval methodology, known as the Constrained Ratio Aerosol Model-fit (CRAM) technique, is a means of exploiting the available dual-wavelength information from CAL¬IOP to constrain the possible solutions to the problem of aerosol retrieval from elastic-scatter lidar so as to be consistent with theoretically or empirically known aerosol models. Constraints applied via CRAM are manifested in spectral ratios of scattering parameters corresponding to observationally-based aerosol models. Consequently, accurate and rep¬resentative models incorporating various spectral scattering parameters are instrumental to the successful implementation of a methodology like CRAM. The aerosol models arising from this work are derived from measurements made by the NASA Langley Research Center (LaRC) airborne HSRL instrument, which has the capability to measure both aerosol scattering parameters (i.e., backscatter and extinction) independently at 532 nm. The instrument also incorporates an elastic-scatter channel at 1064 nm, facilitating the incorporation of dual-wavelength information by way of particu¬lar constraints. The intent in developing these new models is to furnish as satisfactory a basis as possible for retrieval techniques such as CRAM, whose approach to the problem of aerosol retrieval attempts to make optimal use of the available spectral information from multi-wavelength lidar, thus providing a framework for improving aerosol retrievals from CALIPSO and furthering the scientific goals related to atmospheric aerosols.
26
Kaufman, Jason R. „Spatial-Spectral Feature Extraction on Pansharpened Hyperspectral Imagery“. Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1408706595.
27
Al, saddik Hania. „Spectral and textural analysis of high resolution data for the automatic detection of grape vine diseases“. Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCK050/document.
Annotation:
La Flavescence dorée est une maladie contagieuse et incurable de la vigne détectable sur les feuilles. Le projet DAMAV (Détection Automatique des MAladies de la Vigne) a été mis en place, avec pour objectif de développer une solution de détection automatisée des maladies de la vigne à l’aide d’un micro-drone. Cet outil doit permettre la recherche des foyers potentiels de la Flavescence dorée, puis plus généralement de toute maladie détectable sur le feuillage à l’aide d’un outil multispectral dédié haute résolution.Dans le cadre de ce projet, cette thèse a pour objectif de participer à la conception et à l’implémentation du système d’acquisition multispectral et de développer les algorithmes de prétraitement d’images basés sur les caractéristiques spectrales et texturales les plus pertinentes reliées à la Flavescence dorée.Plusieurs variétés de vigne ont été considérées telles que des variétés rouges et blanches; de plus, d’autres maladies que ‘Flavescence dorée’ (FD) telles que Esca et ‘Bois noir’ (BN) ont également été testées dans des conditions de production réelles. Le travail de doctorat a été essentiellement réalisé au niveau feuille et a impliqué une étape d’acquisition suivie d’une étape d’analyse des données.La plupart des techniques d'imagerie, même multispectrales, utilisées pour détecter les maladies dans les grandes cultures ou les vignobles, opèrent dans le domaine du visible. Dans DAMAV, il est conseillé que la maladie soit détectée le plus tôt possible. Des informations spectrales sont nécessaires, notamment dans l’infrarouge. Les réflectances des feuilles des plantes peuvent être obtenues sur les longueurs d'onde les plus courtes aux plus longues. Ces réflectances sont intimement liées aux composants internes des feuilles. Cela signifie que la présence d'une maladie peut modifier la structure interne des feuilles et donc altérer sa signature.Un spectromètre a été utilisé sur le terrain pour caractériser les signatures spectrales des feuilles à différents stades de croissance. Afin de déterminer les réflectances optimales pour la détection des maladies (FD, Esca, BN), une nouvelle méthodologie de conception d'indices de maladies basée sur deux techniques de réduction de dimensions, associées à un classifieur, a été mise en place. La première technique de sélection de variables utilise les Algorithmes Génétiques (GA) et la seconde s'appuie sur l'Algorithme de Projections Successives (SPA). Les nouveaux indices de maladies résultants surpassent les indices de végétation traditionnels et GA était en général meilleur que SPA. Les variables finalement choisies peuvent ainsi être mises en oeuvre en tant que filtres dans le capteur MS.Les informations de réflectance étaient satisfaisantes pour la recherche d’infections (plus que 90% de précision pour la meilleure méthode) mais n’étaient pas suffisantes. Ainsi, les images acquises par l’appareil MS peuvent être ensuite traitées par des techniques bas-niveau basées sur le calcul de paramètres de texture puis injectés dans un classifieur. Plusieurs techniques de traitement de texture ont été testées mais uniquement sur des images couleur. Une nouvelle méthode combinant plusieurs paramètres texturaux a été élaborée pour en choisir les meilleurs. Nous avons constaté que les informations texturales pouvaient constituer un moyen complémentaire non seulement pour différencier les feuilles de vigne saines des feuilles infectées (plus que 85% de précision), mais également pour classer le degré d’infestation des maladies (plus que 74% de précision) et pour distinguer entre les maladies (plus que 75% de précision). Ceci conforte l’hypothèse qu’une caméra multispectrale permet la détection et l’identification de maladies de la vigne en plein champ‘Flavescence dorée’ is a contagious and incurable disease present on the vine leaves. The DAMAV project (Automatic detection of Vine Diseases) aims to develop a solution for automated detection of vine diseases using a micro-drone. The goal is to offer a turnkey solution for wine growers. This tool will allow the search for potential foci, and then more generally any type of detectable vine disease on the foliage. To enable this diagnosis, the foliage is proposed to be studied using a dedicated high-resolution multispectral camera.The objective of this PhD-thesis in the context of DAMAV is to participate in the design and implementation of a Multi-Spectral (MS) image acquisition system and to develop the image pre-processing algorithms, based on the most relevant spectral and textural characteristics related to ‘Flavescence dorée’.Several grapevine varieties were considered such as red-berried and white-berried ones; furthermore, other diseases than ‘Flavescence dorée’ (FD) such as Esca and ‘Bois noir’ (BN) were also tested under real production conditions. The PhD work was basically performed at a leaf-level scale and involved an acquisition step followed by a data analysis step.Most imaging techniques, even MS, used to detect diseases in field crops or vineyards, operate in the visible electromagnetic radiation range. In DAMAV, it is advised to detect the disease as early as possible. It is therefore necessary to investigate broader information in particular in the infra-red. Reflectance responses of plants leaves can be obtained from short to long wavelengths. These reflectance signatures describe the internal constituents of leaves. This means that the presence of a disease can modify the internal structure of the leaves and hence cause an alteration of its reflectance signature.A spectrometer is used in our study to characterize reflectance responses of leaves in the field. Several samples at different growth stages were used for the tests. To define optimal reflectance features for grapevine disease detection (FD, Esca, BN), a new methodology that designs spectral disease indices based on two dimension reduction techniques, coupled with a classifier, has been developed. The first feature selection technique uses the Genetic Algorithms (GA) and the second one relies on the Successive Projection Algorithm (SPA). The new resulting spectral disease indices outperformed traditional vegetation indices and GA performed in general better than SPA. The features finally chosen can thus be implemented as filters in the MS sensor.In general, the reflectance information was satisfying for finding infections (higher than 90% of accuracy for the best method) but wasn’t enough. Thus, the images acquired with the developed MS device can further be pre-processed by low level techniques based on the calculation of texture parameters injected into a classifier. Several texture processing techniques have been tested but only on colored images. A method that combines many texture features is elaborated, allowing to choose the best ones. We found that the combination of optimal textural information could provide a complementary mean for not only differentiating healthy from infected grapevine leaves (higher than 85% of accuracy), but also for grading the disease severity stages (higher than 73% of accuracy) and for discriminating among diseases (higher than 72% of accuracy). This is in accordance with the hypothesis that a multispectral camera can enable detection and identification of diseases in grapevine fields
28
Boer, Gregory Jon. „Investigation of high spectral resolution signatures and radiative forcing of tropospheric aerosol in the thermal infrared“. Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34001.
Annotation:
An investigation of the high spectral resolution signatures and radiative forcing of tropospheric aerosol in the thermal infrared was conducted. To do so and to support advanced modeling of optical properties, a high spectral resolution library of atmospheric aerosol optical constants was developed. This library includes new optical constants of sulfate-nitrate-ammonium aqueous solutions and the collection of a broad range of existing optical constants for aerosol components, particularly mineral optical constants. The mineral optical constants were used to model and study infrared dust optical signatures as a function of composition, size, shape and mixing state. In particular, spherical and non-spherical optical models of dust particles were examined and compared to high spectral resolution laboratory extinction measurements. Then the performance of some of the most common effective medium approximations for internal mixtures was examined by modeling the optical constants of the newly determined sulfate-nitrate-ammonium mixtures. The optical signature analysis was applied to airborne and satellite high spectral resolution thermal infrared radiance data impacted by Saharan dust events. A new technique to retrieve dust microphysical properties from the dust spectral signature was developed and compared to a standard technique. The microphysics retrieved from this new technique and from a standard technique were then used to investigate the effects of dust on radiative forcing and cooling rates in the thermal IR.
29
Morampudi, Rajesh. „Development of A High Resolution Wavelength Filter and A Spatially Multiplexed Raman Imaging System“. Cleveland State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=csu1429127073.
30
Rozario, Hoimonti Immaculata. „Spectroscopic study of acetylene and hydrogen cyanide“. Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Physics and Astronomy, c2012, 2012. http://hdl.handle.net/10133/3415.
Annotation:
High-resolution molecular spectroscopy has been used to study acetylene line parameters and emission spectra of hydrogen cyanide. All acetylene spectra were recorded in our laboratory at the University of Lethbridge using a 3-channel tuneable diode laser spectrometer. N2-broadened line widths and N2-pressure induced line shifts have been measured for transitions in the v1+v3 band of acetylene at seven temperatures in the range 213–333K to obtain the temperature dependences of broadening and shift coefficients. The Voigt and hard-collision line profile models were used to retrieve the line parameters.
The line-broadening and line-shift coefficients as well as their temperature-dependent parameters have been also evaluated theoretically, in the frame work of a semi-classical approach based on an exponential representation of the scattering operator, an intermolecular potential composed of electrostatic quadrupole–quadrupole and pairwise atom–atom interactions as well as on exact trajectories driven by an effective isotropic potential. The experimental results for both N2-broadening and shifting show good agreement with the theoretical results.
We have studied the line intensities of the 1νl20←0νl20 band system from the HCN emission spectrum. The infrared emission spectrum of H12C14N was measured at the Justus-Liebig University, Giessen, Germany. The emission spectrum was analyzed with the spectrum analysis software Symath running using Mathematica as a platform. This approach allowed us to retrieve information on band intensity parameters.viii, 112 leaves : ill. ; 29 cm
31
Padgett, Miles John. „Techniques for ultra-high resolution saturation spectroscopy and laser stabilization in the 10#mu#m spectral region“. Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305843.
32
McPherson, Christopher J., und John A. Reagan. „Extension of the constrained ratio approach to aerosol retrievals from elastic-scatter and high spectral resolution lidars“. SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 2016. http://hdl.handle.net/10150/622580.
Annotation:
A methodology is presented, by which atmospheric aerosol retrievals from a standard, elastic-scatter, lidar can be constrained by using information from coincident measurements from a high spectral resolution lidar (HSRL) or Raman lidar at a different wavelength. As high spectral resolution or inelastic-scattering lidars are now being incorporated coaxially into instruments with traditional, elastic-scatter channels at different wavelengths, a standard approach is needed to incorporate or fuse the diversity of spectral information so as to make maximal use of the aerosol measurements made from the elastic-scatter channel or channels. The approach is evaluated through simulation and with data from the NASA Langley Research Center Airborne HSRL instrument. The generality and extensibility of the method is also explored and discussed in the context of aerosol modeling. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.
33
Taylor, Joseph. „Achieving 0.1 K absolute calibration accuracy for high spectral resolution infrared and far infrared climate benchmark measurements“. Doctoral thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25639.
Annotation:
Mesurer le rayonnement infrarouge de manière résolue spectralement à partir de satellites avec une très haute précision radiométrique constitue un besoin critique pour les futures missions de référence climatique. Pour les spectres de rayonnement infrarouge, il a été déterminé qu'une précision de mesure exprimée comme une erreur de température de brillance inférieure à 0,1 K est nécessaire pour la détection de tendances au-delà de la variabilité naturelle des signatures climatiques sur une décennie. Le “Space Science and Engineering Center” de l'Université du Wisconsin (UW-SSEC), avec le soutien financier du programme d'incubateur d'instrument de la NASA, a développé “l'Absolute Radiance Interferometer” (ARI). L' ARI est conçu pour répondre aux exigences nécessaires afin de réaliser des mesures de radiance absolue résolues spectralement à partir de l’espace, dans le cadre d’une mission de référence pour suivre les tendances du climat. Le défi dans le développement de capteurs infrarouges pour une telle mission est d'atteindre cette haute précision avec un design qui peut être qualifié pour le vol spatial, qui a une longue durée de vie et qui est relativement petit, simple et abordable. L’approche pour la conception de l’ARI fait usage de composants ayant un historique de vol spatial qui sont combinés en un ensemble fonctionnel pour tester les performances détaillées. La simplicité requise est réalisable en raison des grandes différences dans les exigences d'échantillonnage et de bruit par rapport à celles des sondeurs infrarouges de télédétection typiques pour la recherche ou les déploiements opérationnels pour la météo. L’aspect original de cet instrument et de cette thèse est donc la démonstration de l’atteinte de la haute précision radiométrique. Le but de cet effort est de démontrer avec succès la possibilité de telles mesures dans des conditions de laboratoire et de vide, sur un sous-ensemble de la gamme des températures de brillance attendues en orbite. Des progrès dans la compréhension de aspects instrumentaux des spectromètres ont été accomplis en lien avec la poursuite de cet objectif et sont également rapportés dans cette thèse.Spectrally resolved infrared radiances measured from orbit with extremely high absolute accuracy constitute a critical observation for future climate benchmark missions. For the infrared radiance spectra, it has been determined that a measurement accuracy, expressed as an equivalent brightness temperature error, of 0.1 K confirmed on orbit is required for signal detection above natural variability for decadal climate signatures. The University of Wisconsin Space Science and Engineering Center (UW-SSEC), with funding support from the NASA Instrument Incubator Program (IIP), developed the Absolute Radiance Interferometer (ARI). The ARI is designed to meet the uncertainty requirements needed to establish a spectrally resolved thermal infrared climate benchmark measurements from space. The challenge in the infrared sensor development for a climate benchmark measurement mission is to achieve this ultra-high accuracy with a design that can be flight qualified, has long design life, and is reasonably small, simple, and affordable. In this area, our design approach for the Absolute Radiance Interferometer (ARI) made use of components with strong spaceflight heritage (direct analogs with high TRL) combined into a functional package for detailed performance testing. The required simplicity is achievable due to the large differences in the sampling and noise requirements for the benchmark climate measurement from those of the typical remote sensing infrared sounders for weather research or operations. The new aspect of the interferometer development is the ultra high absolute accuracy sought, and is the subject of this thesis. The goal of this effort is to successfully demonstrate this measurement capability under laboratory and vacuum conditions, over a subset of the range of equivalent earth scene brightness temperatures expected on-orbit. Advances in instrumental aspects have been achieved in the pursuit of this goal.
34
Adamczyk, Aleksandra Katarzyna. „Analysis of the high-resolution ro-vibrational spectrum of DC3N in the far and mid infrared regions“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21732/.
Annotation:
Cyanoacetylene HC3N is a molecule of great astronomical importance and it has been observed in many interstellar environments. Its deuterated form DC3N has been detected in number of sources from external galaxies to Galactic interstellar clouds, star-forming regions and planetary atmospheres. All these detections relied on previous laboratory investigations, which however still lack some essential information concerning its infrared spectrum. In this project, high-resolution ro-vibrational spectra of DC3N have been recorded in two energy regions: 150 – 450 cm-1 and 1800 – 2800 cm-1. In the first window the ν7← GS, 2ν7 ← ν7, ν5 ← ν7, ν5+ν7 ← 2ν7, ν6+ν7 → 2v7, 4ν7 ← 2ν7 bands have been assigned, while in the second region the three stretching fundamental bands ν1, ν2, ν3 have been observed and analysed. The 150 – 450 cm-1 region spectra have been recorded at the AILES beamline at the SOLEIL synchrotron (France), the 1800 – 2800 cm-1 spectra at the Department of Industrial Chemistry “Toso Montanari” in Bologna. In total, 2299 transitions have been assigned. Such experimental transition, together with data previously recorded for DC3N, were included in a least-squares fitting procedure from which several spectroscopic parameters have been determined with high precision and accuracy. They include rotational, vibrational and resonance constants. The spectroscopic data of DC3N have been included in a line catalog for this molecule in order to assist future astronomical observations and data interpretation. A paper which includes this research work has been published (M. Melosso, L. Bizzocchi, A. Adamczyk, E. Cane, P. Caselli, L. Colzid, L. Dorea, B. M. Giulianob, J.-C. Guillemine, M-A. Martin-Drumel, O. Piralif, A. Pietropolli Charmet , D. Prudenzano, V. M. Rivillad, F. Tamassia, Extensive ro-vibrational analysis of deuterated-cyanoacetylene (DC3N) from millimeter wavelengths to the infrared domain, Jour. of Quant. Spectr. and Rad. Tran. 254, 107221, 2020).
35
Senay, Gabriel B. „Using High Spatial Resolution Spectral Data To Study Spatial and Temporal Variability in Corn and Soybean Management Systems /“. The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487935125879758.
36
Shibata, Kosuke. „High-sensitivity in situ imaging of atoms in an optical lattice with narrow optical transitions“. 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/185216.
37
Correia, Fábio Gonçalves. „Quality control of ultra high resolution seismic data acquisition in real-time“. Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22007.
Annotation:
Mestrado em Engenharia GeológicaA aquisicção de grandes volumes de dados durante uma campanha sísmica exige, necessariamente, mais tempo para o controlo de qualidade (QC). No entanto, o tempo de QC não pode ser extendido devido a limitações do tempo de operação, tendo de ser feito mais rápido, o que pode comprometer a qualidade. A alternativa, alocar mais pessoas e recursos para QC e melhorar a eficiência, leva a aumentos de custo e à necessidade de maiores embarcações. Além disso, o QC tradicional requer tempo de análise após a aquisição, atrasando a desmobilização da embarcação, aumentando assim os custos da aquisição. A solução proposta passou pelo desenvolvimento de um QC automático em tempo real eficiente, testando a Comparação Espetral e o Atributo Razão Sinal-Ruído - ferramentas desenvolvidas no software SPW, usado para processamento de dados sísmicos. Usando este software foi testada a deteção e identificação de dados de fraca qualidade através das ferramentas de QC automáticas e os seus parâmetros ajustados para incluir pelo menos todos os maus registos encontrados manualmente. Foi também feita a deteção e identificação de vários problemas encontrados durante uma campanha de aquisição, tais como fortes ondulações e respetiva direção, o ruído de esteira provocado pelas hélices da embarcação e consequente Trouser’s Effect e mau funcionamento das fontes ou dos recetores. A deteção antecipada destes problemas pode permitir a sua resolução atempada, não comprometendo a aquisição dos dados. Foram feitos vários relatórios para descrever problemas encontrados durante os testes de versões beta do software SPW e os mesmos reportados à equipa da Parallel Geoscience, que atualizou o software de forma a preencher os requisitos necessários ao bom funcionamento do QC em tempo real. Estas atualizações permitiram o correto mapeamento dos headers dos ficheiros, otimização da velocidade de análise das ferramentas automáticas e correção de erros em processamento dos dados em multi-thread, para evitar atrasos entre o QC em tempo real e a aquisição dos dados, adaptação das ferramentas à leitura de um número variável de assinaturas das fontes, otimização dos limites de memória gráfica e correção de valores anómalos de semelhança espetral. Algumas atualizações foram feitas através da simulação da aquisição de dados na empresa, de forma a efetuar alguns ajustes e posteriormente serem feitos testes numa campanha futura. A parametrização destas ferramentas foi alcançada, assegurando-se assim a correta deteção automática dos vários problemas encontrados durante a campanha de aquisição usada para os testes, o que levará à redução do tempo gasto na fase de QC a bordo e ao aumento da sua eficácia.
The acquisition of larger volumes of seismic data during a survey requires, necessarily, more time for quality control (QC). Despite this, QC cannot be extended due operational time constraints and must be done faster, compromising its efficiency and consequently the data quality. The alternative, to allocate more people and resources for QC to improve efficiency, leads to prohibitive higher costs and larger vessel requirements. Therefore, traditional QC methods for large data require extended standby times after data acquisition, before the vessel can be demobilized, increasing the cost of survey. The solution tested here consisted on the development of an efficient Real- Time QC by testing Spectral Comparison and Signal to Noise Ratio Attribute (tools developed for the SPW seismic processing software). The detection and identification of bad data by the automatic QC tools was made and the parameters adapted to include at least all manual QC flags. Also, the detection and identification of common problems during acquisition, such strong wave motion and its direction, strong propeller’s wash, trouser’s effect and malfunction in sources or receivers were carried out. The premature detection of these problems will allow to solve them soon enough to not compromise the data acquisition. Several problem reports from beta tests of SPW were transmitted to the Parallel Geoscience team, to be used as a reference to update the software and fulfil Real-Time QC requirements. These updates brought the correct mapping of data headers in files, optimization of data analysis speed along with multi-thread processing debug, to assure it will be running fast enough to avoid delays between acquisition and Real-Time QC, software design to read a variable number of source signatures, optimization of graphic memory limits and debugging of anomalous spectral semblance values. Some updates resulted from a data acquisition simulation that was set up in the office, to make some adjustments to be later tested on an upcoming survey. The parameterization of these tools was finally achieved, assuring the correct detection of all major issues found during the survey, what will eventually lead to the reduction of time needed for QC stage on board, as also to the improvement of its efficiency.
38
Brindley, Helen Elizabeth. „An investigation into the impact of greenhouse gas forcings on the terrestrial radiation field : sensitivity studies at high spectral resolution“. Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/8302.
39
Lévesque, Josée. „Modelling forest structure and health using high-resolution airborne imagery, investigation of spectral unmixing and spatial analysis of radiometric fractions“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60963.pdf.
40
Yu, Young Sam. „High spatial/spectral resolution X-ray observations and volumetric 3D modeling of superheated plasma in the planetary nebula BD+30°3639 /“. Online version of thesis, 2009. http://hdl.handle.net/1850/11193.
41
Damsel, Jonathan R. „Wavelength Discrimination for Spectroscopy and Spectral Imaging Using a Phased Array“. Cleveland State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=csu1579863912293855.
42
Faijan, François. „Vers une meilleure utilisation des observations du sondeur IASI pour la restitution des profils atmosphériques en conditions nuageuses“. Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0101/document.
Annotation:
Le sondeur hyperspectral infrarouge IASI, dont le premier modèle vole depuis 2006 sur le satellite défilant météorologique Metop-A, a déjà conduit a des retombées scientifiques très spectaculaires, en prévision météorologie et pour l’étude de la composition atmosphérique et du climat. Les mesures du sondeurs sont toutefois largement sous exploitées en grande partie du a la présence des nuages dans l’atmosphère. Ces derniers interagissent avec le rayonnement incident de façon hautement non-linéaire rendant le traitement de la mesure du sondeur bien plus complexe, voire parfois rédhibitoire pour accéder depuis l’espace aux propriétés des couches atmosphériques situées au-dessus du nuage, mais également en dessous dans le cas de semi-transparence. Cependant, au vue de la quantité d’informations potentielles qu’offre les sondeurs, la communauté scientifique s’intéresse de près a l’exploitation des radiances nuageuse, c’est dans ce cadre que s’inscrivent les travaux de recherche de cette thèse. Nous proposons d’étudier deux schémas nuageux radicalement différents : la clarification nuageuse et un schéma permettant de simuler la radiance nuageuse en utilisant les propriétés optique et microphysique des nuages. La première de ces méthodes, initiée par Smith et al. (1968), permet sous certaines conditions, de faire abstraction du nuage dans le pixel IASI. La méthode est basée sur l’algorithme du logiciel Scenes Heterogenes du CNES. Apres une première étape de validation, les performances de la méthode sont évaluées a travers la quantité d’information indépendante qu’offre la clarification par rapport a une chaine de traitement des radiances nuageuses mise en place au CMS. Les résultats sont favorables à la méthode testée permettant de traiter les couches atmosphériques situées sous le nuage, possédant donc une quantité plus importante. Cependant la clarification repose a la fois sur une hypothèse forte d’homogénéité atmosphérique et ne s’applique qu’à 15% des situations nuageuses. La seconde méthode est une simulation de la radiance nuageuse par des modèles de transfert radiatif rapides utilisant les propriétés optique et microphysique du nuage. Cette méthode présente l’avantage majeur d’utiliser les mêmes profils nuageux que ceux produits par les modèles de prévision numérique, laissant entrevoir l’assimilation de ces profils à partir de la mesure IASI. Cependant, l’utilisation de ces modèles de transfert radiatif rapide dans le cadre d’une assimilation de données n’en est encore qu’à ces prémices, très peu d’études ont été menées sur ce sujet. Nous proposons une étude en trois étapes permettant une utilisation en opérationnel de ces modèles de transfert radiatif. La première étape est une compréhension des modèles et de leur validité en réalisant quelques études de cas s’appuyant sur la campagne de mesures de Lindenberg. Ensuite, dans le cadre de la campagne ConcordIasi, une statistique est réalisée mettant en place des filtrage pour sélectionner uniquement les profils nuageux cohérent avec l’observation IASI. La dernière étape est une application en global, les statistiques révèlent une nette amélioration des écarts a l’ébauche grâce aux filtres, passant de 8K a 2K. Nous proposons tout au long de l’étude une discussion sur les modèles utilises (RTTOV et HISCRTM), leurs points forts et leurs défaillances. Enfin l’ultime étape, permet d’évaluer les performances des profils nuageux issus des modèles de prévision numériqueThe IASI hyperspectral infrared sounding interferometer, the first model of which has been flown on board the meteorological polar orbiting satellite MetOp-A since 2006, has already led to spectacular scientific breakthroughs in both weather forecasting and research into atmospheric composition and the climate. Measurements from the sounders are however largely underutilised, mainly because of the presence of clouds in the atmosphere. The highly non-linear way in which the clouds interact with incident radiation makes analysis of the readings much more complex, and can sometimes even prohibit access from space to the properties of not only the atmospheric layers located above the cloud, but also below them in the case of semi-transparency. However, in view of the potential amount of information offered by the sounders, the scientific community is very interested in exploiting cloud radiance. The research for this thesis stems from this interest. We plan to study two radically different cloud schemes: cloud clarification and a scheme which allows for simulation of cloud radiance by using the optical and microphysical properties of clouds. The first of these methods, initiated by Smith et al. (1968), allows us under certain conditions to disregard the cloud in the IASI pixel. This method is based on the CNES Heterogeneous Scenes software algorithm. After a first validation step, method performance is evaluated by the amount of independent information offered by the clarification, compared to a cloud radiance process chain established at CMS. The results are favorable to the tested method allowing us to deal with atmospheric layers under the cloud, which have therefore larger quantities. However clarification is based on a strong assumption of atmospheric homogeneity and only applies to 15% of cloud situations. The second method is a simulation of cloud radiance by fast radiative transfer models using the optical and microphysical properties of the cloud. The major advantage of this method is that it uses the same cloud profiles as those produced by numerical weather prediction models, allowing assimilation of these profiles from the IASI measurement. However, the use of these fast radiative transfer models in the context of data assimilation is still in the early stages, very few studies have been conducted on this topic. We are proposing a three-phase study which will allow for an operational use of these radiative transfer models. The first step is validation. This is done by conducting several case studies based on Lindenberg’s measurement campaign. Then, within the framework of the ConcordIasi campaign, a statistical analysis will be carried out by introducing filtering, to select cloud profiles which are consistent with the IASI observations. The last step is an overall application, the statistics showing a clear improvement in deviation from the draft thanks to the filters, going from 8K to 2K. Throughout the study we will discuss the models used (RTTOV and HISCRTM), their strengths and weaknesses. Finally the last step allows us to evaluate the performance of the cloud profiles obtained by the digital forecasting models
43
Arkun, Sedat. „Hyperspectral remote sensing and the urban environment : a study of automated urban feature extraction using a CASI image of high spatial and spectral resolution“. Title page, contents, research aims and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09ARM/09arma721.pdf.
44
Khosravian, Ghadikolaei Kobra [Verfasser], Ulrich [Gutachter] Löhnert, Andreas [Gutachter] Wagner und David D. [Gutachter] Turner. „CO2 Profiling in the Lower Troposphere using a High Spectral Resolution Infrared Radiometer / Kobra Khosravian Ghadikolaei ; Gutachter: Ulrich Löhnert, Andreas Wagner, David D. Turner“. Köln : Universitäts- und Stadtbibliothek Köln, 2017. http://d-nb.info/1169301487/34.
45
Rexer, Moritz [Verfasser], Christian [Akademischer Betreuer] [Gutachter] Hirt, Pavel [Gutachter] Novak und Roland [Gutachter] Pail. „Spectral Solutions to the Topographic Potential in the context of High-Resolution Global Gravity Field Modelling / Moritz Rexer ; Gutachter: Pavel Novak, Christian Hirt, Roland Pail ; Betreuer: Christian Hirt“. München : Universitätsbibliothek der TU München, 2017. http://d-nb.info/1136422773/34.
46
Rexer, Moritz Verfasser], Christian [Akademischer Betreuer] [Gutachter] Hirt, Pavel [Gutachter] Novak und Roland [Gutachter] [Pail. „Spectral Solutions to the Topographic Potential in the context of High-Resolution Global Gravity Field Modelling / Moritz Rexer ; Gutachter: Pavel Novak, Christian Hirt, Roland Pail ; Betreuer: Christian Hirt“. München : Universitätsbibliothek der TU München, 2017. http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20170531-1349781-1-7.
47
Seaman, Shane Thomas. „Material Related Effects on the Structural Thermal Optical Performance of a Thermally Tunable Narrowband Interferometric Spectral Filter“. Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/90799.
Annotation:
High Spectral Resolution Lidar (HSRL) is a backscatter lidar technique that employs an optical/spectral filter to distinguish between particulate (Mie) and molecular (Rayleigh) backscattered light. By separating the two types of returns, higher accuracy measurements are possible that will enable improved climate models, air quality measurements, and climate forecasting. A spaceborne HSRL instrument can provide great impact in these areas by enabling near-continuous measurements across the Earth, however the optical filter technology has typically been too complex for reliable long-duration space flight due to the need for complicated and costly electro-optic feedback loops, extra alignment detectors, and additional laser sources. Furthermore, these complexities limit the filter from use in other applications. In this research, a high-performance, ultra-narrowband interferometric optical filter with a specific thermo-optical behavior has been designed and built. The interferometer has been designed such that it can be reliably adjusted/tuned by simply monitoring and adjusting the temperature. The greatly reduced operational complexity was made possible through high-accuracy thermal characterization of the interferometer materials, combined with detailed Structural-Thermal-Optical-Performance (STOP) modeling to capture the complicated interactions between the materials. The overall design process, fabrication procedures, and characterization of the optical filter are presented.Doctor of Philosophy
LiDAR (an acronym for Light Detection and Ranging) is a technology that can be used to measure properties of the atmosphere. It is similar to radar, but uses much smaller light waves rather than larger radio waves, enabling more detailed information to be obtained. High Spectral Resolution Lidar (HSRL) is a lidar technique that uses a high precision optical filter to distinguish between light that scatters from particulates (such as dust, smoke, or fog) and light that scatters from molecules (such as oxygen, nitrogen, or carbon dioxide) in the atmosphere. By separating the two types of backscattered light, higher accuracy measurements are possible that will enable improvements in climate models, air quality measurements, and climate forecasting. A spaceborne HSRL instrument can provide great impact in these areas by enabling near-continuous measurements across the Earth; however, the optical filter technology has typically been too complex for reliable long-duration spaceflight due to the need for complicated and expensive additional hardware. In this research, a high-performance HSRL optical filter that can be reliably operated by simply monitoring and adjusting the temperature has been designed, built, and tested. The greatly-reduced operational complexity has been made possible through a new process that enables more accurate prediction of the complicated interactions between the materials of the optical filter. This process is based on a combination of high-accuracy characterization of the materials and detailed structural-thermal-optical-performance (STOP) modeling. The overall design process, fabrication procedures, and characterization of the optical filter are presented.
48
Warren, Georgina. „Developing land management units using Geospatial technologies: An agricultural application“. Thesis, Curtin University, 2007. http://hdl.handle.net/20.500.11937/740.
Annotation:
This research develops a methodology for determining farm scale land managementunits (LMUs) using soil sampling data, high resolution digital multi-spectral imagery (DMSI) and a digital elevation model (DEM). The LMUs are zones within a paddock suitable for precision agriculture which are managed according to their productive capabilities. Soil sampling and analysis are crucial in depicting landscape characteristics, but costly. Data based on DMSI and DEM is available cheaply and at high resolution.The design and implementation of a two-stage methodology using a spatiallyweighted multivariate classification, for delineating LMUs is described. Utilising data on physical and chemical soil properties collected at 250 sampling locations within a 1780ha farm in Western Australia, the methodology initially classifies sampling points into LMUs based on a spatially weighted similarity matrix. The second stage delineates higher resolution LMU boundaries using DMSI and topographic variables derived from a DEM on a 10m grid across the study area. The method groups sample points and pixels with respect to their characteristics and their spatial relationships, thus forming contiguous, homogenous LMUs that can be adopted in precision agricultural applications. The methodology combines readily available and relatively cheap high resolution data sets with soil properties sampled at low resolution. This minimises cost while still forming LMUs at high resolution.The allocation of pixels to LMUs based on their DMSI and topographic variables has been verified. Yield differences between the LMUs have also been analysed. The results indicate the potential of the approach for precision agriculture and the importance of continued research in this area.
49
Warren, Georgina. „Developing land management units using Geospatial technologies: An agricultural application“. Curtin University of Technology, Department of Spatial Sciences, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=17509.
Annotation:
This research develops a methodology for determining farm scale land managementunits (LMUs) using soil sampling data, high resolution digital multi-spectral imagery (DMSI) and a digital elevation model (DEM). The LMUs are zones within a paddock suitable for precision agriculture which are managed according to their productive capabilities. Soil sampling and analysis are crucial in depicting landscape characteristics, but costly. Data based on DMSI and DEM is available cheaply and at high resolution.The design and implementation of a two-stage methodology using a spatiallyweighted multivariate classification, for delineating LMUs is described. Utilising data on physical and chemical soil properties collected at 250 sampling locations within a 1780ha farm in Western Australia, the methodology initially classifies sampling points into LMUs based on a spatially weighted similarity matrix. The second stage delineates higher resolution LMU boundaries using DMSI and topographic variables derived from a DEM on a 10m grid across the study area. The method groups sample points and pixels with respect to their characteristics and their spatial relationships, thus forming contiguous, homogenous LMUs that can be adopted in precision agricultural applications. The methodology combines readily available and relatively cheap high resolution data sets with soil properties sampled at low resolution. This minimises cost while still forming LMUs at high resolution.The allocation of pixels to LMUs based on their DMSI and topographic variables has been verified. Yield differences between the LMUs have also been analysed. The results indicate the potential of the approach for precision agriculture and the importance of continued research in this area.
50
Xia, Ye, und 夏晔. „High resolution spectroscopy of scandium monohalides“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49617886.
Annotation:
This thesis reports the study of the molecular and electronic structure of scandium monohalides using the technique of laser ablation/reaction with supersonic free jet expansion used for producing the target molecules and laser induced fluorescence (LIF) spectroscopy for recording their electronic transition spectrum. The scandium diatomic molecules studied in this work were scandium monoiodide (ScI) and scandium monobromide (ScBr), which were produced by the reaction of Sc atoms with 2% CH3I and 2% C2H5Br gases seeded in Ar carrier gas, respectively. The LIF spectrum of the electronic transition of ScI and ScBr were recorded in the visible and near infrared spectral region between 613 and 854 nm. The analysis of the high resolution electronic spectra of ScI and ScBr yielded molecular constants and information of electronic structures. For all the transition bands observed, rotationally-resolved transition lines were fit to a theoretical model to retrieve molecular constants for both upper and lower electronic states.
For the ScI molecule, seven vibrational bands of the D1П –X^1 Σ^+ system were recorded and analyzed. Accurate molecular constants for the v = 0 – 2 levels of the D^1П state and the v = 0 – 3 levels of the X^1 Σ^+ state were obtained. The equilibrium bond lengths, re (Å), for the electronic states of ScI were determined as follows:
ScI X^1 Σ^+ D^1П
r_e(Å) 2.6078 2.7146
For the ScBr molecule, three electronic transition systems were recorded and analyzed, which include six vibrational bands of the C^1 Σ^+– X^1 Σ^+ system, seven vibrational bands of the e^3Δ–a^3Δsystem and two vibrational bands of the d3Φ – a3Δ system. Rotationally resolved transition lines of both Sc79Br and Sc81Br isotopes were observed and analyzed. Least-squares fitting of the measured line positions yielded accurate molecular constants for the v = 0 – 2 levels of the X^1 Σ^+ state, the v = 0 – 3 levels of the C^1 Σ^+ state, the v = 0 and 1 levels of the d3Φ state and the v = 0 – 2 levels of both e3Δ and a3Δ states, respectively. The equilibrium bond lengths, re (Å), determined for electronic states of ScBr are given as follows:
ScBr X^1 Σ^+ a^3Δ C^1 Σ^+
r_e(Å) 2.3806 2.4767 2.4776
A molecular orbital (MO) energy level diagram has been used to examine the electronic configurations giving rise to the different observed electronic states of ScI and ScBr. An attempt has been made to put the MOs of all the scandium monohalides under a single picture. A comparison of the molecular constants for the different electronic states of scandium monohalides indicates a weakening of the chemical bonding between the scandium atom and the halogen atoms down the group.published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy