Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"H-alpha"”.
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Development of an H-Alpha Index for the Detection of PMS Candidates in Young Open Clusters
<p>One phase of formation of medium- and low-mass stars is the optically visible phase known as the pre-main-sequence or PMS phase. In order to further the understanding of this phase, more of these PMS objects need to be identified and classified. Previous techniques have used photometry to …
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The Scattering of H-alpha Emission Associated with the Rosette Nebula in the Monoceros Region Studied Using Polarimetry
… cooled CCD camera to image diffuse, extended H-alpha emission over a 10° angular extent. A rotating polarizer device was placed in front of the H-alpha filter with images recorded at every 45° with respect to a fiducial setting. Stoke's parameters and were obtained and polarization maps of …
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Tools, techniques, and early results in studies of 21 cm, Lyman-alpha, and H-alpha emission from the cosmic dawn
We present advances in antenna characterization for low frequency radio observations of 21 cm emission from the Epoch of Reionization (EOR). Using satellite transmissions as probe signals, we map the all-sky, high dynamic range antenna response of the Murchison Widefield Array (MWA) and the …
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Diagnostic Development of Gas Delivery and Viewing System for Analysing the Electric Field Stark Effect on H-Alpha Light Emissions close to a Plasma Excitation Antenna
… the Stark splitting and polarization of Balmer-alpha light emissions emanating from a supersonic hydrogen gas beam injected into the plasma volume directly under the antenna system could be used to give information about the sheath field and a better understanding of near field ion heating …
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Diagnostic Development of Gas Delivery and Viewing System for Analysing the Electric Field Stark Effect on H-Alpha Light Emissions close to a Plasma Excitation Antenna
… the Stark splitting and polarization of Balmer-alpha light emissions emanating from a supersonic hydrogen gas beam injected into the plasma volume directly under the antenna system could be used to give information about the sheath field and a better understanding of near field ion heating …
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An Arcminute-Resolution Imaging Study of the H-alpha & [S II] Emission of the ISM from the Local Perseus Arm Using the Virginia Tech Spectral-Line Survey
… greater than -15 degrees. The Wisconsin Hydrogen-Alpha Mapper (WHAM) studies the kinematics and distribution of this same material on an angular scale of one degree. Comparing the spatially-resolved images of the VTSS with WHAM's high spectral resolution images shows that the ISM's characteristics …
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Investigations of Bicyclo(3.1.1)heptane Terpenes in Higher Plants: Stereochemistry of Pinene Biosynthesis and Isolation of Bergamoten-12-Oic Acids
… (GPP) to the bicyclic monoterpenes (+)-$\alpha$-pinene (cyclase I) and ($-$)-$\alpha$-pinene and ($-$)-$\beta$-pinene (cyclase II). The stereochemical course of these cyclizations at the gem dimethyl position of the pinene products was investigated. (6E)- (8-$\sp3$H) GPP was synthesized in …
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The Nature of Emission-Line Galaxies in Hierarchical Cosmologies
… In particular, we focus on the properties of Ly-alpha and H-alpha emitters, due to their many cosmological applications being considered for current and future observational studies. By combining a semianalytical model with a large N-body simulation we predict the clustering of Ly-alpha emitters. …
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Contributions of aromatic pairs of human Gamma-D-Crystallin to its folding, stability, aggregation, and interaction with human Alpha B-Crystallin
… with the chaperone human aB-crystallin (H[alpha][Beta]-Crys). H[gamma]D-Crys is a highly stable protein that remains folded in the nucleus of the eye lens for the majority of an individual's lifetime. Like other [Beta][gamma]-crystallins, H[gamma]D-Crys exhibits two homologous crystallin …
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Development of advanced algorithms to detect, characterize and forecast solar activities
… feature on the bright solar disk in H[alpha] (Hydrogen-alpha) full-disk solar images. In this dissertation, an automatic solar filament detection and characterization method is presented. The investigation illustrates that the statistical distribution of the Laplacian filter responses …
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Analyzing Spectra of Type Iin Supernovae and their Host Environments To Determine If Some Arise From Runaway Progenitors
… is a signicant offset in the peak of the SN H-alpha emission with respect to the predicted H-alpha peak wavelength of the host galaxy at the SN position along the slit. An offset of 30 km/s or greater may imply a runaway progenitor star, ejected via dynamical interaction or as the mass-gaining …
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The development of automatic and solar imaging techniques for the accurate detection, merging, verification and tracking of solar filaments
… by observing and analysing successive solar H-alpha images. After filament regions are obtained from individual H-alpha images, a NN classifier is used to categorize the detected filaments as Disappeared Filaments (DFs) or Miss-Detected Filaments (MDFs). Features such as Area, Length, Mean, …
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Direct observation of fast protein folding: Distinct nanosecond and microsecond events in the folding of apomyoglobin
… tryptophan fluorescence (residue 14 in the A alpha helix) serves as a local probe of the A-helix and the disposition of the H alpha helix. Methionine (residue 131 in the H-helix) quenching of tryptophan fluorescence at the interface of the A- and H-helices in the compact or native-like …
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A Study on Quenching and Galaxy Growth in z~1 Clusters using HST WFC3 Grism Observations
… for the construction of spatially resolved H$\alpha$ maps, providing the possibility to directly observe environmental quenching at $z\sim1$ for the first time. This allows us to understand the detailed physics behind environmental quenching mechanisms and how they operate on galaxies at this …
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ON THE LYAPUNOV-TYPE DIAGONAL STABILITY
… types of matrix stability involving a partition alpha of {1,..., n}. We introduce the notions of additive H(alpha)-stability and P_0(alpha)-matrices, extending those of additive D-stability and nonsingular P_0-matrices. Several new results are developed, connecting additive H(alpha)-stability and …
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Image enhancement techniques applied to solar feature detection
… of filaments in solar images. Series of H-alpha full-disk images are taken in regular time intervals to observe the changes of the solar disk features. In each picture, the solar chromosphere filaments are identified for further evolution examination. The initial preprocessing step involves …
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Toward accurate free energy calculations in biomolecular simulation: advances in Markov model reweighting and expanded ensemble method
… NOE distances, chemical shifts, and $³J_H^N$ $H^\alpha$ couplings. The resulting folding landscapes accurately capture the effects of subtle chemical modifications on stability (≤2 kJ/mol changes), aligning with experimental trends and outperforming prior NAMFIS estimates, demonstrating robustness …
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Automatic solar feature detection using image processing and pattern recognition techniques
… filaments have been successfully applied on H[alpha] full-disk images that are continuously obtained at Big Bear Solar Observatory (BBSO). For automatically detecting and classifying CMEs, the image enhancement, segmentation, and pattern recognition techniques are applied to Large Angle …
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New facet of solar activities revealed by high-resolution imaging at he i 10830 Å
… than other chromospheric lines, such as H[alpha] 6563 [Angstrom] or Ca II 8542 [Angstrom], making the photosphere visible as a background. In this way, the solar activity could be traced from the photosphere, the chromosphere to the transition region. The purpose of the present work has …
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Dynamische Stabilisierung von Hochgeschwindigkeitswolken im galaktischen Halo
… compact HVC. In addition, the observed strong H/alpha fluxes from cloud edges can be explained by applying the critical velocity effect to the magnetic barrier. In a second part, the thesis addresses the phenomenon of cometary ion-tail disconnection events (DE) in terms of the theory of magnetic …
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