Tesis sobre el tema "Neutral mask"
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Przibislawsky, Csilla. "Authentic neutral mask : a new method of drama therapy". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ47878.pdf.
Texto completoCui, Jun. "Analysis of Titan's Neutral Upper Atmosphere from Cassini Ion Neutral Mass Spectrometer Measurements in the Closed Source Neutral Mode". Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195580.
Texto completoWheeler, Susan F. "Structural determination of complex anionic oligosaccharides by mass spectrometry". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365367.
Texto completoChen, Xiaohong. "Neutralization-reionization mass spectrometric and computational studies of elusive neutral intermediates /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8643.
Texto completoNogowski, René. "Precision Measurement of the Mass Difference of Neutral and Charged B Mesons". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1200514656539-83248.
Texto completoLenkewitz, Mark [Verfasser]. "Neutral Pion Electroproduction off Light Nuclei in Chiral Perturbation Theory / Mark Lenkewitz". Bonn : Universitäts- und Landesbibliothek Bonn, 2013. http://d-nb.info/1045872075/34.
Texto completoNogowski, René. "Precision Measurement of the Mass Difference of Neutral and Charged B Mesons". Doctoral thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A23992.
Texto completoSangaroon, Siriyaporn. "Study of Collimated Neutron Flux Monitors for MAST and MAST Upgrade". Doctoral thesis, Uppsala universitet, Tillämpad kärnfysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-221591.
Texto completoWoods, P. J. "Mass measurements of light neutron rich nuclei". Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374579.
Texto completoKlimek, Iwona. "Modelling and Measurements of MAST Neutron Emission". Doctoral thesis, Uppsala universitet, Tillämpad kärnfysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-282122.
Texto completoParry, Christopher Mark. "Spectroscopy of neutron deficient mass A=130 nuclei". Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313864.
Texto completoChen, Hongwen. "Investigations of ionic and neutral species in the gas phase by tandem mass spectrometry". Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7647.
Texto completoBekele, Selemon. "Neutral kaon correlations in Au-Au collisions at center of mass energy of 200 GeV per nucleon pair". The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1086177649.
Texto completoViel, Simon. "Search for new neutral high-mass resonances decaying into muon pairs with the ATLAS detector". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/49948.
Texto completoScience, Faculty of
Physics and Astronomy, Department of
Graduate
Savaloni, Hadi. "Elastic scattering of 3.0 MeV polarised neutrons by medium mass nuclei". Thesis, University of Edinburgh, 1985. http://hdl.handle.net/1842/11370.
Texto completoCaamano, Monica. "New isomers in the neutron-rich A~190 mass region". Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/844621/.
Texto completoKrauss, Miriam Ilana. "X-ray spectroscopy of neutron star low-mass X-ray binaries". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/45408.
Texto completoIncludes bibliographical references (p. 133-150).
In this thesis, I present work spanning a variety of topics relating to neutron star lowmass X-ray binaries (LMXBs) and utilize spectral information from X-ray observations to further our understanding of these sources. First, I give an overview of important X- ray astrophysics relevant to the work I present in subsequent chapters, as well as information about the X-ray observatories from which I obtained my data. In the next three chapters, I consider spectra-both high- and low-resolution--of accretion-powered millisecond X-ray pulsars, a unique and relatively new class of objects. In addition to analysis of the pulsar XTE J1814-338, I compare a broader sample of pulsars with a sample of atoll sources in order to better understand why the latter class do not contain persistently pulsating neutron stars. In particular, I test the hypothesis that pulsations in the atoll sources are suppressed by a high-optical- depth scattering region. Using X-ray color-color diagrams to define a selection criterion based on spectral state, I analyze Rossi X-ray Timing Explorer (RXTE) spectra from all the sources, and use a Comptonization model to obtain measurements of their optical depths. I then discuss efforts to spatially resolve X-ray jets from the accretion-powered millisecond pulsar SAX J1808.4-3658 and the Z source XTE J1701-462. Each was observed by the Chandra X-ray Observatory to produce a high-spatial-resolution image. This work was motivated in part by my analysis of XTE J1814-338, which found an apparent excess of infrared flux which could be attributed to jet emission. Next, I discuss the measured temperatures of thermonuclear X-ray bursts. The detection of line features in these bursts, and hence from the surfaces of neutron stars, has been an important goal for high-resolution X-ray spectroscopy. A measurement of the wavelengths of identified line features would yield a measurement of the neutron star's gravitational redshift, which would help constrain current models for the neutron star equation of state.
(cont.) Although such a measurement has been made for one source, other searches have not been able to repeat this measurement. I consider the effects of burst temperature on the formation of discrete spectral features, using a large sample of bursts observed by the RXTE PCA. Finally, I present analysis of high-resolution Chandra HETG spectra of a sample of Galactic LMXBs. High-resolution spectra are able to resolve line features, such as the prominent Ne and O emission lines in the ultracompact X-ray binary 4U 1626-67. They also allow for more precise measurements of photoelectric absorption edges, which can otherwise hinder the determination of continuum spectral components, particularly in the lower-energy spectral regions.
by Miriam Ilana Krauss.
Ph.D.
Lin, Dacheng. "The accretion process in neutron-star low-mass X-ray binaries". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/62866.
Texto completoThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 207-221).
There had been long-standing fundamental problems in the spectral studies of accreting neutron stars (NSs) in low-mass X-ray binaries involving the X-ray spectral decomposition, the relations between subtypes (mainly atoll and Z sources), and the origins of different X- ray states. Atoll sources are less luminous and have both hard and soft spectral states, while Z sources have three distinct branches (horizontal(HB)/normal(NB)/flaring(FB)) whose spectra are mostly soft. I analyzed more than twelve-year RXTE observations (~ 2500 in total) of four atoll sources Aql X-1, 4U 1608-522, 4U 1705-44, and 4U 1636-536. I developed a hybrid spec- tral model for accreting NSs. In this model, atoll hard-state spectra are described by a single-temperature blackbody (BB), presumed to model emission from the boundary layer where the accreted material impacts the NS surface, and a strong Comptonized compo- nent, modeled by a cutoffpl power law (CPL). Atoll soft-state spectra are described by two thermal components, i.e., a multicolor disk (MCD) and a BB, with additional weak Comp- tonized component, modeled by a single power law. I found that the accretion disk in most of the soft state is truncated at a constant value, most probably at the innermost stable circular orbit (ISCO), predicted by general relativity. This allows us to derive upper limits of magnetic fields on the NS surface of the above four atoll sources. The apparent emission area of the boundary layer is small, ~1/16 of the whole NS surface, but is fairly constant, spanning the hard and soft states. All this was not seen if the classical models for thermal emission plus high Comptonization were used instead. By tracking the accretion rate onto the NS surface, I inferred a strong mass jet in the hard state. My study of 4U 1705-44 using broadband spectra from Suzaku and BeppoSAX supported the above results. From my spectral study of the above four atoll sources, I also found that in a part of the soft state with frequent occurrences of kilohertz quasi-periodic oscillations (kHz QPOs), the accretion disk appears to be truncated at larger radii than in other parts of the soft state where the disk is presumably truncated at the ISCO. Thus the production of kHz QPOs in accreting NSs should be closely related to the behavior of the accretion disk. It is well known that the kHz QPO amplitude spectrum tracks the BB, even though we see no changes in the BB spectral evolution track when kHz QPOs are present. The simplest interpretation is that accretion oscillations are imparted in the inner disk and then seen as the waves impact the NS surface in the boundary layer. The transient XTE J1701-462 (2006-2007) is the only source known to exhibit properties of both the Z and atoll types. I carried out the state/branch classifications of all the ~900 RXTE observations. The Z-source branches evolved substantially in the X-ray color-color diagram during this outburst. In the decay, the HB, NB and FB disappeared successively, with the NB/FB transition evolving to the atoll-source soft state. Spectral analyses using my new spectral model show that the inner disk radius maintains at a nearly constant value, presumably at ISCO, when the source behaves as an atoll source in the soft state, but increases with accretion rates when the source behaves as a Z source at high luminosity. We interpreted this as local Eddington limit effects and advection domination in the accretion disk. The disks in the two Z vertices probably represent two stable accretion configurations, and we speculate that the lower (NB/FB) vertex represents a standard thin disk and the upper (HB/NB) vertex a slim disk. The changes in the accretion rate are responsible for movement of Z-source branches and the evolution from one source type to another. However, the three Z-source branches are caused by three mechanisms that operate at a roughly constant accretion rate. The FB is an instability tied to the Eddington limit. It is formed as the inner disk radius temporarily decreases toward the ISCO. The NB is traced out mostly due to changes in the boundary layer emission area, as a result of the system transiting from a standard thin disk to a slim disk. The HB is formed with the increase in Comptonization, consistent with strong radio emission detected from this branch.
by Dacheng Lin.
Ph.D.
Ryan, Garrett. "Maximum Mass Restraint of Neutron Stars: Quarks, Pion, Kaons, and Hyperons". Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/cmc_theses/1535.
Texto completoGarcia, Krystine. "Bioinformatics Pipeline for Improving Identification of Modified Proteins by Neutral Loss Peak Filtering". Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1440157843.
Texto completoDeWolf, R. S. "Charged and neutral particle production in proton-antiproton interactions at 200 and 900 GeV centre of mass energies". Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481568.
Texto completoWilson, Roderick Charles. "The design, construction and characterisation of an ion optical system for Sputtered Neutral and Secondary Ion Mass Spectrometry". Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334920.
Texto completoCui, J., Y. T. Cao, P. P. Lavvas y and T. T. Koskinen. "THE VARIABILITY OF HCN IN TITAN’S UPPER ATMOSPHERE AS IMPLIED BY THE CASSINI ION-NEUTRAL MASS SPECTROMETER MEASUREMENTS". IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/621401.
Texto completoBlom, Erik. "Characterization of γ-rays at MAST". Thesis, Uppsala universitet, Tillämpad kärnfysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388424.
Texto completoAl-Garni, Sareh D. "Search for long lived isomers in the neutron-rich mass 180 region". Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/843292/.
Texto completoAllen, Jessamyn Leigh. "Accretion flows and neutron star heating in low-mass X-ray binaries". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/115023.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references (pages 149-166).
X-ray binaries are excellent test beds for studies of high-energy accretion flows and the properties of compact objects. Neutron star (NS) low-mass X-ray binaries (LMXBs) vary in brightness by almost 8 orders of magnitude and are hosts to diverse accretion flows, transporting varying amounts of energy and mass toward the central NS, as well as expelling significant mass from the binary. This thesis aims to shed light on the accretion flow properties across the mass and luminosity scale, with particular emphasis on constraining the matter accreted on the neutron star surface and the resulting heating, which has important implications for measurements of the NS mass and radius. We have utilized X-ray instruments with substantially different sensitivities in flux and resolving power, each suited to our focused study of the accretion flows in a particular luminosity regime. In our study of the accretion disk wind in GX 13+1, we analyzed the Chandra High-Energy Transmission Grating spectrum of the NS binary accreting near its Eddington limit. We found multiple plasmas with different ionization states and velocities produce the observed absorption complex, in contrast to previous analyses that only found one absorption zone. The accretion disk wind expels mass from the disk at a rate comparable to the accretion onto the NS, and is consistent with a Comptonheated outflow, the driving mechanism likely behind all accretion disk winds in NS LMXBs and, possibly, all BH LXMBs. Frequent monitoring with the Swift X-Ray Telescope allowed us to observe SAX J1750.8-2900 in the relatively short-lived transition between outburst and quiescence. We found its X-ray spectrum softens towards lower luminosities, which can either be due to a radiatively-inefficient accretion flow or an increasing contribution of the boundary layer emission as the source's flux decreases. This work contributes to the establishment of spectral softening as a common property of the accretion flow in NS LMXBs between outburst and quiescence. We also found the transition does not produce significant NS heating. In our studies of NS LMXB quiescent emission, we utilized an XMM-Newton observation of Cen X-4 while the source was at its brightest quiescent luminosity ever recorded. We found the first evidence of multi-temperature thermal emission in a non-pulsing quiescent NS. We have interpreted the hotter of the two thermal components as a potential hotspot on the NS surface, indicative of a magnetically channeled accretion flow and motivation for further studies into NS heating in quiescence. Finally, we present the results from a recent XMM observation of the extremely faint system SAX J1810.8-2609. We find that the thermal component is consistent with a cooling NS radiating heat from nuclear reactions activated during outburst. We also present a revised estimate of the time-averaged mass accretion rate based on a more detailed outburst history and a range of outburst properties, finding the outburst history is in agreement with the quiescent thermal luminosity and discounting assertions of enhanced cooling mechanisms in the NS of SAX J1810.8-260.
by Jessamyn Leigh Allen.
Ph. D.
Nättilä, J. (Joonas). "Mass and radius constraints for neutron stars using the cooling tail method". Master's thesis, University of Oulu, 2013. http://urn.fi/URN:NBN:fi:oulu-201312041966.
Texto completoBrinkfeldt, Klas. "Instrumentation for energetic Neutral atom measurements at Mars, Venus and The Earth". Doctoral thesis, Kiruna : Swedish Institute of Space Physics, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-657.
Texto completoHe, Yanyi. "2+1 correlation between neutral pions and charged hadrons in gold-gold collisions at center of mass energy = 200GeV". [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1465704.
Texto completoAtanasov, Dinko [Verfasser] y Klaus [Akademischer Betreuer] Blaum. "Precision mass measurements for studies of nucleosynthesis via the rapid neutron-capture process : penning-trap mass measurements of neutron-rich cadmium and caesium isotopes / Dinko Atanasov ; Betreuer: Klaus Blaum". Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://d-nb.info/1180615743/34.
Texto completoSong, Yang. "Unstructured Nodal Discontinuous Galerkin Method for Convection-Diffusion Equations Applied to Neutral Fluids and Plasmas". Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/99291.
Texto completoDoctor of Philosophy
High-energy density (HED) plasma science is an important area in studying astrophysical phenomena as well as laboratory phenomena such as those applicable to inertial confinement fusion (ICF). ICF plasmas undergo radial compression, with an aim of achieving fusion ignition, and are subject to a number of hydrodynamic instabilities that can significantly alter the implosion and prevent sufficient fusion reactions. An understanding of these instabilities and their mitigation mechanisms is important allow for a stable implosion in ICF experiments. This work aims to provide a high order accurate and robust numerical framework that can be used to study these instabilities through simulations. The first half of this work aims to provide a detailed description of the numerical framework, texttt{PHORCE}. texttt{PHORCE} is a high order numerical package that can be used in solving convection-diffusion problems in neutral fluids and plasmas. Outstanding challenges exist in simulating high energy density (HED) hydrodynamics, where very large gradients exist in density, temperature, and transport coefficients (such as viscosity), and numerical instabilities arise from these region if there is no intervention. These instabilities may lead to inaccurate results or cause simulations to fail, especially for high-order numerical methods. Substantial work has been done in texttt{PHORCE} to improve its robustness in dealing with numerical instabilities. This includes the implementation and design of several high-order limiters. An novel algorithm is also proposed in this work to solve the diffusion term accurately and efficiently, which further enriches the physics that texttt{PHORCE} can investigate. The second half of this work involves rigorous benchmarks and experimentally relevant simulations of hydrodynamic instabilities. Both advection and diffusion solvers are well verified through convergence studies. Hydrodynamic and plasma models implemented are also validated against results in existing literature. Rayleigh-Taylor instability growth with experimentally relevant parameters are performed on both planar and radially converging domains. Although this work is motivated by physics in HED hydrodynamics, the emphasis is placed on numerical models that are generally applicable across a wide variety of fields and disciplines.
Simutkin, Vasily. "Fragment Mass Distributions in Neutron-Induced Fission of 232Th and 238U from 10 to 60 MeV". Doctoral thesis, Uppsala universitet, Tillämpad kärnfysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-134952.
Texto completoFelaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 723
Shirley, Robert Edward 1972. "Mass transfer and accretion in the eccentric neutron-star binary Circinus X-1". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47699.
Texto completoIncludes bibliographical references (p. 199-206).
I have carried out a project to study the eccentric neutron-star binary Circinus X-1 through an extensive series of observational studies with the Rossi X-ray Timing Explorer satellite and through theoretical computer models I developed to explore mass transfer and evolution in an eccentric binary. We also organized two multi-frequency campaigns to study correlated variability in different frequency bands. The X-ray observations showed that the intensity of Cir X- 1 currently maintains a bright baseline level, with strong flares occurring after phase zero of each 16.55-day cycle of the source. This behavior is thought to be due to enhanced mass transfer occurring near periastron of a highly eccentric binary orbit. Dips below the baseline intensity level also occur near phase zero. I modeled the evolution of the energy spectrum during dips with a variably absorbed bright component plus a fainter unabsorbed component. I show that variability not attributable to absorption dips is related to the spectral/intensity states of the "Z source" class of low-mass X-ray binaries (LMXBs), namely motion along (or shifts of) the horizontal, normal, and flaring branches of the "Z" track in color-color and hardness-intensity diagrams. I found rapid X-ray variability properties associated with each spectral/intensity state: On the horizontal branch, quasi-periodic oscillations (QPOs) in the X-ray intensity shift in frequency from 1.3 to 35 Hz. On the normal branch, a different QPO occurs at about 4 Hz. On the flaring branch only strong aperiodic variability occurs. I modeled the evolution of the energy spectra associated with each of these branches. To study mass transfer in an eccentric binary, I developed computer codes for transfer via Rochelobe overflow and from a stellar wind. I derive theoretical mass accretion profiles and compare them to the observed profile of the X-ray intensity. In order to explore the possible evolutionary history of Circinus X-1, I developed a binaryevolution computer code for a neutron-star and low-mass companion in an eccentric orbit. I use this code in a population-synthesis study to show that the number of systems in the Galaxy expected to resemble Cir X-1 is of order unity, consistent with its unique status as an LMXB with high eccentricity.
by Robert E. Shirley.
Ph.D.
Joshi, Ubisha. "Characterization of Ionic Liquid As a Charge Carrier for the Detection of Neutral Organometallic Complexes Using Electrospray Ionization Mass Spectrometry". Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc149615/.
Texto completoDominguez, David Aaron Matzner. "Search for neutral Higgs Bosons in e+e- interactions at center-of-mass energies between 130 GeV and 183 GeV /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9907602.
Texto completoBogdanov, Slavko, Craig O. Heinke, Feryal Özel y Tolga Güver. "NEUTRON STAR MASS–RADIUS CONSTRAINTS OF THE QUIESCENT LOW-MASS X-RAY BINARIES X7 AND X5 IN THE GLOBULAR CLUSTER 47 TUC". IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/622762.
Texto completoBrodeur, Maxime. "First direct mass measurement of the two and four neutron halos ⁶He and ⁸He using the TITAN Penning trap mass spectrometer". Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/24251.
Texto completoGriffin, Jeffrey Cliff. "Decay of mass-separated [superscript]195Bi to levels in [superscript]195Pb : collinear laser spectroscopy on mass-separated neutron-deficient lead isotopes". Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/27319.
Texto completoMatoš, Milan. "Isochronous mass measurements of short-lived neutron rich nuclides at the FRS-ESR facilities". [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972168656.
Texto completoDietrich, Tim [Verfasser], Bernd [Gutachter] Brügmann, Stephan [Gutachter] Rosswog y Mark [Gutachter] Hannam. "Binary neutron star merger simulations / Tim Dietrich ; Gutachter: Bernd Brügmann, Stephan Rosswog, Mark Hannam". Jena : Friedrich-Schiller-Universität Jena, 2016. http://d-nb.info/1177612704/34.
Texto completoMayet, Pascale. "Isomers populated by projectile fragmentation in the neutron-rich A=180-200 mass region". Université Louis Pasteur (Strasbourg) (1971-2008), 2001. http://www.theses.fr/2001STR13131.
Texto completoClark, Michael A. R. "Application of thermal neutron radiography for the mass transport of moisture through freezing soil". Thesis, Aston University, 1989. http://publications.aston.ac.uk/14320/.
Texto completoAnsari, Saba. "Shape evolution in neutron-rich Zr, Mo and Ru isotopes around mass A=100". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS384/document.
Texto completoThe shape of an atomic nucleus, ie. the deviation of its mass distribution from sphericity, is a fundamental property and governed by a delicate interplay of macroscopic and microscopic effects, such as the liquid-drop like binding energy and the nuclear shell structure, respectively. Studying nuclear shape properties using gamma ray spectroscopic methods allows detailed tests of different nuclear models, which were originally developed for stable nuclei. We proposed a project to study the evolution of nuclear shapes in exotic nuclei, far from the valley of stability, specifically in neutron-rich nuclei in the isotopic chains from Zr (Z=40) to Pd (Z=46). Usually, nuclear shapes are slowly evolving from spherical shapes around closed-shell or (doubly-) magic nuclei to elongated (prolate) shapes in nuclei with many valence nucleons. The nuclei of interest, however, show rapidly evolving patterns of excited states, which can be interpreted as rapid variations of the nuclear shape, including the rare observation of oblate (disk-like) and triaxial shapes. So far the known properties for these nuclei are (mainly) limited to excitation energies. Information on the nuclear collectivity, which can be deduced from the lifetime of the excited states, are sparse, while direct information of the shape is practically non existing. The simplest estimate of nuclear deformation in even-even nuclei can be obtained from the energy of the first 2⁺ state. For Sr (Z = 38) and Zr (Z = 40) isotopes this energy is observed to decrease dramatically at N = 60, while its evolution is much more gradual in Mo nuclei (Z = 42). Precise lifetime measurements provide a key ingredient in the systematic study of the evolution of nuclear deformation and the degree of collectivity in this region. Neutron-rich nuclei in the mass region of A = 100-120 were populated through the fusion-fission reaction of a ²³⁸U beam at 6.2 MeV/u on a ⁹Be target. The compound nucleus ²⁴⁷Cm was produced at an excitation energy of around 45 MeV before undergoing fission. The setup used for this study comprised the high-resolution mass spectrometer VAMOS in order to identify the nuclei in Z and A, the Advanced gamma ray Tracking Array AGATA of 35 germanium detectors to perform gamma ray spectroscopy, as well as a plunger mechanism to measure lifetimes down to a few ps using the Recoil Distance Doppler Shift method (RDDS). In addition, the target was surrounded by 24 Lanthanum Bromide (LaBr₃) detectors for a fast-timing measurement of lifetimes longer than 100 ps. The sophisticated set of spectrometers used in this experiment allowed measurement of nuclear lifetimes in a range from 100’s of picoseconds down to a few picoseconds. In this thesis, we will report on new lifetime results for short-lived states in neutron-rich (A ~ 100) nuclei, with an emphasis on the Zr, Mo and Ru chains. We will discuss the experimental techniques used to evaluate the lifetimes as well as their interpretation in terms of state-of-the-art nuclear structure models
Collins, S. P. "Coincidence and directional correlation studies of '1'1'8Te, and a search for mixed-symmetry states in the A-50 mass region". Thesis, University of Sussex, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378260.
Texto completoMougeot, Maxime. "Nuclear Collectivity Studied through High Precision Mass Measurements of Neutron-rich Argon and Chromium Isotopes". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS455/document.
Texto completoDue to their inherent relationship with the binding energy, nuclear masses are the fingerprint of all the interactions taking place within the nucleus. As such, precise and accurate mass values are an essential ingredient to the comprehensive understanding of nuclear phenomena in exotic regions of the chart of nuclides. In this thesis, two key regions exhibiting dramatic structural evolution are investigated by means of high precision mass measurements performed with the online mass spectrometer ISOLTRAP at ISOLDE/CERN. Numerous spectroscopy results indicate that the chromium isotopic chain exhibits the most dramatic structural changes within the region situated south of 68Ni. This thesis reports on the first high-precision mass measurements of the neutron-rich 58-63Cr isotopes using the well established Penning trap mass spectrometry technique as well as the MRToF-MS technique pioneered at ISOLTRAP in recent years. The obtained mass values are up to 300 times more precise than the ones currently available in the literature. At odds with previous results, the new mass values exclude a sudden onset of ground-state collectivity rather favouring a smooth transition towards deformation approaching N=40. The question of the persistence of the N=28 shell closure in the Argon chain is also studied in this PhD work through the measurement of the neutron-rich 46-48Ar isotopes. The results of improved precision confirm the presence of a strong N=28 shell closure in the Argon chain. For both datasets, the detailed data analysis procedure will be presented. The implication of the obtained mass values for nuclear structure will be discussed through a phenomenological discussion of the binding energy trend. The results will also be discussed in the light of state of the art nuclear models including results from the promising valence-space formulation of the ab-initio IM-SRG formalism
Troyer, Jon S. "Spectral-Timing Analysis of Kilohertz Quasi-Periodic Oscillations in Neutron Star Low Mass X-Ray Binaries". Thesis, Wayne State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10747548.
Texto completoKilohertz quasi-periodic oscillations or kHz QPOs are X-ray intensity variations observed in neutron star low-mass X-ray binary (LMXB) systems. In such systems, matter is transferred from a secondary low-mass star to a neutron star via the process of accretion. kHz QPOs occur on the timescale of the inner accretion flow and may carry signatures of the physics of strong gravity (c2 ~ GM/R) and possibly clues to constraining the neutron star equation of state (EOS). No model to date has been able to illuminate the origin of kHz QPOs. Spectral-timing is a set of analysis techniques useful in deriving information about the nature of physical processes occurring within the accretion flow on the timescale of the kHz QPO. We present a comprehensive study of spectral-timing products of kHz QPOs from systems where data is available in NASA’s Rossi X-ray Timing Explorer (RXTE) archive to demonstrate the promise of these techniques and to gain insights regarding the origin of kHz QPOs. Using data averaged over the entire RXTE archive, we show correlated time-lags as a function of QPO frequency and energy, as well as energy-dependent covariance spectra for the various LMXB systems where spectral-timing analysis is possible. The similarity in trends in all sources suggest a common physical origin for kHz QPOs across the population. The diferences in results between lower and upper kHz QPOs lend further support to the evidence of the differing nature of the lower and upper kHz QPOs.
GUIMARAES, GUILHERME M. "Avaliação da concentração de metais e elementos traço em amostras de sedimento do reservatório Guarapiranga, São Paulo-SP, Brasil". reponame:Repositório Institucional do IPEN, 2011. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10002.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
Sugimura, Hitoshi. "Search for 6ΛH hypernucleus by the (π-,K+) reaction at J-PARC". 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188482.
Texto completoTrach, Maria S. "A Q-study of the effects of Novy Kanal reporters' gender on their preferences in coverage of gender neutral issues". Virtual Press, 2003. http://liblink.bsu.edu/uhtbin/catkey/1272771.
Texto completoDepartment of Journalism
Moussaoui, Roba. "Study of negative ions surface production in cesium-free H2 and D2 plasmas". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0328/document.
Texto completoThis thesis deals with negative ions (NI) surface production for applications in thermonuclear fusion. This work was conducted using a plasma source PHISIS. NI formed on a negatively biased sample surfaceare collected and analyzed with energy mass spectrometer (MS). Negative ion distribution function NIEDF is measured. A SIMION calculation was done to have a complete idea about MS transmission effect on the NIEDF. In the course of this thesis, a DC pulsed bias technique is introduced to enable the study of negative ion surface production on insulating samples as non-doped diamond layers. A model that calculate the rate of change of bias on insulator surface biased in pulsed mode is developed. Surprisingly, negative-ion surface production on boron-doped or non-doped diamond is much higher in pulsed mode than in continuous mode. This thesis deals also with negative ion surface production in low bias condition. The best NI yield measured at low bias is obtained with Boron doped diamond (BDD) ant it is 2 times higher than the one measured on HOPG (highly oriented pyrolytic graphite) surface. Analysis of NI surface production at different surface bias for different material were performed in order to correlate the NI yield evolution to the surface state changes.An extensive study of NI surface production was performed on Nanoporous 12CaO.7Al2O3 electride surface. The influence of surface temperature, bias and plasma exposure time on negative-ion yield was investigated. In this contribution, we show that the electride material has potentials to be used as a production surface in negative ion sources devoted to nuclear fusion application