<p> The reaction 165Ho (3He,d) 166Er was studied using the University of Rochester Tandem Van de Graaff accelerator and an Enge-type split-pole magnetic spectrograph. The observed cross sections for the ground state rotational band and the gamma vibrational band were consistent with predictions based on the unified nuclear model. The population of the 1574 keV level was consistent with that expected for the K^π=4^-, 7/2-[523] + 1/2+[411] assignment obtained from decay scheme studies. The K^π=2^- octupole vibrational band based on the 1460 keV state was not populated as strongly as expected, indicating that the admixture of the 7/2-[523] - 3/2+[411] two proton state into this vibration is only about one-fifth as large as predicted by Soloviev et al.</p> / Thesis / Master of Science (MSc)

The growing demand for wireless communication systems is driving the integration of radio frequency (RF) front-ends on the same chip with multi-band functionality and higher spectral efficiency. Microelectromechanical systems (MEMS) have an overarching applicability to RF communications and are critical components in facilitating this integration process. Among a variety of RF MEMS devices, piezoelectric MEMS resonators have sparked significant research and commercial interest for use in oscillators, filters, and duplexers. Compared to their bulky quartz crystal and surface acoustic wave (SAW) counterparts, MEMS resonators exhibit impressive advantages of compact size, lower production cost, lower power consumption, and higher level of integration with CMOS fabrication processes. One of the promising piezoelectric MEMS resonator technologies is the aluminum nitride (AlN) contour mode resonator (CMR). On one hand, AlN is chemically stable and offers superior acoustic properties such as large stiffness and low loss. Furthermore, CMRs offer low motional resistance over a broad range of frequencies (few MHZ to GHz), which are lithographically-definable on the same silicon substrates. To date, RF MEMS resonators (include CMRs) have been extensively studied; however, one aspect that was not thoroughly investigated is how to modulate/tune their equivalent parameters to enhance their performance in oscillators and duplexers. The goal of this thesis is to investigate various modulation methods to improve the thermal stability of the resonator, its “effective” quality factor when used in an oscillator, and build completely novel non-reciprocal components. Broadly defined, modulation refers to the exertion of a modifying or controlling influence on something, herein specifically, the resonator admittance. In this thesis, three categories of modulation methods are investigated: thermal modulation, force modulation, and external electronic modulation. Firstly, the AlN CMR’s center frequency can be tunned by the applied thermal power to the resonator body. The resonator temperature is kept constant (for example, 90 °C) via a temperature sensor and feedback control such that the center frequency is stable over the whole operation temperature range of interest (e.g. –35 to 85 °C). The maximum power consumption to sustain the maximum temperature difference (120 ºC in this thesis) between resonator and ambient is reduced to a value as low as 353 μW – the lowest ever reported for any MEMS device. These results were attained while simultaneously maintaining a high quality factor (up to 4450 at 220 MHz device). The feedback control was implemented by either analog circuits or via a microprocessor. The analog feedback control, which innovatively utilized a dummy resistor to compensate for temperature gradients, resulted in a total power consumption of 3.8 mW and a frequency stability of 100 ppm over 120 ºC. As for the digital compensation, artificial neural network algorithm was employed to facilitate faster calibration of look-up tables for multiple frequencies. This method attained a frequency stability of 14 ppm over 120 ºC. The second modulation method explored in this thesis is based on the use of an effective external force to enhance the 3-dB quality factor of AlN CMRs and improve the phase noise performance of resonator-based oscillators. The force modulation method was embodied in a two-port device, where one of the two ports is used as a one-port resonator and the other is driven by an external signal to effectively apply an external force to the first port. Through this technique, the quality factor of the resonator was boosted by 140 times (up to 150,000) and the phase noise of the corresponding oscillator realized using the resonator was reduced by 10 dBc/Hz. Lastly, a novel magnetic-free electrical circulator topology that facilitates the development of in-band full duplexers (IBFD) for simultaneous transmit and receive (STAR) is proposed and modeled. Fundamentally, a linear time-invariant (LTI) filter network parametrically modulated via a switching matrix is used to break the reciprocity of the filter. The developed model accurately predicts the circulator behavior and shows very good agreement with the experimental results for a 21.4 MHz circulators built with MiniCircuit filter and switch components. Furthermore, a high frequency (1.1 GHz) circulator was synthesized based on AlN MEMS bandpass filters and CMOS RF switches, hence showing a compact approach that can be used in handheld devices. The modulation frequency and duty cycle are optimized so that the circulator can provide up to 15 dB of isolation over the filter bandwidth while good power transfer between the other two ports is maintained. The demonstrated device is expected to intrinsically offer low noise and high linearity. The combination of the first two modulation methods facilitates the implementation of monolithic, temperature-stable, ultra-low noise, multi-frequency oscillator banks. The third modulation technique that was investigated sets the path for the development of CMOS-compatible in-band full duplexers for simultaneous transmit and receive and thus facilitates the efficient utilization of the electromagnetic spectrum. With the aid of all these three modulation approaches, the author believes that a fully integrated, multi-frequency, spectrum-efficient transceiver is enabled for next-generation wireless communications.

L’huître creuse, Crassostrea gigas, est une espèce dont la production aquacole représente un intérêt économique tant au niveau mondial qu’aux niveaux européen et français. Cependant, cette espèce subit des mortalités estivales enregistrées dès le début du 20ème siècle et, depuis 2008, ce phénomène s’est amplifié et menace essentiellement les huîtres juvéniles. La production aquacole d’huître creuse subit les conséquences de ces mortalités massives ; c’est pourquoi ce phénomène est étudié depuis de nombreuses années. En France, la bactérie Vibrio splendidus et le virus Ostreid Herpes Virus 1 (OsHV-1) sont le plus souvent associés aux épisodes de mortalités massives d’huîtres creuses juvéniles et il a été démontré que les individus sélectionnés pour leur résistance aux mortalités estivales étaient capables de ralentir l’augmentation de la charge virale en OsHV-1 dans leurs tissus puis de la faire régresser. Ces mêmes individus présenteraient également un effort reproducteur plus modeste que des individus sélectionnés pour leur sensibilité aux mortalités estivales. Ce travail de thèse s’inscrit dans ce contexte et a donc eu pour principal objectif d’améliorer la connaissance de l’architecture génétique de la reproduction de C. gigas en identifiant des régions du génome ou QTLs (Quantitative Trait Loci) impliquées dans l’effort reproducteur et de mettre en évidence d’éventuelles relations génétiques entre survie et reproduction, des QTLs impliqués dans la survie ayant déjà été détectés. Afin de caractériser l’effort reproducteur, il a été nécessaire de développer un ensemble de nouveaux outils. D’un point de vue biologique, 21 familles F2 ont été produites à partir des lignées sélectionnées pour leur réponse contrastée aux mortalités estivales. D’un point de vue moléculaire, de nouveaux marqueurs SNP (Single Nucleotide Polymorphism) ont été développés afin d’augmenter la densité de la carte génétique déjà disponible pour C. gigas. D’un point de vue technique, l’Imagerie par Résonance Magnétique (IRM) a permis d’observer la gamétogenèse de 300 individus d’une même famille F2 au cours de huit sessions réparties sur deux années alors que les études précédentes étaient limitées à une observation ponctuelle; les méthodes classiques d’observation de la gamétogenèse entrainant nécessairement la mort des animaux. Une forte corrélation a été mise en évidence entre les observations par IRM et par la méthode classique de l’histologie. En plus de l’estimation du rapport gonado-somatique (indice traditionnellement utilisé pour caractériser l’effort reproducteur), l’IRM a également permis d’observer des variations individuelles de la cinétique de la gamétogenèse ainsi que des différences entre les mâles et les femelles; le sexe étant identifiable sur les images obtenues par IRM. Parallèlement, 300 individus de deux autres familles F2 ont été sacrifiés pour estimer le rapport gonado-somatique par histologie. Cette approche a ainsi permis de détecter des QTLs impliqués dans de nombreux traits concernant la gamétogenèse. Des individus provenant des trois familles F2 caractérisés pour l’effort reproducteur ont été caractérisés pour la survie à un épisode de mortalités estivales. Cette étude a permis de détecter des QTLs impliqués dans le caractère « survie ». Ces QTLs correspondent, pour certains, à ceux détectés au cours d’une étude précédente. De plus, ces QTLs sont parfois colocalisés avec des QTLs impliqués dans l’effort reproducteur. Bien que la reproduction de l’huître creuse soit un caractère complexe à suivre, les nouveaux outils utilisés au cours de ce travail de thèse ont permis d’acquérir de nouvelles connaissances. Le séquençage du génome complet de Crassostrea gigas ainsi que les nouvelles méthodes de séquençage pourront peut-être permettre d’affiner les régions QTLs détectées. / The Pacific oyster, Crassostrea gigas, is a major aquacultured species whose production represents an economic interest at worldwide, european and french levels. However, this species undergoes summer mortalities recorded from the beginning of the 20th century and, since 2008, this phenomenon increased and threatens mainly juvenile oysters. Aquaculture production of oysters suffers consequences of mass mortalities, that’s why this phenomenon has been studied for many years. In France, the bacterium Vibrio splendidus and the Ostreid virus Herpes Virus 1 (OsHV-1) are often associated with mass mortality outbreaks of juveniles oysters and it was demonstrated that selected individuals for resistance to summer mortality were able to slow the increasing in viral load OsHV-1 in their tissues and then to decline it. These same individuals also present a lighter reproductive effort than individuals selected for their sensitivity to summer mortality. In this context, this study aimed to improve the knowledge of genetic architecture of reproduction of C. gigas by identifying some regions of the genome called QTLs (Quantitative Trait Loci) involved in reproductive effort and highlighting possible genetic relationships between reproduction and survival; QTLs involved in survival being already detected. To characterize the reproductive effort, it was necessary to develop a set of new tools. From a biological point of view, 21 F2 families were produced from lines selected for their contrasting response to summer mortality. From a molecular point of view, new SNPs (Single NucleotidePolymorphism) were developed to increase density of the genetic map already available for C. gigas. On a technical point of view, Magnetic Resonance Imaging (MRI) allowed to observe the gametogenesis of 300 individuals of the same family F2 during eight sessions over two years while previous studies were limited to a one-time observation because of the conventional methods of observation of gametogenesis leading necessarily to the death of the animals. A strong correlation was found between observations by MRI and observations by the conventional method of histology. In addition to the estimation of gonadic index (index traditionally used to characterize there productive effort), MRI also revealed individual variations in kinetics of gametogenesis and differences between males and females, the sex being identifiable on MRI images. In parallel, 300 individuals from two F2 families were sacrificed to estimate the gonadic index by histology. This approach enabled the detection of QTLs involved in many gametogenesis traits. Individuals from the three families characterized for F2 reproductive effort were characterized for survival during a summer mortality outbreak. This study was able to detect QTLs involved in the trait "survival". These QTLs correspond to some of those detected in a previous study. In addition, these QTLs are often collocated with QTLs involved in reproductive effort. Although there production of the Pacific oyster is a complex trait to follow, the new tools used in this thesis allowed acquiring new knowledges. The sequencing of genome of Crassostrea gigas and Next-Generation Sequencing technologies may be able to help to refine the detected QTL regions.