Tesi sul tema "Oscillateur à résistance négative"
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Mao, Yuqing. "Nouvelle génération de générateurs de fréquence par auto-calibration de la grille arrière des transistors en technologie FDSOI". Electronic Thesis or Diss., Université Côte d'Azur, 2023. http://www.theses.fr/2023COAZ4123.
Modern data communication systems heavily rely on synchronous transmission techniques to optimize bandwidth and minimize power consumption. In such systems, only the data signal is transmitted, necessitating the implementation of Clock and Data Recovery (CDR) circuits at the receiver end. This thesis explores the novel application of Fully-Depleted Silicon-On-Insulator (FDSOI) 28nm technology to enhance the performance of CDR circuits by mitigating short-channel effects through innovative transistor structures.One contribution of this thesis is the development of a negative resistance circuit using the back gate of the FDSOI transistor. This circuit employs a current mirror controlled by the back gate to create a negative resistance LC oscillator. In parallel, this work presents the implementation of two types of oscillators: a complementary ring oscillator and a fast ring oscillator. The complementary ring oscillator capitalizes on complementary inverters, offering automatic bias feedback by the back gate control, thereby enhancing its performance. Meanwhile, the fast ring oscillator uses fast inverters in combination with complementary inverters designed to minimize propagation delays. The thesis presents a detailed comparative analysis of these oscillators, highlighting their individual strengths and limitations. Furthermore, we introduce an injection signal into the ring oscillator, resulting in the creation of a low-jitter Injection-Locked Oscillator (ILO). This ILO exhibits remarkable performance characteristics, particularly in reducing phase noise and enhancing frequency stability. Taking advantage of the good performance of the ILO, we propose a novel low-cost and low-power Injection-Locked Clock and Data Recovery (ILCDR) with a fast-locking time and good jitter for burst-mode applications.To validate the proposed designs and their performance at different operational frequencies, extensive simulations have been carried out using Cadence Virtuoso at 868 MHz and 2.4 GHz. In addition, the layout design and post layout simulation of the ILCDR based on the complementary ring oscillator are also studied
Druelle, Yves. "Contribution à la compréhension de fonctionnements particuliers du transistor bipolaire en hyperfréquences". Lille 1, 1985. http://www.theses.fr/1985LIL10041.
Boucherit, Mohamed. "Etude et réalisation de dispositifs hyperfréquences sur matériaux grand gap : diode à effet tunnel résonant AlxGa1-xN/GaN, transistor HEMT boré à base de nitrure de gallium". Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10004/document.
The work described in this thesis contributes to the improvement on some circuit based on wide band gap semiconductors. The first concerns the oscillators and the second RF amplifiers at microwave frequencies. Components selected to build these two devices are resonant tunneling diodes and high electron mobility transistors. This thesis is divided into two distinct parts:-The resonant tunneling diodes AlGaN/GaN: a software that provides a rigorous description of vertical transport in nitride heterostructures does not exist or are not available in Europe. In this thesis, we developed a model based on the self-consistent resolution of the Schrödinger and Poisson equation using the non-equilibrium Green functions. The strategy employed to obtain some heterostructures free from dislocations is based on the realization of nano-diodes in the following two approaches. The first approach "bottom-up" implements the technique of selective epitaxy on nano-patterned GaN template. The second approach called "top down" is based on the reduction of device size and consequently the number of dislocations. The electrical characteristics of these nano-diodes have been measured by FIB, Nanoprobe and vector network analyzer. The negative differential resistance is studied depending in both direction of bias, electrical treatment, temperature and aluminum incorporation in the AlGaN barriers layers.- The high electron mobility transistors AlGaN/GaN: the second part was aimed to perform a conventional AlGaN/GaN HEMT structure exhibiting in the state of the art performance. To do that, we focused on improving the resistivity of the GaN buffer layer by incorporating either of aluminum or boron. Several positions and thicknesses of BGaN layer in the conventional AlGaN /GaN HEMT structure were tested to determine the optimal structure. Comparative studies between AlGaN/GaN HEMT structures with and without BGaN layer have shown that the use of BGaN layer as a back-barrier drastically improves the carrier confinement in the 2DEG channel and significantly reduces the residual doping of the active area
Hombrouck, Cécile. "Haemophilus influenzae, B-lactamase négative - "ampicilline résistants" : détection et étude de la résistance". Paris 5, 1999. http://www.theses.fr/1999PA05P172.
Baraton, Laurent. "Fabrication et étude d'une diode moléculaire à résistance différentielle négative greffé sur silicium terminé hydrogène". Paris 11, 2004. https://tel.archives-ouvertes.fr/tel-00150238.
Nowdays the microelectronic and semiconductor industry is challenged by economical and fundamental issues. In that context of developpement of alternative technologies, this work aimed to developp an electronic device, that can be handled at macroscpic scale, but in which the active component is a small number of molecules. That vertical device is made of complex molecule sandwiched between a silicon bottom electrode and a nanotube as a top electrode. In order to achieve it, work was made in two directions. In a first part, we studied feasibility of a complex monolayer, covalently bounded of a silicon substrat, trough a multistep process. In order to preserve the properties of electronic injection between silicon and the monolayer, a particluar attention was paied to the stability of the silicon substrat. In a second part, a top down process was set up to manufacture a chip. It is intend to reciev the monolayer and to connect it to macroscopic leads. It is achieved using carbon nanoutubes. The complet monolayer and the device were achieved separatly but no electrical measure could be perform at this day
Stolar, David. "Expression phénotypique et difficulté de détection de la méticillino-résistance chez les staphylocoques à coagulase négative". Paris 5, 1999. http://www.theses.fr/1999PA05P179.
Barbier, François. "Diffusion de la résistance à la méticilline chez les souches communautaires de staphylocoques à coagulase négative". Paris 7, 2013. http://www.theses.fr/2013PA077243.
Our objectives were to appraise the epidemiological patterns of methiillin-resistant coagulase-negative staphylococci (MRCNS) carriage in the community and to assess the role of MRCNS in the dissemination of Staphylococcal Cassette Chromosome mec (SCCmec) elements in this environment. Rates of MRCNS nasal carriage ranged from 11% to 50% (6 distinct geographic regions). Chronic comorbidities and living with other persons at home were associated with an increased risk of carriage. MR Staphylococcus epidermidis (MRSE) (from 32% to 78% of MRCNS isolates) were characterized by MLST and MLVA: a marked diversity was observed, suggesting that new strains commonly emerge in the community. SCCmec elements were highly polymorphic. SCCmec IV, the leading type in community-acquired MRSA (CA-MRSA), was the most frequent cassette in MRSE. Complete sequences of SCCmec IV from MRSE were >99% identical to those described in epidemic clones of CA-MRSA. These findings strongly suggest that CA-MRSE are a potential source of SCCmec IV for S. Aureus in the community. The Arginine Catabolic Mobile Element (ACME) found in 68% of CA-MRSE strains may esse their persistence in the skin and mucosal microbiota. The impact of antimicrobials on CA-MRCNS carriage was investigated in 479 primary care patients. CA-MRCNS acquisitions were more frequent in patients receiving penicillinase-resistant penicillins than in those treated by fluoroquinolones, macrolides or pristinamycin. These results point out that MRSE and other MRCNS are widely disseminated in the community, and form a dynamic reservoir of SCCmec elements in this environment
Meunier, Philippe. "Etude de circuits monolithiques simulant une résistance négative intégrables dans des filtres actifs microondes à résonateurs microruban". Limoges, 1995. http://www.theses.fr/1995LIMO0003.
Boukrout, Nihad. "Rôle de la boucle de régulation négative MUC4-miR-210-3p dans la cancérogenèse pancréatique et la chimio-résistance". Thesis, Université de Lille (2022-....), 2022. https://pepite-depot.univ-lille.fr/LIBRE/EDBSL/2022/2022ULILS003.pdf.
Background: Pancreatic adenocarcinoma (PDAC) is a deadly cancer with anextremely poor prognosis. MUC4 membrane-bound mucin is neoexpressed in earlypancreatic neoplastic lesions and is associated with PDAC progression andchemoresistance. In cancers, miRNA (small noncoding RNAs) are crucial regulatorsof carcinogenesis, chemotherapy response and even metastatic processes. In thisstudy, we aimed at identifying and characterizing miRNAs activated downstream ofMUC4-associated signaling in pancreatic adenocarcinoma. MiRnome analysiscomparing MUC4-KD versus Mock cancer cells showed that MUC4 inhibitionimpaired miR-210-3p expression. Therefore, we aimed to better understand themiR-210-3p biological roles.Methods: miR-210-3p expression level was analyzed by RT-qPCR in PDACderivedcell lines (PANC89 Mock and MUC4-KD, PANC-1 and MiaPACA-2), as wellas in mice’s and patients’ tissues. The MUC4-miR-210-3p regulation wasinvestigated using luciferase reporter construct and chromatin immunoprecipitationexperiments. Stable cell lines expressing miR-210-3p or anti-miR-210-3p wereestablished using Crispr/Cas9 technology or lentiviral transduction. We evaluated thebiological activity of miR-210-3p in vitro by measuring cell proliferation and migrationand in vivo using a model of subcutaneous xenograft.Results: miR-210-3p expression is correlated with MUC4 expression inPDAC-derived cells and human samples, and in pancreatic PanIN lesions of Pdx1-Cre; LstopL-KrasG12D mice. MUC4 enhances miR-210-3p expression levels viaalteration of the NF-κB signaling pathway. Chromatin immunoprecipitationexperiments showed p50 NF-κB subunit binding on miR-210-3p promoter regions.We established a reciprocal regulation since miR-210-3p repressed MUC4expression via its 3′-UTR. MiR-210-3p transient transfection of PANC89, PANC-1and MiaPACA-2 cells led to a decrease in cell proliferation and migration. Thesebiological effects were validated in cells overexpressing or knocked-down for miR-210-3p. Finally, we showed that miR-210-3p inhibits pancreatic tumor growth andproliferation in vivo.Conclusion: We identified a MUC4-miR-210-3p negative feedback loop inearly-onset PDAC, but also revealed new functions of miR-210-3p in both in vitro andin vivo proliferation and migration of pancreatic cancer cells, suggesting a complexbalance between MUC4 pro-oncogenic roles and miR-210-3p anti-tumoral effects
Lepercq, Pierre. "Supraconducteurs à haute température critique : caractérisation en microondes et réalisation d'un oscillateur quasi-intégré à 12 GHz". Lille 1, 1996. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1996/50376-1996-101.pdf.
Zhang, Tianchen. "Composants mémoires et effet NDR dans les dispositifs à base de matériaux hybrides : organiques/nanoparticules d’or". Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10215/document.
The work presented in this thesis deals with the study of the electrical properties and physical mechanism of a device based on the functional hybrid material: PTEDOT-AuNPs and its application in the field of non-volatile resistive memory. Firstly, we demonstrate the synthesis of this hybrid material as well as its electrical and physical characterization. The fabrication of nanodevice is then carried out by combining the photolithography and electropolymerization. During the electrical characterization, the forming process which is accompanied by a resistive switching of the device is demonstrated in the following. We discuss the physical nature of this phenomenon, and believed that it is related to a local change in temperature and the creation of a metal conducting paths. After that, the device exhibits two electrical behaviors: a negative differential resistance effect and a memory effect. The results obtained in the reliability test make it possible to demonstrate promising applications in nonvolatile resistive memories. In the study of the physical mechanisms of resistive switching between two distinct conductance states of our device, the formation of the conductive path between the two electrodes and the effect of trapping and trapping are the main mechanisms responsible for the forming process and the memory effect. Finally, we were interested in the realization of the "NanoCell" logic gate for molecular computing which based on our multi-terminal devices (6 electrodes). We proved that it is possible to realize two basic logic gates by choosing the level of the external threshold current after the configuration of "Nanocell"
Rigal, Claudine. "Contribution à l'étude de la résistance à la teicoplanine de deux souches de staphylocoques à coagulase négative isolées de septicémies". Paris 5, 1990. http://www.theses.fr/1990PA05P186.
Étienne, Jérôme. "Les marqueurs épidémiologiques des staphylocoques coagulase négatifs : évaluation de deux marqueurs moléculaires". Lyon 1, 1989. http://www.theses.fr/1989LYO1T119.
Biron, Frédéric. "Conceptions de profils d'impédances actifs pour la compensation des pertes, la réduction de taille et l'augmentation de sélectivité de structures de filtrages planaires microondes". Limoges, 2001. http://www.theses.fr/2001LIMO0026.
Danneville, François. "Résistance différentielle négative et transfert spatial dans les transistors à effet de champ à grille isolée GaAlAs/GaAs : analyse théorique et applications potentielles". Lille 1, 1991. http://www.theses.fr/1991LIL10023.
Pierre, Josiane. "Étude des protéines de liaison à la pénicilline chez les staphylocoques à coagulase négative et les Listeria : intérêt taxonomique : rôle dans la résistance intrinsèque aux B-lactamines". Paris 11, 1991. http://www.theses.fr/1991PA114826.
Tilhac, Cyrille. "Développement d’architectures de filtres à base de résonateurs à ondes acoustiques de volume et contribution à l’intégration dans une technologie avancée silicium industrielle pour des applications radio-fréquences". Limoges, 2007. http://aurore.unilim.fr/theses/nxfile/default/80d92337-b229-40e2-a75a-1b8eb28464c8/blobholder:0/2007LIMO4012.pdf.
For reasons of cost, consumption, and volume, the complete integration of communication systems seems a subject carrying for the micro-electronic industry. That is why, new resonators with bulk acoustic waves (BAW) are developed. One of the advantages of these resonators is the possibility of integrating them in a complete system on silicon substrate for filtering applications. On the other band, there are variations in the manufacturing process which make that the thicknesses of the deposited materials fluctuate slightly. That directly impacts the resonance frequency of the resonators and it is necessary to compensate these variations if one wishes to carry out an integrated system. The thesis work subject deals with the study and the realization of new filters architectures allowing the use of tuneable BAW resonators
Nanoukon, Chimène Nadège Mahoussi. "Importance des staphylocoques à coagulase négative dans les infections primitives sévères : recherche de nouveaux facteurs de virulence". Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ059/document.
Coagulase-negative staphylococci (CNS) are generally considered as opportunistic pathogens with low virulence. However, previous studies have reported pathogenicity of some strains similar to that observed in S. aureus. This thesis aims to contribute to the importance of SCN in severe primitive infections. First, we evaluated the pathogenic potential of clinical CNS strains in Benin. To achieve this objective, CNS associated with various severe clinical infections were collected over at the Hubert Koutoukou Maga National Hospital and University Center in Cotonou. These strains are identified as well as their susceptibility to antibiotics and their ability to produce virulence factors. This part of the study showed that the most involved species in Benin are: S. haemolyticus and S. epidermidis followed by other species such as S. cohnii, S. sciuri, S. arlettae, S. capitis. We also demonstrated the multi-resistance of strains to antibiotics, as well as the presence of potential virulence factors such as protease, esterase, hemolysin, leukotoxin and, enterotoxin Staphylococcal C in 44% of strains tested particularly in hospital strains isolated from blood cultures. We, then, characterized a new virulence factor identified in two strains of S. epidermidis: staphylococcal enterotoxin C called SECepi, which was secreted at ~100 μg/mL in bacterial culture supernatants. The secepi gene consists of 801 bp corresponding to 266 amino acids. On the basis of the comparison between the peptide chain of SECepi and the already known peptide sequences of the SEC, we found that SECepi is close to SEC3 of S. aureus Mu3 strain with three amino acids substitutions in the signal peptide and nine amino acid substitutions in the mature protein. However, most residues involved in formation of the tri-molecular complex CMH-SEC-TCR are conserved in SECepi. Analysis of the recombinant protein (rSECepi) revealed antigenic relationships and a strong structural homology is predicted with SECaureus. Moreover, this toxin exhibits the biological activities characteristic of a SAg including the stimulation of the mitogenicity and the concomitant production of high doses of pro-inflammatory and suppressive cytokines in activated human T lymphocytes. Moreover, SECepi is resistant to heating at 100 °C and digestion by gastrointestinal enzymes such as pepsin and trypsin. These results provide evidence that SECepi can act as a superantigen in humans although the wild type has several mutations in S. epidermidis. The study of the medical record of one of the patients showed that the enterotoxin produced by the strain of S. epidermidis might be at the origin of severity of the clinics presented at hospital admission. Finally, genomic analysis of the two toxigenic S. epidermidis strains confirms the varied possibilities of genetic exchange between this species and S. aureus. This thesis underscores the importance of monitoring CNS infections in humans because some strains, like S. aureus, produce virulence factors that can aggravate the overall host condition
Bedidi-Madani, Nora. "Contribution à l'étude des staphylocoques à coagulase négative isolés de laits de chèvres : identification, profils protéiques : virulence in-vitro et in-vivo, étude particulière de Staphylococcus caprae : ribotype et résistance à la fosfomycine". Lyon 1, 1996. http://www.theses.fr/1996LYO10183.
Filleron, Anne. "Dynamique et émergence infectieuse des staphylocoques au sein des communautés bactériennes pathologiques en pédiatrie". Thesis, Montpellier 1, 2013. http://www.theses.fr/2013MON13509.
Staphylococci are prevalent opportunistic bacteria in children' microbiota. Two models were used in order to 1) describe the dynamic of colonization of the digestive microbiota in premature neonate and the transmission of pathogenic bacteria as coagulase negative staphylococci from the gastrointestinal tract via breast milk, 2) search and characterize opportunistic bacteria with emerging antibiotic resistance in a complex microbiota with the example of Staphylococcus aureus with reduced susceptibility to glycopeptides in respiratory tract in cystic fibrosis
Delcroix, Pierre. "Etude à l'échelle nanométrique par sonde locale de la fiabilité de diélectriques minces pour l'intégration dans les composants microélectroniques du futur". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00822926.
Fakih, Ali. "Current controlled negative differential resistance in niobium dioxide". Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS099.
Niobium dioxide (NbO2) has been recently gaining a lot of interest in the fields of solid state physics and technological nano-devices. On one hand, NbO2 undergoes a structural distortion accompanied by an electronic phase transition where the material changes from an insulating state at room temperature into a metallic state at temperatures above ∼ 1080 K. On the other hand, NbO2 exhibits a negative differential resistance phase under the application of electric current, a phenomenon known as current-controlled negative differential resistance CC-NDR. In this thesis, we have fabricated thin films of NbO2 by RF-mangentron sputtering technique on amorphous and crystalline substrates (glass and silicon). The deposited films were always amorphous, and annealing treatment of the as-deposited films was necessary to achieve crystallinity. . Upon performing electronic studies on NbO2, we witnessed CC-NDR with a hysteresis in the V(I) curves. We showed that hysteresis in CC-NDR is due to temperature inhomogeneity. Simultaneous electronic transport and Raman measurements show that CC-NDR is not associated to a phase transition. Moreover, we showed that there is a similar temperature driven change in conductivity in both the amorphous and the crystalline samples, however, the amorphous sample is a better electronic and thermal conductor. Finally, we proved that the CC-NDR may be simplyexplained by the creation of carriers by temperature in a semiconductor, without the need for invoking more complicated transport mechanisms
Randrianantenaina, Cyriaque Donat. "Contribution à l'étude expérimentale des écoulements confinés à surfaces libres : application à l'interaction fluide-structure dans un compartiment de JIG artisanal". Thesis, Le Havre, 2016. http://www.theses.fr/2016LEHA0033/document.
The work realized under this co-supervised thesis concerns two study areas of fluid-structure interaction. The first concerned the Mineral Engineering and deals with the interaction between a moving grate in a sluice and the confined flow associated. The second concerns the fundamental Hydrodynamics and deals with the interaction of a cylinder mounted on flexible supports and a free surface flow in presence of plane wall. Our work contributes to the study a confined free surface flow by experimental approach. We coupled techniques of CCD camera visualization, velocity fields measurements by PIV and hydrodynamic forces to qualify the dynamics of structure motion in the flow. Experimental methods and devices are applied to the study the flow around two simplified models of a moving JIG grate and then to study a vibrating cylinder due to flow. Treatments of PIV data acquisitions by multivariable statistical POD enabled us to describe evolution of recirculation zones in the compartment and unsteady velocity field. Experimental study was completed by a numerical simulation of Jig model by using ANSYS14.5 and a numerical wake oscillator model for the case of the cylinder. This work highlighted a simple technique to give motion, in a sluice, a attached net to a cylinder and to study effects of free surface flow confinement on a vibrating cylinder
Foissac, Romain. "Etude à l'échelle nanométrique par sonde locale de la fiabilité et de la dégradation de films minces d'oxyde pour applications MOS et MIM". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT047/document.
Integration of High-k dielectrics in gate oxides of MOS raised new issues concerning the reliability of futur technology nodes. The constant miniaturisation of devices leads to thinner gate oxides, making their electrical caracterisation more complex at the device scale. To solve this problem, an atomic force microscope in conductive mode under ultra high vacuum can be used thanks to the readuce contact area between the tip and the sample which allow a drastic decrease of the tunneling current and thus the study of the degradation and the dielectric breakdown of ultra-thin oxides. The systematic comparaison of the TDDB distributions obtained on the High-k gate oxide of the 28nm technology node on one side and obtained on the Interfacial layer alone revealed that the failure probability of High-k oxides is governed by the failure probability of each layer present in the stack. This allow to give an extrapolation law of the High-k gate oxide lifetime as a function of the applied voltage and the electrode area and to predict the failure statistic of the 28nm tehcnology node. The impact of voltage pre-stress with a microseconde range of duration on the TDDB and VBD distributions of both single layer and High-k gate oxides is given is the manuscript. The results are then interpreted by an invasive degradation nucleating from an interface during a stress and leading to a local thinned oxide. Pre-breakdown negative differential resistance have been studied and modeled for several oxide thickness, using a growing mecanism of the elctrical degradation. An analytic expression linking the growth caracteristic time of the filament and the mean time to breakdown observed on the statistical distributions has then been given. Finally, C-AFM measurements developped in this work has been extended to MIM structures used for oxide resistive random access memories (OxRAM). A self healing has been observed at the nanometric scale for these samples
Weisz, Mario. "Electrothermal device-to-circuit interactions for half THz SiGe∶C HBT technologies". Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14909/document.
The power generate by modern silicon germanium (SiGe) heterojunction bipolar transistors (HBTs) can produce large thermal gradients across the silicon substrate. The device opering temperature modifies model parameters and can significantly affect circuit operation. This work characterizes and models self-heating and thermal coupling in SiGe HBTs. The self-heating effect is evaluated with low frequency and pulsed measurements. A novel pulse measurement system is presented that allows isothermal DC and RF measurements with 100ns pulses. Electrothermal intra- and inter-device feedback is extensively studied and the impact on the performance of two analog circuits is evaluated. Novel test structures are designed and fabricated to measure thermal coupling between single transistors (inter-device) as well as between the emitter stripes of a multi-finger transistor (intra-device). Thermal coupling factors are extracted from measurements and from 3D thermal simulations. Thermally coupled simulations of a ring oscillator (RO) with 218 transistors and of a 60GHz power amplifier (PA) are carried out. Current mode logic (CML) ROs are designed and measured. Layout optimizations lead to record gate delay of 1.65ps. The thermal performance of a 60GHz power amplifier is compared when realized with a multi-transistor array (MTA) and with a multi-finger trasistor (MFT). Finally, perspectives of this work within a CAD based circuit design environment are discussed