267 research outputs found
Carrier Mobility in Field-Effect Transistors
Authors investigate the carrier mobility in field-effect transistors mainly when fabricated on Si(110) wafers. They showed that the methods developed to extract the conduction parameters cannot be implemented for Si(110) p-MOSFETs. Authors then developed a more accurate mobility model able to simulate not only the drivability but also the transconductance for these same devices. The study of the relation between the mobility, channel direction and wafer orientation revealed that the channel direction had a significant impact on the mobility for transistors fabricated on Si(110) wafers, the highest electron and hole mobilites being obtained for a channel along the and directions, respectively. No relations were found for Si(100) wafers. The study of the dependence of the scattering mechanism limiting the mobility in Si(110) n-MOSFETs showed that the Coulomb and surface roughness scattering mechanisms were responsible for the degradation of the mobility when compared to the one on Si(100) wafers. Finally, the measurement of the mobility in an accumulation-mode MOSFETs is not straightforward since a bulk contribution, owing to the SOI layer, is adding to channel current. A methodology has been successfully implemented that led to the experimental verification of the universal behaviour of the mobility in an accumulation layer
New Processes and Technologies to Reduce the Low‐Frequency Noise of Digital and Analog Circuits
The chapter is intended to provide the reader with means to reduce low‐frequency noise in Metal-Oxide-Semiconductor Field-Effect-Transistor (MOSFET). It is demonstrated that low‐resistivity source and drain electrodes can greatly lower the low‐frequency noise level by suppressing their contribution to the total noise. Furthermore, new plasma processes having the advantages to work at low electron temperature can achieve a further reduction, thanks to the fabrication of a better gate oxide and to a reduction of damages generally induced by conventional plasma processes. Reducing the impact of the traps on the carrier flowing inside the channel by burying the channel can also achieve a reduction of the noise level, but unfortunately at the cost of a degradation of the electrical performances. Finally, the noise analysis of the low‐frequency noise in accumulation‐mode MOSFETs showed that these newly developed devices have a lower noise level than conventional structures, which, in addition to their superiority in term of electrical performances, establishes them as a serious platform for the next Complementary Metal-Oxide-Semiconductor Field-Effect-Transistor (CMOS) technology
CFD analysis of industrial multi-staged stirred vessels
This paper presents tools for analysis of CFD results adapted for flows in multi-stage stirred vessels through out two industrial cases. Those tanks fitted with double-flow impellers are used first to cool down highly viscous resins and subsequently for indirect emulsification. Since the simulation of these processes in their whole complexity would be unrealistic, it considers single-phase flows without heat transfer. The result analysis in order to prove that the mixing and the circulation are effective is not usual; in these cases, the circulation and impeller numbers are not adapted. The average axial flow numbers are relevant of the circulation in the whole tank and of the connection between the flows produced by the propellers in the given configuration. The velocity profiles give relevant results, but are not sufficient whereas the particle tracking validates that the propellers do not work together in one case and do work together in a second one
Has the common genet (Genetta genetta) spread into south-eastern France and Italy ?
The common genet (Genetta genetta) is a small carnivoran that was probably introduced from Maghreb into south-western Europe. We reassessed its easternmost European distribution from 110-mostly new-data collected in south-eastern France and Italy, and tested for potential habitat selection, to finally re-evaluate the role of the Rhone as a geographic barrier against eastward migrations. The species was more frequent in river valleys, wetlands and low-mountainous areas (south-eastern France), but also occurred in high-mountainous zones at the French-Italian border. Our results evidenced a significant increase of records (13-fold the number of occurrences previously known) and an apparent absence of habitat selection by the common genet, suggesting a recent, natural spread from the right bank of the Rhne through a zone of 30km with artificial bridges. We finally provide a synthetic, re-assessed distribution map of the common genet in France and Italy, combining 4317 occurrences from French national databases and the 110 records collected herein
Trophic ecology of the Golden Jackal in Djurdjura National Park (Kabylie, Algeria)
Since the rediscovery of the African Wolf, a certain level of uncertainty surrounds the ecological
status of the golden Jackal in northern Africa. We characterized the trophic spectrum of the ‘Golden Jackal’
phenotype (distinct from the ‘African Wolf’ phenotype) and its possible seasonal variations in relation with
availability of resources (waste included) in the Djurdjura National Park (DNP), northern Algeria. The analysis
of 360 faeces collected over one year shows that 91 % of the items consumed by the Golden Jackal belong
to five categories: mammals (27 %), non-energetic plants (20 %), energetic plants (19 %), arthropods (16 %)
and waste (10 %). Our results confirm that the Golden Jackal is a generalist and opportunistic predator, with
mammals representing the principal energy source. The Golden Jackal in PND shows an original predilection
for the mammalian preys of medium size (Wild Boar –– the main contributor in terms of biomass ––Barbary
Macaque and Sheep). This illustrates its potential for maximizing net energy gain (hunting cost vs. biomass
supply) thanks to its capacity to reach larger preys. The high indices of trophic diversity observed throughout
the year suggest dietary habits following levels of resource availability rather than strict seasonal “specializations”.
The existence of peaks of consumption of Wild Boars and Barbary Macaques outside ‘critical’ seasons
(spring and winter) together with the weak probability to feed on carcasses (absence of local hunting activities)
support the hypothesis of an active hunting of these preys by the Golden Jackal. However, this would
imply a behaviour of co-operative hunting seldom observed in Maghreb. The high representation of plants
in the trophic spectrum of the Golden Jackal confirms that the diet of the Carnivores from the Mediterranean
areas generally includes more vegetable material than in northern latitudes. Waste (as well as livestock and
poultry) is a weak contributor to the diet of the Golden Jackal. This is potentially linked to the quality of the
habitat and to the important availability of food items in the DNPDepuis la redécouverte du Loup africain, une incertitude entoure le statut écologique
du Chacal doré en Afrique du Nord. Nous avons souhaité caractériser le spectre trophique du phénotype
‘Chacal doré’ (distinct du phénotype ‘Loup africain’) ainsi que ses éventuelles variations saisonnières en
rapport avec la disponibilité des ressources dans le Parc National du Djurdjura (PND), en Algérie du nord.
L’analyse de 360 fèces récoltées sur une année montre que 91 % des items consommés par le Chacal doré
appartiennent à cinq catégories : les mammifères (27 %), les plantes non énergétiques (20 %), les plantes
énergétiques (19 %), les arthropodes (16 %) et les déchets (10 %). Nos résultats confirment le comportement
de prédateur généraliste et opportuniste du Chacal doré, les mammifères représentant la principale source
énergétique. Le Chacal doré présente dans le PND une prédilection originale pour les proies mammaliennes
de tailles moyennes (Sanglier –– principal contributeur en termes de biomasse –– Magot et Mouton). Ceci
illustre son potentiel de maximisation du gain d’énergie net (coût de la chasse vs. apport en biomasse) grâce
à sa capacité d’accéder à des proies plus grosses. Les indices de diversité trophique élevés observés tout
au long de l’année suggèrent des tendances alimentaires suivant la disponibilité des ressources plutôt que
des « spécialisations » saisonnières strictes. L’existence de pics de consommation du Sanglier et du Magot
hors des saisons « critiques » (printemps et hiver) ainsi que la probabilité faible de trouver des carcasses
(absence de chasse villageoise) soutiennent l’hypothèse d’une chasse active de ces proies par le Chacal
doré. Ceci implique toutefois un comportement de chasse coopérative rarement observé au Maghreb. La
forte représentation des plantes observée dans le spectre trophique du Chacal doré confirme que le régime alimentaire des Carnivores dans les régions méditerranéennes inclut généralement plus de matériel végétal
que dans les latitudes septentrionales. Les déchets ménagers (ainsi que le bétail et la volaille) sont de faibles
contributeurs au régime alimentaire du Chacal doré. Ceci est potentiellement lié à la qualité de l’habitat et à
la disponibilité importante des items alimentaires dans le PN
1/f Noise Suppression of pMOSFETs Fabricated on Si(100) and Si(110) Using an Alkali-Free Cleaning Process
Parvovirus 4 in French in-patients: a study of haemodialysis and lung transplant cohorts
International audienceThe epidemiology and the clinical implication of human parvovirus 4 (PARV4) in human populations is still under evaluation. The distribution of PARV4 DNA was determined in cohorts of French haemodialysis and lung transplant patients. Plasma samples (n=289) were tested for PARV4 by real-time PCR assay (ORF2), and amplification products selected at random were sequenced. Analysis of available serological and biological markers was also undertaken. Fifty-seven samples out of 185 (30.8%) were positive for PARV4 DNA in the cohort of haemodialysis patients. A higher prevalence of the virus was identified in individuals with markers of HBV infection. PARV4 was also identified in 14 out of 104 samples (13.5%) from lung transplant recipients, with no clear-cut association with available clinical markers. Point mutations located on the zone of real-time detection were identified for some amplification products. This study describes the detection of PARV4 in the blood of haemodialysis and lung transplanted patients with significant difference in prevalence in these two cohorts. Further studies will be needed in order to understand better both the potential implication in host health and the natural history of this virus
Insights from 180 years of mitochondrial variability in the endangered Mediterranean monk seal (Monachus monachus)
Mediterranean monk seals (MMS) are among the most endangered marine mammals on Earth.We screened mitochondrial variability (control region [CR1] and mitogenomes) of the species through a 180‐yr timeframe and extended by 20% (n = 205) the number of samples from a previous investigation, including historical specimens from 1833 to 1975. Although we detected two new, rare CR1 haplotypes, genetic diversity remained extremely low. Fully resolved haplotype median network and rarefaction analysis both suggested low probability for further unscreened haplotypes. There was no clear phylogeographic structure across the 12 marine subdivisions covered by the species' range. Haplotypes previously considered diagnostic of the extant North Atlantic and eastern Mediterranean populations had their distributions extended into the western Mediterranean and the North Atlantic, respectively, by both historical and recent samples. Our study suggests that MMS have been genetically depauperate since at least the mid‐19th century, and that the massive 1997 die‐off in Western Sahara (North Atlantic) could have caused local haplotype extinctions. Our results support the hypothesis of past metapopulation dynamics across the species range, where the current segregation into geographically distant and genetically depauperate breeding populations (i.e., North Atlantic and eastern Mediterranean Sea) derives from the combined effects of historical extinctions, genetic drift on small breeding groups, and persistently low levels of genetic diversity
Representaciones extraordinarias de bailes por el Cuerpo de Baile del Teatro Nacional de la Ópera de París
De cada obra s'ha digitalitzat un programa sencer. De la resta s'han digitalitzat les parts que són diferents.Direcció artística Juan Mestres CalvetElvire de Domenico Scarlatti; Alejandro el Grande de Philippe Gaubert; Coppelia de Léo DelibesEmpresa Juan Mestres Calve
Despedida de la compañía de bailes del Teatro Nacional de la Ópera de París
De cada obra s'ha digitalitzat un programa sencer. De la resta s'han digitalitzat les parts que són diferents.Direcció artística Juan Mestres CalvetEl Festín de la Araña d'Albert Roussel; Dafnis y Cloe de Maurice Ravel; Alejandro el Grande de Philippe GaubertEmpresa Juan Mestres Calve
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