Modélisation de l’impédance de transfert des câbles coaxiaux à blindages multiples

The shielding effectiveness of multishielded coaxial cables is determinated through the concept of the equivalent transfer impedance. The transfer impedance is computed from the main parameters of the coaxial structure. We describe in this paper the theoretical formulation to evaluate the amplitude of the disturbing voltage at the end of the cable flowed by the disturbing current. This result is used for the computation of the equivalent transfer impedance when the cable is made of various shields for exemple: homogeneous screens or braids. A comparison with the experimental results is also described.     

Size effects on the DC characteristics and low frequency noise of double polysilicon NPN bipolar transistors

DC and low frequency noise measurements have been carried out for double polysilicon NPN bipolar transistors. Our experiments have highlighted unexpected geometrical dependencies for the base saturation current density and low frequency noise. A model, taking into account a variation of the interfacial oxide thickness at the periphery of the emitter has been proposed and it has been successfully applied to the experimental results.     

Response of the Rhône deltaic margin to loading and subsidence during the last climatic cycle

Passive continental margin subsidence is initiated by the synrift mechanical stretching of the lithospheric upper brittle layer and continues during the postrift phase; the thermal cooling and contraction of the upwelled asthenosphere forces the margin to subside in addition to the overloads from sea water and sediments. Therefore, the total subsidence in stretched basins includes fault-controlled initial sinking, thermal subsidence and flexural isostatic compensations. Decoupling and estimating the different components of this subsidence from stratigraphic analysis and restricted geophysical and sedimentological databases remains problematic. In particular, backstripping the sediment layers requires a well-constrained geological framework. A method is proposed here to investigate the subsidence history of a margin based on forward stratigraphic modelling. Using the Sedflux model, several experiments are done using generally agreed upon assumptions on the parameters describing lithospheric rheology and isostatic behaviour of a margin. The stratigraphic modelling of the Rhône deltaic margin during the last climatic cycle (125 kyr) provides an assessment of these parameter estimates and their influence on geohistory (tectonic/thermal subsidence and sediment loading). The model results confirm the important impact of water loading on vertical deflection along the platform between glacial low sea-level and interglacial high sea-level. Based on Gulf of Lions (NW Mediterranean) observations, a conceptual method that uses the stratigraphic simulations is produced in order to evaluate the different components of the total subsidence of a margin, and, in particular, the relative impact of tectonic subsidence and sediment load.     

Dogmatisme paternel, niveau socio-économique et performance cognitive de pré-adolescent(e)s.

Studied the association among paternal dogmatism, socioeconomic status (SES), and cognitive development using Piagetian tasks. Human subjects: 98 male and female French-Canadian schoolage children and adolescents (aged 144–171 mo) (1st class of students in the secondary school). 98 male French-Canadian adults (aged 32–62 yrs). All Ss were from 2-parent families and consisted of 50 father–daughter and 48 father–son dyads. Paternal dogmatism was measured using the French-Canadian version of the Rokeach Scale by M. Rokeach (1960). Cognitive levels were evaluated using Piaget and Inhelder"s Permutations Test (1951). Ss" SES was measured using B. R. Blishen and H. A. McRobert"s Socioeconomic Index (1976). The results of the cognitive performance tests were analyzed statistically according to age, sex, dogmatism, and SES, using an analysis of variance (ANOVA). (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scattering on a ring of processors

In this note, we prove that the complexity of scattering in an oriented ring of p processors is (p - 1) (β + Lτ) where L is the length of the messages, β the communication startup, and τ the elemental propagation time.     

Efficient and Scalable Kinetic Resolution of Racemic 4‐Formyl[2.2]paracyclophane via Asymmetric Transfer Hydrogenation

Herein we wish to report a new non‐enzymatic kinetic resolution of racemic 4‐formyl[2.2]paracyclophane based on Noyori asymmetric transfer hydrogenations (KR‐ATH). Our approach, which provides an efficient access to enantiopure (R_p)‐ and (S_p)‐4‐formyl[2.2]paracyclophane (>99% ee, 39% and 41% isolated yields, respectively), is operationally simple and can be run on the gram‐scale thus confirming the practical applicability of this method.

     

Comprehensive study of the influence of total pressure on products yields in fluidized bed gasification of wood sawdust

Wood sawdust gasification experiments were performed in a steam fluidized bed at 800 °C between 2 and 10 bar. An evolution of gas yields with time was measured during the tests, and especially an increase of hydrogen and carbon dioxide yields. This test duration effect was ascribed to char build-up in the bed. As tests proceed, the contribution of char steam gasification to gas yield increases, and the catalytic effect of char on hydrocarbons and tar conversion and on water-gas shift reaction is enhanced.As total pressure increases from 2 to 10 bar, hydrogen, carbon dioxide and methane yields increase by 16%, 53% and 38% respectively, whereas carbon monoxide yield decreases by 33%. The changes in gaseous yields with pressure can be partly explained by the influence of pressure on gas phase reactions (acceleration of water-gas shift kinetics and change in hydrocarbon reactions). The increase of methane yield with pressure is rather suggested to be linked to a change in secondary pyrolysis reactions scheme under high pressure.