2,230 research outputs found
Recuit laser de cellules solaires fonctionnant sous concentration
La résistance série élevée des cellules conventionnelles au silicium rend leur fonctionnement difficile sous concentration. Nous montrons ici que l'irradiation de la couche superficielle diffusée par un faisceau laser pulsé de grande intensité permet de réduire notamment la résistance série, de sorte que des rendements de conversion de 15 % sous 30 soleils et de 12,5 % sous 100 soleils (10 W/cm2) sont prévus par le calcul
Real time 3D US-tagging combined with 3D phase-based motion estimation
International audienceBy contrast with 2D imaging, quantitative analysis of 3D motion from ultrasound images can provide improved information in several applications, such as arterial mechanical assessment, heart motion and blood flow. Unfortunately, it remains difficult to obtain a high definition of the motion estimate in the lateral and elevation directions (i.e. perpendicular to the beam axis). To increase the definition in both these directions, this paper presents a 3D extension of a the transverse oscillations method that enables one to obtain ultrasound fields featuring oscillations along the 3 spatial dimensions, using a single apodization function. The 3D motion method is estimated using the phases of the images. Simulation results show that a 3D trajectory can be followed with a relative mean error smaller than 8%
EFFETS DES TRAITEMENTS THERMIQUES SUR LES PROPRIETES ELECTRIQUES DES CELLULES SOLAIRES A BASE DE SILICIUM POLYCRISTALLIN
On a étudié l'effet de recuits à haute température sur les caractéristiques électriques à l'obscurité et sous éclairement de cellules solaires à base de silicium polycristallin dont la jonction était préparée à froid par incrustation ionique et recuit par laser pulsé. Dans certains cas des dégradations notables sont observées pour des recuits à 900°C
Scalability of GHZ and random-state entanglement in the presence of decoherence
We derive analytical upper bounds for the entanglement of generalized
Greenberger-Horne-Zeilinger states coupled to locally depolarizing and
dephasing environments, and for local thermal baths of arbitrary temperature.
These bounds apply for any convex quantifier of entanglement, and exponential
entanglement decay with the number of constituent particles is found. The
bounds are tight for depolarizing and dephasing channels. We also show that
randomly generated initial states tend to violate these bounds, and that this
discrepancy grows with the number of particles.Comment: 9 pages, 3 figure
On the effects of roughness on the nonlinear dynamics of a bolted joint: a multiscale analysis
Accurate prediction of the vibration response of friction joints is of great importance when estimating both the performance and the life of build-up structures. The contact conditions at the joint interface, including local normal load distribution and contact stiffness, play a critical role in the nonlinear dynamic response. These parameters strongly depend on the mating surfaces, where the surface roughness is well known to have a significant impact on the contact conditions in the static case. In contrast, its effects on the global and local nonlinear dynamic response of a build-up structure is not as well understood due to the complexity of the involved mechanisms. To obtain a better understanding of the dependence of the nonlinear dynamic response on surface roughness, a newly proposed multiscale approach has been developed. It links the surface roughness to the contact pressure and contact stiffness, and in combination with a multiharmonic balance solver, allows to compute the nonlinear dynamic response for different interface roughness. An application of the technique to a single bolted lap joint highlighted a strong impact of larger roughness values on the pressure distribution and local contact stiffness and in turn on the nonlinear dynamic response
Bell inequalities for three systems and arbitrarily many measurement outcomes
We present a family of Bell inequalities for three parties and arbitrarily
many outcomes, which can be seen as a natural generalization of the Mermin Bell
inequality. For a small number of outcomes, we verify that our inequalities
define facets of the polytope of local correlations. We investigate the quantum
violations of these inequalities, in particular with respect to the Hilbert
space dimension. We provide strong evidence that the maximal quantum violation
can only be reached using systems with local Hilbert space dimension exceeding
the number of measurement outcomes. This suggests that our inequalities can be
used as multipartite dimension witnesses.Comment: v1 6 pages, 4 tables; v2 Published version with minor typos correcte
Associação norgestomet-cloprostenol na indução do parto em cabras leiteiras.
O trabalho objetivou avaliar a eficiencia da associacao entre um agente progestageno, o norgestomet, e um agente luteolitico, o cloprostenol, na inducao sincronizada do parto em cabras leiteiras.bitstream/item/41913/1/PL-Associacao.pd
Einstein-Podolsky-Rosen entanglement and steering in two-well BEC ground states
We consider how to generate and detect Einstein-Podolsky-Rosen (EPR)
entanglement and the steering paradox between groups of atoms in two separated
potential wells in a Bose-Einstein condensate (BEC). We present experimental
criteria for this form of entanglement, and propose experimental strategies for
detecting entanglement using two or four mode ground states. These approaches
use spatial and/or internal modes. We also present higher order criteria that
act as signatures to detect the multiparticle entanglement present in this
system. We point out the difference between spatial entanglement using
separated detectors, and other types of entanglement that do n}ot require
spatial separation. The four-mode approach with two spatial and two internal
modes results in an entanglement signature with spatially separated detectors,
conceptually similar to the original EPR paradox.Comment: 15 pages, changes mad
Características reprodutivas de ovelhas Santa Inês cruzadas com reprodutores Dorper e Somalis brasileira.
Os cruzamentos na ovinocultura tornaram-se um importante instrumento para aumentar a velocidade de crescimento dos animais e incrementar os parâmetros reprodutivo, sendo justificadas as pesquisas que gere tecnologias. Objetivou-se, com o presente trabalho, comparar a prolificidade e a fertilidade, de ovelhas Santa Inês (SI) cruzados com as raças Dorper (DP) e Somalis Brasileira (SB). A pesquisa foi conduzida no Campo Experimental Pedro Arle, da Embrapa Tabuleiros Costeiros/SE. Foram utilizadas 95 ovelhas da raça SI com idade variando de dois a sete anos e peso médio de 45,3 kg, criadas em regime semi-intensivo. As fêmeas foram inseminadas por laparoscopia (IL) com sêmen congelado de dois reprodutores das raças DP, SB e SI, formando assim três grupos genéticos: GG1 : SI x SI, GG2 : DP x SI e GG3 : SB x SI. Observou-se que não houve associação entre taxa de fertilidade ao parto e o tipo de acasalamento, obtendo-se taxa média de 43,16 %. A prolificidade média foi de 1,19, não apresentando diferença significativa (P>0,05) entre grupos genéticos. Com base nos resultados, conclui-se que as ovelhas SI apresentaram razoável taxa de fertilidade ao parto, quando submetidas à Inseminação Artificial Laparoscópica em nível de campo, com indução do estro apenas pelo efeito macho; o efeito da heterose sobre a prolificidade pode ser desprezível. Reproductive characteristics of sheep Santa Inês crossed with reproducers Dorper and Somalis Brasileira. Abstract - Interbreedings from the sheep raising become an important means to increase the rapidity of animals growth and even increase reproductive parameters, the searches have been justified for the technological. Advanced development the actual performance considered to confer the prolification and the fertility sheep Santa Snês breed (SI) interbred with the Dorper (DP) and Somalis Brazilian breeds (SB). The search was conduced at experimental rural rustic camp denominated Pedro Arle, to belong to Embrapa Tabuleiros Costeiros/SE. It were utilized ninety five sheeps of the SI breed with age between from two to seven ages and 45,3 medium weight, they were breeding in a half-active regime. The females were inseminated by laparoscopia ( IL) with frozen semen that belongs reproducers of the DP, SB and SI breeds, producing in this manner three genetical groups: GG1: SI x SI, GG2: DP x SI and GG3: SB x SI. So it was understood that there wasn´t any association between the fertility parturition rate in comparison to mating type, obtaining consequently a medium rate of 43,16 %. The prolification average was 1,19, it didn´t present any significative diference ( p>0,05) among to geneticals groups. Basing at these results, it has been concluded that the SI sheeps showed reasonable fertlility rate for the artificial insemination laparoscopic in search level, with induction oestrum only by effect male animal; contrasting the heterose effect and prolification can be worthless
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