969 resultados para AC IMPEDANCE
Resumo:
Numérisation partielle de reliure
Resumo:
[Notitia dignitatum omnium tam civilium quam militarium (latin). 1552]
Resumo:
Within a drift-diffusion model we investigate the role of the self-consistent electric field in determining the impedance field of a macroscopic Ohmic (linear) resistor made by a compensated semi-insulating semiconductor at arbitrary values of the applied voltage. The presence of long-range Coulomb correlations is found to be responsible for a reshaping of the spatial profile of the impedance field. This reshaping gives a null contribution to the macroscopic impedance but modifies essentially the transition from thermal to shot noise of a macroscopic linear resistor. Theoretical calculations explain a set of noise experiments carried out in semi-insulating CdZnTe detectors.
Resumo:
The study of the thermal behavior of complex packages as multichip modules (MCM¿s) is usually carried out by measuring the so-called thermal impedance response, that is: the transient temperature after a power step. From the analysis of this signal, the thermal frequency response can be estimated, and consequently, compact thermal models may be extracted. We present a method to obtain an estimate of the time constant distribution underlying the observed transient. The method is based on an iterative deconvolution that produces an approximation to the time constant spectrum while preserving a convenient convolution form. This method is applied to the obtained thermal response of a microstructure as analyzed by finite element method as well as to the measured thermal response of a transistor array integrated circuit (IC) in a SMD package.
Resumo:
Numérisation partielle de reliure
Resumo:
Comprend : [Planche entre les p. 48-49. Deux planches. Représentation du côté ouest et du côté est d'une ville. Habitations burgondes.] [Cote : BNF C214317] ; [Planche dépliante entre les p. 48-49. Partie gauche de la planche représentant le côté est d'une ville. Habitations burgondes.] [Cote : BNF C94455]
Resumo:
Comprend : [ Folios A1v ° et A2r °. Vue des deux cartes en couleur de l'hémisphère Européen-Africain et de l'hémisphère Américain. XVIè siècle.] [ Cote : BNF RCB 8010. ]
Resumo:
Comprend : [Fig. au verso de la Page de Titre : un trois-mâts, enseigne de l'imprimeur.] [Cote : G 3486/Microfilm R 122140] ; [pl. double après le Titre :] Planisphère. [Cote : G 3486/Microfilm R 122140] ; [Carte double et dépl. après le Prologue : carte nautique de l'Atlantique Nord. Blason armorié avec devise "Dieu est mon droit".] Tabula Nautica (...). [Cote : G 3486/Microfilm R 122140] ; [Fig. après folio C2 : un Samoyède sur son traineau. Idoles vôtives.] [Cote : G 3486/Microfilm R 122140] ; [Carte dépl. et double avant folio C3 : carte de l'Arctique.] [Cote : G 3486/Microfilm R 122140] ; [Fig. au verso du Second Titre : un trois-mâts, enseigne de l'imprimeur.] [Cote : G 3486/Microfilm R 122140] ; [Carte double en reg. folio A2 : carte du Pôle, Norvège, Groënland, Nouvelle-Zélande etc.] [Cote : G 3486/Microfilm R 122140] ; [pl. double après p.16 : morses du grand Nord. Région du Spitzsberghe.] [Cote : G 3486/Microfilm R 122140] ; [Fig. p.18 : baleine du cercle polaire. Région du Spitzsberghe.] [Cote : G 3486/Microfilm R 122140]
Resumo:
Introduction: Growth is a central process in paediatrics. Weight and height evaluation are therefore routine exams for every child but in some situation, particularly inflammatory bowel disease (IBD), a wider evaluation of nutritional status needs to be performed. Objectives: To assess the accuracy of bio-impedance analysis (BIA) compared to the gold standard dual energy X-ray absorptiometry (DEXA) in estimating percentage body fat (fat mass; FM) and lean body mass (fat free mass; FFM) in children with inflammatory bowel disease (IBD). To compare FM and FFM levels between patients with IBD and healthy controls. Methods: Twenty-nine healthy controls (12 females; mean age: 12.7 ± 1.9 years) and 21 patients (11 females; 14.3 ± 1.3 years) were recruited from August 2011 to October 2012 at our institution. BIA was performed in all children and DEXA in patients only. Concordance between BIA and DEXA was assessed using Lin's concordance correlation and the Bland-Altman method. Between-group comparisons were made using analysis of variance adjusting for age. Results: BIA-derived FM% showed a good concordance with DEXA-derived values, while BIA-derived FFM% tended to be slightly higher than DEXA-derived values (table). No differences were found between patients and controls regarding body mass index (mean ± SD: 19.3 ± 3.3 vs. 20.1 ± 2.8 kg/m2, respectively; age-adjusted P = 0.08) and FM% (boys: 25.3 ± 10.2 vs. 22.6 ± 7.1%, for patients and controls, respectively; P = 0.20; girls: 28.2 ± 5.7 vs. 26.4 ± 7.7%; P = 0.91). Also, no differences were found regarding FFM% in boys (74.9 ± 10.2 vs. 77.4 ± 7.1%; P = 0.22) and girls (71.8 ± 5.6 vs. 73.5 ± 7.7%; P = 0.85). Conclusion: BIA adequately assesses body composition (FM%) in children with IBD and could advantageously replace DEXA, which is more expensive and less available. No differences in body composition were found between children with IBD and healthy controls.