Spelling suggestions: "subject:"esistance efficiency"" "subject:"aesistance efficiency""
1 |
Analysis, Design, and Implementation of Integrated Charge Pumps with High PerformanceAllasasmeh, Younis 25 August 2011 (has links)
This thesis presents the design of new integrated charge pumps with high performance. An analysis method is determined to evaluate the voltage gain, the output resistance and the conversion efficiency parameters of integrated charge pumps. An optimization method is developed to improve the performance through capacitor sizing based on area constraints. Several charge pumps structures are optimized and compared including the losses due to devices parasitics. Results show that the Dickson charge pump (voltage doubler) is the best structure for integration. Therefore, techniques to improve per- formance and conversion efficiency of integrated voltage doubler are proposed. Switch bootstrapping technique prevents short-circuit losses, improves driving capability, and enhances the overall efficiency. The application of charge reuse technique reduces the dynamic power losses of integrated voltage doublers and double charge pumps. A pro- totype of the integrated voltage doublers was fabricated in a 0.18-μm CMOS process with the proposed techniques. Measured results have been presented, demonstrating the improvements in performance and conversion efficiency, with a good correlation between measured and predicted results.
|
2 |
Water relations in Salix with focus on drought responses /Wikberg, Jenny, January 2006 (has links) (PDF)
Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2006. / Härtill 3 uppsatser.
|
3 |
Bases génétiques de la résistance vis-à-vis des nématodes du genre Meloidogyne chez le piment / Genetic bases of resistance to root-knot nematodes, Meloidogyne spp., in pepperBarbary, Arnaud 10 December 2014 (has links)
Les nématodes à galles (Meloidogyne spp.) sont des pathogènes cosmopolites extrêmement polyphages. L’emploi de la majorité des nématicides chimiques étant désormais interdit, la meilleure alternative repose sur l’utilisation de gènes majeurs de résistance (gènes R). Cependant, il existe un risque de contournement de ceux-ci et les ressources génétiques en termes de gènes R sont limitées. Une gestion qui permette de pérenniser l’utilisation de ces ressources d’intérêt agronomique est donc primordiale. Me1 et Me3 sont deux gènes R à large spectre du piment actuellement utilisés dans les programmes de sélection. La confrontation vis-à-vis de M. incognita de différents génotypes possédant l’un de ces deux gènes a montré que (1) le fond génétique de la plante joue un rôle clé sur l’efficacité de ces gènes R, (2) il n’existe pas d’effet du dosage d’allèles pour ces gènes R. Suite à ces résultats, une recherche de loci à caractère quantitatif (QTLs) a été réalisée afin d’identifier et de localiser des facteurs de résistance partielle susceptibles d’expliquer les différences observées entre les différents fonds génétiques. L’étude de tels facteurs vis-à-vis de M. incognita, M. arenaria et M. javanica, les trois principales espèces de nématodes à galles, a mis en évidence quatre nouveaux QTLs. Tous sont regroupés sur le chromosome P1 du piment, sauf un efficace vis-à-vis de M. javanica situé sur le chromosome P9. C’est la première fois que des facteurs de résistance aux nématodes à galles sont localisés sur le chromosome P1. Ce travail ouvre de nouvelles perspectives quant à la création de nouvelles variétés avec un potentiel accru en termes de résistance aux Meloidogyne. / Root-knot nematodes (RKNs), Meloidogyne spp., are extremely polyphagous plant parasites worldwide. Since the use of most chemical nematicides is being prohibited, genetic resistance is an efficient alternative way to protect crops against these pests. However, nematode populations proved able to breakdown plant resistance, and genetic resources in terms of resistance genes (R-genes) are limited. Sustainable management of these valuable resources is thus a key point of R-gene durability. In pepper, Me1 and Me3 are two dominant major R-genes, currently used in breeding programs to control M. arenaria, M. incognita and M. javanica, the three main RKN species. Challenging these two genes in different genetic backgrounds against M. incognita demonstrated that (1) the efficiency of the R-genes in reducing the reproductive potential of RKNs is strongly affected by the plant genetic background, (2) the allelic status of the R-genes has no effect on nematode reproduction. According to these first results, a QTL analysis was performed to identify and to localize partial resistance factors against RKNs which could explain the differences observed between the genetic backgrounds. Focusing on M. incognita, M. arenaria and M. javanica, four new major QTLs were localized. They are all regrouped on pepper chromosome P1 except one QTL efficient against M. javanica, which was located on pepper chromosome P9. The cluster on chromosome P1, regrouping most of the newly discovered resistance factors, is described for the first time with respect to RKN resistance. As a conclusion, this work should contribute to the breeding of new pepper varieties with a high level of resistance against RKNs.
|
Page generated in 0.0999 seconds