986 resultados para 128-799
Resumo:
[ES]El presente documento expone el trabajo realizado en el diseño y la fabricación de un basculante para una moto de competición el cual deberá cumplir unos requisitos técnicos, formando parte del conjunto de la moto y principalmente de la suspensión trasera, teniendo presente que dicho basculante corresponderá a una moto de competición, cuyo objetivo será el de medirse con otros prototipos en una carrera y no el de una moto de calle, en la cual las prestaciones buscadas no tienen porqué ser las mismas, también se buscará cumplir unos requisitos estéticos ya que dicho basculante ha de ser también atractivo visualmente. A su vez se expondrá el método de fabricación del mismo atendiendo a criterios económicos y de obtención de los requisitos que dicho basculante debe cumplir. El método de fabricación del basculante condicionará en gran parte su diseño. A lo largo del presente documento se expondrán también diferentes alternativas a la finalmente escogida, analizando las posibles ventajas y desventajas de las mismas y justificando así la solución escogida. Dicho trabajo se enmarca en el contexto de la competición internacional MotoStudent, que se celebra en el circuito de Aragón, en el cual cada dos años universidades de todo el mundo se miden en el desafío de diseñar y fabricar una moto de 250cc con la que se medirán con sus competidores en una serie de pruebas, entre ellas, una carrera en la que se pondrán a prueba la aplicación directa de los conocimientos y experiencia adquiridos a lo largo de la vida académica de los participantes.
Resumo:
Lattice-matched (Delta(a/a) = 1.8-3.4%) (001) LiGaO2 substrates have been employed for the first time to grow ZnO thin films by pulsed-laser deposition at 350-650 degrees C with oxygen partial pressure of 20Pa. XRD shows that a highly c-axis-oriented ZnO film can be deposited on (001) LiGaO2 substrate at 500 degrees C. AFM images reveal the surfaces of as-deposited ZnO films are smooth and root-mean-square values are 6.662, 5.765 and 6.834 nm at 350, 500 and 650 degrees C, respectively. PL spectra indicate only near-band-edge UV emission appears in the curve of ZnO film deposited at 500 degrees C. The deep-level emission of ZnO film deposited at 650 degrees C probably results from Li diffusion into the film. All the results illustrate substrate temperature plays a pretty important role in obtaining ZnO film with a high quality on LiGaO2 substrate by pulsed-laser deposition. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
Background: In the present study we have assessed whether the Carpathian Mountains represent a genetic barrier in East Europe. Therefore, we have analyzed the mtDNA of 128 native individuals of Romania: 62 of them from the North of Romania, and 66 from South Romania. Results: We have analyzed their mtDNA variability in the context of other European and Near Eastern populations through multivariate analyses. The results show that regarding the mtDNA haplogroup and haplotype distributions the Romanian groups living outside the Carpathian range (South Romania) displayed some degree of genetic differentiation compared to those living within the Carpahian range (North Romania). Conclusion: The main differentiation between the mtDNA variability of the groups from North and South Romania can be attributed to the demographic movements from East to West (prehistoric or historic) that differently affected in these regions, suggesting that the Carpathian mountain range represents a weak genetic barrier in South-East Europe.
Resumo:
报道了以掺Yb介质硅酸镥钇晶体为增益介质的激光行为。在自由运转的条件下,在1086nm的中心波长处用2.5%的输出耦合镜得到7.8W的连续激光输出,相应的斜效率为64%。利用SF14棱镜作为腔内调谐元件,激光输出的调谐范围为1014-1091nm。
Resumo:
Este trabajo se ha desarrollado a partir de la edición de las inscripciones romanas del País Vasco dentro del proyecto PETRAE Hispaniarum (Université Michel de Montaigne-Bordeaux III, Francia).
Resumo:
The community structure of fishes associated with pelagic Sargassum spp. and open water lacking Sargassum was examined during summer and fall cruises, 1999–2003, in the Gulf Stream off North Carolina. Significantly more individual fishes (n= 18,799), representing at least 80 species, were collected from samples containing Sargassum habitat, compared to 60 species (n=2706 individuals) collected from openwater habitat. The majority (96%) of fishes collected in both habitats were juveniles, and planehead filefish (Stephanolepis hispidus) dominated both habitats. Regardless of sampling time (day or night), Sargassum habitat yielded significantly higher numbers of individuals and species compared with open-water collections. Overall, fishes collected by neuston net tows from Sargassum habitat were significantly larger in length than fishes collected from open-water habitat with neuston nets. A significant positive, linear relationship existed between numbers of fishes and the quantity of Sargassum collected by neuston net. Underwater video recordings indicated a layered structure of fishes among and below the algae and that smaller fishes were more closely associated with the algae than larger fishes. Observations of schooling behaviors of filefishes (Monacanthidae), dolphinfish (Coryphaena hippurus), and jacks (Carangidae), and fish-jellyfish associations were also recorded with an underwater video camera. Our data indicate that Sargassum provides a substantial nursery habitat for many juvenile fishes off the U.S. southeast coast.