992 resultados para 143-865B
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作为发射在1μm波段的二极管抽运全固态激光器的增益介质,掺Yb离子的晶体备受关注。掺Yb晶体具有能级结构简单,量子缺陷低(〈0.1),量子效率高等优点。目前成功使用掺Yb的晶体作为增益介质的飞秒激光振荡器已有很多报道,如Yb:BOYSE,Yb:KYW,Yb:SYSE等。
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本文综述了铈离子掺质硅酸钆(Ce:Gd2SiO5)闪烁晶体的结构、闪烁性能、闪烁机理及晶体生长的研究现状,重点讨论了Ce:GsO闪烁晶体生长的研究进展;提出了硅酸钆闪烁晶体未来研究发展的几个方向为:大尺寸晶体的生长、高光输出的研究、混合型硅酸钆晶体的研究等。
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[EN] Se ensaya la aplicación del procedimiento analítico de series de Uranio para el conocimiento de la seriación artística de obras parietales de estilo paleolítico. El resultado obtenido muestra la validez del método y abre nuevas vías para la obtención de fechas absolutas "ante quem" y "post quem" que sirvan para enmarcar momentos de ejecución de obras rupestres.
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用电子柬蒸发方法在三种不同取向的三硼酸锂(LiB3O3,简称LBO)晶体上沉积了ZrO2薄膜。采用分光光度计和X射线衍射技术对LBO晶体基底结构对薄膜光学性质和显微结构的影响进行了研究。实验结果表明:基底结构对薄膜的显微结构和光学性质具有明显影响,即X-LBO,Y-LBO和Z-LBO上沉积的ZrO3薄膜分别沿m(-212),m(021)和o(130)择优生长,且m(021)择优取向的ZrO3薄膜具有最高的折射率和最小的晶格不匹配。
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166 p. : il. col.
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Este artículo forma parte de la investigación realizada en el marco de la tesis de licenciatura de su autora: "La red viaria romana en el norte de Burgos. Valles de Mena, Losa y Sotoscueva. Vía Pisoraca- Flauiobriga. Via Flauiobriga-Iuliobriga. Vías secundarias", leída en el Departamento de Estudios Clásicos de la Facultad de Filología, Geografía e Historia de la UPV/EHU el 9 de octubre de 1996.
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Two sympatric populations of “transient” (mammal-eating) killer whales were photo-identified over 27 years (1984–2010) in Prince William Sound and Kenai Fjords, coastal waters of the northern Gulf of Alaska (GOA). A total of 88 individuals were identified during 203 encounters with “AT1” transients (22 individuals) and 91 encounters with “GOA” transients (66 individuals). The median number of individuals identified annually was similar for both populations (AT1=7; GOA=8), but mark-recapture estimates showed the AT1 whales to have much higher fidelity to the study area, whereas the GOA whales had a higher exchange of individuals. Apparent survival estimates were generally high for both populations, but there was a significant reduction in the survival of AT1 transients after the Exxon Valdez oil spill in 1989, with an abrupt decline in estimated abundance from a high of 22 in 1989 to a low of seven whales at the end of 2010. There was no detectable decline in GOA population abundance or survival over the same period, but abundance ranged from just 6 to 18 whales annually. Resighting data from adjacent coastal waters and movement tracks from satellite tags further indicated that the GOA whales are part of a larger population with a more extensive range, whereas AT1 whales are resident to the study area.
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Spawning periodicities of white seabass (Atractoscion nobilis) were evaluated by observing spawning behavior, by collecting eggs, and monitoring recognizable sounds produced during the release of gametes. A total of 297 spawning events were documented from 15 male and 47 female white seabass contained within the seminatural confines of a 526-m3 net pen located in Catalina Harbor, Santa Catalina Island, California. Consistent spawning occurred from March through July 2001−03, and peaked in May at a photoperiod of 14 hours. Most spawning occurred within the 2-hour period following sunset or from 19:00−20:00 hours Pacific Standard Time. White seabass spawned at every phase of the lunar cycle; but an increase in successive spawning events followed the new moon. Most spawning occurred in water temperatures from 15 to 18°C, and there was no apparent correlation with tidal cycles. Seasonal and diel spawning periods were directly correlated with increases in the rate, intensity, and variety of white seabass sounds; this correlation may indicate that sounds function to enhance reproductive success. These findings can be extended to further develop seasonal fishery regulations and to better comprehend the role of sound in the reproduction of sound-producing fishes.