998 resultados para 139-858B
Resumo:
Researchers compared nest architecture in loggerhead sea turtles at natural beaches in Florida, USA and Brazil to determine how similarities and differences in female morphology and reproductive output in these two populations are reflected in the structure of the nest.
Resumo:
El Congreso "Humanizar la Educación / Hezkuntza Gizatiartu", desarrollado en Bilbao los días 27, 28 y 29 de junio de 2014, es una propuesta dirigida a todos los agentes que constituyen la comunidad educativa. La finalidad de este evento consiste en generar un espacio de dimensión humana para compartir experiencias de trabajo, propiciar vivencias técnicas orientadas al autoconocimiento, y estimular actitudes responsables y creativas que posibiliten humanizar la educación. Está dirigido a todas las personas implicadas y comprometidas con la educación, independientemente del nivel, ámbito y rol en el que ésta se desarrolle; nos referimos a personas receptivas y que confíen en que el cambio comienza en uno mismo. Este marco ofrece una oportunidad para reconocer y hacer visibles realidades educativas ya existentes en esta línea y para nutrir aquellas que pudieran gestarse. Este evento, organizado por la UPV/EHU, se oferta en el marco de los Cursos de Verano / Cursos Europeos de la Fundación Cursos de Verano de la UPV/EHU y cuenta con la colaboración especial de la Fundación Claudio Naranjo. Para su desarrollo, además, cuenta con la ayuda de numerosas entidades, asociaciones, centros y profesionales que tienen la convicción de que educar es mucho más que compartir conocimiento; es una responsabilidad conjunta de todos los que configuramos el mapa educativo.
Resumo:
根据菲涅尔全内反射相变理论,给出了双菱体λ/4消色差器的结构设计、性能分析和测量方法.由有效通光孔径和光线追迹设计出BK7玻璃在波长532 nm时相位延迟λ/4的双菱体的结构,用作532 nm至1 064 nm波长范围的标准λ/4相位延迟器.理论分析了入射角变化和波长变化对双菱体相位延迟的影响,当入射角变化限制在±4.3°以内时,其影响得到补偿;波长从532 nm到1 064 nm产生的误差为-0.65°.采用椭偏法中的消光技术,分别实测了双菱体在532 nm和1 064 nm波长下的相位延迟为:90.08±0.14°和88.99±0.1°,可知两不同波长产生的相位延迟误差为-1.09°.
Resumo:
Er3+/Yb3+ cocloped fluorophosphate glasses were prepared and their thermal stabilities, Raman spectra, absorption spectra, and fluorescence spectra were measured. It is found that proper content of NaF or PbF2 is helpful for the increase of stability against crystallization. The variation of AI(PO3)3 or NaF content in the composition affects not the maximum phonon energy but the phonon density. The introduction of PbF2 decreases the phonon energy slightly. Intense green and red upconversion luminescence was observed for the fluorophosphate glass with low phosphate content. A glass matrix for upconversion luminescence requiring neither expensive raw material nor special atmospheric conditioned preparation is provided. Infrared luminescence around 1530 nm was researched. Fluorophosphate glasses with bandwidth properties and stimulated-emission cross sections better than tellurite, germanate and silicate glasses are obtained. Through the introduction of NaF, the bandwidth properties are decreased. Through the introduction of PbF2 the gain properties are increased. On the whole, it is difficult to obtain a material with the best gain properties and bandwidth properties simultaneously. There should be a compromise between them according to the demand. (C) 2006 Elsevier B.V. All rights reserved.
Resumo:
Eu-doped and Eu/Al-codoped high silica glass to investigate the properties of europium ions in high silica glasses were obtained. The porous glasses were immersed into europium nitrate solution or mixed solution of europium nitrate and aluminum nitrate. After dried, the doped porous glasses were sintered at 1200°C to obtain Eu-doped and Eu/Al-codoped high silica glasses. The reduction of Eu3+&rarrEu2+ was observed in Eu/Al-codoped high silica glass. The ratio of trivalent and bivalent europium ions was adjusted by the addition of aluminum ions and then the luminescent color of the glasses was controlled. A detailed mechanism was given to explain this reduction process.