为实现对太阳光的宽波段高效吸收,引入光学黑洞(optical black hole,OBH)概念,用有限元方法对单纳米线太阳电池(SNSCs)进行电磁仿真和结构设计。剖析了极化模式、OBH尺寸、核壳匹配、折射率阶梯分层等因素对OBH SNSCs的陷光和光学吸收...为实现对太阳光的宽波段高效吸收,引入光学黑洞(optical black hole,OBH)概念,用有限元方法对单纳米线太阳电池(SNSCs)进行电磁仿真和结构设计。剖析了极化模式、OBH尺寸、核壳匹配、折射率阶梯分层等因素对OBH SNSCs的陷光和光学吸收性能的影响。研究表明:较以往介电常数匹配方式,利用折射率匹配设计可进一步提高OBH系统的光学吸收性能;借助微纳结构对光波的调控,可实现全向宽带高效吸收,从而将OBH应用于微纳光伏系统;进一步发现,可通过优化内核半径和外壳折射率分布来提高基于OBH的非晶硅(a-Si:H)SNSCs吸收效率,获得的光电流较传统无包层a-Si:H SNSCs提升约300%。展开更多
Evidence for the long-term optical curve variability and colour behaviour of the BL Lac object Mkn 421 is presented. Our results show that the amplitude of the optical variations of Mkn 421 is only about △B=4.7 magni...Evidence for the long-term optical curve variability and colour behaviour of the BL Lac object Mkn 421 is presented. Our results show that the amplitude of the optical variations of Mkn 421 is only about △B=4.7 magnitude in the B-band for its photometric history from 1899 to 2002. The results of optical photometric monitoring of the Mkn 421 from April 2000 to Jan 2002 are provided. During our observation, Mkn 421 shows significant rapid variations and exhibits short time variability of 2.42 hours in the B band. A strong correlation between the B - V colour index and the magnitude in the B band is found. Our charge coupled device （CCD） photometry of Mkn 421 shows that the measured results are in good agreement with the predicted optical variability period of about 23 years.展开更多
文摘为实现对太阳光的宽波段高效吸收,引入光学黑洞(optical black hole,OBH)概念,用有限元方法对单纳米线太阳电池(SNSCs)进行电磁仿真和结构设计。剖析了极化模式、OBH尺寸、核壳匹配、折射率阶梯分层等因素对OBH SNSCs的陷光和光学吸收性能的影响。研究表明:较以往介电常数匹配方式,利用折射率匹配设计可进一步提高OBH系统的光学吸收性能;借助微纳结构对光波的调控,可实现全向宽带高效吸收,从而将OBH应用于微纳光伏系统;进一步发现,可通过优化内核半径和外壳折射率分布来提高基于OBH的非晶硅(a-Si:H)SNSCs吸收效率,获得的光电流较传统无包层a-Si:H SNSCs提升约300%。
基金Project supported by an CRCG grant of the University of Hong Kong, Yunnan Provincial Foundation of Science of China （Grant No 2004A0027M） and the National Natural Science Foundation of China（Grant No 10363002）, and the Natural Science Foundation of China Education Department（Grant No 02142）.
文摘Evidence for the long-term optical curve variability and colour behaviour of the BL Lac object Mkn 421 is presented. Our results show that the amplitude of the optical variations of Mkn 421 is only about △B=4.7 magnitude in the B-band for its photometric history from 1899 to 2002. The results of optical photometric monitoring of the Mkn 421 from April 2000 to Jan 2002 are provided. During our observation, Mkn 421 shows significant rapid variations and exhibits short time variability of 2.42 hours in the B band. A strong correlation between the B - V colour index and the magnitude in the B band is found. Our charge coupled device （CCD） photometry of Mkn 421 shows that the measured results are in good agreement with the predicted optical variability period of about 23 years.
