A stimulated emission depletion （STED） microscopy scheme using axially symmetric polarized vortex beams is pro- posed based on unique focusing properties of such kinds of beams. The concept of axially symmetric pola...A stimulated emission depletion （STED） microscopy scheme using axially symmetric polarized vortex beams is pro- posed based on unique focusing properties of such kinds of beams. The concept of axially symmetric polarized vortex beams is first introduced, and the basic principle about the scheme is described. Simulation results for several typical beams are then shown, including radially polarized vortex beams, azimuthally polarized vortex beams, and high-order axi- ally symmetric polarized vortex beams. The results indicate that sharper doughnut spots and thus higher resolutions can be achieved, showing more flexibility than previous schemes based on flexible modulation of both phase and polarization for incident beams.展开更多
A versatile and inexpensive super-resolution fluorescent microscope that functions as easily as a conventional confocal microscope is described. Components of the microscope were designed on a platform which was place...A versatile and inexpensive super-resolution fluorescent microscope that functions as easily as a conventional confocal microscope is described. Components of the microscope were designed on a platform which was placed atop a surplus microscope frame. All optical components and equipments used are given. The excitation and depletion beams are extracted from a compact low-cost supercontinuum light source. The focal spot of the depletion beam at the focal plane is studied and imaged by a 100 nm aperture near-field fiber tip. The collinear excitation and depletion beam focused by a 0.9 numerical aperture microscope objective produce a 90 nm lateral super-resolution as verified by imaging 100 nm diameter fluorescent beads.展开更多
针对全局平稳特征和时空非平稳特征同时存在的现象,提出了混合时空地理加权回归方法(Mixed Geographically and Temporally Weighted Regression,MGTWR),给出了MGTWR的数学定义和回归参数的两步估计。同时,介绍了调整型带宽选择机制下...针对全局平稳特征和时空非平稳特征同时存在的现象,提出了混合时空地理加权回归方法(Mixed Geographically and Temporally Weighted Regression,MGTWR),给出了MGTWR的数学定义和回归参数的两步估计。同时,介绍了调整型带宽选择机制下的权重计算方法和基于Akaike信息准则(Akaike Information Criterion,AIC)的参数优化方法。采用复杂程度不同的模拟数据来测试方法的性能。结果表明,MGTWR和GTWR的R2大于0.8,能模拟全局平稳特征和时空非平稳特征的现象,但MGTWR显著优于GTWR。MGWR因无法探测时间平稳特征,模拟效果最差。此外,数据复杂程度影响MGTWR,GTWR和MGWR的性能,数据越简单模拟效果越好。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61108047 and 61475021)the Natural Science Foundation of Beijing,China(Grant No.4152015)+2 种基金the Program for New Century Excellent Talents in Universities of China(Grant No.NCET-13-0667)the Top Young Talents Support Program of BeijingChina(Grant No.CIT&TCD201404113)
文摘A stimulated emission depletion （STED） microscopy scheme using axially symmetric polarized vortex beams is pro- posed based on unique focusing properties of such kinds of beams. The concept of axially symmetric polarized vortex beams is first introduced, and the basic principle about the scheme is described. Simulation results for several typical beams are then shown, including radially polarized vortex beams, azimuthally polarized vortex beams, and high-order axi- ally symmetric polarized vortex beams. The results indicate that sharper doughnut spots and thus higher resolutions can be achieved, showing more flexibility than previous schemes based on flexible modulation of both phase and polarization for incident beams.
文摘A versatile and inexpensive super-resolution fluorescent microscope that functions as easily as a conventional confocal microscope is described. Components of the microscope were designed on a platform which was placed atop a surplus microscope frame. All optical components and equipments used are given. The excitation and depletion beams are extracted from a compact low-cost supercontinuum light source. The focal spot of the depletion beam at the focal plane is studied and imaged by a 100 nm aperture near-field fiber tip. The collinear excitation and depletion beam focused by a 0.9 numerical aperture microscope objective produce a 90 nm lateral super-resolution as verified by imaging 100 nm diameter fluorescent beads.
文摘针对全局平稳特征和时空非平稳特征同时存在的现象,提出了混合时空地理加权回归方法(Mixed Geographically and Temporally Weighted Regression,MGTWR),给出了MGTWR的数学定义和回归参数的两步估计。同时,介绍了调整型带宽选择机制下的权重计算方法和基于Akaike信息准则(Akaike Information Criterion,AIC)的参数优化方法。采用复杂程度不同的模拟数据来测试方法的性能。结果表明,MGTWR和GTWR的R2大于0.8,能模拟全局平稳特征和时空非平稳特征的现象,但MGTWR显著优于GTWR。MGWR因无法探测时间平稳特征,模拟效果最差。此外,数据复杂程度影响MGTWR,GTWR和MGWR的性能,数据越简单模拟效果越好。
