Diffractive lenses(DLs)can realize high-resolution imaging with light weight and compact size.Conventional DLs suffer large chromatic and off-axis aberrations,which significantly limits their practical applications.Al...Diffractive lenses(DLs)can realize high-resolution imaging with light weight and compact size.Conventional DLs suffer large chromatic and off-axis aberrations,which significantly limits their practical applications.Although many achromatic methods have been proposed,most of them are used for designing small aperture DLs,which have low diffraction efficiencies.In the designing of diffractive achromatic lenses,increasing the aperture and improving the diffraction efficiency have become two of the most important design issues.Here,a novel phase-coded diffractive lens(PCDL)for achromatic imaging with a large aperture and high efficiency is proposed and demonstrated experimentally,and it also possesses wide field-of-view(FOV)imaging at the same time.The phase distribution of the conventional phase-type diffractive lens(DL)is coded with a cubic function to expand both the working bandwidth and the FOV of conventional DL.The proposed phase-type DL is fabricated by using the laser direct writing of grey-scale patterns for a PCDL of a diameter of 10 mm,a focal length of 100 mm,and a cubic phase coding parameter of 30π.Experimental results show that the working bandwidth and the FOV of the PCDL respectively reach 50 nm and 16°with over 8%focusing efficiency,which are in significant contrast to the counterparts of conventional DL and in good agreement with the theoretical predictions.This work provides a novel way for implementing the achromatic,wide FOV,and high-efficiency imaging with large aperture DL.展开更多
目的分析抑郁在老年人社会参与和认知功能间的中介作用。方法基于2018年中国健康与养老追踪调查数据,筛选出符合标准的研究对象7 403人,采用结构方程模型分析抑郁在老年人社会参与和认知功能间的中介作用。结果患认知功能障碍的老年人有...目的分析抑郁在老年人社会参与和认知功能间的中介作用。方法基于2018年中国健康与养老追踪调查数据,筛选出符合标准的研究对象7 403人,采用结构方程模型分析抑郁在老年人社会参与和认知功能间的中介作用。结果患认知功能障碍的老年人有2 332(31.50%)人。社会参与和认知功能呈正相关(r=0.103,P<0.001);社会参与和抑郁呈负相关(r=-0.050,P<0.001);抑郁与认知功能呈负相关(r=-0.242,P<0.001)。结构方程模型各项拟合指标结果显示:χ^(2)=4.094,P<0.001,渐进残差均方和平方根(root mean square error of approximation, RMSEA)=0.020,比较拟合指数(comparative fit index, CFI)=0.985,塔克-刘易斯指数(Tucker-Lewis Index, TLI)=0.979,增量拟合指数(incremental fit index, IFI)=0.985,模型拟合较好。社会参与对认知功能的直接效应为0.380(95%CI:0.292~0.467),以抑郁为中介的间接效应为0.050(95%CI:0.027~0.073)。结论社会参与与老年人认知功能正相关,抑郁与老年人认知功能负相关,抑郁在社会参与和认知功能关系中起部分中介作用。展开更多
基金the National Natural Science Foundation of China(Grant No.61775154)the Natural Science Foundation of the Jiangsu Higher Education Institutions,China(Grant No.18KJB140015)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions,Chinathe Open Research Fund of CAS Key Laboratory of Space Precision Measurement Technology,China(Grant No.SPMT2021001)。
文摘Diffractive lenses(DLs)can realize high-resolution imaging with light weight and compact size.Conventional DLs suffer large chromatic and off-axis aberrations,which significantly limits their practical applications.Although many achromatic methods have been proposed,most of them are used for designing small aperture DLs,which have low diffraction efficiencies.In the designing of diffractive achromatic lenses,increasing the aperture and improving the diffraction efficiency have become two of the most important design issues.Here,a novel phase-coded diffractive lens(PCDL)for achromatic imaging with a large aperture and high efficiency is proposed and demonstrated experimentally,and it also possesses wide field-of-view(FOV)imaging at the same time.The phase distribution of the conventional phase-type diffractive lens(DL)is coded with a cubic function to expand both the working bandwidth and the FOV of conventional DL.The proposed phase-type DL is fabricated by using the laser direct writing of grey-scale patterns for a PCDL of a diameter of 10 mm,a focal length of 100 mm,and a cubic phase coding parameter of 30π.Experimental results show that the working bandwidth and the FOV of the PCDL respectively reach 50 nm and 16°with over 8%focusing efficiency,which are in significant contrast to the counterparts of conventional DL and in good agreement with the theoretical predictions.This work provides a novel way for implementing the achromatic,wide FOV,and high-efficiency imaging with large aperture DL.
文摘目的分析抑郁在老年人社会参与和认知功能间的中介作用。方法基于2018年中国健康与养老追踪调查数据,筛选出符合标准的研究对象7 403人,采用结构方程模型分析抑郁在老年人社会参与和认知功能间的中介作用。结果患认知功能障碍的老年人有2 332(31.50%)人。社会参与和认知功能呈正相关(r=0.103,P<0.001);社会参与和抑郁呈负相关(r=-0.050,P<0.001);抑郁与认知功能呈负相关(r=-0.242,P<0.001)。结构方程模型各项拟合指标结果显示:χ^(2)=4.094,P<0.001,渐进残差均方和平方根(root mean square error of approximation, RMSEA)=0.020,比较拟合指数(comparative fit index, CFI)=0.985,塔克-刘易斯指数(Tucker-Lewis Index, TLI)=0.979,增量拟合指数(incremental fit index, IFI)=0.985,模型拟合较好。社会参与对认知功能的直接效应为0.380(95%CI:0.292~0.467),以抑郁为中介的间接效应为0.050(95%CI:0.027~0.073)。结论社会参与与老年人认知功能正相关,抑郁与老年人认知功能负相关,抑郁在社会参与和认知功能关系中起部分中介作用。
