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Performance analysis of single-focus phase singularity based on elliptical reflective annulus quadrangle-element coded spiral zone plates
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作者 臧华平 王宝珍 +7 位作者 郑程龙 魏来 范全平 王少义 杨祖华 周维民 曹磊峰 郭海中 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期441-448,共8页
Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we pr... Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we propose an efficient methodology to combine the merit of elliptical reflective zone plates(ERZPs) and the advantage of spiral zone plates(SZPs) in establishing a specific single optical element, termed elliptical reflective annulus quadrangle-element coded spiral zone plates(ERAQSZPs) to generate single-focus phase singularity. Differing from the abrupt reflectance of the ERZPs, a series of randomly distributed nanometer apertures are adopted to realize the sinusoidal reflectance. Typically, according to our physical design, the ERAQSZPs are fabricated on a bulk substrate;therefore, the new idea can significantly reduce the difficulty in the fabrication process. Based on the Kirchhoff diffraction theory and convolution theorem, the focusing performance of ERAQSZPs is calculated. The results reveal that apart from the capability of generating optical vortices,ERAQSZPs can also integrate the function of focusing, energy selection, higher-order foci elimination, as well as high spectral resolution together. In addition, the focusing properties can be further improved by appropriately adjusting the parameters, such as zone number and the size of the consisted primitives. These findings are expected to direct a new direction toward improving the performance of optical capture, x-ray fluorescence spectra, and forbidden transition. 展开更多
关键词 optical vortex single-focus spiral zone plate topological charges
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统筹城乡医疗保障制度的难点和原因分析
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作者 王保真 《中国公共政策评论》 2011年第1期16-26,共11页
建立统筹城乡的社会保障制度是我国社会建设的重要目标。如何建立统筹城乡的医疗保障制度,是我国建立统筹社会保障制度的难点之一。本文揭示了现行三大医保制度由于对象、筹资、缴费标准、偿付水平及实际报销率等具体方案设计不同,致使... 建立统筹城乡的社会保障制度是我国社会建设的重要目标。如何建立统筹城乡的医疗保障制度,是我国建立统筹社会保障制度的难点之一。本文揭示了现行三大医保制度由于对象、筹资、缴费标准、偿付水平及实际报销率等具体方案设计不同,致使制度之间的相互衔接、整合存在难点与体制性障碍;分析了其政治、经济与体制性原因;提出了实现统筹城乡医保的建议。 展开更多
关键词 医疗保险 城乡统筹 体制 碎片化
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Performance of landfill leachate treatment system with disc-tube reverse osmosis units 被引量:2
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作者 Yanping LIU Xiujin LI +1 位作者 baozhen wang Shuo LIU 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2008年第1期24-31,共8页
Reverse osmosis system with the disc-tube mod-ule(DT-RO)was applied to treat landfill leachate on full scale at the Changshengqiao Sanitary Landfill,Chongqing City,China.In the first six-mouth operation phase,the trea... Reverse osmosis system with the disc-tube mod-ule(DT-RO)was applied to treat landfill leachate on full scale at the Changshengqiao Sanitary Landfill,Chongqing City,China.In the first six-mouth operation phase,the treatment performance of DT-RO system had been excel-lent and stable.The removal rate of chemical oxygen demand(COD),total organic carbon(TOC),electrical con-ductivity(EC),and ammonia nitrogen(NH 3-N)reached 99.2–99.7%,99.2%,99.6%,and over 98%,respectively.The rejection of Ca^(2+),Ba^(2+),and Mg^(2+)was over 99.9%,respectively.Suspended solid(SS)was not detectedin prod-uct water.Effective methods had been adopted to control membrane fouling,of which chemical cleaning is of utmost importance to guarantee the long smooth operation of the DT-ROsystem.The DT-ROsystemiscleanedinturnswith Cleaner A and Cleaner C.At present,the 1st stage cleaning cycle by Cleaner A and Cleaner C is conducted every 100 and500 h,respectively,dependingonrawthewaterquality. 展开更多
关键词 Disc-tube reverse osmosis(DT-RO) landfill leachate PERFORMANCE chemical cleaning
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