Benefiting from the abrupt phase changes within subwavelength thicknesses,metasurfaces have been widely applied for lightweight and compact optical systems.Simultaneous broadband and high-efficiency characteristics ar...Benefiting from the abrupt phase changes within subwavelength thicknesses,metasurfaces have been widely applied for lightweight and compact optical systems.Simultaneous broadband and high-efficiency characteristics are highly attractive for the practical implementation of metasurfaces.However,current metasurface devices mostly adopt discrete micro/nano structures,which rarely realize both merits simultaneously.In this paper,dielectric metasurfaces composed of quasi-continuous nanostrips are proposed to overcome this limitation.Via quasi-continuous nanostrips metasurface,a normal focusing metalens and a superoscillatory lens overcoming the diffraction limit are designed and experimentally demonstrated.The quasi-continuous metadevices can operate in a broadband wavelength ranging from 450 nm to 1000nm and keep a high power efficiency.The average efficiency of the fabricated metalens reaches 54.24%,showing a significant improvement compared to the previously reported metalenses with the same thickness.The proposed methodology can be easily extended to design other metadevices with the advantages of broadband and high-efficiency in practical optical systems.展开更多
As a nonmetallic charge carrier,ammonium ion(NH_(4)^(+))has garnered significant attention in the construction of aqueous batteries due to its advantages of low molar mass,small hydration size and rapid diffusion in a...As a nonmetallic charge carrier,ammonium ion(NH_(4)^(+))has garnered significant attention in the construction of aqueous batteries due to its advantages of low molar mass,small hydration size and rapid diffusion in aqueous solutions.Polymers are a kind of potential electro-active materials for aqueous NH_(4)^(+)storage.However,traditional polymer electrodes are typically created by covering the bulky collectors with excessive additives,which could lead to low volume capacity and unsatisfactory stability.Herein,a nanoparticle-like polyimide(PI)was synthesized and then combined with MXene nanosheets to synergistically construct an additive-free and self-standing PI@MXene composite electrode.Significantly,the redox-active PI nanoparticles are enclosed between conductive MXene flakes to create a 3D lamination-like network that promotes electron transmission,while theπ-πinteractions existing between PI and MXene contribute to the enhanced structural integrity and stability within the composite electrode.As such,it delivers superior aqueous NH_(4)^(+)storage behaviors in terms of a notable specific capacity of 110.7 mA·h·cm^(–3) and a long lifespan with only 0.0064%drop each cycle.Furthermore,in-situ Raman and UV–Vis examinations provide evidence of reversible and stable redox mechanism of the PI@MXene composite electrode during NH_(4)^(+)uptake/removal,highlighting its significance in the area of electrochemical energy storage.展开更多
目的系统评价口服中药治疗微血管性心绞痛(MVA)的有效性和安全性。方法检索PubMed数据库、Embase数据库、Cochrane图书馆、科学网(Web of Srience)、Congle学术、中国知网(CNKI)、中国生物医学文献数据库(CBM)、维普数据库、万方数据库1...目的系统评价口服中药治疗微血管性心绞痛(MVA)的有效性和安全性。方法检索PubMed数据库、Embase数据库、Cochrane图书馆、科学网(Web of Srience)、Congle学术、中国知网(CNKI)、中国生物医学文献数据库(CBM)、维普数据库、万方数据库1979年1月1日至2020年8月1日公开发表的中药治疗MVA的随机对照试验。按照纳入标准筛选文献后采用Corhrane Handbook 5.1评价标准进行偏倚风险评价,使用Review Manager 5.3软件对口服中药治疗MVA患者的心绞痛发作持续时间和发作次数,平板运动试验持续时间、心电图有效率、不良反应发生率进行Mea分析,并用漏斗图评价心电图有效率的发表偏倚。结果最终纳入27篇文献,其中高质量文献2篇,中低质量文献25篇。Meta分析显示,与单纯常规治疗比较,中药治疗可缩短心绞痛发作持续时间[均数差(MID)=-1.70.95%可信区间(95%CI)为-2.30~-1.11.P<0.00001],减少心纹痛发作次数(MD=-3.49.95%CI为-4.58~-2.39,P<0.00001),延长平板运动试验持续时间(MD=0.79.95%CI为0.21~1.37.P=0.007),提高心电图改善率[相对危险度(RR)=1.32.95%CI为1.18~1.47.P<0.00001]。10项研究报告了不良事件,其中3项研究报告了不良反应,表明两组间不良反应发生率比较差异无统计学意义(P=0.63)。结论口服中药联合常规治疗MVA可进一步改善心绞痛症状心电图疗效及运动试验疗效,优于单纯西药治疗,且具有安全性。展开更多
基金the financial support by National Natural Science Foundation of China under contract No.61905031,61905073National Key R&D Program of China under contract No.2020YFC1522900Natural Science Foundation of Chongqing under contract No.CSTB2023NSCQMSX0992。
文摘Benefiting from the abrupt phase changes within subwavelength thicknesses,metasurfaces have been widely applied for lightweight and compact optical systems.Simultaneous broadband and high-efficiency characteristics are highly attractive for the practical implementation of metasurfaces.However,current metasurface devices mostly adopt discrete micro/nano structures,which rarely realize both merits simultaneously.In this paper,dielectric metasurfaces composed of quasi-continuous nanostrips are proposed to overcome this limitation.Via quasi-continuous nanostrips metasurface,a normal focusing metalens and a superoscillatory lens overcoming the diffraction limit are designed and experimentally demonstrated.The quasi-continuous metadevices can operate in a broadband wavelength ranging from 450 nm to 1000nm and keep a high power efficiency.The average efficiency of the fabricated metalens reaches 54.24%,showing a significant improvement compared to the previously reported metalenses with the same thickness.The proposed methodology can be easily extended to design other metadevices with the advantages of broadband and high-efficiency in practical optical systems.
基金supported by the National Natural Science Foundation of China(52002157)the Undergraduate Research&Practice Innovation Program of Jiangsu Province(202310289033Z).
文摘As a nonmetallic charge carrier,ammonium ion(NH_(4)^(+))has garnered significant attention in the construction of aqueous batteries due to its advantages of low molar mass,small hydration size and rapid diffusion in aqueous solutions.Polymers are a kind of potential electro-active materials for aqueous NH_(4)^(+)storage.However,traditional polymer electrodes are typically created by covering the bulky collectors with excessive additives,which could lead to low volume capacity and unsatisfactory stability.Herein,a nanoparticle-like polyimide(PI)was synthesized and then combined with MXene nanosheets to synergistically construct an additive-free and self-standing PI@MXene composite electrode.Significantly,the redox-active PI nanoparticles are enclosed between conductive MXene flakes to create a 3D lamination-like network that promotes electron transmission,while theπ-πinteractions existing between PI and MXene contribute to the enhanced structural integrity and stability within the composite electrode.As such,it delivers superior aqueous NH_(4)^(+)storage behaviors in terms of a notable specific capacity of 110.7 mA·h·cm^(–3) and a long lifespan with only 0.0064%drop each cycle.Furthermore,in-situ Raman and UV–Vis examinations provide evidence of reversible and stable redox mechanism of the PI@MXene composite electrode during NH_(4)^(+)uptake/removal,highlighting its significance in the area of electrochemical energy storage.
