Solar-driven water splitting for photocatalytic hydrogen evolution is considered a highly promising and costeffective solution to achieve a stable renewable energy supply.However,the sluggish kinetics of electron-hole...Solar-driven water splitting for photocatalytic hydrogen evolution is considered a highly promising and costeffective solution to achieve a stable renewable energy supply.However,the sluggish kinetics of electron-hole pairs’separation poses challenges in attaining satisfactory hydrogen production efficiency.Herein,we synthesized the exceptional performance of highly crystalline C_(3)N_(5)(HC–C_(3)N_(5))nanosheet as a photocatalyst,demonstrating a remarkable hydrogen evolution rate of 3.01 mmol h^(-1)g^(-1),which surpasses that of bulk C_(3)N_(5)(B–C_(3)N_(5))by a factor of 3.27.Experimental and theoretical analyses reveal that HC-C_(3)N_(5)nanosheets exhibit intriguing macroscopic photoinduced color changes,effectively broadening the absorption spectrum and significantly enhancing the generation of excitons.Besides,the cyano groups in HC-C_(3)N_(5)efficiently captures and converts photoexcited electrons into bound states,thereby prolonging their lifetimes and effectively separating electrons and holes into catalytically active regions.This research provides valuable insights into the establishment of bound electronic states for developing efficient photocatalysts.展开更多
Under investigation in this paper is a complex modified Korteweg–de Vries(KdV) equation, which describes the propagation of short pulses in optical fibers. Bilinear forms and multi-soliton solutions are obtained thro...Under investigation in this paper is a complex modified Korteweg–de Vries(KdV) equation, which describes the propagation of short pulses in optical fibers. Bilinear forms and multi-soliton solutions are obtained through the Hirota method and symbolic computation. Breather-like and bound-state solitons are constructed in which the signs of the imaginary parts of the complex wave numbers and the initial separations of the two parallel solitons are important factors for the interaction patterns. The periodic structures and position-induced phase shift of some solutions are introduced.展开更多
The measurement of the bound-state decay of^(205)Tl at the Experimental Storage Ring(ESR)at GSI,Darmstadt,has recently been reported,with substantial impact on the use of^(205)Pb as an early Solar System chronometer a...The measurement of the bound-state decay of^(205)Tl at the Experimental Storage Ring(ESR)at GSI,Darmstadt,has recently been reported,with substantial impact on the use of^(205)Pb as an early Solar System chronometer and on the low-energy measurement of the solar neutrino spectrum via the LOREX project.Owing to the technical challenges in producing a high-purity^(205)T^(l81+)secondary beam,a robust statistical method was developed to estimate the variation in the contaminant^(205)Pb^(81+)produced in the fragmentation reaction,which was subsequently transmitted and stored in the ESR.Here,we show that Bayesian and Monte Carlo methods produce comparable estimates for the contaminant variation,each with unique advantages and challenges given the complex statistical problems for this experiment.We recommend the adoption of such methods in future experiments that exhibit unknown statistical fluctuations.展开更多
传统THz器件长期受限于衍射极限导致的辐射损耗,其品质因子(Q因子)普遍低于10~5,严重制约了通信与传感性能。针对这一技术瓶颈,本研究基于拓扑光子学理论,设计了一种具有C6v对称性的硅基超表面,在THz频段实现了拓扑保护的高Q因子谐振。...传统THz器件长期受限于衍射极限导致的辐射损耗,其品质因子(Q因子)普遍低于10~5,严重制约了通信与传感性能。针对这一技术瓶颈,本研究基于拓扑光子学理论,设计了一种具有C6v对称性的硅基超表面,在THz频段实现了拓扑保护的高Q因子谐振。通过构建三角形晶格光子晶体平板,在晶胞内引入圆柱型蚀刻孔实现对称性保护,并采用理想磁导体边界条件分离TE模式,将连续域束缚态(bound states in the continuum,BIC)的拓扑保护机制引入THz频段。结果显示,Γ点处Q因子达到1010量级,且BIC位于远场辐射的偏振涡旋中心,验证了BIC机制及其拓扑特性,仿真结果良好。最终实现的Q因子较传统器件提升了多个数量级,且拓扑保护机制可以显著抑制加工缺陷与环境扰动对谐振性能的影响,为低损耗通信器件、光学可编程技术与量子光源设计提供了新范式。展开更多
为了解决连续谱中束缚态空间响应带宽偏小的技术难题,本文设计了一种简单的光子晶体平板,并进行能带的计算和模式Q因子分析.通过结构参数的优化,在k空间发现一种正方形环状的且边长可调节的准连续谱中束缚态(bound state in the continu...为了解决连续谱中束缚态空间响应带宽偏小的技术难题,本文设计了一种简单的光子晶体平板,并进行能带的计算和模式Q因子分析.通过结构参数的优化,在k空间发现一种正方形环状的且边长可调节的准连续谱中束缚态(bound state in the continuum, BIC)分布.分析准BIC环与等频线的关系以及模场分布的特征发现,这种正方形环状的准BIC来自结构的全内反射和驻波干涉效应.分别通过入射角度和频率扫描计算结构的透射谱,得到了高Q因子的法诺共振谱线,进而验证了环状准BIC的存在.展开更多
In this work,we investigate the thermodynamic variables of a harmonic oscillator in a conical geometry metric.Moreover,we introduce an external field in the form of a Wu-Yang magnetic monopole(WYMM)and an inverse squa...In this work,we investigate the thermodynamic variables of a harmonic oscillator in a conical geometry metric.Moreover,we introduce an external field in the form of a Wu-Yang magnetic monopole(WYMM)and an inverse square potential into the system and analyze the results.Using an analytical approach,we obtain the energy level and study the thermodynamics at finite temperature.Our findings demonstrate that thermodynamic variables,except for the specific heat and entropy,are influenced by the topological parameters,the strength of the WYMM,and the inverse square potential.展开更多
激光器在信息通信、智能制造等关键技术中发挥着核心作用。然而,传统半导体激光器尽管结构紧凑、效率高,却面临品质因子(Quality Factor,简称Q值)有限、光束质量较差及难以实现特殊光场等瓶颈。连续域中束缚态(Bound States in the Cont...激光器在信息通信、智能制造等关键技术中发挥着核心作用。然而,传统半导体激光器尽管结构紧凑、效率高,却面临品质因子(Quality Factor,简称Q值)有限、光束质量较差及难以实现特殊光场等瓶颈。连续域中束缚态(Bound States in the Continuum,BIC)是一种存在于辐射连续谱中的局域模态,因其与辐射通道完全解耦,可实现能量完全局域化,理论上具备无限大的Q值。基于BIC的激光器兼具高Q值与高局域化效应,能有效降低激光阈值,并显著抑制多模竞争从而输出高纯度单模激光。当前研究聚焦于通过结构设计提升BIC模式的稳定性与耦合效率,并探索其在集成光子学、拓扑激光器等前沿方向的应用。未来,BIC激光器有望在片上集成、主动调控等方面取得突破,推动高性能激光技术的发展。展开更多
与传统的光子晶体或超表面等微纳光学系统相比,基于连续域束缚态(bound states in the continuum,BIC)的光学体系通常具有更高的品质因子(quality factor,Q)与更窄的工作线宽,更高的Q值给高性能的光电元件提供了更广阔的可能性,但是更...与传统的光子晶体或超表面等微纳光学系统相比,基于连续域束缚态(bound states in the continuum,BIC)的光学体系通常具有更高的品质因子(quality factor,Q)与更窄的工作线宽,更高的Q值给高性能的光电元件提供了更广阔的可能性,但是更窄的线宽往往给实际应用造成一定麻烦,因为加工过程中的制造误差无可避免地导致实际的光学元件与理想情况存在差异,表现为实际工作波长与理想工作波长不匹配.为了克服该问题,本文利用带十字结构孔的光子晶体产生的对称保护型准连续域束缚态(quasi-bound states in the continuum,q-BIC),探索液晶(liquid crystal,LC)对q-BIC的动态调谐效应,以补偿加工误差导致的工作波长偏移.相比于入射光倾斜角对q-BIC的调制效应,在移动相同的波长时,LC对系统的Q值影响更小,例如使用入射光倾斜角调制q-BIC中心波长移动5.32 nm时,Q值下降75.84%,而使用LC调制q-BIC中心波长移动5.63 nm时,Q值上升了14.27%,这证明LC对高Q因子、超窄带的q-BIC元件具有极大的应用潜力.最后讨论了LC在q-BIC体系中的工作机理,可为广泛q-BIC的相关研究提供参考.展开更多
基金supported by the National Natural Science Foundation of China(No.22006057,21906072 and 21908115)Postgraduate Research&Practice Innovation Program of Jiangsu Province(China)(SJCX23_2197)Natural Science Foundation of Zhejiang Province of China(LY20E080014).
文摘Solar-driven water splitting for photocatalytic hydrogen evolution is considered a highly promising and costeffective solution to achieve a stable renewable energy supply.However,the sluggish kinetics of electron-hole pairs’separation poses challenges in attaining satisfactory hydrogen production efficiency.Herein,we synthesized the exceptional performance of highly crystalline C_(3)N_(5)(HC–C_(3)N_(5))nanosheet as a photocatalyst,demonstrating a remarkable hydrogen evolution rate of 3.01 mmol h^(-1)g^(-1),which surpasses that of bulk C_(3)N_(5)(B–C_(3)N_(5))by a factor of 3.27.Experimental and theoretical analyses reveal that HC-C_(3)N_(5)nanosheets exhibit intriguing macroscopic photoinduced color changes,effectively broadening the absorption spectrum and significantly enhancing the generation of excitons.Besides,the cyano groups in HC-C_(3)N_(5)efficiently captures and converts photoexcited electrons into bound states,thereby prolonging their lifetimes and effectively separating electrons and holes into catalytically active regions.This research provides valuable insights into the establishment of bound electronic states for developing efficient photocatalysts.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12161061)the Fundamental Research Funds for the Inner Mongolia University of Finance and Economics (Grant No. NCYWT23036)+2 种基金the Young Innovative and Entrepreneurial Talents of the Inner Mongolia Grassland Talents Project in 2022,Autonomous Region “Five Major Tasks” Research Special Project for the Inner Mongolia University of Finance and Economics in 2024 (Grant No. NCXWD2422)High Quality Research Achievement Cultivation Fund for the Inner Mongolia University of Finance and Economics in 2024 (Grant No. GZCG2426)the Talent Development Fund of Inner Mongolia Autonomous Region, China。
文摘Under investigation in this paper is a complex modified Korteweg–de Vries(KdV) equation, which describes the propagation of short pulses in optical fibers. Bilinear forms and multi-soliton solutions are obtained through the Hirota method and symbolic computation. Breather-like and bound-state solitons are constructed in which the signs of the imaginary parts of the complex wave numbers and the initial separations of the two parallel solitons are important factors for the interaction patterns. The periodic structures and position-induced phase shift of some solutions are introduced.
基金funding from the European Research Council(ERC)under the European Union's Horizon 2020 research and innovation programme(Grant Agreement No.682841"ASTRUm"and No.654002"ENSAR2")The research of G.Leckenby,I.Dillmann,and C.Griffin was funded by the Canadian Natural Sciences and Engineering Research Council(NSERC)via the grant SAPIN-2019-00030+1 种基金J.Glorius,M.S.Sanjari,Yu.A.Litvinov and C.Brandau acknowledge support by the State of Hesse within the Research Cluster ELEMENTS(Project ID 500/10.006)E.Menz and Yu.A.Litvinov acknowledge support by the project"NRW-FAIR",a part of the programme"Netzwerke 2021",an initiative of the Ministry of Culture and Science of the State of North Rhine-Westphalia.R.Gernhäuser acknowledges support by the Excellence Cluster ORIGINS from the German Research Foundation DFG(Excellence Strategy EXC-2094-390783311)。
文摘The measurement of the bound-state decay of^(205)Tl at the Experimental Storage Ring(ESR)at GSI,Darmstadt,has recently been reported,with substantial impact on the use of^(205)Pb as an early Solar System chronometer and on the low-energy measurement of the solar neutrino spectrum via the LOREX project.Owing to the technical challenges in producing a high-purity^(205)T^(l81+)secondary beam,a robust statistical method was developed to estimate the variation in the contaminant^(205)Pb^(81+)produced in the fragmentation reaction,which was subsequently transmitted and stored in the ESR.Here,we show that Bayesian and Monte Carlo methods produce comparable estimates for the contaminant variation,each with unique advantages and challenges given the complex statistical problems for this experiment.We recommend the adoption of such methods in future experiments that exhibit unknown statistical fluctuations.
文摘传统THz器件长期受限于衍射极限导致的辐射损耗,其品质因子(Q因子)普遍低于10~5,严重制约了通信与传感性能。针对这一技术瓶颈,本研究基于拓扑光子学理论,设计了一种具有C6v对称性的硅基超表面,在THz频段实现了拓扑保护的高Q因子谐振。通过构建三角形晶格光子晶体平板,在晶胞内引入圆柱型蚀刻孔实现对称性保护,并采用理想磁导体边界条件分离TE模式,将连续域束缚态(bound states in the continuum,BIC)的拓扑保护机制引入THz频段。结果显示,Γ点处Q因子达到1010量级,且BIC位于远场辐射的偏振涡旋中心,验证了BIC机制及其拓扑特性,仿真结果良好。最终实现的Q因子较传统器件提升了多个数量级,且拓扑保护机制可以显著抑制加工缺陷与环境扰动对谐振性能的影响,为低损耗通信器件、光学可编程技术与量子光源设计提供了新范式。
文摘为了解决连续谱中束缚态空间响应带宽偏小的技术难题,本文设计了一种简单的光子晶体平板,并进行能带的计算和模式Q因子分析.通过结构参数的优化,在k空间发现一种正方形环状的且边长可调节的准连续谱中束缚态(bound state in the continuum, BIC)分布.分析准BIC环与等频线的关系以及模场分布的特征发现,这种正方形环状的准BIC来自结构的全内反射和驻波干涉效应.分别通过入射角度和频率扫描计算结构的透射谱,得到了高Q因子的法诺共振谱线,进而验证了环状准BIC的存在.
文摘In this work,we investigate the thermodynamic variables of a harmonic oscillator in a conical geometry metric.Moreover,we introduce an external field in the form of a Wu-Yang magnetic monopole(WYMM)and an inverse square potential into the system and analyze the results.Using an analytical approach,we obtain the energy level and study the thermodynamics at finite temperature.Our findings demonstrate that thermodynamic variables,except for the specific heat and entropy,are influenced by the topological parameters,the strength of the WYMM,and the inverse square potential.
文摘激光器在信息通信、智能制造等关键技术中发挥着核心作用。然而,传统半导体激光器尽管结构紧凑、效率高,却面临品质因子(Quality Factor,简称Q值)有限、光束质量较差及难以实现特殊光场等瓶颈。连续域中束缚态(Bound States in the Continuum,BIC)是一种存在于辐射连续谱中的局域模态,因其与辐射通道完全解耦,可实现能量完全局域化,理论上具备无限大的Q值。基于BIC的激光器兼具高Q值与高局域化效应,能有效降低激光阈值,并显著抑制多模竞争从而输出高纯度单模激光。当前研究聚焦于通过结构设计提升BIC模式的稳定性与耦合效率,并探索其在集成光子学、拓扑激光器等前沿方向的应用。未来,BIC激光器有望在片上集成、主动调控等方面取得突破,推动高性能激光技术的发展。
文摘与传统的光子晶体或超表面等微纳光学系统相比,基于连续域束缚态(bound states in the continuum,BIC)的光学体系通常具有更高的品质因子(quality factor,Q)与更窄的工作线宽,更高的Q值给高性能的光电元件提供了更广阔的可能性,但是更窄的线宽往往给实际应用造成一定麻烦,因为加工过程中的制造误差无可避免地导致实际的光学元件与理想情况存在差异,表现为实际工作波长与理想工作波长不匹配.为了克服该问题,本文利用带十字结构孔的光子晶体产生的对称保护型准连续域束缚态(quasi-bound states in the continuum,q-BIC),探索液晶(liquid crystal,LC)对q-BIC的动态调谐效应,以补偿加工误差导致的工作波长偏移.相比于入射光倾斜角对q-BIC的调制效应,在移动相同的波长时,LC对系统的Q值影响更小,例如使用入射光倾斜角调制q-BIC中心波长移动5.32 nm时,Q值下降75.84%,而使用LC调制q-BIC中心波长移动5.63 nm时,Q值上升了14.27%,这证明LC对高Q因子、超窄带的q-BIC元件具有极大的应用潜力.最后讨论了LC在q-BIC体系中的工作机理,可为广泛q-BIC的相关研究提供参考.
