Designing Fano-Like Quantum Routing via Atomic Dipole-Dipole Interactions

Fano-like quantum routing of single photons in a system with two waveguides coupled to two collocated atoms is investigated theoretically. Using a full quantum theory in real space, photonic scattering amplitudes along four ports of the waveguide network are analytically obtained. It is shown that, by adjusting the atomic dipole-dipole interaction, an evident Fano-line shape emerges in the scattering spectra of the single-dot configuration system.Moreover, Fano resonance can also be achieved by varying the atom-waveguide coupling strength and atomic detuning, in the presence of the atomic dipole-dipole interaction. Therefore, the atomic dipole-dipole interaction may be utilized as a possible way to control spectral Fano-like resonance. The feasibility with the experimental waveguide channels is also discussed.     

非富勒烯有机太阳能电池研究进展:从器件物理到磁场效应

非富勒烯受体(NFA)材料是现阶段非常受欢迎的有机光电材料之一。基于非富勒烯受体的有机体异质结(BHJ)太阳能电池发展迅速,其单结能量转换效率(PCE)现已达到18%。有机半导体中单线态与三线态在磁场作用下的相互转换会影响其电子-空穴的解离与复合,从而对光伏性能有一定的影响。此外,三线态激子寿命和扩散距离较长,三线态-电荷反应的几率较大,增加光电流,使得三线态材料对于光伏性能的提高具有一定的作用。因此,本文主要从以下几个方面对非富勒烯有机太阳能电池进行叙述,首先讨论了有机太阳能电池中电荷分离、重组及能量损失对开路电压的影响;其次总结了有机太阳能电池磁场下自旋依赖的光物理过程及三线态材料在有机太阳能电池中的应用,了解二者对提高光伏性能的影响;最后对有机光伏性能的进一步提高以及有机半导体磁场下的自旋问题进行了展望。     

Bidirectional highly-efficient quantum routing in a T-bulge-shaped waveguide

Quantum routing in a T-bulge-shaped waveguide system coupled with a driven cyclic three-level atom and a twolevel atom is investigated theoretically.By employing the discrete-coordinate scattering method,exact expressions of the transport coefficients along three ports of the waveguide channels are derived.Our results show that bidirectional high transfer-rate single-photon routing between two channels can be effectively implemented,with the help of the effective potential generated by two atoms and the external driving.Moreover,multiple band zero-transmission emerges in the scattering spectra,arising from the quantum interferences among photons scattered by the boundary and the bulged resonators.The proposed system may suggest an efficient duplex router with filtering functions.     

核磁共振显微术的DESIRE效应模拟(英文)

要在合理时间內进行微米等级解析度的扫描时,核磁共振波谱的信噪比一直是一个很大的限制. DESIRE效应利用扩散现象来增强信号强度及解析度的概念被提出后,信噪比在一维的情况下大约可以增加一个数量级.在先期的研究中,模拟外加磁场的效应通常是使用叠代数值计算,而扩散的效应则是利用有限微分法解Bloch-Torrey e-quation ,这样的模拟方法通常很耗时.该研究中,分别使用Shinnar-LeRoux演算法及基于旋积的扩散模拟方法来加速计算出外加磁场及扩散对于信号的影响,因此可以节省大量计算时间以进行复杂的计算.利用一维模拟结果预测在不同参数实验中解析度的改变和信号增加值,并找出最佳的参数值.而由模拟结果指出,Sinc3脉冲波形可以得到最佳的信号增加量及不错的解析度.     

氮掺杂中空环形碳的制备及其可逆锌-空电池性能

将Co基金属有机框架材料(二甲基咪唑钴,ZIF-67)与多巴胺经原位吸附、聚合、碳化、活化,制备高吡啶氮、石墨氮掺杂的中空环形碳(N-doped hollow cycle-like carbon,NHCC),并考察了其氧催化性能。结果表明,最优条件制备的NHCC-0.4氧还原反应(oxygen reduction reaction,ORR)半波电位0.782 V;氧析出反应(oxygen evolution reaction,OER)达到10mA/cm²的电流密度,过电位为277 mV,低于同载量标准催化剂RuO₂(341 mV);同时,其电位差值(0.725 V)低于标准催化剂电对Pt/C||RuO₂(0.755 V),表明具备优异的可逆充放电性能。以NHCC-0.4||NHCC-0.4为空气电极的锌-空电池开路电位1.445 V、功率密度138 mW/cm²,可逆充放电循环老化电位差稳定于1.01 V,显著优于标准催化剂Pt/C||RuO₂空气电极(1.348 V,108 ...     

超声辅助加工系统的刀具状态自感知算法

超声波振动台内含压电材料,可以拾取切削过程产生的振动信号,实现不借助外部传感器刀具工作状态的自感知。为了从刀具振动信号中获取有效信息,该文提出一种基于经验模态分解的时频域重构算法。首先,采用经验模态分解算法将原始信号分解,得到多个固有模态函数分量和残差分量;其次,计算原始信号与各分量之间的时频域互相关系数;再次,归一化时频域互相关系数作为权重值,将固有模态函数分量和残差进行重构;最后,通过数值仿真和超声辅助加工实验,验证了基于经验模态分解的时频域重构算法的去噪性能,提取了信噪比为5.03 dB的目标信号,从而实现了超声辅助加工系统的自感知功能。