关于集值映射的相依导数与多目标最优化问题的灵敏度分析

本文在序锥P具有弱紧基的条件下讨论了集值映射F的切导数与F P的切导数之间的关系；引进了集值映射的新的上半局部Lipschitz概念，利用这个概念，我们在有限维空间中给出了多目标最优化问题的灵敏度分析的一个新的结果.     

A flat-topped etched diffraction grating demultiplexer with low polarization-dependent loss using a tapered MMI structure

A flat-topped etched diffraction grating(EDG)demultiplexer with a low polarization-dependent loss(PDL)is designed.A design and simulation method based on the method of moment(MoM)is proposed.A 65-channel EDG demultiplexer with channel spacing of 100 GHz is considered as a design example.A tapered multi-mode interferometer(MMI)is used to flatten the passband of the EDG demultiplexer.The numerical results show that the exit width of the tapered waveguide impacts the loss of the TE case more than that of the TM case.Based on this fact,the exit width of the taper is optimized to obtain the lowest PDL.The tapering angle is also optimized where the minimal ripple is obtained.The designed EDG demultiplexer has an excellent flat-topped spectral response and a very low PDL.     

时域有限差分法分析蚀刻衍射光栅的后向衍射效率

采用时域有限差分法(FDTD)结合理想匹配层(PML)边界条件及周期性边界条件对两种结构槽面的后向衍射效率进行了分析,在P偏振和S偏振两种情况下,均得到了比传统差分方法和射线近似方法更精确的解.数值计算结果表明:全内反射(TIR)结构在高折射率材料(如InP)的蚀刻衍射光栅(EDG)中很有效,而在低折射率材料(如SiO₂)的EDG中效果不理想.     

Schwinger Bose实现下自旋相干态Wigner函数的特性分析

在Schwinger Bose实现下,引入纠缠态表象及Wigner算符在该表象下的表示,得到自旋相干态的Wigner函数,数值计算画出相空间中Wigner函数的分布图,并加以分析,发现在SchwingerBose实现下自旋相干态确实体现出纠缠特性。     

原子吸收自吸背景校正中杂散光的研究Ⅰ——杂散光的性质及其对背景校正性能的影响

在自吸背景校正中不被样品基体吸收的杂散光有不同于氘灯和塞曼背景校正的特殊性。用截止溶液法检验了杂散光的存在,并用重铬酸钾溶液分子吸收模拟背景吸收的方法研究了杂散光的影响。源于空心阴极灯光源的杂散光在样品束(常规脉冲低电流)和参比束(窄脉冲高电流)中的比率有很大的差异,前者比后者更高。这种差异是自吸背景校正误差的重要来源,在高背景校正时引起的误差不容忽视。文章还对杂散光比率与灯电流、光能量和光谱带宽等方面的关系进行了研究。结果表明,杂散光比率与灯电流大小有很大关系,灯电流大,杂散光比率小,但杂散光比率随灯电流的变化与被检测的分析线能量无直接关系;杂散光比率随着光谱带宽的减小而降低,其性质类同于连续光谱。     

Responsive mechanism and molecular design of di-2-picolylamine-based two-photon fluorescent probes for zinc ions

The properties of one-photon absorption(OPA), emission and two-photon absorption(TPA) of a di-2-picolylaminebased zinc ion sensor are investigated by employing the density functional theory in combination with response functions.The responsive mechanism is explored. It is found that the calculated OPA and TPA properties are quite consistent with experimental data. Because the intra-molecular charge transfer(ICT) increases upon zinc ion binding, the TPA intensity is enhanced dramatically. According to the model sensor, we design a series of zinc ion probes which differ by conjugation center, acceptor and donor moieties. The properties of OPA, emission and TPA of the designed molecules are calculated at the same computational level. Our results demonstrate that the OPA and emission wavelengths of the designed probes have large red-shifts after zinc ions have been bound. Comparing with the model sensor, the TPA intensities of the designed probes are enhanced significantly and the absorption positions are red-shifted to longer wavelength range. Furthermore, the TPA intensity can be improved greatly upon zinc ion binding due to the increased ICT mechanism. These compounds are potential excellent candidates for two-photon fluorescent zinc ion probes.     

Isomerism and coordination mode effects on two-photon absorption of tris(picolyl)amine-based fluorescent probes for zinc ions

One-photon absorption and two-photon absorption(TPA) properties of three tris(picolyl)amine-based zinc ion sensors are investigated by employing the density functional response theory in combination with the polarizable continuum model.The different isomer and coordination geometry of each probe are taken into account. Special emphasis is placed on the effects of isomerism and the coordination mode on the optical properties. The intra-molecular charge transfer(ICT)properties are specified by natural bond orbital charge analysis. It is shown that the isomerism has non-negligible effects on TPA properties of free ligands. It is found that both the TPA wavelength and the cross section are highly dependent on the coordination mode. When the zinc ion connects with the picolyl unit in the middle of a ligand, the zinc complex has a large TPA intensity in a long wavelength range due to the increased ICT mechanism.     

给体位置和数目对四苯基乙烯衍生物双光子吸收性质的影响

在杂化密度泛函水平上,利用响应函数方法,计算了一类四苯基乙烯衍生物的双光子吸收性质.考虑了四苯基乙烯上给电子基团的位置和数目对双光子吸收性质的影响.并且,根据实验者采用的分子,通过增加分子的平面性和共轭长度,以及增强给体强度,理论设计了三种分子结构,并计算了它们的双光子吸收性质.结果表明,给体位置和数目对双光子吸收性质有重要影响.位于分子末端的给体取代基能有效提高双光子吸收强度.随着给体数目的增加,双光子吸收波长发生红移.在四苯基乙烯的不同侧位上添加给体取代基对双光子吸收性质的影响有明显差异.与实验者采用的分子相比,理论设计的分子结构双光子吸收截面均明显增大.当三苯胺基代替四苯基乙烯基之后,双光子吸收峰发生较大红移,双光子吸收截面明显增大.     

Banach空间中向量均衡问题的灵敏度分析

通过使用切导数的概念,研究与向量均衡问题有关的集值映射和间隙函数的可微性质,讨论他们之间的切导数的关系,得到了一个计算间隙函数切导数的公式。引入了二元函数的锥凸的概念,通过使用这一新的概念,得到了间隙函数G的切导数和集值映射G-C的切导数的关系。在自反的Banach空间     

Na3ZrF7:Er/Yb纳米颗粒的合成及荧光性能研究

采用热分解法制备多种核壳结构的Na3ZrF7:Er/Yb纳米颗粒,并对制备的上转换纳米颗粒的形貌、晶相以及发光特性进行研究.在980nm激发光激发下,与单核的Na3ZrF7:Er3+2;,Yb3+20;纳米颗粒相比,核壳结构的Na3ZrF7:Er3+2;,Yb3+20;@CaF2上转换纳米颗粒荧光强度提高了5倍.把Yb3+/Nd3+共掺的四方相NaYF4层包覆在Na3ZrF7:Er3+2;,Yb3+20;@CaF2纳米颗粒上,我们实现了Na3ZrF7@CaF2@NaYF4纳米颗粒在808nm激发下较强的上转换红光发射,发射光的红绿比在10左右,并对其发光机制作出了解释.