Influence of disorder and deformation on the optical properties of a two-dimensional photonic crystal waveguide

We investigate the effect of disorder and mechanical deformation on a two-dimensional photonic crystal waveguide. The dispersion characteristics and transmittance of the waveguide are studied using the finite element method. Results show that the geometric change of the dielectric material perpendicular to the light propagation direction has a larger influence on the waveguide characteristics than that parallel to the light propagation direction. Mechanical deformation has an obvious influence on the performance of the waveguide. In particular, longitudinal deformed structure exhibits distinct optical characteristics from the ideal one. Studies on this work will provide useful guideline to the fabrication and practical applications based on photonic crystal waveguides.     

Kinetic Monte Carlo simulations of optimization of self-assembly quantum rings growth strategy based on substrate engineering

In this paper, the kinetic Monte Carlo simulations of the self-assembly quantum rings (QRs) based on the substrate engineering, which is related to the eventual shape of the formed quantum ring, are implemented. According to the simulation results, the availability of the QR with tunable size and the formation of smooth shape on the ideal flat substrate are checked. Through designing the substrate engineering, i.e., changing the depth, the separation and the ratio between the radius and the height of the embedded inclusions, the position and size of QR can be controlled and eventually the growth strategy of optimizing the self-assembly QRs is accomplished.     

Two-photon emission in coupled biexciton quantum dot–cavity system： Phonon-assisted model

We theoretically analyze the steady state emission spectrum and transient temporal dynamics in a coupled biexciton quantum dot（QD）–cavity system. For steady state, a phonon-assisted biexciton–exciton cascade model under continuous wave（CW） excitation is presented to explain the asymmetric QD–cavity emission spectrum intensities（intensities of cavity,exciton, and biexciton emission peak） in off-resonance condition. Results demonstrate that the electron–phonon process is crucial to the asymmetry of emission spectrum intensity. Moreover the transient characteristics of the biexciton–exciton cascade system under pulse excitation show abundant nonlinear temporal dynamic behaviors, including complicated oscillations which are caused by the four-level structure of QD model. We also reveal that under off-resonance condition the cavity outputs are slightly reduced due to the electron–phonon interaction.     

填充比和格点方向对二维三角晶格光子晶体带隙的影响

采用有限元法,计算了二维三角晶格椭圆形格点空气孔型光子晶体的TE、TM模式的带隙结构。通过对椭圆形空气孔格点的大小、方向进行改变,研究了填充比、格点方向对带隙的影响。计算结果表明,在空气孔型光子晶体中TE模式更容易形成带隙;不同填充比情况下,格点方向对TE模式和TM模的带隙变化都具有不同影响;不论格点方向如何变化,均未出现完全带隙。     

Adaptive PMD compensation in 10-Gb/s RZ optical communication system

We report an experiment of adaptive compensation for first-order polarization mode dispersion (PMD) in 10-Gb/s return zero (RZ) optical communication system. The compensated differential group delay (DGD) is up to 30 ps. The quasi-real-time, less than one second, PMD compensation is realized. In the experiment, for the first time, the algorithm so-called particle swarm optimization (PSO) is used to control feedback compensation system.     

树脂催化甲缩醛法降低乙二醛水溶液甲醛含量的研究

应用强酸性阳离子交换树脂催化,使甲醛与甲醇反应生成甲缩醛,可除去乙二醛水溶液中75％的甲醛,而不改变乙二醛的含量。此法简便可行,树脂无需再生,可重复使用多次,与乙二醛水溶液分离处理容易。     

聚乙烯苄胺树脂合成条件的研究

利用NICOLET 5DX红外光谱仪研究了聚乙烯苄胺树脂的合成条件和反应历程。结果表明,在适当的条件下采用不同合成方法均可得到聚乙烯苄胺树脂。在某些条件下将引起明显的副反应发生。     

基于惩罚似然比的高维空间相关过程EWMA质量监控模型

变量选择控制图是高维统计过程监控的重要方法。针对传统变量选择控制图较少考虑高维过程空间相关性而造成监控效率低的问题,提出一种基于Fused-LASSO的高维空间相关过程监控模型。首先,利用Fused LASSO算法对似然比检验进行改进;然后,推导出基于惩罚似然比的监控统计量;最后,通过仿真模拟和真实案例分析所提监控模型的性能。仿真实验和真实案例均表明:在高维空间相关过程中,当相邻监控变量同时发生异常时,利用所提监控方法能够准确识别潜在异常变量,取得较好的监控效果。     

Electronic structures of stacked layers quantum dots: influence of the non-perfect alignment and the applied electric field

Electronic structures of the artificial molecule comprising two truncated pyramidal quantum dots vertically coupled and embedded in the matrix are theoretically analysed via the finite element method.When the quantum dots are completely aligned,the electron energy levels decrease with the horizontally applied electric field.However,energy levels may have the maxima at non-zero electric field if the dots are staggered by a distance of several nanometers in the same direction of the electric field.In addition to shifting the energy levels,the electric field can also manipulate the electron wavefunctions confined in the quantum dots,in company with the non-perfect alignment.     

基于超高效液相色谱-四极杆飞行时间高分辨质谱的高通量血清代谢组学方法

采用超高效液相色谱-四极杆飞行时间高分辨质谱(UPLC-QTOFMS)联用技术, 对血清前处理进行了考察和优化, 并对液-质联用分析条件进行了优化, 旨在建立用于血清中广谱小分子代谢物分析的高通量强耐用代谢组学方法, 以期满足大批次生物样本数代谢组学研究的要求(样本数≥400个). 通过考察不同有机溶剂沉淀蛋白对血清中蛋白的去除程度及38个代表性标准品化合物的提取效果, 确定采用甲醇/乙腈(体积比1: 9)沉淀蛋白法. 血清和有机溶剂的体积比不小于1: 4时, 达到最佳的沉淀蛋白处理效果, 符合大批量样本测试的要求; 预先冷藏沉淀蛋白的有机溶剂, 涡旋2 min, 超声1 min, 加入有机溶剂后冷冻静置10 min, 可以进一步提高前处理沉淀蛋白和化合物提取的效果. 通过对不同流动相体系和梯度条件的考察, 对液-质联用分析条件进行了优化. 方法学考察结果表明, 本方法重现性、 精密度及稳定性均良好. 对重现性和48 h稳定性数据进行变异系数分析和主成分分析法的多维分析, 证明本方法在代谢组学研究中的可重复性及所得数据的可靠性. 本方法高通量强耐用, 每天可测定100多个血清样本(13 min测定1个样本), 适用于代谢组学研究, 特别是大批次生物样本的代谢组学研究.