变系数非线性Schrdinger方程的孤子解及其相互作用

在光孤子通信和Bose-Einstein凝聚体动力学研究中,求解广义非线性Schrdinger方程是一个重要的研究方向.稳定的孤子模式具有潜在的应用,可为实验技术的实现提供依据.本文引进一种相似变换,将变系数非线性Schrdinger方程转化成非线性Schrdinger方程,并利用已知解深入研究变系数非线性Schrdinger方程解的单孤子解、两孤子解和连续波背景下的孤子解.同时通过选择不同的具体参数,给出它们的图像分析和相应的讨论.     

BESⅢ主漂移室径迹的外推和径迹匹配

BESⅢ主漂移室重建径迹的外推算法采用面向对象的设计方法, 利用GEANT4部分代码开发实现, 它提供主漂移室带电径迹外推到外部其他子探测器上的预期径迹信息. 该算法的外推过程考虑了带电径迹在磁场中的偏转以及与探测器物质相互作用造成的电离能损, 并为径迹参数计算考虑了库仑多次散射效应影响在内的参数误差矩阵. 经检查, 主漂移室径迹的外推结果和完全模拟结果一致, 并且径迹外推的结果能够成功用于各个子探测器测量径迹间的匹配, 这些工作为分析实验数据作了必要的准备, 能够满足BESⅢ实验的使用要求.     

Calibration study of the X-T relation for the BESⅢ drift chamber

Offline calibration plays an important role in BES offline data processing. In order to achieve good spatial and momentum resolution, it is necessary to implement high precision offline calibration for the BES drift chamber. This paper studies the time-to-distance relations, which are important calibration constants for track reconstruction. The parameterization of the time-to-distance relation, studies of left-right asymmetry and studies of variation with entrance angle are performed. The impact of dead channels on the time-to-distance relation is given special attention in order to reduce the shift in measured momentum for tracks passing near dead cells. Finally we present the resolutions for barrel Bhabha events(|cos θ|< 0.8) from a J/ψ data set taken in 2012. The average spatial resolution is 123 μm and the momentum resolution for 1.548 Ge V/c Bhabha tracks is 11.9 Me V/c.     

BESⅢ主漂移室基于模式匹配的径迹重建

BESⅢ主漂移室径迹重建算法MdcPatRec, 是采用面向对象技术用C++开发的软件. 该算法使用模式匹配的方式寻找径迹段, 连接径迹段为径迹并进行最小二乘拟合. 使用模拟数据对算法进行了检验, 结果表明该径迹重建算法能够提供高的重建效率和好的动量分辨, 各项指标均达到设计要求. 同时具有好的抗噪声能力, 可以满足BESⅢ的使用要求.     

变系数非线性Schr(o)dinger方程的孤子解及其相互作用

在光孤子通信和Bose-Einstein凝聚体动力学研究中,求解广义非线性Schr(o)dinger方程是一个重要的研究方向.稳定的孤子模式具有潜在的应用,可为实验技术的实现提供依据.本文引进一种相似变换,将变系数非线性Schr(o)dinger方程转化成非线性Schr(o)dinger方程,并利用已知解深入研究变系数非线性Schr(o)dinger方程解的单孤子解、两孤子解和连续波背景下的孤子解.同时通过选择不同的具体参数,给出它们的图像分析和相应的讨论.     

石墨炉原子吸收光谱法测定食品添加剂磷酸氢二铵中的铅含量

采用石墨炉原子吸收光谱法（GF．AAS）测定食品添加剂磷酸氢二铵中的铅含量,并且对样品中铅的线性范围、检测限、回收率和精密度进行了分析[1]。结果表明,在本实验条件下,铅的最低检测限为O．0082μg／g,线性回归方程为y=0．0091x＋0．00619,线性系数为0．9999,样品回收率都在97％以上。在采用同样前处...     

Track reconstruction using the TSF method for the BESⅢ main drift chamber

We describe the algorithm to reconstruct the charged tracks for BESⅢ main drift chamber at BEPCⅡ, including the track finding and fitting. With a new method of the Track Segment Finder (TSF), the results of present study indicate that the algorithm can reconstruct the charged tracks over a wide range of momentum with high efficiency, while improving the robustness against the background noise in the drift chamber. The overall performances, including spatial resolution, momentum resolution and secondary vertices reconstruction efficiency, etc. satisfy the requirements of BESⅢ experiment.     

Crosstalk analysis of silicon-on-insulator nanowire-arrayed waveguide grating

The factors influencing the crosstalk of silicon-on-insulator(SOI) nanowire arrayed waveguide grating(AWG) are analyzed using the transfer function method. The analysis shows that wider and thicker arrayed waveguides, outsider fracture of arrayed waveguide, and larger channel space, could mitigate the deterioration of crosstalk. The SOI nanowire AWGs with different arrayed waveguide widths are fabricated by using deep ultraviolet lithography(DUV) and inductively coupled plasma etching(ICP) technology. The measurement results show that the crosstalk performance is improved by about 7 d B through adopting 800 nm arrayed waveguide width.