Chaos control in the nonlinear Schrdinger equation with Kerr law nonlinearity

The nonlinear Schrdinger equation with Kerr law nonlinearity in the two-frequency interference is studied by the numerical method.Chaos occurs easily due to the absence of damping.This phenomenon will cause the distortion in the process of information transmission.We find that fiber-optic transmit signals still present chaotic phenomena if the control intensity is smaller.With the increase of intensity,the fiber-optic signal can stay in a stable state in some regions.When the strength is suppressed to a certain value,an unstable phenomenon of the fiber-optic signal occurs.Moreover we discuss the sensitivities of the parameters to be controlled.The results show that the linear term coefficient and the environment of two quite different frequences have less effects on the fiber-optic transmission.Meanwhile the phenomena of vibration,attenuation and escape occur in some regions.     

Influences of total ionizing dose on single event effect sensitivity in floating gate cells

The influences of total ionizing dose(TID) on the single event effect(SEE) sensitivity of 34-nm and 25-nm NAND flash memories are investigated in this paper. The increase in the cross section of heavy-ion single event upset(SEU) in memories that have ever been exposed to TID is observed, which is attributed to the combination of the threshold voltage shifts induced by γ-rays and heavy ions. Retention errors in floating gate(FG) cells after heavy ion irradiation are observed.Moreover, the cross section of retention error increases if the memory has ever been exposed to TID. This effect is more evident at a low linear energy transfer(LET) value. The underlying mechanism is identified as the combination of the defects induced by γ-rays and heavy ions, which increases the possibility to constitute a multi-trap assisted tunneling(mTAT) path across the tunnel oxide.     

单摄像机立体视觉测量系统的高精度变焦标定技术

针对现有用于光学测量的双目变焦系统标定方法难度大、测量精度受限于两摄像机内参一致性等问题。提出一种基于单摄像机的平行双目立体视觉系统实现及其高精度变焦标定方法。方法基于三角测量原理采集图像,利用高精度位移台驱动单摄像机进行平移以保证基线精度;求解离散焦距下的预标定结果并利用BP神经网络模型对其进行拟合,以实现任意焦距下系统内外参数动态估计。实验结果表明,系统预标定的重投影误差小于0.1664 pixel,变焦后图像畸变校正平均误差为0.0982 pixel,立体视觉测量尺寸绝对误差小于0.05mm。方法能弥补传统变焦标定方法的不足,消除双目内参不一致引入的误差,提高视觉系统的测量精度。     

Transition state to mode locking in a passively mode-locked erbium-doped fibre ring laser

The transition state between the continuous wave region and the mode-locked region in a passively mode-locked erbium-doped fibre ring laser has been experimentally observed by utilizing the nonlinear polarization rotation technique.When the pump power reaches the mode-locked threshold,the metastable pulse train with a tunable repetition rate is obtained in the transition from the continuous wave state to the passive mode-locked state via proper adjustment of the polarization controller.A simple model has been established to explain the experimental observation.     

仪器分析CAI课件的开发研究

仪器分析是分析化学的重要组成部分,是以测量物质的物理性质、物理化学性质为基础而建立起来的分析方法。由于它具有分析速度快、选择性好、灵敏度高、检出限低和适用范围广等特点,越来越受到化学、化工工作者的重视。     

New ways of deriving Arnowitt—Deser—Misner constraint equations in four—dimensional gravity

In this paper,the Arnowitt-Deser-Misner (ADM) constraint equations are naturally derived in two different ways.One method is to construct a one-parametric gravitational action in the Lorentzian spacetime.Hence,the oneparametric ADM constraint equations can be obtained.The other method is to apply the double complex function method to Einstein-Hilbert gravitational fields in Hamiltonian formulation,Therefore the double ADM constraint equations can be obtained,in which the well-known ADM constraint equations are included as a special case.     

在玻璃的TiO2涂膜上有机物分子的吸附及光催化分解对水接触角的影响

研究了有机物分子在玻璃的TiO₂ 和WO₃/TiO₂ 复合物涂膜上的吸附及光催化分解对水接触角的影响.结果表明:有机物在空白玻璃及其膜的表面的吸附为不可逆化学吸附,WO₃/TiO₂ 复合物膜可钝化玻璃表面对大气污染物分子的吸附能力并具有较好的光催化活性.     

两步电泳沉积制备TiO2光阳极用于高效染料敏化太阳能电池

采用不同沉积电压制备TiO₂光阳极,研究电压对薄膜沉积速率、厚度和形貌的影响。通过台阶仪、光学照片、扫描电子显微镜（SEM）、电化学交流阻抗谱、开路电压衰减曲线对光阳极和电池进行系统表征,并测试了染料敏化太阳能电池器件的电流密度-电压（J-V）曲线,计算其光电转换效率。结果表明,提高沉积电压时,光阳极薄膜的沉积速率加快,膜厚也增加,但是电压过高时,薄膜会有裂缝和覆盖不全的问题,这会对电池的效率造成负面影响。综合考虑低沉积电压条件下薄膜均匀无裂缝和高沉积电压条件下沉积速率快的优点,采用先30 V电压、后60 V电压的电泳沉积方式来制备光阳极,结果呈现协同效果,既降低了制备时间又得到高质量的薄膜,在无其他修饰的情况下,电池的光电转换效率可以达到7.29%。     

把握数学本质 凸显数学思维——高三微专题“多元函数的最值问题”复习课

多元函数的最值问题是近几年高考的热点话题,此类问题涉及到函数、方程、不等式、三角函数等诸多重要的知识点,同时还体现了函数与方程、转化与化归、数形结合等核心数学思想,因此成为探索的热点问题,深受命题者青睐.而有关多元函数的最值问题往往给人形式简单、但难以捉摸的感觉,让学生感到十分棘手.针对学生这一困惑之处,笔者专门设计了多元函数的最值问题的微专题,引导学生揭示该类问题的本质所在,探求这类问题的解题策略,挖掘其中蕴含的数学思想方法,进行有效的数学思维训练.     

充液弯管连续/离散模型振动的动刚度解法

由充液弯管三维振动模型切入，应用动刚度法构建了弯管及直管单元的振动求解方法，进而用于组装求解充液管系的振动，可同时适用于含弯管单元的连续模型或只含直管单元的离散模型；通过算例对比，证明动刚度法比传递矩阵法和有限元法在计算效率和精度上有所提升；与充液L型管道振动实验测得的加速度频响曲线对比，验证了本文对于管道组装的计算方法的有效性，此外还分析了连续模型和离散模型的区别及适用范围。