TM-like and TE-like Modes Coupling in a Two-Dimensional Photonic Crystal Slab Composed of Truncated Cone Silicon Rods

We numerically investigate the coupling of TE-like modes and TM-like modes in a two-dimensional （2D） photonic crystal （PC） slab composed of truncated cone silicon rods. In such structures, the classification of TE-like modes and TM-like modes is generally impossible and the coupling occurs due to vertical structural asymmetries. The frequency and wavevector dependences of the mode coupling are discussed by investigating the photonic band structures, and the coupling efficiency is studied by examining the transmittance. The results show that the efficiency of mode conversion is strengthened by the vertical asymmetry and weakened by the clear sinall gap. These structures could be used as polarization conversion devices in integrated optics.     

Class of Unlockable Bound Entangled States and Their Applications

A class of unlockable bound entangled states and their applications are presented. They can be considered as quasi generalized Smolin states [Phys. Rev. A 63 （2001） 032306], which are the states of N ＋ N qubits. No pure entanglement can be distilled from this class of states by local quantum operations and classical communications. However, if certain parties group together, they become distillable. Although they are bound entangled states, they could be used to achieve some non-trivial tasks, such as quantum secret sharing shown in the study.     

Hopping Parameter Expansion Technique in Noise Method for Disconnected Quark Loops

We investigate the effectiveness of the hopping parameter expansion(HPE) combined with the Z(2) noise method in the calculation of the trace of the inverse of Wilson's Dirac operator and some other disconnected contributions.A numerical comparison of the standard deviation for the Z(2) noise method and HPE with the Z(2) noise method is carried out. It is found that there are noise reductions in all the quantities we calculated using the HPE with the Z(2) noise method. For the trace of the inverse of Wilson's Dirac operator, the HPE can reduce the statistical error by about 60%.     

二次四元数系统正定解的迭代法

二次四元数系统XAX-BX=P是离散型Lyapunov方程正定解反问题的推广形式.本文在四元数体上讨论它的正定解存在性及迭代求解方法.利用等价二次方程的系数矩阵的极大极小特征值,获得其正定解的存在区间,并针对系数矩阵的不同情况构建出三种收敛的迭代格式.同时根据每种迭代的特点,给出了迭代初始矩阵的选取方法.最后通过四元数...     

带变动偏序结构的集优化问题的适定性

针对带变动偏序结构的集优化问题,引入了LP适定性及广义LP适定性概念,进一步给出了其LP适定性及广义LP适定性的充分条件与刻画,发展了固定偏序结构下的相关成果.     

脉冲爆震发动机尾焰温度测量与数值模拟

本文采用新型研制的脉冲温度和水蒸气浓度测量仪测量了吸气式脉冲爆震发动机多循环工作过程中的尾焰温度,结果表明该测量仪不仅能够很好地捕捉每一个脉冲温度,与热成像仪测量的结果比较证明其测量温度在误差范围内.并采用了三阶TVD迎风格式和 Strang-splitting 算子分裂法,C3H8/air单步反应机理对混合物爆震燃烧进行了二维数值计算.与测量结果对比,说明采用本文的计算方法能够很好地捕捉到爆震波的点火和传播过程.     

应用于多视点视频编码的基于深度特征的图像区域分割与区域视差估计

基于多视点视图深度特征,提出一种通过简单块匹配运算划分多视点视图区域并估计区域视差的算法.首先基于深度对象的概念确定图像中具有不同深度的区域数量以及这些区域对应的区域视差,再根据误差最小化准则初步确定每个图像块所属区域.当区域中图像块数量小于某个阈值时,采用区域合并算法将该区域中的每个图像块合并到与它的视差最为接近的其它图像区域,通过迭代形成最终的有效图像区域划分.实验表明,该算法能够以图像块为基本单元有效地划分各深度层区域,并准确估计对应的区域视差.     

光纤水听器远程全光放大系统相位噪声研究

光功率冗余不足及相位噪声增加是制约光纤水听器传输距离及探测性能的关键因素。基于光纤水听器全光模拟传输系统，建立远程放大相位噪声模型，设计大有效面积低损耗光纤组合传输链路，在100 km传输4波分×8时分复用系统中，远程放大引入的相位噪声仅为-98.1 dB@1 kHz(1 kHz为频率)，优于常规单模光纤4.3 dB，模型的有效性得到了验证。将模型应用于150 km传输系统，对远程增益单元位置进行优化，获得了-93.2 dB@1 kHz的远程放大噪声性能。所提噪声模型及优化方法可应用于不带电中继的光纤水听器系统设计及研制中，对增大全光传输距离及提升远程探测性能具有重要意义。     

充分发挥物理学史的集体意识培育功能

培养中学生的集体意识是中学物理课堂的德育功能之一.从科学本质视角，通过合理有机地组织和展示具体的物理学史，并避免使用“个人化”特征的语言，强调集体对于物理学探索和物理学家个人的作用，让学生体会物理学探索的曲折性、经验性和批判性、统一性和未完成性，意识到集体力量的巨大作用和不可或缺，达到培养集体意识的目的.