Bessel光束自重建的模拟仿真与实验验证

Bessel光束的重建特性对于粒子多层面操控具有特殊意义. 依据Hankel波理论,分析了无衍射Bessel光束的产生及重建原理, 系统地对轴上圆形障碍物、方形障碍物和离轴圆形障碍 物进行了详细论述.利用光学设计软件ZEMAX对轴棱锥产生Bessel光束经过各 种障碍物的重建现象进行了系统的模拟仿真. 对建立的仿真模型进行实验验 证,实验结果与模拟仿真符合得很好. 结果表明 ZEMAX软件可以对轴棱锥产 生Bessel光束的重建特性进行灵活直观的建模仿真,且仿真结果具有很高的 准确性.     

Hyponormal Toeplitz operators on the polydisk

By bounded vector-valued functions and block matrix representations of Hankel operators, we completely characterize the hyponormality of Toeplitz operators on the Hardy space of the polydisk.     

Toeplitz Type Operators on the Hardy-Orlicz Space

In this article, we consider Toeplitz type operators and Hankel type operators in the Hardy-Orlicz space H_φ (Ω) and find a condition for the symbol so that they behave well on H_φ (Ω). Furthermore, we will show that Gleason's problem is solved affirmatively in some Hardy-Orlicz spaces.     

Some new exact analytical solutions for helical flows of second grade fluids

The helical flow of a second grade fluid, between two infinite coaxial circular cylinders, is studied using Laplace and finite Hankel transforms. The motion of the fluid is due to the inner cylinder that, at time t = 0⁺ begins to rotate around its axis, and to slide along the same axis due to hyperbolic sine or cosine shear stresses. The components of the velocity field and the resulting shear stresses are presented in series form in terms of Bessel functions J₀(•), Y₀(•), J₁(•), Y₁(•), J₂(•) and Y₂(•). The solutions that have been obtained satisfy all imposed initial and boundary conditions and are presented as a sum of large-time and transient solutions. Furthermore, the solutions for Newtonian fluids performing the same motion are also obtained as special cases of general solutions. Finally, the solutions that have been obtained are compared and the influence of pertinent parameters on the fluid motion is discussed. A comparison between second grade and Newtonian fluids is analyzed by graphical illustrations.     

非线性双重介质模型的精确解及动态特征

考虑了二次梯度项的非线性双重介质模型．在模型中假设岩块和裂缝间的压力差作为初始未知量,在岩块中是拟先态的,从而避免了解联立方程组．利用广义Hankel变换求得了径向流动的解析解,由于解析解是无穷级数,无法得到具体的值．通过数值求解特征值问题,从而算得了窟体的压力值,并探讨了非线性参数和双重介质参数变化时压力的变化规律,给出了典型压力曲线图版,这些结果可用于实际的试井分析．     

Bergman空间L_a~1(D)上的Toeplitz和Hankel算子

本文讨论了Bergman空间L1a(D)中Toeplitz和Hankel算子的w 紧性 ,得到与L2 a(D)上Toeplitz、Hankel算子紧性类似的某些结果     

L2(B2, d(z))正交分解及 Hankel型算子

令B2是2维复平面C2上的单位球,d(z)=((+1)(+2))/(2)(1-|z|2)dm(z) ( > - 1)是它上的加权测度.由Cauchy-Riemann算子观点和［1］中给出的三角域上的正交多项式, 我们得到了正交分解L2(B2,d(z)) = n = 0(An(+,+) An(+,-) An(-,+) An(-,-))和正交基,其中A0(+,+)和A0(-,-)分别是Bergman空间和共轭Bergman空间.利用单纯形上的正交多项式,可以将这种分解推广到L2(Bn, d(z))上去.另外,我们还得到了Hankel型算子的一些结果.     

L~2(B_2,dμ_α(z))正交分解及Hankel型算子

令B2是2维复平面C2上的单位球,（α＞－1）是它上的加权测度．由Cauchy－Riemann算子观点和[1]中给出的三角域上的正交多项式,我们得到了正交分解和正交基,其中A0（＋,＋）和A0（－,－）分别是Bergman空间和共轭Bergman空间．利用单纯形上的正交多项式,可以将这种分解推广到L2（Bn,dμα（z））上去．另外,我们还得到了Hankel型算子的一些结果．     

轴对称横观各向同性层状弹性半空间问题受力分析

本文从柱坐标系弹性力学基本方程出发,将位移场和应力场在径向进行Ｈａｎｋｅｌ变换,利用常微分主程求解原理,直接得出在轴对称荷载作用下横观各向同性半无限弹性空间的位移场,利用此结果推导出单层元的刚度矩阵。     

离散Hankel变换

首次提出了离散Hankel变换,从理论上给出了离散Parseval定理和变换矩阵。引入了抽样权重因子。并讨论了抽样原则及S因子对计算精度的影响。