由Lévy过程驱动的一类特殊的高维的BSRDE解的存在唯一性

讨论由Brownian运动和Lévy过程共同驱动的线性随机系统的随机LQ问题,其中代价泛函是关于Lévy过程生成的σ-代数取条件期望.得到由Lévy过程驱动的新的多维的倒向随机Riccati方程,利用Bellman拟线性原理和单调收敛方法证明了此随机Riccati方程的解的存在性.     

Separation of Variable Treatment for Solving Time—Dependent Potentials

We use the separation of variable treatment to treat some time-dependent systems,and point out that the condition of separability is the same as the condition of existence of invariant,and the separation of variable treatment is interrelated with the quantum-invariant method and the propagator method.We directly use the separation of variable treatment to obtain the wavefunctions of the time-dependent Coulomb potential and the time-dependent Hulthen potential.     

Simplified Forms of Generalized MHD Equations in a Cylindrical Plasma

The simplified forms of generalized magnetohydrodynamic equations have been derived. The K. Appert theory and Hain-Lüst equation are two special cases of our results when p→0 and ω/ω_ci→0. It is shown that the process of taking any limits (p→0 or ω/ω_ci→0) will result in a singularity at the Alfvén resonant layer.     

基于任意系统位置关系的投影云纹形貌测量技术研究

提出了一套完整的基于投影云纹系统的物体表面形貌测量方法,包括理论公式推导、系统线性近似误差分析、全场灵敏度系数标定方法、实际物体的实验测量结果。所提出的方法既不需要特定的系统硬件位置关系设置,也无需人为确定系统的几何参数。该方法在允许测量系统组件任意放置的情况下仍然能够获得很高的分辨率和精度,其有效性及正确性通过真实物体的实验得到证实。     

点集Bézier曲线

提出了点集Bézier曲线的概念,给出了点集Bézier曲线的性质及细分算法.按照点集算术的定义,当点集是长方形闭域或圆盘时,点集Bézier曲线就是区间Bézier曲线或圆盘Bézier曲线,因此,点集Bézier曲线是对区间Bézier曲线和圆盘Bézier曲线的推广.     

Liénard型系统全局稳定性的充要条件

本文研究Lienard型系统x=φ（h（y）-F（x））,y=－g（x）的全局稳定性问题．利用Filippov变换和一些新的方法建立了系统为全局稳定的系列充要条件．     

Effects of Heavy Ions on Kinetic Alfvén Waves

Kinetic Alfvén Wave (KAW) is one of the low-frequency electromagnetic fluctuations that are identified extensively in space plasmas by in situ observations of satellites and has been an interesting topic for discussion widely in the fields of laboratory, space, and astrophysical plasmas because of its potential importance in plasma particle energization. Some satellite observations show that the number density ratio of the oxygen ions to the ambient plasma is 30%～50%, sometimes, even as high as 80%. In this paper, effects of heavy ion species on KAWs are studied in a low-beta plasma. The results show that heavy ions not only considerably reduce the propagation speed of KAWs, but also remarkably influence the parallel component of perturbed electric field of KAWs (to the ambient magnetic field). The ratio of parallel to perpendicular components of perturbed field decreases (or increases) with the heavy ion abundance for KAWs dominated by the electron inertial length (or by ion acoustic gyroradius). In particular, the resonant condition of KAWs with thermal electrons is modified by the heavy ion species.     

非本征敏感法布里-珀罗腔高精度光纤液位传感器输出特性

依据光学法布里珀罗(F-P)腔基本原理,分析了非本征敏感法布里珀罗腔光纤液位传感器工作原理及设计方案。实验结果表明,传感器具有良好的多周期输出特性和局部的线性特性,但法布里珀罗腔输出光强幅度随腔长增大逐渐衰减,传感器输出特性曲线中不同部分相同长度的线性工作区间却对应不同的测量量程和灵敏度。改变传感头中敏感组件的尺寸可满足对不同液位测量的需要。本传感器最大量程为20 m,精度为±0.5 mm,最小分辨力为0.3 mm。传感器特别适用于对易燃易爆液位精确测量,具有很强的实用性。     

基于Laguerre节点系Hermite-Fejér插值逼近的精确阶

For the nonpositive Hermite-Fejér interpolation based on the Laguerre abscissas, a pointwise two-sided estimate of the degree of approximation in the aleatoric interval [0, A] is first established.     

关于锥拉伸与锥压缩不动点定理

本文给出Fréchet空间中集值映射的锥拉伸与锥压缩不动点定理。同时也讨论Banach空间与Hilbert空间中集值映射的相应不动点定理。并导出逼近定理作为应用。