辐射传递蒙特卡洛法精度分析及数值试验

本文建立了蒙特卡洛法模拟散射参与性介质内辐射传递计算模型。对蒙特卡洛法的计算精度及运行时间进行了较为详细的分析,提出了几种判断计算精度的方法。同时,借助蒙特卡洛法模拟辐射传递过程,进行数值“辐射实验”。利用该“实验结果”进行了物性反问题研究。在已知光学厚度的前提下,得到散射反照率与后半球辐射热流之间的单值函数关系。     

DISTRIBUTIONS OF LIMIT CYCLES FOR POLYNOMIAL VECTOR FIELDS (P_2, Q_3)

The distributions of limit cycles of cubic vector fields (P2, Q3) are considered in this paper, where P2 and Q3 are polynomials of x and y of order two and three, respectively. It is possibly seven different distributions of limit cycles given in [1]. We now prove that in which three kinds of distributions are impossible and other four kinds all can be realized by concrete vector fields of (P2,Q3). Some related results are also given.     

数字散斑干涉技术在振动分析中的应用

首次将相移技术应用于频闪数字散斑干涉计量中,对物体的振动进行了定量分析.实验证明,这种方法有广泛的实用价值.另外,介绍了一套自动分析系统,讨论了各参数对测量结果的影响.     

Tesla变压器型电子束加速器初步实验

 介绍了一种Tesla变压器型的强流电子束加速器。当变压器初级输入20kV左右的电压时，加速器二极管输出电压500kV，电流9kA，信号脉宽大约50ns，该装置具有结构简单，安装方便，运行可靠等特点。     

BIFURCATION DIAGRAMS OF SYSTEM =-y δx lx~2 ny~2,=x ax~2

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Compact Single-Stage Femtosecond Multipass Ti：Sapphire Amplifier at 1 kHz with High Beam Quality

A compact femtosecond Ti：sapphire amplifier system is reported using single-stage multipass configuration with high beam quality. A high dispersion glass stretcher and a pair of double prisms for compression are introduced based on broadband femtosecond seed pulses. The non-grating-based pulse stretcher and compressor are advantageous to increase high beam quality and to reduce the high-order dispersion. A Gaussian filter is used to reduce the gain narrowing effect in amplification. The compact femtosecond Ti：sapphire nine-pass amplifier delivers pulses with a duration of 26 fs and an energy of 800μJ at 7mJ pumping pulses energy at I kHz. The 1-kHz femtosecond amplifier with high beam quality and high stability is very suitable for ultrafast physics research applications, such as attosecond science, ultra-precision micromachining, and THz wave generation.     

特殊向量丛的存在定理

本文给出紧 Riemann 曲面上特殊不可分解向量丛的一个存在定理和特殊单向量丛、特殊稳定向量丛存在假设的一个反例及2维特殊稳定向量丛的一个存在定理.     

关于自双反函数的性质之研究

阐述了双反函数、自双反函数和多数函数的定义,提出了自双反函数的性质.根据上述定义利用布尔代数中的基本概念、定理和公式证明了这些性质,展示了自双反函数在RM展开系数图(bj图)中的特点,讨论了自双反函数在函数分类中的应用.