Mode-field half-widths of Gaussian approximation for the fundamental mode of two kinds of optical waveguides

This paper analyzes the characteristic of matching efficiency between the fundamental mode of two kinds of optical waveguides and its Gaussian approximate field.Then, it presents a new method where the mode-field half-width of Caussian approximation for the fundamental mode should be defined according to the maximal matching efficiency method. The relationship between the mode-field half-width of the Gaussian approximate field obtained from the maximal matching efficiency and normalized frequency is studied; furthermore, two formulas of mode-field half-widths as a function of normalized frequency are proposed.

地下金属管线管径的探测

用现有的一台电磁感应式地下金属管线探测仪在现场进行人工数据采样,然后拟合出一个地下金属单管线二次场分布的经验公式,再用该分布函数曲线半宽度参数,伴以地下全属管线埋深的探测,便可探测出管径值,探测误差约为实际管径的±10％。

氯丁橡胶/高密度聚乙烯共混物的研究

研究了氯丁橡胶/高密度聚乙烯(CR/HDPE)共混物的结晶行为,测定了其拉伸性能、耐环境应力开裂(ESCR)性能和流变性能。用示差扫描量热法熔融(结晶)峰的正规半峰宽(△T_(0.5)~N)表征了共混物的熔程和结晶规整性。发现△T_(0.5)~N随CR用量的增加而增加,尤其是熔融前期和结晶后期增加较大,表明CR这一极性橡胶的链段也能被HDPE的晶区夹持,从而起到连接分子的作用,提高了HDPE的ESCR性能和拉伸性能。CR用量为5～10g(以100g HDPE计)时改性效果最佳。

高速内燃机凸轮与挺柱付润滑过程的数值分析

本文利用一种快速求解非稳态弹流润滑方程的数值方法，获得了高速内燃机凸轮与挺柱付非稳态弹流润滑方程的完全数值解，深入地研究了这对摩擦付的表面油膜形状及压力分布在接触过程中的变化规律，指出了正常运转工况时凸轮与挺柱在开启与关闭过程中各自润滑过程的特点以及最危险的部位。为合理设计凸轮型线、制定跑合机制，本文提供了最接近工况的润滑理论依据。