We numerically investigated the grating-assisted phase matching (GAPM) of high harmonic generation (HHG) from the interaction of intense femtosecond laser pulse and rare gas in hollow core photonic crystal fiber (HCPCF). Our results show that the GAPM of HHG in HCPCF is especially suitable for photon energies in the range of 100~1keV. The calculated modulation period for GAPM of HHG in HCPCF is on the order of micrometer or sub-micrometer. This makes it easy to implement the GAPM of HHG with a counter-propagating modulation laser light in HCPCF. The high harmonic conversion efficiency is expected to be dramatically improved for the longer interaction length provided by the very low loss of HCPCF.

在光学的教学中,我们发现学生对于干涉现象中的半波损失问题很难掌握,部分教材中对这部分的论述不充分甚至是错误的。本文对干涉现象中的半波损失问题做了总结,在实际的教学实践中取得了很好的效果。

The effective areas of triangular lattice photonic crystal fiber(PCF) are calculated using the finite element method both for single-rod core and three-rod core PCF.We have compared the numerical results of effective area between them and find that they have similar varying tendency.When the structural parameters of PCF are fixed,the effective areas of them is increased with increasing wavelength and is decreased with increasing ratio of hole diameter and hole pitch as the normalized wavelength keeps constant.Our results show that the effective area of three-rod core PCF is larger than that of single-rod core PCF as the normalized wavelength is small.And the situation is reversed when the normalize wavelength is increased beyond a certain value.

论文基于3D bodyscanWorX非接触式三维人体测量的技术方法,探讨了关于4岁—17岁未成年人体型特征和立姿、坐姿测量与相关人类工效学的关系。研究了未成年人的身高增长速率以及应用测量数据,提出了对未成年人课桌椅和教室课桌间距的合理设计。

To improve the method of adding pre-tension and unable to twist-in when producing double-deck fabric in single beam loom,practice of producing double-deck fabric in Gammax single beam rapier loom was studied.It is considered that producing difficulty is shed clinging that caused by different warp shrinkage.Through changing heddle draft and drop wire draft method,in weaving process increasing loom tension,adopting low back beam,adjusting shed time,increasing creel height,strengthening operations et al,finally loom efficiency could be improved from 50% to 90%,fabric surface quality is increased and twist-in is available.

This article analyzes that the stereo shaping is one of the appropriate technology for dressing design, tests the property of thirteen usual dressing materials and designs three of the style used often, compares the effect of stereo shaping of different material with different properties in the same pattern and then, reaches a conclusion of what material property is the fittest for different styles.\;