Modification of Absorption of a Bulk Material by Photonic Crystals

We show theoretically that it is possible to modify absorption of a bulk absorbing material by inserting another non-absorbing dielectric slab periodically to form one-dimensional photonic crystals.It is found that,for frequencies within photonic bandgaps,absorption is always suppressed.For frequencies located at photonic bands,absorption can be suppressed or enhanced,which depends on the relative values of the real refractive index of the absorbing and non-absorbing dielectric layers.     

Fluorescence Microscopy of Nanoscale Silver Oxide Thin Films

The experimental conditions for photoactivated intermittent fluorescence from nanoscale silver oxide were studied with fluorescence microscopy.Strong fluorescence was observed from the Ag2O particles with size of 10-20nm excited with both blue and green light .We observed the saturation of Photoexcitation with blue light and explained the experimental results using the model of agglomeration of silver atoms to form small clusters and the fluorescence of Ag2 and Ag3 clusters.     

像增强器用中波红外辐射可激励的新型荧光材料

1 引言目前,许多研究都集中于研制各种用途的中波红外成像系统。这些应用从工业用热成像一直扩展到探测车辆、导弹等的军用热成像。可反映中波红外成像目前技术水平的是加工碲镉汞、锑化铟等半导体探测器的线阵或面阵,并把它们组装到一适当光学成像系统。但是,材料和器件的产额低,这种器件不仅制作难而且成本高。本文介绍一种加工成本低用于中波红外成像的新型探测介质,具体地讲,这种新介质是一种可将中波红外     

POROSITY CALCULATION OFMIXTURES OF FIBROUS PARTICLES

The initial forming of fiber blend to high green density, i.e. the packing of fibrous particles, is important to the reinforcement of composite materials. It is very useful to develop a general predictive method for the optimum selection of particle mixtures for the property control of ceramic or composite products. This paper presents such a mathematical model developed on the basis of the similarity analysis between the spherical and non-spherical particle packings and assesses its applicability to the packing of fibrous particles with discrete and/or continuous length distributions. The results indicate that the model can predict this packing system well and hence provide an effective way to solve various packing problems in the composite materials processing.     

Cr^4＋：YAG可饱和吸收特性测量

测量了Cr4+:YAG材料的可饱和吸收特性,用多种数据分析方法处理了实验结果,Cr4+:YAG的基态吸收截面σgs=11×10-19cm2,激发态吸收截面σes=1.2×10-19cm2。     

热电材料研究进展

在介绍热电材料制冷工作原理，分析热电材料优值系数的基础上，介绍了300K以下热电材料的研究进展，分析了热电材料的制冷特点、现状和应用前景．     

对一道高考压轴题的探讨

历年高考都十分重视对考生的后继学习潜能以及研究素质的考查，命题越来越科学合理、新颖巧妙．其中，以某些高等数学知识为背景材料设计而成的高考题，尤其为广大中学数学教师所津津乐道．新课程引入导数后，给我们研发具有高等数学背景的数学试题，提供了更广阔的空间．