Design of off-axis reflective projection lens using spherical Fresnel surface

In this paper, an off-axis reflective projection lens with single Fresnel reflective surface and three aspheric surfaces were designed. The design method of reflective lens using spherical Fresnel surface is discussed. The MTF (Modulation Transfer Function) of the off-axis reflective lens, with optical magnification 100×, F-number 2.5 and field of view 120°, is over 40% at 0.6 lp/mm on the image side, the distortion is less than 2%. This design method can provide reference for application of Fresnel surface in wide field of view imaging, and possesses a bright future with the continuous development of fabrication technique.     

线性菲涅耳聚光装置的聚光比分析

在设计聚光太阳能热发电系统时,有必要分析聚光装置的聚光比.线性菲涅耳聚光反射装置是对连续抛物面聚光镜的一种离散化近似,该聚光装置中每一行反射镜面均实时跟踪太阳,将太阳人射光反射至固定位置的线性吸热器上,故每一镜元在吸热器上形成的反射光带宽度均时刻变化,这使系统聚光比分析变得非常复杂.利用二维光学分析,得到线性菲涅耳反射...     

Narrowing effect of focused polychromatic laser with small Fresnel number

Starting from Huygens-Fresnel diffraction integral, the field representation of focused polychromatic laser beams is derived. Intensity distributions of the focused polychromatic laser are investigated with different Fresnel number and bandwidth at focal plane. It is found that the width of transverse intensity distribution of the focused polychromatic laser decreases with increasing the bandwidth at the focal plane and zero local time, and the transverse intensity presents more obvious narrowing effects with smaller Fresnel number. A physical explanation for the narrowing effects is given based on a simplified expression.     

Hard X‐ray microbeam lithography using a Fresnel zone plate with a long focal length

Focused hard X‐ray microbeams for use in X‐ray nanolithography have been investigated. A 7.5 keV X‐ray beam generated at an undulator was focused to about 3 µm using a Fresnel zone plate fabricated on silicon. The focused X‐ray beam retains a high degree of collimation owing to the long focal length of the zone plate, which greatly facilitates hard X‐ray nanoscale lithography. The focused X‐ray microbeam was successfully utilized to fabricate patterns with features as small as 100 nm on a photoresist.     

The precise asymptotic behavior of parameter estimators in Ornstein-Uhlenbeck process

In the present paper, we study the asymptotic behavior for estimator of the drift parameter in an Ornstein-Uhlenbeck process. The Lr-convergence rate and the precise asymptotics in the law of iterated logarithm and in the law of logarithm for the estimator are obtained. Moreover, we also get the complete moment convergence of this estimator. The main method of this paper is the deviation inequality for the quadratic functional.     

A law of the iterated logarithm for the product limit estimator with doubly censored data

We establish the law of the iterated logarithm for the product limit estimator, when the data are subject to double censoring. This investigation extends the results available for the model for singly censored data.     

从统计物理学看复杂网络研究

从统计物理学来看,网络是一个包含了大量个体及个体之间相互作用的系统。本文从统计物理学的角度整理与总结了复杂网络目前的主要研究结果,并对将来的研究工作做了一个展望。文章把网络分为三个层次———无向网络、有向网络与加权网络,对不同网络的静态几何量研究的现状分别做了综述,并结合网络机制模型设计与评价的需要,提出了新的有待研究的静态几何量;对网络机制模型做了总结与分析,提出了有待解决的关于双向幂律网络的机制模型的问题;部分地概括了网络演化性质,网络的结构稳定性以及网络上的动力学模型的研究。然后,以我们目前正在进行的两个方面的工作—科学家网络和产品生产关系网络—为例,粗略地介绍了网络研究在一些实际问题中的应用。最后,作为一个简单的补充和索引,我们整理了复杂网络研究中部分常用的解析与数值计算的方法。     

威布尔分布对整体旋转式斯特林制冷机的可靠性计算

介绍了威布尔分布的计算过程,对Thales整体旋转式斯特林制冷机的可靠性试验数据进行了分析,比较了威布尔分布可靠性计算的数值解析法与图估法的计算结果,总结了Thales整体旋转式斯特林制冷机的可靠性计算过程和加速因子的确定,为国内同类产品可靠性试验方案和寿命计算方法提供借鉴.     

知识体系与认知规律相结合建设分析化学课程教材

阐述教材是提高教学质量重要且必备的条件之一,回顾我国分析化学工作者编写教材的实践历程,提出编写教材应体现＂注重学科基础、关注学科前沿、适当拓展学科交叉,体现知识体系与认知规律相结合＂的特点。     

菲涅尔多缝衍射的数值计算

本文直接由菲涅尔一基尔霍夫衍射积分公式出发,通过数值积分的方法,计算菲涅尔单缝、双缝以及多缝衍射的光强分布,绘制出其相应的光强分布曲线.同时给出了计算菲涅尔多缝衍射的光振动分布的具体表达式.研究结果对于理解菲涅尔衍射现象具有重要的理论参考意义.