X射线聚束透镜原理及其应用

本文阐述了一种新型的Ｘ射线聚束装置─—Ｘ射线透镜的聚束原理。给出了透镜的基本设计方法，并对它应用于Ｘ射线光刻研究领域的前景作了展望。     

Effect of pretreatments and freezing rate on the firmness of potato tissue after a freeze–thaw cycle

The texture of potato tissue after a freeze–thaw process using different freezing rates and different pretreatments was analysed, in order to select the best strategy for optimum preservation of the textural characteristics of pre‐frozen potato. Ten blanching conditions were tested and a two‐step blanching process with calcium chloride (0.07 g mL^?1) proved the most effective in protecting the tissue after a freeze–thaw process (maximum load force around 10–55% of the raw tissue, depending on potato batch, for air‐blast freezing and 20–60% for immersion freezing). Vacuum impregnation at 100 and 400 mbar, even when followed by different pre‐drying treatments to remove excess water, was very detrimental to resistance to a freeze–thaw process (maximum load force below 10% of the raw tissue for air‐blast freezing and below 20% for immersion freezing). Microstructure analysis confirmed better tissue integrity retention with ethyleneglycol immersion freezing instead of air‐freezing. Differences were found between batches with a 6‐month difference in storage time, indicating that the fresher batch was more suitable for freezing.     

Compressibility of fine-grained soils subjected to closed-system freezing and thaw consolidation

In order to investigate the effects of freezing and thawing on the compressibility of fine-grained soils, freezing and thawing tests and subsequent compression tests with fine-grained soils in an oedometer were carried out. During the freezing, a part of the soils is loosened and another part is over-consolidated under the freezing pressure ?E. The compression curves after the freezing and thaw consolidation are neither different from the normal consolidation curve nor from the rebound curve of an unfrozen soil, until the consolidation pressure ?z = ?E is arrived. Based on the experimental results, a theoretical model has been developed to predict the frost heaves, the thaw-settlements and the compressive deformations of fine-grained soils after the thaw consolidation. The theoretical results are very close to the experimental results.     

水轮发电机镜板研磨工艺的改进

介绍云峰发电厂4号机组现状,分析镜板研磨工艺存在的不足,采用改进研磨平台旋转螺杆结构、重新精加工研磨平台等措施,较好的解决了镜板研磨存在的问题。     

梯度折射率纤维端面耦合成像元件的设计

根据抛物型梯度折射率纤维透镜的近轴成像公式,分析了具有一定缩放倍率的梯度折射率纤维端面耦合成像的特性,探讨了这种纤维端面耦合成像元件的设计。     

提高硫化铅红外探测器的探测率和可靠性的有效途径

本文通过对不同结构的硫化铅红外探测器的剖析和性能优劣对比,说明了新型场镜—硫化铅组合结构是提高硫化铅红外探测器的探测率和可靠性的有效途径。     

LED信号灯二次光学设计

随着科学技术的发展,LED在很多领域中被应用得越来越广泛,如在信号灯中的应用,因此就需要对LED发出的光线进行二次光学设计。文中介绍了一种LED信号灯的二次光学设计思路和方法,通过对光通量的估算,设计出合理的LED分布、光学面罩和菲涅耳透镜。     

CRT投影电视接收机关键部件——投影镜头

投影镜头是CRT投影电视接收机光学系统的主要部件，其性能的好坏对投影机图像质量有很大的影响。通过对投影镜头结构特点的分析，阐述了投影镜头的设计特点，主要参数及其对图像质量的影响。     

用深紫外光刻波带片制作全息透镜阵列和椭圆波带片

本文报道用电子束扫描和深紫外曝光获得的离子刻蚀波带片的一级衍射波和二级衍射波干涉,分别在银盐干板和光致抗蚀剂上制作平面全息透镜阵列和椭圆波带片,并给出用它们聚焦和成像的实验结果。     

罗特曼透镜独立设计参数探讨

介绍了罗特曼透镜的理论设计公式,探讨了独立设计参数的选取范围及各独立设计参数的变化对透镜性能的影响。实际制作的宽频带罗特曼透镜实测结果印证了独立设计参数选取范围的合理性。