光栅波像差对脉冲压缩的影响

 采用光线追迹的方法,对脉冲压缩光栅系统波像差进行理论研究,构建了有像差脉冲压缩光栅对分析模型,使用该模型通过模拟计算得出了波像差对脉冲压缩效果的影响。理论分析结果表明：脉冲压缩光栅系统最大波像差不大于λ/4时,脉冲压缩比的最大变化率约为2%。脉冲压缩光栅对系统达到衍射极限时,在选择适当的入射角度时,光栅波像差所引起的脉冲压缩比变化并不大。     

Sorption of small molecules in various polycarbonates and Kapton-H

Pressure-composition isotherms were determined at 20°C for CO₂ in Kapton and various substituted polycarbonates and for H₂O, Ar, N₂, CH₄, and acetone in bisphenol-A-polycarbonate. The isotherms are described by two parameters an average free energy of sorption and a width of a Gaussian distribution of free sorption energies. Within the framework of a recent model these parameters can be calculated assuming an elastic distortion of the polymer caused by the incorporation of solute atoms in preexisting holes. By comparing experimental values with predictions of the model the experimental width of the free energy distribution is only 30% smaller than the theoretical one. Functional relationships are obeyed between the sorption parameters on the one hand and glass transition temperature, average hole volume, and molecular volume of the solute on the other hand. Deviations occur for larger molecules like acetone and ethylene which are attributed to a viscoelastic distortion of the polymer. Comparing free energies of solution for the rubbery and glassy state of the polymer reveals more negative values for the glassy polymers despite their extra elastic distortion energy. This discrepancy is overcome by taking into account that the occupied volume has to be re-formed in the case of the rubbery or liquid polymer. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 483–494, 1998     

大孔径静态干涉成像光谱仪径向畸变导致的谱线偏移误差的校正

为提高大孔径静态干涉成像光谱仪在视场增大时的光谱定标精度,减小径向畸变对光谱精度的影响,本文提出一种基于光谱——畸变关联模型的光谱定标系数修正方法,给出了波数和波长修正公式.采用594.1?nm和632.8?nm气体激光器对成像光谱仪进行了光谱成像实验,并对数据进行了处理和分析.结果表明,当存在0.3％的桶形畸变时,边...     

Struktur und Magnetismus von Fluoriden Cs2MCu3F10 (M = Mg,Mn, Co,Ni), Varianten des CsCu2F5‐Typs

Structure and Magnetism of Fluorides Cs₂MCu₃F₁₀ (M = Mg, Mn, Co, Ni), Variants of the CsCu₂F₅ Type X‐ray structure determinations of single crystals showed that compounds Cs₂MCu₃F₁₀ crystallize with Z = 2 in space group P2₁/n (No.14) (M = Mn) of the CsCu₂F₅ type resp. in its supergroup I2/m (No.12) (M = Mg, Co, Ni). Cs₂MgCu₃F₁₀: a = 714.9(1), b = 736.8(1), c = 940.4(1) pm, b = 96.29(1)°, (Mg‐F: 199.2 pm); Cs₂MnCu₃F₁₀: a = 725.1(1), b = 742.7(1), c = 951.0(2) pm, b = 97.28(3)°, (Mn‐F: 209.1 pm); Cs₂CoCu₃F₁₀: a = 717.8(3), b = 739.1(2), c = 939.4(4) pm, b = 97.49(2)°, (Co‐F: 203.1 pm); Cs₂NiCu₃F₁₀: a = 716.3(1), b = 737.7(1), c = 938.2(2) pm, b = 97.09(1)°, (Ni‐F: 201.0 pm). As determined directly for the Mg compound and generally concluded from the average distances M‐F noted, M substitution concerns mainly the octahedrally coordinated position of the CsCu₂F₅ structure, the distortion of which is very much reduced thereby. Within the remaining [CuF₄] and [CuF₅] coordinations, in contrast to CsCu₂F₅, one F ligand is disordered, in case of the Mn compound the pyramidally coordinated Cu atom, too. The magnetic properties are complex and point to frustration and spin glass effects. Only at the diamagnetically substituted variants with M = Mg, Zn no Néel point appears, which is reached at 27, 23, 36 and 55 K for M = Mn, Co, Ni and Cu, resp. At lower temperatures ferri‐ resp. weak ferromagnetism and hysteresis is observed.     

网格法及其在大变形测量中的应用

网格法具有操作简单、测量范围大、易于自动处理等特点。本文首先介绍了网格法测量的基本原理,其次用仿真的实验对网格法进行了检验,最后用皮革材料进行了拉伸实验。由于对镜头误差得到了修正、变形前后的网格点得到了自动匹配,从而实现了大变形的自动高精度测量。     

非约束维纳滤波综合鉴别函数算法研究

通过去掉最小平均相关能量匹配滤波器推导过程中对输出相关峰值的约束条件,定义相关判据,得出畸变不变相关识别综合鉴别函数形式为维纳滤波函数,不仅抗噪能力强,且把非约束匹配滤波器畸变容限大的优点引入其中.模拟结果表明,所设计匹配滤波器畸变容限大、抗噪能力强.     

扬声器定心支片的非线性失真研究

本文在扬声器线性失真产生原因的分析基础上,设计了一种测量扬声器位移的新方法,并以大量的实验数据证明,大扬声器的结构中,定心支片的力学性能对扬声器非线性失真有极大地影响,指出于扬声器定心支片的研究,将有望成为一项新的课题。     

Study on Graphic Distortion in Laser Display

１　ＩｎｔｒｏｄｕｃｔｉｏｎＦｉｇ．１ＤｕａｌｇａｌｖａｎｏｍｅｔｅｒｓｃａｎｉｎｇｓｙｓｔｅｍＦｏｒｌａｓｅｒｄｉｓｐｌａｙｔｅｃｈｎｏｌｏｇｙ,ｔｈｅｓｃａｎｎｉｎｇｓｙｓｔｅｍｂａｓｅｄｏｎｇａｌｖａｎｏｍｅｔｅｒｉｓａｋｅｙｄｅｖｉｃｅ（Ｆｉｇ．１）．ＢｙｃｏｎｔｒｏｌｌｉｎｇｔｈｅＸＹｓｃａｎｎｅｒ,ｔｈｅｌａｓｅｒｂｅａｍｓａｒｅｓｔｅｅｒｅｄｓｏｑｕｉｃｋｌｙ,ｔｈａｔｔｈｅｇｒａｐｈｉｃｓａｎｄｃａｒｔｏｎｃａｎｂｅｄｉｓｐｌａｙｅｄｏｎａｓｃｒｅｅｎｏｒｔｈｅｂｅａｍｅｆｆ…     

一种应用于X射线成象系统的多CCD图象传感器

我们设计了一种基于多CCD的X射线图象传感器。这种图象传感器由X射线增感屏、光学系统和多个CCD传感器组成。与传统的单CCD图象传感器相比,本传感器不但成象面积大,空间分辨力高,而且图象在信噪比,病灶检测灵敏度等方面都有所改善,并且系统具有较高的效费比。研究了多CCD图象传感器的成象形式、图象几何失真(主要是桶形失真)的矫正方法、亮度矫正方法及图象重建方法。实验系统(增感屏+2×2CCD)的实验结果验证了设计思想的可行性和系统的实用性。     

书籍扫描图像畸变参数自动计算精度的提高

建立了一个数据文件,用于存储一些在不同弯曲状态下书籍扫描图像页边灰度的曲线数据以及对应的多项式系数。利用多项式来描述在某种弯曲状态下像素灰度与页面上的对应点到扫描仪工作平面之间的距离关系。任意弯曲状态下的书籍扫描图像可以在数据文件中搜索到与其最接近的弯曲状态,并利用对应的多项式系数自动求得最佳畸变参数,用于图像的畸变校正实验,获得了较好的校正效果,最大误差由未校正时的63%下降到了4.4%。这使得在无需人工测量或调整畸变参数的条件下可自动校正书籍扫描图像。