基于矢量衍射理论的相位型光瞳滤波器设计

根据矢量衍射理论,提出了一种设计纯相位型光瞳滤波器的新方法根据该方法所设计的滤波器主要应用于采用高数值孔径显微物镜的成像系统对点扩散函数中的指数因子进行二次近似处理后,可以得到超分辨参量与滤波器参量的近似关系式以三区相位型滤波器为例,讨论了该近似关系式的有效性给出一个设计实例,根据所要求的超分辨性能要求设计滤波器.模拟结果表明,该滤波器达到了设计要求,最后利用共焦系统点扩散函数的乘积特性,大大减弱了旁瓣的影响.     

An error estimate on a Galerkin method for modeling heat and moisture transfer in fibrous insulation

We propose a Galerkin finite element method for numerically modeling the process of heat and moisture transfer in porous clothing assemblies, which takes into account radiative heat transfer and sorption of water vapor into the fibers of the medium. We prove an optimal‐order error estimate for the finite element method in energy norm. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2008     

利用三色光栅实现彩色图像相减

本文提出了一种彩色图像相减的新方法.该方法利用互相错动半个周期的两组三色光栅,在黑白底片上分别对待处理的两幅图像进行一次编码记录,然后在白光处理器上对黑白编码片进行彩色译码,即可实现彩色图像的强度相减,文中讨论了三色光栅实时生成和两组三色光栅条纹自动错动半个周期的方法,并给出了实验结果。     

Pyridine based thorium(IV) phosphate hybrid fibrous ion exchanger

Pyridine based thorium(IV) phosphate (PyThP) has been synthesized by drop-wise addition of the thorium(IV) nitrate with constant stirring into a mixture of pyridine and phosphoric acid. This material has been characterized using X-ray, IR spectra, TG, DTG and SEM studies in addition to its ion exchange capacity, elution and pH titrations. The material has been found amorphous and fibrous in nature on the basis of X-ray diffraction and SEM studies. TG has revealed the changes incurred in the material on thermal treatment and IR spectral studies have shown the presence of various groups in its structure.     

Orientation mechanisms during biaxial drawing of polymer films

Summary Second drawing of monoaxially drawn PP and PET films perpendicular to the first drawing direction has been investigated. At low draw ratios structural systems having an angle of 45° with regard to the second draw direction are formed. By increasing the draw ratio the structures rotate into the new preferred direction. The results lead to the impression that the structural transformations do not turn out molecule by molecule, but domain by domain.

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Zusammenfassung Die Zweitverstreckung monoaxial verstreckter PP- und PET-Folien senkrecht zur Erstverstreckrichtung wird untersucht. Bei kleinen Verstreckgraden bilden sich Struktursysteme unter 45° zur Zweitverstreckrichtung; bei weiterer Verdehnung drehen sich die Strukturen in die Vorzugsrichtung. Die Ergebnisse vermitteln den Eindruck, daß die Strukturänderung nicht Molekül für Molekül, sondern Bereich für Bereich abläuft.

With 10 figures and 2 tables     

一种新颖结构的高温超导信道滤波器设计

文章提出了一种新颖结构的高温超导信道滤波器设计方法,采用Sonnet软件进行微带电路的全波电磁场仿真.设计了一个一分二的高温超导信道滤波器,信道滤波器工作在S波段,每个信道的相对带宽约为0.4‰,采用的材料为多源热共蒸发法制备的DyBCO双面超导薄膜,衬底为0.5mm厚度的氧化镁.本文给出了本信道滤波器的等效电路、理论曲线、耦合参数和模拟仿真结果.     

用两端对称缺陷复合光子晶体实现多通道滤波和光开关

用传输矩阵法计算了两端对称缺陷复合光子晶体结构的光传输特性。计算结果表明:两端对称缺陷复合光子晶体[D(AB)mD]2结构中的禁带出现两个完全共振透射峰。通过控制入射光强来微调光子晶体材料的介电常数,使得完全共振透射峰移动,且介电常数变化越大,共振透射峰偏移越大,从而形成高效率的双通道光开关。当光子晶体为[D(AB)mD]N结构时,每个完全共振透射峰都分裂为N-1条,这样可通过调节N同时实现所需要通道数目的高效多通道光开关和多通道滤波器。     

云层背景目标识别的匹配滤波器设计

提出一种利用最大平均相关高度(MACH)算法识别复杂云层背景目标的改进滤波器设计方法。在MACH滤波器设计中,通过对云层背景功率谱的统计特性分析,数据拟合得到云层背景功率谱的分布函数,用以代替传统的白噪声模型;提取飞行目标的姿态变化图像,并作阈值化处理,得到训练样本。对不同云层背景和姿态变化目标的相关识别结果表明:改进滤波器的平均峰值相关能量比为0.71%,峰值鉴别率为0.92,可以有效抑制云层背景的干扰,对姿态变化目标识别的鲁棒性较好。