反射式双峰值全息滤光片的研制

本文利用重铬酸盐明股作为记录介质,采用双曝光记录工艺,试制了反射式双峰值波长的全息滤光片.这种全息滤光片双峰值衍射效率可达87%,带宽小于10nm,是一种新的具有潜在应用前景的全息光学元件.     

实模上序的拓展

主要目的是将交换环上序的拓展的结论推广到模上.首次提出了"模的序的拓展"的定义,并得到了模的序可拓展的充要条件.方法是通过取模的局部化以及商模,使环上的模的问题转化到域上来解决.     

Self-Adaptive Pre-Filtering Reconstruction for Optical Computed Tomography with Noisy Data

Optical computed tomography (OCT) is a kind of technique that has been widely adopted to reconstruct three-dimensional distributions of physical parameters of various kinds of fluid fields, such as flame, plasma, etc. In most cases, projection data are often stained by noises due to environmental disturbance, instrumental inaccuracy, and other random interruptions. To improve the reconstruction performance of traditional iterative computed tomography algorithms, a self-adaptive pre-filtering approach was used to denoise before iteration. Firstly, a frequency domain statistic method was taken to evaluate levels of noises approximately. Then the cut-off frequency of a Butterworth lowpass filter was fixed based on the evaluated noise energy. The results show traditional iterative algorithms are obviously improved with pre-filtering approach in the case of noisy data reconstructions.     

相场法模拟多元合金过冷熔体中的枝晶生长

在二元合金相场模型研究的基础上，进行扩展获得了多元合金相场模型.以Al-Si-Mg三元合金为例，采用该相场模型实现了逼真地模拟多元合金凝固过程的等轴枝晶生长，得到了二次或更高次晶臂生长等复杂的枝晶形貌.随着第三组元Mg含量的减少，枝晶的二次枝晶越发达，枝晶中溶质的偏析越严重，枝晶尖端的生长速率和半径越大，与丁二腈-丙酮体系中枝晶尖端生长速率、半径随溶质浓度变化关系的理论计算和实验结果相符合.另外，枝晶初生晶臂中心的溶质浓度最低，在被二次晶臂包围的界面区域的溶质浓度最高；固液界面区域具有较大的浓度梯度，其中枝晶尖端前沿的梯度最大. 关键词： 相场法 多元合金 凝固过程 枝晶生长     

Formation of nanoporous poly(aryl amide ether) (PAAE) films by selective removal of poly(ethylene glycol) (PEG) from PEG/PAAE composite films

Poly(aryl amide ether) (PAAE) thin films with nanometer-sized pores have been prepared in two steps: (1) solution casting of partially miscible poly(ethylene glycol) (PEG)/PAAE blends from one of their common solvents, dimethyl sulfoxide (DMSO), results in formation of PEG/PAAE nanocomposite films; (2) selective removal of PEG component by water washing yields nanosized, porous PAAE films. The pores have been found to have a small size variation and cover the whole surface homogeneously. With an increase in PEG contents, the sizes of the pores increase but the size distributions do not have much changes. This has been ascribed to formation of small PEG domains in PEG/PAAE composite films, which is facilitated by the strong interactions, mostly hydrogen bonds, between PEG and PAAE macromolecular chains.     

高效液相色谱法测定(E)-3-乙基-(2,3-二氢苯并呋喃-5-基)-2-丙烯酸乙酯及其相关物质的含量

提出了一种测定(E)-3-乙基-(2,3-二氢苯并呋喃-5-基)-2-丙烯酸乙酯[(E)-EDHBFP]及其合成中的副产物含量的高效液相色谱分析方法。色谱条件:固定相为Diamonsil-C_(18)色谱柱(250 mm×4.6 mm,5μm),流动相为甲醇-水(72+28),流量0.8 mL·min~(-1),检测波长为319 nm。结果表明:在方法所建立的最佳条件下,目的产物即(E)-EDHBFP可达到与其异构体副产物,合成的反应物以及一种结构不明的副产物的完全分离,并同时定量测定。(E)-EDHBFP的质量浓度在10～80 mg·L~(-1)范围与峰面积呈线性,检出限(3S/N)为35μg·L~(-1)。方法已用于(E)-EDHBFP的质量控制。     

反重力充填二维流形的显示、观察及分析

本文介绍了反重力充填二维流形的颗粒显示、拍摄和数据测取方法。作为分析实例,给出了充型扩散角随内浇道扩张角变化的实验结果。     

微机化超声螺栓轴向应力仪的原理与误差分析

本文提出用沿轴向纵波声时差以测螺栓的轴向应力，推导了声时差与应力的关系．利用声时差测螺栓轴向应力，能克服耦会误差”“，同时还能克服温度引起的伸缩及波速变化的声时误差·本文还导出并且从实验上测出了，只与螺栓材料有关，而与螺栓的夹紧长度，直径，总长无关的常数，简化了测量过程．经实验测定，在夹紧长度大于30mm，应力低于240MPa时，应力最大误差小于±4MPa．本文还分析了声时，夹紧长度测量误差所导致的应力误差．