Magnetic reconnection (MR) is a universal physical process in plasma, in which the stored magnetic energy is converted into high-velocity flows and energetic particles. It is believed that MR plays an important role in many plasma phenomena such as solar fare, gamma-ray burst, fusion plasma instabilities, etc.. The process of MR has been studied in detail by dedicated magnetic-driven experiments. Here, we report the measurements of magnetic reconnection driven by Shenguang II lasers and Gekko XVII lasers. A collimated plasma jet is observed along the direction perpendicular to the reconnection plane with the optical probing. The present jet is very different from traditional magnetic reconnection outflows as known in the two-dimensional reconnection plane. In our experiment, by changing the delay of optical probing beam, we measure the temporal evolution of jet from 0.5 ns to 2.5 ns and its velocity around 400 km/s is deduced. Highcollimated jet is also confirmed by its strong X-ray radiation recorded by an X-ray pinhole camera. With the help of optical interferograms we calculate the jet configuration and its density distribution by using Abel inverting technique. A magnetic spectrometer with an energy range from hundred eV up to one MeV is installed in front of the jet, in the direction perpendicular to the reconnection plane, to measure the accelerated electrons. Two cases are considered for checking the acceleration of electrons. The results show that more accelerated electrons can be found in the reconnection case than in the case without reconnection. We propose that the formation and collimation of the plasma jet, and the electron energy spectrum may be possible directly influenced by the reconnection electric field, which is very important for understanding the energy conversion in the process of MR and establishment of the theoretical model. Finally the electron energy spectra of three different materials Al, Ta and Au are also shown in our work. The results indicate that the higher atomic number material can obtain a better signal-noise ratio, which provides some helpful references for our future work.

利用“神光Ⅱ”激光装置的两束激光烧蚀半圆柱壳层靶产生了高速等离子体喷流。喷流的参数由光学和X射线诊断测量。喷流是准直的,在真空中传播。一维流体力学模拟被用来间接地计算喷流的速度。喷流的准直可能来源于高Z等离子体的辐射冷却。由于和年轻恒星喷流具有某些几何相似性,实验室喷流对于在实验室中模拟年轻恒星喷流具有潜在应用。

设计了一种基于压缩传感理论的红外或毫米波无源成像系统。 压缩传感是一种利用稀疏或可压缩的先验信息进行信号获取和重建的技术，它能以远低于奈奎斯特采样率的速率对信号 进行采样，并可实现高精度的重建。针对传统系统的固有缺点设计的上述毫米波无源成像系统，能在压缩传感理论的指导下进行成像。仿真结果表 明，该系统具有良好的成像性能，提高了峰值信噪比，改善了分辨率，并大大压缩了数据存储量。

本文通过紫外可见漫反射吸收光谱法研究了铁硅分子筛的晶化过程.通过对比不同晶化时间的铁硅分子筛的紫外可见吸收谱图,我们认为在未完全晶化的无定型物质中存在一种四配位的铁-硅氧结构的铁物种.这种铁物种的结构和完全晶化后分子筛中的骨架铁物种结构类似.进一步的研究发现,随着晶化的完全,这种铁-硅氧结构中铁-氧配键键长在慢慢变短.

本文采用常规的等体积浸渍法制备了不同担载量的V₂O₅/γ-Al₂O₃担载氧化物催化剂,在水气存在的条件下分别使用不同的激发波长得到了相应的可见拉曼光谱和紫外拉曼光谱.结果表明在表面钒物种微弱水合的情况下,325nm波长紫外激光激发的紫外拉曼光谱由于部分的共振拉曼效应,仍然可以灵敏的检测到表面钒物种配位结构随担载量增加而发生的变化.低担载时表面钒物种主要以孤立状态存在,随担载量增加逐渐向聚合态结构过渡,当担载量超过钒在载体表面的单层分散容量时形成体相V2O5晶体覆盖表面钒物种造成拉曼信号的减弱,由此可以从另一个角度判断表面单层分散容量.

本文用紫外拉曼,近可见拉曼光谱和XRD检测了不同焙烧温度下Y₂O₃-ZrO₂的相变过程.紫外拉曼光谱对样品表面相变极其灵敏,而近可见拉曼光谱和XRD提供的主要是体相和表面的混合信息.在紫外拉曼谱图中,只观察到单斜相的谱峰,没有明显的四方晶相的信号,这表明样品的表面主要是单斜晶相.然而,XRD和近可见拉曼光谱的结果显示Y₂O₃-ZrO₂体相是四方晶相.焙烧温度超过400.时,紫外拉曼,近可见拉曼和XRD晶之间明显不同的结果表明Y₂O₃-ZrO₂在表面区四方相很易转变为单斜相,体相中的四方相由于钇的添加而稳定存在.根据紫外拉曼和XRD结果,当升高温度时,在样品的表面形成一单斜相层,体相钇稳定的四方相,且由于Y₂O₃-ZrO₂的存在抑制了单斜相进一步向体相发展.