透过散射介质对直线运动目标的全光成像及追踪技术

光散射是限制光传输以及降低和破坏光学成像性能的主要因素,透过复杂散射介质对运动目标的全光成像是光学领域极具挑战性的技术之一.本文提出一种利用散斑差值自相关透过散射介质对运动目标进行实时追踪的方法.采用赝热光照明,基于光学记忆效应理论,通过对运动目标采集的两帧散斑做差值,然后做自相关运算,计算目标移动的距离,实现对目标的实时追踪,并且利用相位恢复算法进行简单处理就可以重建隐藏目标.对该方法进行了实验验证,成功地对隐藏的运动目标实现了成像与追踪.这种透过散射介质对运动目标的全光成像及实时追踪技术,在生物医学等领域具有重要应用潜力.     

Total ionizing dose effect in an input/output device for flash memory

Input/output devices for flash memory are exposed to gamma ray irradiation. Total ionizing dose has been shown great influence on characteristic degradation of transistors with different sizes. In this paper, we observed a larger increase of off-state leakage in the short channel device than in long one. However, a larger threshold voltage shift is observed for the narrow width device than for the wide one, which is well known as the radiation induced narrow channel effect. The radiation induced charge in the shallow trench isolation oxide influences the electric field of the narrow channel device. Also, the drain bias dependence of the off-state leakage after irradiation is observed, which is called the radiation enhanced drain induced barrier lowing effect. Finally, we found that substrate bias voltage can suppress the off-state leakage, while leading to more obvious hump effect.     

铝在镀锌板镀层中的分布

用ＧＤ－ＡＥＳ法测定镀锌板镀层中的Ｚｎ，Ａｌ，Ｆｅ的分布，看到在镀层界面上Ａｌ的富集现象，而且富集程度随锌液中Ａｌ含量的增加而更显著，认为这可能与热浸时首先生成Ｆｅ－Ａｌ相有关。     

外加磁场对磁控溅射制备氮化硅陷光薄膜的影响

在基底与靶材之间放置磁性强弱不同的永久磁铁来研究外加磁 场对磁控溅射制备氮化硅陷光薄膜的影响. 通过X射线衍射、原子力显微镜 (AFM) 以及紫外分光光度计分别测试了外加磁场前后所制备薄膜的组织结构、表面形貌和光学性能. 结果表明, 外加磁场后, 氮化硅薄膜依然呈现非晶结构; 但是表面形貌发生明显改变, 中心磁场1.50 T下, 薄膜表面为特殊锥状尖峰结构"类金字塔"的突起, 而且这些突起颗粒垂直于基底表面; 在 可见光及近红外范围内, 中心磁场1.50 T 下的薄膜样品平均透射率最大, 平均透射率达到90% 以上, 比未加磁场的样品提高了近1 倍, 具有很好的陷光特性. 关键词： 外加磁场 磁控溅射 氮化硅薄膜 陷光效应     

Silicon micro-hemispheres with periodic nanoscale rings produced by the laser ablation of single crystalline silicon

We describe the fabrication of silicon micro-hemispheres by adopting the conventional laser ablation of single crystalline silicon in the vacuum condition without using any catalysts or additives. The highly oriented structures of silicon micro-hemispheres exhibit many periodic nanoscale rings along their outer surfaces. We consider that the self-organized growth of silicon micro-structures is highly dependent on the laser intensity and background air medium. The difference between these surface modifications is attributed to the amount of laser energy deposited in the silicon material and the consequent cooling velocity.     

复合材料层合板在激光辐照下的应变测试与分析

对T300/AG80碳纤维复合材料层合板在激光辐照下的应变变化情况进行了测试。利用动态应变仪对不同半径激光光斑照射下的试件正面和背面的0,45,90三个方向的应变进行记录,通过对消除温升影响后的试验数据进行分析得知：各处应变随测试点到光斑中心的距离增大而减小;0方向应变最小,90方向应变最大,光斑辐照层合板5 s时,90方向应变值至少是0方向应变值的1.5倍。采用有限元分析软件对试验过程进行模拟,光斑外各处热应力随其到光斑中心距离的增大而减小。将模拟中得到的应变与试验过程中的测试值对比,得到温升影响造成的最大相对误差为16.9%.     

应用于WLAN/WiMAX的多频带印刷单极子天线

设计了一种应用于WLAN和WiMAX的多频带印刷单极子天线。该天线制作在以聚四氟乙烯为材料的基板上,天线正面部分具有三个条带结构,背面则添加了带有矩形槽的反射地结构以改进天线的阻抗匹配。利用三维电磁仿真软件（Ansoft HFSS13.0）进行仿真,并将该天线通过SMA连接器连接到矢网仪(Agilent Technologies N5230C 10 MHz~20 GHz) 进行测试。实际测试结果与仿真结果基本吻合,符合设计要求,验证了设计的正确性。     

如何建设好实验MOOC——以《大学物理实验》MOOC建设为例

从线下实验课程的现状和弊端入手,结合《大学物理实验》MOOC的建设经验,对实践类MOOC建设涉及的内容,如,建立建设队伍,确定教学理念建立相关体系,凝练知识点等要素并制作适合学生有效关注时间的短视频,构建线上实践主体,充分利用线下实验室资源以及保障建设质量等给出了建议.     

Multiwavelength All-Optical Clock Recovery of Non-Return-to-Zero Data

A novel scheme of all-optical clock recovery from mutiwavelength non-return-to-zero （NRZ） data stream is proposed and demonstrated. The chirp induced by a chirped fibre Bragg grating and a semiconductor optical amplifier is used to enhance the clock. The clock is recovered after injecting the enhanced signal into the scheme based on the stimulated Brillouin scattering. The experiment is carried out and the dual-wavelength clock is recovered. This novel scheme can realize clock recovery of multiwavelength NRZ signal in the total wavelength range of 3.3nm. This clock recovery technology is transparent to the data bit rate and modulation format, also without pattern dependence.     

基于邻域总变分和边缘检测的遥感影像道路提取

针对道路提取的同物异谱和同谱异物难题,提出了一种基于邻域总变分和边缘检测的遥感影像道路提取方法,先对原始影像进行邻域总变分分割,提取出影像中具有均匀材质的地物,并采用Canny边缘检测方法获得原始影像的边缘数据;然后将边缘数据和分割结果融合,使均匀材质区域中的非道路地物和道路分离;最后采用多方向结构进一步提取狭长并具有一定宽度的道路.实验证明本文提出的道路提取方案能同时提取影像中光谱略有差异的道路,能有效剔除和道路黏连在一起的同谱异物地物,并能提取具有一定弯度的道路.