An applied research on approach of dyadic wavelet transform for Remote Sensing image edge detection

In the edge detection of Remote Sensing （RS） image, the useful detail losing and the spurious edge often appear. To solve the problem, the authors uses the dyadic wavelet to detect the edge of surface features by combining the edge detecting with the multi-resolution analyzing of the wavelet transform. Via the dyadic wavelet decomposing, the RS image of a certain appropriate scale is obtained, and the edge data of the plane and the upright directions are respectively figured out, then the gradient vector module of the surface features is worked out. By tracing them, the authors get the edge data of the object, therefore build the RS image which obtains the checked edge. This method can depress the effect of noise and examine exactly the edge data of the object by rule and line. With an experiment of an RS image which obtains an airport, the authors certificate the feasibility of the application of dyadic wavelet in the object edge detection.     

基于NVMe的超高速多通道遥感相机模拟源设备研制

针对当前遥感卫星电荷耦合器件(CCD)相机幅宽越来越大,速率越来越高,现有相机模拟源设备数据输出带宽不足的问题,提出并实现了一种基于非易失性存储器Express(NVMe)的超高速多通道遥感相机模拟源设备。该设备利用现场可编程逻辑门阵列(FPGA)实现4组NVMe SSD主机控制器,完成对固态硬盘(SSD)的读写操作;同时利用DMA控制器读取DDR4中缓存数据,数据经封装处理后通过光纤接口输出。实验结果表明：NVMe主机控制器的写平均速率可以达到1.7 GBps,读平均速率达到3.2 GBps。模拟源系统整体存储容量8 TB,对外输出带宽高达80 Gbps,支持8路光纤接口输出。该模拟源具有较强的稳定性及良好的可扩展性,已成功应用在某遥感卫星CCD相机模拟源系统中,为数传等设备的测试以及调试提供了充分保障。     

温度/应变/扭曲三参量同时测量低成本传感系统

提出了一种利用布喇格光纤光栅反射光作信号源、高频CO2激光脉冲写入的长周期光纤光栅和超周期光纤光栅作传感器实现温度、应变和扭曲同时测量的全光栅型低成本强度解调传感方案.文中利用长周期光纤光栅边缘滤波效应实现了温度、应变和扭曲传感信号的实时解调.实验结果表明,其温度和应变的测量灵敏度分别为－0.211 dB/℃和－0.012 dB/10με;而扭曲率的测量灵敏度为0.4394 dB/(rad·m－1),是该法写入普通LPFG的4倍以上.     

荧光光纤光栅传感特性的实验研究

在载氢掺铒光纤上写入Bragg光纤光栅,得到新型光子学器件-荧光光纤光栅.分别对其Bragg波长（λB）及荧光寿命（τ）的温度（T）及应变（ε）响应特性进行了实验研究,并且给出了λB和τ分别关于（T,ε）的拟合方程.实验结果表明：荧光光纤光栅的λB对T和ε的响应具备一般Bragg光纤光栅的优良特性,测得温度灵敏度为11.1pm /℃,应变灵敏度为1.19pm/με;而且τ对T和ε的响应也具有良好的线性关系,温度灵敏度为0.59 μs/℃,应变灵敏度为6.16 ns/με.实验结论为解决温度应力交叉敏感、实现温度应力的同时监测提供一条新颖的途径.     

腐蚀介质中混凝土/钢筋界面电极电位分布的立体分析

由于混凝土的隔离和高绝缘性 ,常规的电化学技术、微探针扫描技术均难于获得在腐蚀介质的浸泡下混凝土 /钢筋界面 ,特别是不同深处的混凝土 /钢筋界面的电位分布 .本文提出用阵列电极法并结合电子技术和微机控制技术 ,获得同一水平面上混凝土 /钢筋界面以及不同深处的混凝土 /钢筋界面的电位分布立体信息图 .结果表明 :在NaCl介质中经过一段时间的浸泡 ,混凝土中的钢筋腐蚀可发生并发展 ;而在Na2 SO4 介质中经过一段时间的浸泡 ,虽钢筋腐蚀一般不发生 ,但混凝土可能破坏 .不同深处混凝土 /钢筋界面腐蚀优先发生在混凝土覆盖较浅的部位 .     

基于FETI的2维阵列电磁特性分析

应用有限元分裂互连方法(FETI)对2维阵列的电磁散射特性进行分析,将原求解区域划分成若干个不重叠的子区域,并根据其特性划分成9种类型。在相邻区域公共面上采用电场连续性条件,保证电场分量的连续性。对每个子域进行独立的有限元分析,通过公共面上的电流进行区域信息交换,确保相邻面上的区域耦合能够准确地被表示。此算法在保持有限元法计算精度的同时,大大减少了计算时间和内存消耗,拓展了有限元方法在周期结构上的应用。     

Modulation of Quorum Sensing in a Gram‐Positive Pathogen by Linear Molecularly Imprinted Polymers with Anti‐infective Properties

We describe the development, characterization, and biological testing of a new type of linear molecularly imprinted polymer (LMIP) designed to act as an anti‐infective by blocking the quorum sensing (QS) mechanism and so abrogating the virulence of the pathogen Streptococcus pneumoniae . The LMIP is prepared (polymerized) in presence of a template molecule, but unlike in traditional molecular imprinting approaches, no cross‐linker is used. This results in soluble low‐molecular‐weight oligomers that can act as a therapeutic agent in vitro and in vivo. The LMIP was characterized by mass spectrometry to determine its monomer composition. Fragments identified were then aligned along the peptide template by computer modeling to predict the possible monomer sequence of the LMIP. These findings provide a proof of principle that LMIPs can be used to block QS, thus setting the stage for the development of LMIPs a novel drug‐discovery platform and class of materials to target Gram‐positive pathogens.     

Facile Synthesis of Ultra‐wide Two Dimensional Bi2S3 Nanosheets: Characterizations,Properties and Applications in Hydrogen Peroxide Sensing and Hydrogen Storage

The ultra‐wide two dimensional Bi₂S₃ nanosheets (2D Bi₂S₃ Ns) as non‐toxic graphene‐like nanomaterials have been prepared through solvothermal decomposition of a single‐source precursor, Bi(S₂CNEt₂)₃, in ethylenediamine media for 2 h in 180 °C. The morphology, structure, properties and catalytic activity of prepared 2D Bi₂S₃ Ns were characterized with XRD, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV‐Visible spectroscopy, cyclic voltammetry (CV), amperometry, electrochemical charge/discharge technique and electrochemical impedance spectroscopy (EIS). The SEM image showed the 2D Bi₂S₃ Ns with a thickness of 15±4 nm and lengths of several micrometers is synthesized. The UV−Vis spectrum of 2D Bi₂S₃ Ns showed high sensitivity to visible‐near infrared light with its direct energy band gap of ≈1.22 eV. These Bi₂S₃ Ns showed high electron transfer ability and good electrochemical behavior and also exhibited electro‐catalytic activity toward the reduction‐oxidation of hydrogen peroxide. It is found that Bi₂S₃ Ns could detect H₂O₂ at wide linear concentration range (50.0 μM–8.0 mM) with detection limit 8 μM, using amperometry as measuring technique. Also the synthesized Bi₂S₃ Ns exhibited excellent electrochemical H₂ storage properties. As a result, based on above properties, the Bi₂S₃ Ns can be used as a valuable and useful nanomaterial for H₂ storage, high‐energy batteries, electrocatalytic fields and electrochemical sensing.     

利用阵列几何设置改善方位估计

本文研究了在非等距线阵情况下用空间平滑 Ｍ Ｕ Ｓ Ｉ Ｃ 方法实现方位估计的问题,提出了一种改善方位估计性能的阵列设置方法———即间距组合法．在阵元数一定的情况下,该方法可使阵列的方位分辨率较之均匀线阵（ Ｕ Ｌ Ａ） 有较大的改善,而且还克服了一般稀布线阵方位估计模糊和去相关能力差的缺点,成功地将空间平滑 Ｍ Ｕ Ｓ Ｉ Ｃ这一经典方法用于非等矩阵．     

GaAs／AIGaAs量子阱红外探测器的发展

半导体超晶格量子阱红外探测器的研制近年来取得了引人注目的成果,其中 GaAs/AlGaAs 红外器件的发展最快。本文在简要综述其单元探测器的基础上,着重介绍这种材料用于红外探测器列阵和焦平面的新成果。