Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further “sustainable” recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both “traditional” (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery.     

基于GF-1 WFV影像和BP神经网络的太湖叶绿素a反演

叶绿素a浓度是可直接遥感反演的重要水质参数之一,常用来评价湖泊水体的富营养化程度.太湖是典型的二类水体,光学性质复杂,应用一类水体线性反演模式拟合较为片面且难以找到最佳拟合模型.BP神经网络模型具有模拟复杂非线性问题的功能.为研究高分一号卫星16m多光谱相机WFV4结合BP神经网络进行太湖叶绿素a浓度监测的可行性,实验利用GF-1 WFV4影像和实时的地面采样数据,建立了BP神经网络模型,同时采用波段比值经验模型进行对比.经精度检验,BP神经网络模型预测值与实测值之间的可决系数R2高达0.9680,而波段比值模型的R2为0.9541,且均方根误差RMSE由波段比值模型的18.7915降低为BP神经网络模型的7.6068,平均相对误差e也由波段比值模型的19.16%降低为BP神经网络模型的6.75%.结果证明,GF-1 WFV4影像应用BP神经网络模型反演太湖叶绿素a浓度较波段比值模型精度有所提高.将经过水体掩膜的GF-1 WFV4影像用于训练好的BP神经网络反演太湖叶绿素a浓度分布,结果显示,叶绿素a高浓度区集中分布在湖心区北部、竺山湾、梅梁湾区域,与之前的研究一致.本文研究结果验证了采用BP神经网络模型对GF-1 WFV4影像进行太湖叶绿素a浓度反演的可行性.     

腐殖酸与典型碳纳米材料协同光致产生活性氧物种的研究

采用电子自旋共振光谱(EPR)技术,分析腐殖酸在光照下对4种典型碳纳米材料诱导产生单线态氧(~1O_2)和羟基自由基(·OH)的影响。基于密度泛函理论计算4种典型碳纳米材料的前线轨道能,比较了它们分别经能量转移诱导产生~1O_2的能力以及经电子传递诱导产生·OH的能力。结果显示,4种不同形状的碳纳米材料(富勒烯、单壁碳纳米管、多壁碳纳米管以及石墨烯)悬浮液在紫外光照下均无~1O_2和·OH产生。与腐殖酸共同存在下,4种碳纳米材料均显著诱导~1O_2的产生,且富勒烯和石墨烯还能光致生成·OH。协同产生~1_O2的能力大小为:单壁碳纳米管富勒烯多壁碳纳米管石墨烯,协同产生·OH的能力大小为:石墨烯富勒烯。~1O_2的产生能力与碳纳米材料的能隙大小和颗粒聚集程度有关,而诱导产生·OH的能力主要取决于化学硬度。总之,我们的研究表明腐殖酸与碳纳米颗粒可协同产生活性氧物种。     

Quantification and reduction of erroneous differences between images in remote sensing

The reliability of image data, along with the difficulty of accurately comparing images acquired at different times or from different sensors, is a generic problem in remote sensing. Measurement repeatability errors occur frequently and can substantially reduce the system’s ability to reliably quantify real spectral and spatial change in a target. This paper outlines methodologies for quantifying and reducing erroneous differences between monochrome and multispectral or hyperspectral images. [Each of these image types is acquired by an instrument that collects light photons across a variable range of the electromagnetic spectrum (often referred to as an image band). The hyperspectral image is often referred to as a hyperspectral cube with XY spatial dimensions and many Z bands (spectral demotions)]. In this paper, we specifically discuss the Pixel Block Transform (PBT), the Spectral Averaging Transform (SAT), and the Wavelet Transform (WAVEL). We briefly address sensor fusion. Results indicate that the PBT is a powerful cross-noise and repeatability error reducing tool, applicable to monochrome, multispectral, and hyperspectral images. The SAT is as powerful as the PBT in reducing error but is suitable only for hyperspectral imagery. WAVEL can reduce some of the finer scale noise, but it is not as powerful in reducing cross-noise as PBT or SAT and it requires some trial and error for selecting the appropriate wavelet function. It is important that those involved in developing statistically sound relationships between remotely sensed imagery and other data sources understand the problems and their solutions to prevent wasting time or developing relationships that are statistically insignificant or unstable, or that lead to faulty conclusions.     

基于信息量的ALI影像最佳波段选择及融合研究

分析了EO-1 ALI多光谱遥感影像各个波段的信息特征,根据信息量大小和波段间的相关性,联合偏度—峰度指数JSKF,提出针对ALI图像新的最佳波段组合方法。在最佳波段组合下对ALI多光谱数据与全色数据分别进行IHS、HPF、PCA和Wavelet变换融合,从信息量角度出发,按照定量指标对融合前后的遥感影像进行评价,并对融合前后影像进行分类应用。     

Ku/Ka双波段天线罩研制

给出了一种宽波段天线罩的工程设计方法,通过仿真设计与实际制作,验证了工程设计方法的有效性,实测天线罩性能与理论计算吻合良好。     

一种应用于双单元MIMO天线的电磁带隙结构设计与仿真

设计了一种应用于工作频率为2.6GHz的双单元多输入多输出（MIMO）天线的新型电磁带隙结构（EBG）。本文基于传统的蘑菇状结构,将贴片改进为螺旋状,调整偏移了过孔圆柱位置,并采用了电磁带隙结构单元的整体倒“T”形状布局。过孔的位置以及结构单元的间隔基于HFSS电磁仿真软件进行了优化,使新的结构在对天线系统传输特性影响很低的情况下更好的减小两个天线单元之间的耦合干扰。     

斑马鱼基因组随机扩增DNA多态性研究

采用随机扩增DNA多态性（RAPD）技术，对毒性试验的模式生物斑马鱼（Danio rerio）基因组进行了分析。结果显示，在Amersham Pharmacia公司随机扩增引物系列中，分别在01号引物的829bp、534bp，02号引物的572bp，及06号引物的495pb，各出现1条稳定条带，而环磷酰胺作用后的斑马鱼基因组DAN随机扩增产物中，缺少了部分稳定条带。这可以明确判定受试斑马鱼的基因发生了改变，为水环境遗传毒性效尖的研究提供了初步的数据基础。     

模拟消落带水华暴发行为的数值沙堆模型

以长江最大支流汉江近年来水华污染的现场资料为例,通过氮磷浓度、水温、流速和光照等实测数据构建了消落带开放水域环境体系的数值沙堆模型,描述了藻类生长及水华暴发的动力学机制;利用数值沙堆系统崩塌行为反映出的频率-尺度幂律关系作为判断消落带水域是否暴发水华以及规模大小的依据,采用有限尺度标度分析从不同侧面验证了水华暴发系统的自组织临界性,并揭示出各种拟合参数与水华暴发规模之间的定量关系.研究表明,沙堆模型如果存在良好的幂律关系,相应的消落带水域将暴发水华,且幂律指数越大,水华污染程度越严重.     

Limb reduction and chorion villus sampling

Upper limb reduction was diagnosed by ultrasound scan at 17 weeks after chorion villus sampling at 9 weeks' gestation. Pregnancy was terminated and necropsy confirmed limb reduction in an otherwise normal fetus. The relationship of limb reduction to amniotic band syndrome is discussed.