Optical Antenna System Design for 3D Imaging Lidar

A new aspheric surface pre-collimation lenses system for the optical antenna of three-dimensional(3D)imaging of lidar has been optimally designed and simulated by optical design software CODE-V.Four kinds of aspheric surfaces spherical lenses including the sections of spherical,elliptical,hyperbola,and parabola have been researched.The optical system,including the elliptical cylinder lenses collimation and the optical antenna,can be realized less than 5μrad collimation angle for dot source semiconductor laser beam.     

Ferrite process of electroplating sludge and enrichment of copper by hydrothermal reaction

In this paper, ferrite process of electroplating sludge and enrichment of copper by hydrothermal reaction was investigated. By the hydrothermal treatment, Zn, Ni, Cu, Cr-bearing electroplating sludge can be transformed into high value-added Ni–Zn–Cr ferrite by adding iron source (FeCl₃·6H₂O) and precipitator. The most optimum reaction conditions were explored: 1.57 g/g dry sludge as the dosage of FeCl₃·6H₂O, pH 8.5 of the slurry adjusted by ammonia, 4 h as the reaction time, and 200 °C as the reaction temperature. Under these conditions, the purer Ni–Zn–Cr ferrite could be prepared, and Cu was extracted to the range from 76 wt% to nearly 84 wt%, when ammonia was selected as the precipitator. Leaching toxicity of heavy metals from Ni–Zn–Cr ferrite prepared with additional iron source and precipitator, was much lower than the regulated limit of Toxicity Characteristic Leaching Procedure (TCLP), indicating that Ni–Zn–Cr ferrite synthesized hydrothermally from electroplating sludge had a better chemical stability. Therefore, the ferrite process by hydrothermal reaction is a feasible method with respect to the reuse and self-purification of electroplating sludge.     

改性粉煤灰对镍渣基地聚合物力学性能的影响

在碱激发剂作用下制备镍渣基地聚合物,考察自制改性粉煤灰对地聚合物力学性能的影响,并结合XRD、IR和SEM等测试方法,对试块的微观结构和性能进行研究。结果表明：改性粉煤灰的掺入有利于镍渣基地聚合物力学性能的提高。当改性粉煤灰掺量为20%时效果最佳,50 ℃养护7 d时地聚合物的抗折强度和抗压强度分别比镍渣地聚合物提高了32.0%和20.2%。主要是改性粉煤灰颗粒表面含有的β-C₂S参与反应后产生更多的凝胶相,有利于改善地聚合物结构的致密性,增强与改性粉煤灰颗粒表面碱激发产物的胶结能力。同时,钙源的引入也有助于改性粉煤灰在碱溶液的溶解,提高体系反应速率。     

锂离子电池复合正极材料xLiFePO4·yLi3V2(PO4)3的制备与性能研究

以FePO4·xH2O、V2O5、NH4H2PO4和Li2CO3为原料,以乙二酸为还原剂,在常温常压下经机械活化并还原嵌锂,形成无定形的5LiFePO4·Li3V2(PO4)3前驱体混合物,然后低温热处理合成出晶态的复合正极材料5LiFePO4·Li3V2(PO4)3.分别研究了复合材料的物相结构、形貌、电化学性能.SEM图像表明合成的材料粒径小、分布均匀,一次粒径为100～200nm.充放电测试结果表明,650℃烧结12h制得的复合正极材料5LiFePO4·Li3V2(PO4)3电化学性能优良,1C放电比容量高达158mAh/g,达到该复合材料的理论比容量(156.8mAh/g).复合材料具有良好的倍率性能和循环性能,在10C放电比容量高达114mAh/g,100次循环后容量几乎无衰减.循环伏安测试表明,复合材料的脱嵌锂性能优良,且明显优于单一的LiFePO4和Li3V2(PO4)3.     

UMXGIS的设计与实现①

WebGIS地理信息系统随着web应用的发展而发展,传统的基于web服务器端服务与基于桌面的客户端服务相独立的模式已经不能满足现实社会生产生活的需求。因此提出优化的基于Web Services的2N模式,该模式使服务器和客户端两者之间数据交互更便捷。通过遴选,整合,优化相关技术,设计并实现了基于2N模式的UMXGIS系统。     

激光辐照引起Ge2Sb2Te5非晶态薄膜的电/光性质变化

研究了激光辐照引起Ge₂Sb₂Te₅非晶态薄膜的电/光性质变化, 当激光功率为580mW时薄膜的方块电阻有四个数量级(10⁷～10³Ω/□)的突变; 对电阻发生突变前、中、后的三个样品进行了XRD测试, 结果表明, 随着激光功率的增大,薄膜由非晶态向晶态转变,用椭偏仪测试了结构转变前、中、后三个样品的光学常数, 在可见光范围内薄膜的光学常数在波长相同情况下有: n_非晶态>n_中间态>n_晶态, k_晶态>k_中间态>k_非晶态, α_晶态>α_中间态>α_非晶态, 结合电阻变化曲线和XRD图谱讨论了激光辐照Ge₂Sb₂Te₅非晶态薄膜的电/光性质变化同激光功率和结构转变之间的关系.     

基于深度学习的卫星图像识别分类方法

卫星遥感技术是一种非常重要的地球空间监测技术.卫星遥感图像经过处理后具有数据量大和数据类型复杂多样的特点,传统方法进行识别分类耗费大量人力物力.为了降低工作量,并为后续处理提供便利,本文将深度学习算法应用于卫星图像的识别分类中,设计了一种基于VGGNet的识别分类方法,利用除雾算法对训练数据进行数据增强处理,并添加岭回归正则化层,利用标签之间的相关性进行预测,使得方法达到90%以上的F2 score,并在实验部分进行了对比验证.最后利用此方法搭建了一个基于Django的在线识别分类展示系统.     

高可靠的计算机模块引导软件

在航天软件领域,为适应相关软件的快速发展与迭代,需要一种引导软件,使其能够对不同应用程序进行重构并保证其高可靠性. 本文基于SPARC架构设计并实现了一种引导软件,该引导软件既可以根据引导标识自动引导某个程序,又可以在地面指令控制下进行应用程序重构、引导等. 同时,采用三冗余架构、反弹墙、EDAC保护等可靠性措施,确保运行过程中的大多数软件错误能够得到恢复. 最终在计算机模块上进行测试,测试结果达到了预期目的.     

Using Wikipedia knowledge to improve text classification

Text classification has been widely used to assist users with the discovery of useful information from the Internet. However, traditional classification methods are based on the “Bag of Words” (BOW) representation, which only accounts for term frequency in the documents, and ignores important semantic relationships between key terms. To overcome this problem, previous work attempted to enrich text representation by means of manual intervention or automatic document expansion. The achieved improvement is unfortunately very limited, due to the poor coverage capability of the dictionary, and to the ineffectiveness of term expansion. In this paper, we automatically construct a thesaurus of concepts from Wikipedia. We then introduce a unified framework to expand the BOW representation with semantic relations (synonymy, hyponymy, and associative relations), and demonstrate its efficacy in enhancing previous approaches for text classification. Experimental results on several data sets show that the proposed approach, integrated with the thesaurus built from Wikipedia, can achieve significant improvements with respect to the baseline algorithm.