基于FPGA的图像中值滤波器的硬件实现

为了实现图像的实时处理,常采用现场可编程门列阵FPGA对采集的数字图像做预处理,在讨论中值滤波算法原理的基础上,利用VHDL硬件描述语言设计一个中值滤波模块对输入图像进行去噪处理,仿真结果说明该算法满足实时性要求,取得较好的仿真效果,并对中值滤波的改进算法进行了讨论。     

短波紫外线照射和60Co-γ辐照处理对大樱桃贮藏品质的影响

为探究不同射线辐照处理对大樱桃果实保鲜效果的影响,采用不同剂量短波紫外线（short-wave ultraviolet light,UV-C）照射（1.37、2.05、2.74 kJ/m2）和60Co-γ辐照（0.75、1.5、2.25 kGy）分别处理大樱桃果实,定期检测其冷藏期间生理品质指标和果皮超微结构变化。结果表明：贮藏15 d内,1.37 kJ/m2照射和0.75 kGy辐照较对照组可显著延缓大樱桃果实好果率下降、抑制果实质量损失,较好保持果实质地特性,促进花青素合成,有效抑制过氧化物酶与超氧化物歧化酶活性下降,但对可溶性固形物含量影响不大,且会引起丙二醛含量增加。由于两种处理对好果率、硬度、质量损失率、花青素等感官品质核心指标具有良好的积极作用,因此对丙二醛的不利变化并不足以影响到果实的商品品质评价。电子显微镜结果显示,大樱桃经1.37 kJ/m2照射和0.75 kGy辐照处理后,与对照组相比,能在一定程度上减轻果皮细胞膜、线粒体、叶绿体等细胞结构的损伤程度,显著延缓果皮细胞衰老。此外,在贮藏前期与末期,1.37 kJ/m2照射和0.75 kGy辐照所发挥的作用并不相同。针对于5 d以内的短期贮藏,可采用1.37 kJ/m2 UV-C照射,而长期贮藏则以0.75 kGy 60Co-γ辐照效果更好。     

稀土修饰铁碳材料对糖蜜酒精废水处理效果的研究

采用还原铁粉、碳粉、稀土铈及黏结剂等为原料混合制成的Ce-Fe/C复合材料深度处理糖蜜酒精废水,研究了铁碳质量比、稀土铈添加量以及废水处理时间等因素对处理效果的影响。结果表明:以铁碳质量比为5∶1,稀土铈添加质量分数为7%制备的Ce-Fe/C复合材料处理糖蜜酒精废水,当反应时间为150 min时,色度去除率达98%以上,COD去除率达70%以上。对制备的复合材料的表征结果表明,稀土元素Ce有效地掺杂到Fe/C材料的晶格中,提高了Fe/C材料的性能。     

Remote-sensing imagery classification using multiple classification algorithm-based AdaBoost

AdaBoost demonstrates excellent performance in remote sensing (RS) image classification, but as it works on only one classification algorithm, the disadvantage of the classification algorithm itself is difficult to overcome, resulting in limitations in the improvement of classification accuracy. In this article, a modified AdaBoost, a multiple classification algorithm-based AdaBoost (MCA AdaBoost), is proposed to improve remote sensing image classification. The new method works on more than one classification algorithm and can make full use of the advantages of different learning algorithms. Based on a Landsat 8 Operational Land Imager (OLI) image whose spatial resolution was enhanced to 15 m with a panchromatic band, a C4.5 decision tree, Naïve Bayes, and artificial neural network were used as objects to verify and compare the performance of both AdaBoost and MCA AdaBoost. The experimental results show that MCA AdaBoost successfully inherits the benefits of the original AdaBoost, combines the advantages of different classification algorithms and lowers overfitting. By increasing diversity and complementarity among base classifiers, MCA AdaBoost outperforms AdaBoost in terms of RS classification accuracy improvement.     

Inherently Eu2+/Eu3+ Codoped Sc2O3 Nanoparticles as High‐Performance Nanothermometers

Luminescent nanothermometers have shown competitive superiority for contactless and noninvasive temperature probing especially at the nanoscale. Herein, we report the inherently Eu²⁺/Eu³⁺ codoped Sc₂O₃ nanoparticles synthesized via a one‐step and controllable thermolysis reaction where Eu³⁺ is in‐situ reduced to Eu²⁺ by oleylamine. The stable luminescence emission of Eu³⁺ as internal standard and the sensitive response of Eu²⁺ emission to temperature as probe comprise a perfect ratiometric nanothermometer with wide‐range temperature probing (77–267 K), high repeatability (>99.94%), and high relative sensitivity (3.06% K^–1 at 267 K). The in situ reduction of Eu³⁺ to Eu²⁺ ensures both uniform distribution in the crystal lattice and simultaneous response upon light excitation of Eu²⁺/Eu³⁺. To widen this concept, Tb³⁺ is codoped as additional internal reference for tunable temperature probing range.     

Dynamic monitoring of land-use/land-cover change and urban expansion in Shenzhen using Landsat imagery from 1988 to 2015

To analyse changes in human settlement in Shenzhen City during the past three decades, changes in land use/land cover (LULC) and urban expansion were investigated based on multi-temporal Landsat Thematic Mapper/Enhanced Thematic Mapper Plus/Operational Land Imager (TM/ETM+/OLI) images. Using C4.5-based AdaBoost, a hierarchical classification method was developed to extract specific classes with high accuracy by combining a specific number of base-classifier decisions. Along with a classification post-processing approach, the classification accuracy was greatly improved. The statistical analysis of LULC changes from 1988 to 2015 shows that built-up areas have increased 6.4-fold, whereas cultivated land and forest continually decreased because of rapid urbanization. Urban expansion driven by human activities has considerably affected the landscape change of Shenzhen. The urban-expansion pattern of Shenzhen is a mixture of three urban-expansion patterns. Among these patterns, traffic-driven urban expansion has been the main form of urban expansion for some time, especially in the Non-Special Economic Zone. In addition, by taking 8 to 10 year periods as time intervals, urban expansion in Shenzhen was divided into three stages: the early-age urbanization stage (1988–1996), the rapid urbanization stage (1996–2005), and the intensive urbanization stage (2005–2015). For different stages, the state of urban expansion is different. In long-term LULC dynamic monitoring and urban-expansion detection, it was possible to obtain 11 LULC maps, which took 2 to 4 years as a research interval. With regard to the short research periods, LULC changes and urban expansion were investigated in detail.     

基于流溪河模型的连江流域洪水模拟

为了提高连江流域洪水预报的技术水平和精度,探讨流溪河模型在大流域洪水预报中应用的效果,该文采用SRTM和USGS的DEM数据,分别建立了连江流域洪水预报流溪河模型,采用1场实测洪水对模型参数进行了优选,并对2场实测洪水进行了模拟,发现流溪河模型可较好的模拟连江流域洪水过程。研究发现,采用空间分辨率为90 m的SRTM的DEM建立的流溪河模型计算量是以1000 m的USGS的DEM建立的模型的计算量的56倍,但两者洪水模拟的效果相当。     

煤矸石制备活性炭-氧化物复合吸附材料及硅铝水处理剂的研究

研究开发了由煤矸石制备活性炭-氧化物复合吸附材料、硅铝水处理剂的清洁生产工艺,即在惰性气体气氛中,焙烧、活化由固体碱调配过的煤矸石原料,使其中的碳转化为活性炭,然后将其通过碱提、酸浸两步法,实现了煤矸石中主要元素的全部利用.讨论了活化、碱提、酸浸和合成硅铝水处理荆过程中各种条件对吸附材料性能的影响.系统研究了材料对淀粉等工业废水的吸附性能,并对该复合材料进行了表征,所制备的吸附材料孔容为1.608 cm3/g,总比表面积为305.63 m2/g,且以中孔为主,适用于淀粉类工业废水的处理.     

高拱坝施工的温控数据库系统

依托溪洛渡高拱坝工程,整理了高拱坝温控信息类型,提出了局部的温控措施要求,形成大量的个性化温控信息,吸纳了高拱坝施工过程与温度场仿真成果,构建成温控数据库,利用Direct3D三维图形接口和Access数据库,在Visual C++编程环境下,开发了温控数据库系统,形成初步成果,该成果适合现场预警和快速反应,可为现场决策提供参考.     

通过外加扰动改善A／D变换器的传递特性

本文阐述了Ａ／Ｄ变换器量化误差的产生,在文献（１）的基础上讨论了Ａ／Ｄ变换器的输出平均量化误差与外加扰动之间的关系,并且利用了中心极限定理,通过多个扰动的合成,生成一个近似的正态分布的扰动,从而提高Ａ／Ｄ变换器的线性,这种扰动形式易于实现,方差可控,并且可以忽略高次谐波的干扰。