基于BP网络的空中交通管制运行品质评价

为改善空中交通管制运行品质综合评价方法,建立了包括空中交通流密度、运行安全性能、运行效率性能及管制员工作负荷的通用评价指标体系;基于BP(back propagation)网络模型给出了运行品质分类评价的人工智能方法.针对成都终端管制区域平行双跑道隔离运行模式,采集60个典型样本进行网络训练测试,确立了拓扑结构为12-7-5型的BP网络模型,并应用于对40个检验样本的分类评价.经与主成分分析法比对,2种综合评价方法所得出的评价结果基本一致.      

终端区空中交通管制运行品质综合评价

为定量评价繁忙终端区空中交通管制运行品质,以成都终端区为研究对象,针对单跑道终端区,建立了包括管制业务量、安全性能、效率性能、工作负荷及交通拥挤度的管制运行品质定量评价指标体系.根据专家意见选取20个相对独立的指标,给出了基于主成分分析法的综合评价方法.采集覆盖一周每日繁忙时段10:00～22:00的84个样本,得到各时段的管制运行品质综合评价结果.经K-均值聚类分析及实际运行表明,本文方法可行,评价结果与实际情况相符.评价结论为终端区的运行策略优化提供了依据.     

Recycling of aluminum from fibre metal laminates

Recycling of aluminum alloy scrap obtained from delaminated fibre metal laminates (FMLs) was studied through high temperature refining in the presence of a salt flux. The aluminum alloy scrap contains approximately mass fraction w(Cu) = 4.4%, w(Mg) = 1.1% and w(Mn) = 0.6% (2024 aluminum alloy). The main objective of this research is to obtain a high metal yield, while maintaining its original alloy compositions. The work focuses on the metal yield and quality of recycled Al alloy under different refining conditions. The NaCl-KCl salt system was selected as the major components of flux in the Al alloy recycling. Two different flux compositions were employed at NaCl to KCl mass ratios of 44:56 and 70:30 respectively, based on either the eutectic composition, or the European preference. Different additives were introduced into the NaCl-KCl system to study the effect of flux component on recycling result. Although burning and oxidation loss of the alloying elements during re-melting and refining take place as the drawbacks of conventional refining process, the problems can be solved to a large extent by using an appropriate salt flux. Experimental results indicate that Mg in the alloy gets lost when adding cryolite in the NaCl-KCl salt system, though the metal yield can reach as high as 98%. However, by adding w(MgF₂) = 5% into the NaCl-KCl salt system (instead of using cryolite) all alloying elements were well controlled to its original composition with a metal yield of almost 98%.     

Durability of concrete made with manganese slag as supplementary cementitious materials

This paper discusses mineral composition and pore microstructure characteristics of water-cooled manganese slag and its effects on durability of concrete. The Mn slag has an alveolate pore structure, and the ground Mn slag is characterized by multiangular shape which consists of α′-C₂S, C₃MS₂, CaO·MnO·2SiO₂ and C₂AS. Experimental results show that the Mn slag has potential hydraulic reactivity. Concrete made with Mn slag as supplementary cementitious materials (SCMs) exhibits very low strength loss and weight loss in the synthetic seawater corrosion and freezing-thawing cycle tests. The research provides useful reference for knowing about Mn slag and for applying Mn slag to improve the durability of concrete.     

基于主成分分析的城市物流发展评价

分析了城市物流的内涵,结合以往研究提出研究城市物流评价体系必须考虑它与物流辐射区经济发展的关系,深入分析了城市物流发展水平的影响因素．在此基础上,建立了科学的城市物流发展评价体系,并构建了城市物流发展水平评价的主成分分析模型．以大连、天津、上海为例进行了实证研究,验证了城市物流发展水平评价体系的有效性．     

四味芳香开窍药的挥发性成分对缺血缺氧PC12细胞及细胞内Ca2+的影响

目的研究四味芳香开窍药的挥发性成分对连二亚硫酸钠(Na2S2O4)致PC12细胞缺血缺氧损伤及细胞内Ca2+的影响。方法体外实验采用5mmol/L的Na2S2O4导致PC12细胞缺血缺氧性损伤,然后观测细胞形态;用二甲基噻唑二苯基四唑溴盐(MTT)比色法,考察水蒸汽蒸馏法提取的麝香、苏合香、安息香挥发性成分及冰片对缺血缺氧PC12细胞活性的影响;并按照试剂盒要求测定模型细胞内Ca2+的含量。结果麝香4、8、16μg/mL,冰片8、16μg/mL,苏合香20、40μg/mL及安息香16μg/mL组均能显著升高模型细胞的吸光度(A)值(P<0.05,P<0.01),显著抑制Na2S2O4对PC12细胞的损伤;苏合香40、80μg/mL,安息香4、8、16μg/mL组均能显著降低模型细胞内Ca2+含量(P<0.05,P<0.01);麝香、冰片有降低模型细胞内Ca2+含量的趋势。结论麝香、苏合香、安息香的挥发性成分及冰片均有保护缺血缺氧PC12细胞的作用,其机制可能与降低细胞内Ca2+的含量,防止钙超载有关。     

基于图像处理的磁选柱溢流液面监控系统设计

对溢流液面的正常情况与跑矿情况进行识别,设计开发了一个用于识别磁选柱溢流液面状态的数字图像处理系统,并利用Visual C＋＋6.0进行了系统实现。系统由图像处理和图像识别两部分组成,利用该系统可以计算磁选柱溢流液面的相关纹理参数,基于纹理参数及其图像识别实验建立一定的样本参数,从而为识别溢流液面的变化情况提供可靠数据依据。     

沥青路面粗集料微观纹理评价方法研究

选取5种不同材质石料,借助自主开发的激光纹理仪,测量集料微观纹理曲线;运用分形分维理论中的盒子计数法,通过MATLAB编程实现对不同粗集料分维数的快速计算。研究表明:该评价方法可以准确的评价粗集料的微观纹理,进而为抗滑层路面选材提供更为丰富的手段和科学依据。     

基于PCA-GA-BP模型对污水BOD的预测

针对污水处理系统的非线性、强耦性,结合主成分分析(PCA)、遗传算法(GA)和BP神经网络,提出了改进阈值参数的模型。以某污水处理厂月数据为例,利用PCA选取主参数的变化因子作为BP神经网络的输入,运用GA优化BP神经网络的权值预测BOD值,并与无优化BP网络的预测结果进行比较。结果表明:新模型对污水处理的预测平均误差为10～12,最大相对误差为1.7%,预测精度高,收敛速度快。     

从中国统计数据看私人汽车发展状况

文中对影响全国私家车拥有量的因素及其对私家车拥有量影响程度进行相关分析,利用建立回归模型、因子分析法分析所选因素与私家车拥有量的相关性,然后通过主成分分析各因素对私家车拥有量的影响程度,得出分析结论并给出相对应的合理建议。