Induced effects of Cu underlayer on（111） orientation of Fe50 Mn50 thin films

Effects of Cu underlayer on the structure of Fe50 Mn50 films were studied. Samples with a structure of Fe50 Mn50 (200 nm)/Cu(tcu) were prepared by rnagnetron sputtering on thermally oxidized silicon substrates at room temperature. The thickness of Cu underlayer varied from 0 to 60 nm in the intervals of 10 nm. High-vacuum annealing treatments, at different temperatures of 200, 300 and 400℃ for 1 h, respectively, on the Fe50Mn50 (200 nm)/Cu(20 nm) thin films were performed. The surface morphologies and textures of the samples were measured by field emission scan electronic microscope (FE-SEM) and X-ray diffraction(XRD). Energy dispersive X-ray spectroscopy (EDX) and Auger electron spectroscopy(AES) were used to analyze the compositional distribution. It is found that Cu underlayer has an obvious induce effect on (111) orientation of Fe50 Mn50 thin films. The induce effects of Cu on (111) orientation of Fe50 Mn50 changed with the increase of Cu layer thickness and the best effect was obtained at the Cu layer thickness of 20 nm. High-vacuum annealing treatments cause the migration of Mn atoms towards surface of the film and interface between Cu layer and substrate. With the increasing annealing temperature, migration of Mn atoms is more obvious, which leads to a Fe-riched Fe-Mn alloy film.     

论现代双线干油集中润滑系统的高压化趋势

本文论述了双线干油(脂)集中润滑系统的发展简史和现代高压双线干油集中润滑系统,并对低压(138bar)、中压(210bar)和高压(400bar)系统的管路内润滑脂滞留时间及它们的综合投资费用和经济性等进行了分析比较,阐明了其高压化趋势的原因。     

铁素体-奥氏体异种钢接头的界面组织及力学性能

为提高电站锅炉过热器铁素体－奥氏体异种钢焊接接头的高温蠕变断裂强度和服役寿命，设计了专用的镍基填充材料及组合焊接接头。通过对不同焊缝接头的高温蠕变力不试验，焊缝界面组织变化分析，碳扩散和热应力的测试分析，认为在高温低力的条件下，接头焊缝界面及热影响区碳元素扩散迁移和碳化物聚集是影响接头蠕变断裂强度的重要原因。     

Environmental Influences on Fish Migration in a Hydropeaking River

Fish have evolved traits and life history characteristics that enable them to survive, exploit and depend on the flow regime of rivers, particularly the timing and predictability of flows for spawning and rearing their young. It is unclear to what degree pulsed flows from hydropower facilities and other environmental variables influence migratory behaviours. We used Dual Frequency Identification Sonar in the Michipicoten River, Canada, to address the relationship between fish migration and environmental factors with a focus on flow magnitude and fluctuation. In both 2007 and 2009, the peak of the Chinook (Oncorhynchus tshawytscha) and pink salmon (Oncorhynchus gorbuscha) migration occurred on 8 September. Mean water temperature on this date was 18 °C and precipitously dropped afterwards. The photoperiod was roughly 12‐h long with sunrise at 700 h and sunset at 2000 h. Most fishes moved upstream during the hours of darkness between 2000 and 600 h. The lowest counts of fish occurred from noon to just before sunset, whereas highest counts commonly occurred from 1 to 2 h after sunset. Fish moved upstream during all magnitudes of flow; however, there was a slight preference for larger flows in 2007 but not in 2009. Changes in flow magnitude occurred both during the day and night, with flows typically increasing during the day to meet electrical demand and decreasing at night. Most fishes moved upstream during periods of little to no change in flow. High flows and changing flows may deter salmon from moving up the Michipicoten River but not likely in a significant manner to cause energetic stress or harm. Other adverse effects of pulsed flows, however, must still be considered for spawning, hatching and rearing success. Copyright © 2014 John Wiley & Sons, Ltd.     

Importance of Reservoir Tributaries to Spawning of Migratory Fish in the Upper Paraná River

Regulation of rivers by dams transforms previously lotic reaches above the dam into lentic ones and limits or prevents longitudinal connectivity, which impairs access to suitable habitats for the reproduction of many migratory fish species. Frequently, unregulated tributaries can provide important habitat heterogeneity to a regulated river and may mitigate the influence of impoundments on the mainstem river. We evaluated the importance of tributaries to spawning of migratory fish species over three spawning seasons, by comparing several abiotic conditions and larval fish distributions in four rivers that are tributaries to an impounded reach of the Upper Paraná River, Brazil. Our study confirmed reproduction of at least 8 long‐distance migrators, likely nine, out of a total of 19 occurring in the Upper Paraná River. Total larval densities and percentage species composition differed among tributaries, but the differences were not consistent among spawning seasons and unexpectedly were not strongly related to annual differences in temperature and hydrology. We hypothesize that under present conditions, densities of larvae of migratory species may be better related to efficiency of fish passage facilities than to temperature and hydrology. Our study indicates that adult fish are finding suitable habitat for spawning in tributaries, fish eggs are developing into larvae, and larvae are finding suitable rearing space in lagoons adjacent to the tributaries. Our findings also suggest the need for establishment of protected areas in unregulated and lightly regulated tributaries to preserve essential spawning and nursery habitats. Copyright © 2014 John Wiley & Sons, Ltd.     

示踪试验在复杂岩溶区工程中的应用

以滇中引水工程某深埋长隧洞为依托,在较深入了解研究区水文地质及工程地质条件的基础上,选取线路对地下水环境影响较大的区域进行示踪试验,通过试验不仅较清晰地查清了地下水运移通道,而且较为准确地查明了研究区地下分水岭,最终为线路的选择提供了合理、准确、可行的依据。     

引入迁移学习的癫痫EEG信号自适应识别

在脑电图( EEG)信号识别中,EEG信号的采样环境、病人状态的多样性导致分类器训练所用的源域与分类器测试所用的目标域不匹配,分类器在目标域上表现不佳。为此,引入邻域适应策略,提出一种基于子空间相似度的改进主成分分析特征提取方法( SSM-PCA),在选择主成分时,考虑源域和目标域数据的几何和统计特性,并结合迁移学习分类器大间隔投射迁移支持向量机( LMPROJ),给出以SSM-PCA为基础的LMPROJ分类识别方法。实验结果表明,与结合PCA特征抽取技术和K近邻分类器实现的识别方法相比,该方法在识别正确率方面得到较大提升。     

基于时序模型迁移的间歇过程监测建模方法

针对工业生产过程频繁变更操作条件的需求, 提出一种基于时序模型迁移的方法, 通过从旧过程数据中挖掘并提取相似性信息, 可以快速建立新过程的监测模型. 将该建模方法与时序模型迁移相结合应用于青霉素发酵仿真过程, 实验结果验证了该方法的有效性.

     

基于人工免疫算法的增量式用户兴趣挖掘

了解用户兴趣是为用户提供个性化服务的关键.用户兴趣有短期兴趣和长期兴趣之分,且具有不稳定性.受人工免疫系统的启发,巧妙地将免疫应答过程应用于用户兴趣挖掘.首先将概率与时间相结合,提出“概念时序动态”的概念,以更好地刻画用户在一段时间内对同一兴趣的关注程度;然后基于人工免疫原理,建立抽取兴趣标签的分类器来提取用户兴趣标签;最后针对增量式学习,建立兴趣标签的“概念时序动态”,刻画出用户兴趣自首次出现以来受关注的程度,以此为依据来判断兴趣是否存在迁移及遗忘现象,并为每个兴趣标签附上权重.其主要贡献是创造性地将人工免疫原理应用于用户短期兴趣和长期兴趣的挖掘,并具有增量特性,可以很好地体现用户兴趣迁移特征,是一种自然完整的用户兴趣模型.实验结果表明,该学习模型能够很好地发现用户关注的领域,其平均精度和召回率分别达到79.5％和74.4％,是目前最贴近用户的兴趣挖掘模型.     

基于信息融合度传递的频域徙动入侵特征挖掘算法

在功率自激混合组合网络中,路由之间的相群特征相异性会产生谐振信号,因此需要有效挖掘入侵信号的频域徙动特征来实现对入侵信号的拦截。传统方法采用混合蛙跳算法挖掘入侵特征并且聚类中心矢量向模糊边缘贴近,因此搜索和挖掘精度不高。提出了一种基于混合蛙跳最优模因组信息融合度传递的频域徙动入侵特征挖掘算法。构建功率自激组合网络的系统模型和入侵信号数学模型,基于频域谐振慢变衰落幅度均衡原理,得到多源网络攻击源信号在相干点积功率累积尺度坐标,采用多普勒频移模糊搜索对入侵信号进行平滑处理,计算入侵信号的多普勒频移状态空间固有模态函数,得到入侵信号的频域特征包络幅度估计值。采用IIR滤波算法,对信号进行降噪滤波处理,提高信号的纯度,提出基于信息融合度传递的混合蛙跳入侵信号检测算法,优化特征挖掘结果,完成入侵信号的频域徙动特征挖掘算法改进。仿真实验结果表明,该算法能准确挖掘入侵信号的频域徙动特征,特征的波脊亮点明显,在低信噪比下提高了入侵信号的检测性能。