Voice spoofing detection based on acoustic and glottal flow features using conventional machine learning techniques

Multimedia Tools and Applications - Automatic Speaker Verification (ASV) systems are vulnerable to spoofing attacks. Most existing spoofing detection systems rely on two main points; the feature...     

中等含水层下留设防砂煤柱开采的试验与研究

百善煤矿主采煤层上方直接覆盖有22－27m的砂砾石含水层,严重威胁矿井的安全生产。为了安全合理地开采,进行了矿区水文地质和上覆岩层岩石力学、水理性质以及“两带”高度试验。结果表明：含水层内含黏量较高,垂直渗透能力较弱;所留煤柱属软弱或极软弱类型;风化带内黏土矿物含量较大;吸水后体积膨胀,再生隔水能力强;受采动影响后,具阻水和抑制导水裂隙带继续发展的双重作用;根据以上研究结果,取得了将垂高50m的防水煤柱缩小到12－20m防砂、防塌煤柱的技术突破,安全地多采煤600多万t,经济效益显著。     

旋转锥形磨料射流钻孔性能的研究

介绍了旋转锥形磨料射流的调制方法以及利用其进行钻孔的试验系统,分析了旋转锥形磨料射流钻孔的机理,研究了加旋元件结构参数及射流参数对钻孔性能的影响关系,结果表明：用旋转形磨料射流在普氏硬度f≈4的硬煤试块上进行钻孔,可以在喷头不旋转的情况下钻出深孔,其直径比喷嘴孔径大20－30倍,具有较好的钻孔性能。     

Effect of current density and oil concentration on hydrodynamic aspects in electroflotation column during oil/water emulsion treatment

The objective of this work is to study the efficiency of electroflotation process by treatment of effluent from vegetable oil refining industry in the form of oil–water emulsion. We will interest in hydrodynamic aspects in electroflotation columns. We will study the effect of current density and oil concentration on bubbles diameter, bubbles rise velocity, Reynolds number and the effect of the latter on the efficiency of the oil recovery. To evaluate bubble’s characteristics we used the method of video recording followed by an image processing, view of its simplicity this method is used widely. The different bubbles flow regimes were predicted by the calculation of Reynolds number. The efficiency of the process was estimated from turbidity.     

考虑单侧翼缘受载腹板屈曲的不锈钢钢管设计

本文给出了冷成型不锈钢方钢管和矩形钢管在腹板屈曲时的设计公式。研究了两种单翼缘加载的情况,一种是端部单翼缘加载,另一种是内部单翼缘加载,此外还研究了内部加载的情况。采用屈服线理论预测了不锈钢管截面的腹板屈曲强度。屈服线理论模型是在试验中观察到的破坏模式的基础上发展起来的。在屈服线模型基础上采用不同的假定,给出了计算冷成型不锈钢方钢管和矩形钢管的腹板屈曲强度的三种设计方法。其中两种腹板屈曲设计方法是完全采用屈服线分析理论推导出来的,另外一种设计方法是综合理论分析和经验分析得到的。将试验得到的腹板屈曲强度和这三种设计方法得到的屈曲强度进行了对比。结果表明采用纯理论推导得到的设计方法计算得到的腹板屈曲设计强度偏于保守,而综合了理论分析和经验分析得到的设计方法其计算的腹板屈曲设计强度值比较合理,可以用于单翼缘受载时冷成型不锈钢管的设计。     

Assessing groundwater contamination risk using the DASTI/IDRISI GIS method: coastal system of western Mamora, Morocco

In this study, the DASTI method was used to evaluate vulnerability to groundwater pollution in the vicinity of Rabat, western Morocco. The model is based on the characterization of five intrinsic parameters: unsaturated zone thickness, saturated zone thickness and lithology, soil texture, topography and hydraulic gradient. A system of classes of the hydrogeological characteristics was applied to evaluate relative vulnerability to groundwater contamination and a susceptibility map was prepared based on land use and the vulnerability index map. The study showed the DASTI method (applied using IDRISI software) can serve as a tool to evaluate vulnerability to pollution and thus facilitate programs to protect groundwater resources. An erratum to this article can be found at     

真空相变散热器

本文指出了传统钢制散热器的缺点并详细介绍了新型真空相变散热器的结构和工作原理，从而证实了此种散热器的优越性，这对于推进小型燃气锅炉供热系统的广泛应用具有十分重要的意义。