语言习得与语言磨蚀:关于复语专业的理论思考

语言磨蚀与语言学习关系密切。本文从语言习得和语言磨蚀的理论出发,讨论复语专业中英语磨蚀的可能性和减少、防御磨蚀的可行性。讨论得出的几个初步结论可供复语专业设计参考。

长春净月区强风化砂岩地层抗钻特性研究

为解决长春净月区强风化砂岩地层长螺旋钻进可行性及对钻具磨蚀程度问题,对该区域强风化砂岩地层通过抗压强度和完整性试验、全岩分析试验和Cerchar试验进行了研究。研究结果表明:该区强风化砂岩为极软岩,岩体整体破碎,单轴抗压强度平均值为2.49MPa,强风化砂岩成分为石英、钾长石、斜长石和黏土矿物,石英是造成钻具磨蚀的主要成分,浅、中、深部强风化砂岩石英含量分别为4.9%、34.9%、54.8%。通过Cerchar试验获得浅部、中部和深部强风化砂岩CAI值分别为0.68~1.55、1.46~2.27、3.13~4.29,对长螺旋桩机钻具磨蚀程度轻微~中等、中等~很强,很强~极强。因此,判定采用长螺旋钻进工艺可以完成本区域强风化砂岩的钻进;但由于浅、中、深部石英含量的不同导致对钻具产生磨蚀强弱不同,在实际施工时应根据不同岩性调整钻具,提高钻进速度和降低施工成本。

Numerical Simulation of Erosion-Corrosion in the Liquid-Solid Two-Phase Flow

Erosion-corrosion of liquid-solid two-phase flow occurring in a pipe with sudden expansion in cross-section is numerically simulated in this paper. The global model for erosion-corrosion process includes three main components: the liquid-solid two-phase flow model, erosion model and corrosion model. The Eulerian-Lagrangian approach is used to simulate liquid-solid two-phase flow, while the stochastic trajectory model was adopted to obtain properties of particle phase. Two-way coupling effect between the fluid and the particle phase is considered in the model. The accuracy of the models is tested by the data in the reference. The comparison shows that the model is basically correct and feasible.