AA 6061-T6 aluminium alloy(Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high specific strength and good corrosion resistance.Compared with the fusion welding p...AA 6061-T6 aluminium alloy(Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high specific strength and good corrosion resistance.Compared with the fusion welding processes that are routinely used for joining structural aluminium alloys,friction stir welding(FSW) process is an emerging solid state joining process in which the material welded does not melt and recast.Joint strength is influenced by the grain size and tensile strength of the weld nugget region.Hence,an attempt was made to develop empirical relationships to predict grain size and tensile strength of friction stir welded AA 6061-T6 aluminium alloy joints.The empirical relationships are developed by response surface methodology(RSM) incorporating FSW tool and process parameters.A linear regression relationship was also established between grain size and tensile strength of the weld nugget of FSW joints.展开更多
Few studies have to date gone behind the scenes to unveil the hidden metaphor-metonymy structure underpinning the input hypothesis （ Krashen 1981 ） despite overt attention paid to it over the years. In an effort to ...Few studies have to date gone behind the scenes to unveil the hidden metaphor-metonymy structure underpinning the input hypothesis （ Krashen 1981 ） despite overt attention paid to it over the years. In an effort to use a fine-grained metaphor-analysis approach（ e. g. , Lakoffand Johnson 1980, 1999） to revisit the input hypothesis, this study looks into its thrust--the causal effect of comprehensible input upon comprehension--in the hope of charting out its hidden organization. By discovering a theme of CAUSATION pivoted on space-based metaphors and metonyrnies, the present study brings to relief two fallacies committed in the input hypothesis. First, the heavy dependence on the prototypicaUy physical-spatial hierarchy leads to a red-herring fallacy, whose inconsistency defies rather than supports its statement about comprehensible input as the overriding cause. Second, although there is no denying that comprehensible input is a significant source of language gains, to enthrone it as the sole causal variable to the exclusion of all the other important variables, especially the agency of the 1.2 learner who should have been positioned in the spotlight in the first place, is another fallacy of immense magnitude.展开更多
文摘AA 6061-T6 aluminium alloy(Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high specific strength and good corrosion resistance.Compared with the fusion welding processes that are routinely used for joining structural aluminium alloys,friction stir welding(FSW) process is an emerging solid state joining process in which the material welded does not melt and recast.Joint strength is influenced by the grain size and tensile strength of the weld nugget region.Hence,an attempt was made to develop empirical relationships to predict grain size and tensile strength of friction stir welded AA 6061-T6 aluminium alloy joints.The empirical relationships are developed by response surface methodology(RSM) incorporating FSW tool and process parameters.A linear regression relationship was also established between grain size and tensile strength of the weld nugget of FSW joints.
文摘Few studies have to date gone behind the scenes to unveil the hidden metaphor-metonymy structure underpinning the input hypothesis （ Krashen 1981 ） despite overt attention paid to it over the years. In an effort to use a fine-grained metaphor-analysis approach（ e. g. , Lakoffand Johnson 1980, 1999） to revisit the input hypothesis, this study looks into its thrust--the causal effect of comprehensible input upon comprehension--in the hope of charting out its hidden organization. By discovering a theme of CAUSATION pivoted on space-based metaphors and metonyrnies, the present study brings to relief two fallacies committed in the input hypothesis. First, the heavy dependence on the prototypicaUy physical-spatial hierarchy leads to a red-herring fallacy, whose inconsistency defies rather than supports its statement about comprehensible input as the overriding cause. Second, although there is no denying that comprehensible input is a significant source of language gains, to enthrone it as the sole causal variable to the exclusion of all the other important variables, especially the agency of the 1.2 learner who should have been positioned in the spotlight in the first place, is another fallacy of immense magnitude.
