This study was conducted with non-English sophomore students,aiming to explore the effects of different interaction combinations and language levels on continuous writing in an online environment,and compare the diffe...This study was conducted with non-English sophomore students,aiming to explore the effects of different interaction combinations and language levels on continuous writing in an online environment,and compare the differences in lexical alignments and composition quality of learners with different interaction combinations and language levels in the same continuous writing task through experiments.The results show that the mean values of the word-phrase alignment of the paired group were higher than those of the individual group in different interaction combinations,and the two groups showed significant differences;in terms of composition quality,the individual group was better than the paired group,but there was no significant difference between the two groups in terms of task continuation.Secondly,the word-phrase alignment and composition scores of the different language-level groups were higher than those of the same language-level groups,and there was a significant difference between the two groups in terms of word-phrase alignments,but not in terms of composition scores.The results of this study can be useful and informative for second language teachers in future continuous teaching in online environments.展开更多
Fluctuation of molten steel level in continuous casting process is a critical issue. The analytic function for the liquid steel surface stability index( F) of the continuous casting slab mold under the action of elect...Fluctuation of molten steel level in continuous casting process is a critical issue. The analytic function for the liquid steel surface stability index( F) of the continuous casting slab mold under the action of electromagnetic stirring was derived. The effects on the F value of the electromagnetic field,casting mold,submerged entry nozzle,and casting speed were observed,and the stability of the process parameters of a practical continuous casting system was evaluated. The main results generated are as follows:①Based on the free flow jet theory,a formula is established for the level stability index of continuous casting slab mold under electromagnetic stirring.②According to the results of calculation,the various parameters in decreasing order of the magnitude of their influence are magnetic flux density,nozzle submersion depth,casting speed,slab width,stirring current frequency,and nozzle side-hole inclination angle.③For practical continuous casting with a slab thickness of 230 mm,the calculated F values are between 3 and 5 for different matches between slab width and casting speed,but the parameter optimization space is much larger for wider slab widths and lower casting speeds.展开更多
Unsteady fluid flows and level fluctuations in a thin slab continuous casting mould have significant influence on product quality. In this study, the phenomena concerning transient flow features and free surface motio...Unsteady fluid flows and level fluctuations in a thin slab continuous casting mould have significant influence on product quality. In this study, the phenomena concerning transient flow features and free surface motions were analyzed by means of the large eddy simulation （LES） software with the smagorinsky SGS model--VisualCast （VCast） II, where the Simpler algorithm on a body-fitted mesh was used to resolve governing equations. A series of water analog experiments on the fluid flow and the surface wave in the moulds of thin slab continuous casting were also performed. The results of fluid regions, middle of vortex and level fluctuation from digital simulations were identical with the results of the water analog experiments.展开更多
The free surface profile and fluid flow in the mold of continuous casting have been calculated by the VOF method couplingthe SIMPLER algorithm. The SIMPLER-VOF model developed is validated by solving a classical exper...The free surface profile and fluid flow in the mold of continuous casting have been calculated by the VOF method couplingthe SIMPLER algorithm. The SIMPLER-VOF model developed is validated by solving a classical experiment, broken damproblem. The calculated surface profile is consistent with water modelling. It is found that the free surface profile is coherentlyrelated to the position of circumfluence in the mold of continuous casting. With the increase of nozzle port inclination, thepositive vortex above the jet is near to the meniscus and the level fluctuation becomes prominent.展开更多
Using 0.6-scale warer modelling based on Fr-We number similitude criteria, the influences of the submerged entry nozzle configuration and operating practices on the level fluctuation in the mold which caused surface d...Using 0.6-scale warer modelling based on Fr-We number similitude criteria, the influences of the submerged entry nozzle configuration and operating practices on the level fluctuation in the mold which caused surface defects and mold power catching, were studied. It was found that the level flunction was resulted from gas injection, impacting of the stream and standing wave. The level turblence raises with the incresing of the gas injection, however the casting rate, immersion depth and jet angel of SEN have a dual influenc on the level fluctuation.展开更多
The reflection and transmission of the level step to the water waves in the linear and continuous layer liquid were studied in this paper. Based on the matching method of the eigenfunction and a Boussinesq approximati...The reflection and transmission of the level step to the water waves in the linear and continuous layer liquid were studied in this paper. Based on the matching method of the eigenfunction and a Boussinesq approximation, the analytical expression of the diffraction was obtained and the computing methods of the reflection and transmission en- ergy of the level step were proposed. For the incident wave with a frequency greater than that of the flotage, there is only one mode of plane traveling wave in the flow field. In the range of this greater frequency, the linear and continuous delamination effect will affect the reflection and transmission energy of the floating rectangular box. When the fre- quency of the incident wave is less than the flotage frequency, the energy of the plane traveling wave with infinite modes in the flow field will change into the energy of different modes for each incident wave of different modes.展开更多
A kind of triple branched continued fractions is defined by making use of Samel- son inverse and Thiele-type partial inverted di?erences [1]. In this paper, a levels-recursive algorithm is constructed and a numerical ...A kind of triple branched continued fractions is defined by making use of Samel- son inverse and Thiele-type partial inverted di?erences [1]. In this paper, a levels-recursive algorithm is constructed and a numerical example is given.展开更多
文摘This study was conducted with non-English sophomore students,aiming to explore the effects of different interaction combinations and language levels on continuous writing in an online environment,and compare the differences in lexical alignments and composition quality of learners with different interaction combinations and language levels in the same continuous writing task through experiments.The results show that the mean values of the word-phrase alignment of the paired group were higher than those of the individual group in different interaction combinations,and the two groups showed significant differences;in terms of composition quality,the individual group was better than the paired group,but there was no significant difference between the two groups in terms of task continuation.Secondly,the word-phrase alignment and composition scores of the different language-level groups were higher than those of the same language-level groups,and there was a significant difference between the two groups in terms of word-phrase alignments,but not in terms of composition scores.The results of this study can be useful and informative for second language teachers in future continuous teaching in online environments.
文摘Fluctuation of molten steel level in continuous casting process is a critical issue. The analytic function for the liquid steel surface stability index( F) of the continuous casting slab mold under the action of electromagnetic stirring was derived. The effects on the F value of the electromagnetic field,casting mold,submerged entry nozzle,and casting speed were observed,and the stability of the process parameters of a practical continuous casting system was evaluated. The main results generated are as follows:①Based on the free flow jet theory,a formula is established for the level stability index of continuous casting slab mold under electromagnetic stirring.②According to the results of calculation,the various parameters in decreasing order of the magnitude of their influence are magnetic flux density,nozzle submersion depth,casting speed,slab width,stirring current frequency,and nozzle side-hole inclination angle.③For practical continuous casting with a slab thickness of 230 mm,the calculated F values are between 3 and 5 for different matches between slab width and casting speed,but the parameter optimization space is much larger for wider slab widths and lower casting speeds.
文摘Unsteady fluid flows and level fluctuations in a thin slab continuous casting mould have significant influence on product quality. In this study, the phenomena concerning transient flow features and free surface motions were analyzed by means of the large eddy simulation （LES） software with the smagorinsky SGS model--VisualCast （VCast） II, where the Simpler algorithm on a body-fitted mesh was used to resolve governing equations. A series of water analog experiments on the fluid flow and the surface wave in the moulds of thin slab continuous casting were also performed. The results of fluid regions, middle of vortex and level fluctuation from digital simulations were identical with the results of the water analog experiments.
文摘The free surface profile and fluid flow in the mold of continuous casting have been calculated by the VOF method couplingthe SIMPLER algorithm. The SIMPLER-VOF model developed is validated by solving a classical experiment, broken damproblem. The calculated surface profile is consistent with water modelling. It is found that the free surface profile is coherentlyrelated to the position of circumfluence in the mold of continuous casting. With the increase of nozzle port inclination, thepositive vortex above the jet is near to the meniscus and the level fluctuation becomes prominent.
文摘Using 0.6-scale warer modelling based on Fr-We number similitude criteria, the influences of the submerged entry nozzle configuration and operating practices on the level fluctuation in the mold which caused surface defects and mold power catching, were studied. It was found that the level flunction was resulted from gas injection, impacting of the stream and standing wave. The level turblence raises with the incresing of the gas injection, however the casting rate, immersion depth and jet angel of SEN have a dual influenc on the level fluctuation.
文摘The reflection and transmission of the level step to the water waves in the linear and continuous layer liquid were studied in this paper. Based on the matching method of the eigenfunction and a Boussinesq approximation, the analytical expression of the diffraction was obtained and the computing methods of the reflection and transmission en- ergy of the level step were proposed. For the incident wave with a frequency greater than that of the flotage, there is only one mode of plane traveling wave in the flow field. In the range of this greater frequency, the linear and continuous delamination effect will affect the reflection and transmission energy of the floating rectangular box. When the fre- quency of the incident wave is less than the flotage frequency, the energy of the plane traveling wave with infinite modes in the flow field will change into the energy of different modes for each incident wave of different modes.
基金Supported by the National Natural Science Foundation of China under Grant No. 10171026.
文摘A kind of triple branched continued fractions is defined by making use of Samel- son inverse and Thiele-type partial inverted di?erences [1]. In this paper, a levels-recursive algorithm is constructed and a numerical example is given.
