In the activity of English teaching, how to improve students＇ communicative competence is always deemed as an important factor on which English teaching hinges. This paper starts from the idea of communicative compet...In the activity of English teaching, how to improve students＇ communicative competence is always deemed as an important factor on which English teaching hinges. This paper starts from the idea of communicative competence proposed by linguist Dwell Hymes and then goes deep to find out 4 ways to apply the ideas to spoken English teaching, namely： strengthening students＇ linguistic input through comprehensible listening; getting a feel of how English is spoken idiomatically; administering the teaching materials according to students＇ current linguistic capacity and finally exposing students massively to the target culture. Since this paper is about teaching, the discussion of teacher＇s role will be dealt with at the last part.展开更多
Given the speed requirements of a mechanical press slider, a differential gear train is adopted instead of the belt and gear drive of a general mechanical press. Two electric motors are used to drive the differential ...Given the speed requirements of a mechanical press slider, a differential gear train is adopted instead of the belt and gear drive of a general mechanical press. Two electric motors are used to drive the differential gear train with hybrid input. Based on the working principle of a differential gear train, the angular speed equations and the power dis- tribution equations of the input-output system are established. By controlling the angular speeds of the two motors, the slider can move at different speeds. Taken a JH23-100 type mechanical press as example, the driving system is designed and the power of two motors determined. The simulated results show that the highest slider speed in the mechanical press approaches 39 mm/s only at the forging-punching stage, far less than the 232 mm/s of a general JH23-100 type mechanical press. This provides a new scheme to realize low-speed forging-punching technology from a mechanical press.展开更多
AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir...AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir welding （FSW） tools and FSW welders. These models may be further helpful for making process parameter choice for this sort of alloy, defining welding program and control of process parameters by using computer numerical control friction stir welding welders. The results show that tool rotational speed, welding speed and tool shoulder diameter are most significant parameters affecting axial force and heat input, while longitudinal force is significantly affected by welding speed and probe diameter.展开更多
To improve design capabilities for the knitted fabric pattern,a preliminary study is carried out for the design method.Based on mathematical theory,pattern could be created automatically by computer with inputting dif...To improve design capabilities for the knitted fabric pattern,a preliminary study is carried out for the design method.Based on mathematical theory,pattern could be created automatically by computer with inputting different parameters for mathematical functions.The knitted fabric simulation is realized by M1 CAD pattern preparation system of STOLL Company.In the pattern,different color unit is replaced by obverse stitch with different color,or by obverse stitch and reverse stitch with the same color separately,after that the effects of knitted fabrics could be simulated.Designing with this method,it would not only help to acquire a great of diversity patterns,but also improve design efficiency and save cost.展开更多
The non-heat-treatable AA3003-H18 plates were joined by friction stir welding（FSW） to achieve a proper joint by optimizing the welding parameters.For this purpose,the effects of heat input on microstructure and mech...The non-heat-treatable AA3003-H18 plates were joined by friction stir welding（FSW） to achieve a proper joint by optimizing the welding parameters.For this purpose,the effects of heat input on microstructure and mechanical properties of the welded samples were investigated by changing the ratios of rotational speed（800-1200 r/min） to travel speed（40-100 mm/min）（w/v）.It was revealed that the grain growth rate was strongly increased with the increase of the heat input by rotational speed at constant travel speed,while the grain growth rate was slightly increased with the increase of the heat input by travel speed at constant rotational speed.Subsequently,hardness reduction was observed in the stir zone at higher rotational speed compared with that at lower one.An interesting observation was that various welding parameters do not have noticeable effect on the tensile strength of the FSW joints.Also,it has been observed that the fracture location of tensile test specimens was placed in the heat-affected zone（HAZ）on the advancing side at lower travel speed,while at higher travel speed,it was placed at the HAZ/thermomechanical affected zone（TMAZ） interface on the retreating side.展开更多
This work proposes a map-based control method to improve a vehicle's lateral stability, and the performance of the proposed method is compared with that of the conventional model-referenced control method. Model-r...This work proposes a map-based control method to improve a vehicle's lateral stability, and the performance of the proposed method is compared with that of the conventional model-referenced control method. Model-referenced control uses the sliding mode method to determine the compensated yaw moment; in contrast, the proposed map-based control uses the compensated yaw moment map acquired by vehicle stability analysis. The vehicle stability region is calculated by a topological method based on the trajectory reversal method. A 2-DOF vehicle model and Pacejka's tire model are used to evaluate the proposed map-based control method. The properties of model-referenced control and map-based control are compared under various road conditions and driving inputs. Model-referenced control uses a control input to satisfy the linear reference model, and it generates unnecessary tire lateral forces that may lead to worse performance than an uncontrolled vehicle with step steering input on a road with a low friction coefficient. However, map-based control determines a compensated yaw moment to maintain the vehicle within the stability region,so the typical responses of vehicle enable to converge rapidly. The simulation results with sine and step steering show that map-based control provides better the tracking responsibility and control performance than model-referenced control.展开更多
Based on the Involvement Load Hypothesis, the present study investigated the differential effects of three post-listening output tasks(gap-filling, translation, and sentence-making) on immediate acquisition and retent...Based on the Involvement Load Hypothesis, the present study investigated the differential effects of three post-listening output tasks(gap-filling, translation, and sentence-making) on immediate acquisition and retention of such vocabulary dimensions as productive knowledge of orthography,receptive recall of meaning and form, and productive knowledge of grammatical functions. Ninety second-year English majors were divided into three groups to finish listening plus one of the postlistening tasks. The results showed that the post-listening output tasks had positive effects on immediate acquisition of productive vocabulary knowledge, partially in agreement with the Involvement Load Hypothesis. However, the effects on vocabulary knowledge retention were found to be largely inconsistent with the Involvement Load Hypothesis. The finding thus challenges this hypothesis in that involvement load is not the only determining factor and suggests that the theoretical construct of involvement load should be constructed with more caution.展开更多
We propose a monomer adsorption model, in which only the monomers are allowed to diffuse and adsorb onto other clusters. By means of the generalized rate equation we investigate the kinetic behavior of the system with...We propose a monomer adsorption model, in which only the monomers are allowed to diffuse and adsorb onto other clusters. By means of the generalized rate equation we investigate the kinetic behavior of the system with a special rate kernel. For the system without monomer input, the concentration aj（t） of the Aj clusters （j 〉 1） asymptotically retains a nonzero quantity, while for the system with monomer input, it decays with time and vanishes finally. We also investigate the kinetics of an interesting model with fixed-rate monomer adsorption. For the ease without monomer source, the evolution of the system will halt at a finite time; while the system evolves infinitely in time in the case with monomer source. Finally, we also suggest a connection between the fixed-rate monomer adsorption systems and growing networks.展开更多
This study was performed to compare storm surges/tide simulated by the regional and coastal storm surges/tide forecast system （RTSM （regional tide/storm surges model）, CTSM （coastal tide/storm surges model）） usi...This study was performed to compare storm surges/tide simulated by the regional and coastal storm surges/tide forecast system （RTSM （regional tide/storm surges model）, CTSM （coastal tide/storm surges model）） using two different inputs from weather models （RDAPS （Regional Data Assimilation and Prediction System） and KWRF （Korea Weather and Research Forecasting）） during two typhoons that occurred between 2007 and 2008. Both the RDAPS and KWRF are the operational weather forecasting system in KMA （Korea Meteorological Administration）. The horizontal resolutions of RDAPS and KWRF are 30 and 10 km, respectively. The storm surges/tide was hind casted using sea wind and pressure fields of two Typhoons which was approaching Korean Peninsula. The CTSM using input from KWRF simulate very well the storm surges/tide pattern in the complex coastal areas. The result showed that the storm surges by the coastal storm surges/tide model with high resolution input was in well agreement with the observed sea level occurred by high tide and storm surges in the coastal areas.展开更多
文摘In the activity of English teaching, how to improve students＇ communicative competence is always deemed as an important factor on which English teaching hinges. This paper starts from the idea of communicative competence proposed by linguist Dwell Hymes and then goes deep to find out 4 ways to apply the ideas to spoken English teaching, namely： strengthening students＇ linguistic input through comprehensible listening; getting a feel of how English is spoken idiomatically; administering the teaching materials according to students＇ current linguistic capacity and finally exposing students massively to the target culture. Since this paper is about teaching, the discussion of teacher＇s role will be dealt with at the last part.
文摘Given the speed requirements of a mechanical press slider, a differential gear train is adopted instead of the belt and gear drive of a general mechanical press. Two electric motors are used to drive the differential gear train with hybrid input. Based on the working principle of a differential gear train, the angular speed equations and the power dis- tribution equations of the input-output system are established. By controlling the angular speeds of the two motors, the slider can move at different speeds. Taken a JH23-100 type mechanical press as example, the driving system is designed and the power of two motors determined. The simulated results show that the highest slider speed in the mechanical press approaches 39 mm/s only at the forging-punching stage, far less than the 232 mm/s of a general JH23-100 type mechanical press. This provides a new scheme to realize low-speed forging-punching technology from a mechanical press.
文摘AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir welding （FSW） tools and FSW welders. These models may be further helpful for making process parameter choice for this sort of alloy, defining welding program and control of process parameters by using computer numerical control friction stir welding welders. The results show that tool rotational speed, welding speed and tool shoulder diameter are most significant parameters affecting axial force and heat input, while longitudinal force is significantly affected by welding speed and probe diameter.
基金Doctoral fundation of Tianjin Polytechnic University,China(No.029066)
文摘To improve design capabilities for the knitted fabric pattern,a preliminary study is carried out for the design method.Based on mathematical theory,pattern could be created automatically by computer with inputting different parameters for mathematical functions.The knitted fabric simulation is realized by M1 CAD pattern preparation system of STOLL Company.In the pattern,different color unit is replaced by obverse stitch with different color,or by obverse stitch and reverse stitch with the same color separately,after that the effects of knitted fabrics could be simulated.Designing with this method,it would not only help to acquire a great of diversity patterns,but also improve design efficiency and save cost.
基金the research board of Sharif University of Technology for the financial supportthe provision of the research facilities used in this work
文摘The non-heat-treatable AA3003-H18 plates were joined by friction stir welding（FSW） to achieve a proper joint by optimizing the welding parameters.For this purpose,the effects of heat input on microstructure and mechanical properties of the welded samples were investigated by changing the ratios of rotational speed（800-1200 r/min） to travel speed（40-100 mm/min）（w/v）.It was revealed that the grain growth rate was strongly increased with the increase of the heat input by rotational speed at constant travel speed,while the grain growth rate was slightly increased with the increase of the heat input by travel speed at constant rotational speed.Subsequently,hardness reduction was observed in the stir zone at higher rotational speed compared with that at lower one.An interesting observation was that various welding parameters do not have noticeable effect on the tensile strength of the FSW joints.Also,it has been observed that the fracture location of tensile test specimens was placed in the heat-affected zone（HAZ）on the advancing side at lower travel speed,while at higher travel speed,it was placed at the HAZ/thermomechanical affected zone（TMAZ） interface on the retreating side.
基金supported by a grant from Research year of Inje University in 2008(0001200811700)
文摘This work proposes a map-based control method to improve a vehicle's lateral stability, and the performance of the proposed method is compared with that of the conventional model-referenced control method. Model-referenced control uses the sliding mode method to determine the compensated yaw moment; in contrast, the proposed map-based control uses the compensated yaw moment map acquired by vehicle stability analysis. The vehicle stability region is calculated by a topological method based on the trajectory reversal method. A 2-DOF vehicle model and Pacejka's tire model are used to evaluate the proposed map-based control method. The properties of model-referenced control and map-based control are compared under various road conditions and driving inputs. Model-referenced control uses a control input to satisfy the linear reference model, and it generates unnecessary tire lateral forces that may lead to worse performance than an uncontrolled vehicle with step steering input on a road with a low friction coefficient. However, map-based control determines a compensated yaw moment to maintain the vehicle within the stability region,so the typical responses of vehicle enable to converge rapidly. The simulation results with sine and step steering show that map-based control provides better the tracking responsibility and control performance than model-referenced control.
文摘Based on the Involvement Load Hypothesis, the present study investigated the differential effects of three post-listening output tasks(gap-filling, translation, and sentence-making) on immediate acquisition and retention of such vocabulary dimensions as productive knowledge of orthography,receptive recall of meaning and form, and productive knowledge of grammatical functions. Ninety second-year English majors were divided into three groups to finish listening plus one of the postlistening tasks. The results showed that the post-listening output tasks had positive effects on immediate acquisition of productive vocabulary knowledge, partially in agreement with the Involvement Load Hypothesis. However, the effects on vocabulary knowledge retention were found to be largely inconsistent with the Involvement Load Hypothesis. The finding thus challenges this hypothesis in that involvement load is not the only determining factor and suggests that the theoretical construct of involvement load should be constructed with more caution.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10775104 and 10305009
文摘We propose a monomer adsorption model, in which only the monomers are allowed to diffuse and adsorb onto other clusters. By means of the generalized rate equation we investigate the kinetic behavior of the system with a special rate kernel. For the system without monomer input, the concentration aj（t） of the Aj clusters （j 〉 1） asymptotically retains a nonzero quantity, while for the system with monomer input, it decays with time and vanishes finally. We also investigate the kinetics of an interesting model with fixed-rate monomer adsorption. For the ease without monomer source, the evolution of the system will halt at a finite time; while the system evolves infinitely in time in the case with monomer source. Finally, we also suggest a connection between the fixed-rate monomer adsorption systems and growing networks.
文摘This study was performed to compare storm surges/tide simulated by the regional and coastal storm surges/tide forecast system （RTSM （regional tide/storm surges model）, CTSM （coastal tide/storm surges model）） using two different inputs from weather models （RDAPS （Regional Data Assimilation and Prediction System） and KWRF （Korea Weather and Research Forecasting）） during two typhoons that occurred between 2007 and 2008. Both the RDAPS and KWRF are the operational weather forecasting system in KMA （Korea Meteorological Administration）. The horizontal resolutions of RDAPS and KWRF are 30 and 10 km, respectively. The storm surges/tide was hind casted using sea wind and pressure fields of two Typhoons which was approaching Korean Peninsula. The CTSM using input from KWRF simulate very well the storm surges/tide pattern in the complex coastal areas. The result showed that the storm surges by the coastal storm surges/tide model with high resolution input was in well agreement with the observed sea level occurred by high tide and storm surges in the coastal areas.
