More focuses of foreign language teaching theory and practice are on the study of first language and second language acquisition. The article deals with the concept of first and second language acquisition, the relati...More focuses of foreign language teaching theory and practice are on the study of first language and second language acquisition. The article deals with the concept of first and second language acquisition, the relationship between them and the factors influencing on them. The characteristics of the children acquisition and adult acquisition are also studied.展开更多
A comparison study is performed to contrast the improvements in the tropical Pacific oceanic state of a low-resolution model respectively via data assimilation and by an increase in horizontal resolution. A low resolu...A comparison study is performed to contrast the improvements in the tropical Pacific oceanic state of a low-resolution model respectively via data assimilation and by an increase in horizontal resolution. A low resolution model (LR) (1°lat by 2°lon) and a high-resolution model (HR) (0.5°lat by 0.5°lon) are employed for the comparison. The authors perform 20-yr numerical experiments and analyze the annual mean fields of temperature and salinity. The results indicate that the low-resolution model with data assimilation behaves better than the high-resolution model in the estimation of ocean large-scale features. From 1990 to 2000, the average of HR's RMSE (root-mean-square error) relative to independent Tropical Atmosphere Ocean project (TAO) mooring data at randomly selected points is 0.97℃ compared to a RMSE of 0.56℃ for LR with temperature assimilation. Moreover, the LR with data assimilation is more frugal in computation. Although there is room to improve the high-resolution model, the low-resolution model with data assimilation may be an advisable choice in achieving a more realistic large-scale state of the ocean at the limited level of information provided by the current observational system.展开更多
The cross sections of fragments produced in the 140 A MeV58,64Ni＋9 Be projectile fragmentation reactions are calculated by using the antisymmetrized molecular dynamics （AMD） model, the modified statistical abrasion...The cross sections of fragments produced in the 140 A MeV58,64Ni＋9 Be projectile fragmentation reactions are calculated by using the antisymmetrized molecular dynamics （AMD） model, the modified statistical abrasion- ablation （SAA） model, and the empirical EPAX2/EPAX3 formulae. The Gogny-gO interaction is taken as the effective nucleon-nucleon interaction in the AMD calculation, and the decays of fragments obtained from the AMD results are calculated by using the GEMINI code. The calculated cross sections of fragments are compared.展开更多
To investigate hedging effectiveness of multinational companies in respect of using currency derivatives,the author adapts an innovative and multi layers GJR-GARCH-based model.This model broke down the currency risk f...To investigate hedging effectiveness of multinational companies in respect of using currency derivatives,the author adapts an innovative and multi layers GJR-GARCH-based model.This model broke down the currency risk faced by MNCs in each business area and added six control variables other than foreign sales ratio,all these variables have been proved to be related to MNCs'currency risk exposure but was not included into previous models.Moreover,this model absorbs advantages of several models built in previous studies and combines them into a whole,intact model.This paper also employed a wide research scope,using a sample of 48 non-financial and 28 financial firms headquartered in USA.Also,comparison between financial and non-financial firms is an innovation of our research.According to the result,hedging of non-financial companies in respect of currency risk is ineffective,and financial companies are more likely using currency derivatives to speculate.展开更多
Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. T...Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. The viscosity-composition plots were represented by sub-cluster equation, the various differences between two systems are interpreted with the equation parameters展开更多
The Story of an Hour was published in 1894 and it is the best one in Chopin's short stories.Translation versions of The Story of an Hour by Shen Dan,Jin Li and Zhang Qiang are analysed and compared in this paper i...The Story of an Hour was published in 1894 and it is the best one in Chopin's short stories.Translation versions of The Story of an Hour by Shen Dan,Jin Li and Zhang Qiang are analysed and compared in this paper in order to show that the subjectivity of the translators is very important and has great influence on the translation version.展开更多
A novel symmetrical 3-degree-of-freedom(DOF) parallel kinematic manipulator(PKM) is firstly presented,which is named 3-P(Qu) RU.According to the structure feature,a double closed loop vector method is proposed to inve...A novel symmetrical 3-degree-of-freedom(DOF) parallel kinematic manipulator(PKM) is firstly presented,which is named 3-P(Qu) RU.According to the structure feature,a double closed loop vector method is proposed to investigate this PKM.Based on this method,kinematic,velocity and error models of this manipulator are established respectively.Since3-PRS PKM has been applied successfully in practice and its structure is similar to the 3-P(Qu) RU PKM,corresponding models of a 3-PRS PKM are given and a performance comparison study between them is investigated on workspace,manipulator dexterity,position error and error sensitivity.The comparison results reveal that the 3-P(Qu) RU PKM has the advantage on velocity performance and the disadvantage on accuracy performance.This novel 3-P(Qu) RU PKM is an available selection for a tool head of a hybrid machine tool and the analysis is greatly helpful for the further applications of this manipulator.展开更多
SalinityGradient Solar Ponds(SGSPs)offer the potential to capture and store solar energy for use in a range of domestic and industrial activities in regions with high solar insolation.However,the evaporation of water ...SalinityGradient Solar Ponds(SGSPs)offer the potential to capture and store solar energy for use in a range of domestic and industrial activities in regions with high solar insolation.However,the evaporation of water from these ponds is a significant problem that must be overcome for them to be deployed successfully.Thus,two ponds were constructed in the city of Nasiriya,Iraq.The two ponds were cylindrical with a diameter of 1.4 m and a total depth of 1.4 m.The water body in the two ponds was constructed with layer depths of 0.5,0.75 and 0.1 m for the lower convective zone(LCZ),non-convective zone(NCZ)and the upper convective zone(UCZ)respectively.One of the two ponds was covered with a thin liquid paraffin layer(0.5 cm)to eliminate evaporation from the surface of the UCZ.The behavior of the standard SGSP and that of the covered pond with evaporation suppressed can be straightforwardly compared.The experimental units were run for six months from 1st of February to 31st of July 2019.It was shown in the first instance that by covering the pond with a thin layer of paraffin,that evaporation could be suppressed.The results showed that for the conventional SGSP,the temperature of the LCZ reached a maximum of ca.76℃ while in the covered pond the temperature of the LCZ was consistently lower than that in the uncovered pond by approximately 5-6℃.The results also indicated that the temperature of the UCZ in the covered pond was higher than that in the uncovered pond by about 10℃ in the second half of the study period.However,it was noted that on rainy days the paraffin layer was swept away from the surface;and this could hinder the implementation of thin liquid cover in the large SGSP.展开更多
Based on the Reddy's theory of plates with the effect of higher-order shear deformations, the governing equations for bending of orthotropic plates with finite deformations were established. The differential quadr...Based on the Reddy's theory of plates with the effect of higher-order shear deformations, the governing equations for bending of orthotropic plates with finite deformations were established. The differential quadrature (DQ) method of nonlinear analysis to the problem was presented. New DQ approach, presented by Wang and Bert (DQWB), is extended to handle the multiple boundary conditions of plates. The techniques were also further extended to simplify nonlinear computations. The numerical convergence and comparison of solutions were studied. The results show that the DQ method presented is very reliable and valid. Moreover, the influences of geometric and material parameters as well as the transverse shear deformations on nonlinear bending were investigated. Numerical results show the influence of the shear deformation on the static bending of orthotropic moderately thick plate is significant.展开更多
Objective To investigate the relationship between baseline serum uric acid and the severity of coronary artery disease(CAD)in the first-degree relatives or nonfirst-degree relatives of men with type 2 diabetes.Methods...Objective To investigate the relationship between baseline serum uric acid and the severity of coronary artery disease(CAD)in the first-degree relatives or nonfirst-degree relatives of men with type 2 diabetes.Methods Three hundred and eighty-one men with negative coronary angiography for the first time were divided into diabetes and non-diabetes groups and followed-up for展开更多
Bionic jumping robot can cross the obstacles by jumping, and it has a good application prospect in the unstructured com- plex environment. The less Degree of Freedom （DOF） jumping leg, which has the characteristics ...Bionic jumping robot can cross the obstacles by jumping, and it has a good application prospect in the unstructured com- plex environment. The less Degree of Freedom （DOF） jumping leg, which has the characteristics of simple control and high rigidity, and is very important in research. Based on the experimental observation of leg physiological structure and take-off process of locust, two 1 DOF jumping leg models, which includes four-bar jumping leg model and slider-crank jumping leg model, are established, and multi objective optimization is conducted to deduce the motion law of two 1 DOF jumping leg models and jumping leg of locust is closer. Then the jumping performance evaluation indices are proposed, which include the mechanical property, body attitude, jumping distance and jumping performances of the two jumping leg models environmental effect. According to these evaluation indices, the are analyzed and compared, and the simulation is conducted for further explanations. The analysis results show that the four-bar jumping leg has smaller structural size and its motion law is closer to the hindleg of locust. The slider-crank jumping leg has better mechanical property, stronger energy storage capacity and the rough ground has less effect on it. This study offers a quantitative analysis and comparison for different jumping leg models of bionic locust jumping robot. Furthermore, a theoretical basis for future research and engineering application is established.展开更多
文摘More focuses of foreign language teaching theory and practice are on the study of first language and second language acquisition. The article deals with the concept of first and second language acquisition, the relationship between them and the factors influencing on them. The characteristics of the children acquisition and adult acquisition are also studied.
基金This study is supported by the Key Program of Chinese Academy of Sciences KZCX3 SW-221the National Natural Science Foundation of China(Grant No.40233033 and 40221503).
文摘A comparison study is performed to contrast the improvements in the tropical Pacific oceanic state of a low-resolution model respectively via data assimilation and by an increase in horizontal resolution. A low resolution model (LR) (1°lat by 2°lon) and a high-resolution model (HR) (0.5°lat by 0.5°lon) are employed for the comparison. The authors perform 20-yr numerical experiments and analyze the annual mean fields of temperature and salinity. The results indicate that the low-resolution model with data assimilation behaves better than the high-resolution model in the estimation of ocean large-scale features. From 1990 to 2000, the average of HR's RMSE (root-mean-square error) relative to independent Tropical Atmosphere Ocean project (TAO) mooring data at randomly selected points is 0.97℃ compared to a RMSE of 0.56℃ for LR with temperature assimilation. Moreover, the LR with data assimilation is more frugal in computation. Although there is room to improve the high-resolution model, the low-resolution model with data assimilation may be an advisable choice in achieving a more realistic large-scale state of the ocean at the limited level of information provided by the current observational system.
基金Supported by the Program for Science and Technology Innovation Talents in Universities of Henan Province under Grant No13HASTIT046
文摘The cross sections of fragments produced in the 140 A MeV58,64Ni＋9 Be projectile fragmentation reactions are calculated by using the antisymmetrized molecular dynamics （AMD） model, the modified statistical abrasion- ablation （SAA） model, and the empirical EPAX2/EPAX3 formulae. The Gogny-gO interaction is taken as the effective nucleon-nucleon interaction in the AMD calculation, and the decays of fragments obtained from the AMD results are calculated by using the GEMINI code. The calculated cross sections of fragments are compared.
文摘To investigate hedging effectiveness of multinational companies in respect of using currency derivatives,the author adapts an innovative and multi layers GJR-GARCH-based model.This model broke down the currency risk faced by MNCs in each business area and added six control variables other than foreign sales ratio,all these variables have been proved to be related to MNCs'currency risk exposure but was not included into previous models.Moreover,this model absorbs advantages of several models built in previous studies and combines them into a whole,intact model.This paper also employed a wide research scope,using a sample of 48 non-financial and 28 financial firms headquartered in USA.Also,comparison between financial and non-financial firms is an innovation of our research.According to the result,hedging of non-financial companies in respect of currency risk is ineffective,and financial companies are more likely using currency derivatives to speculate.
文摘Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. The viscosity-composition plots were represented by sub-cluster equation, the various differences between two systems are interpreted with the equation parameters
文摘The Story of an Hour was published in 1894 and it is the best one in Chopin's short stories.Translation versions of The Story of an Hour by Shen Dan,Jin Li and Zhang Qiang are analysed and compared in this paper in order to show that the subjectivity of the translators is very important and has great influence on the translation version.
基金Supported by the National Natural Science Foundation of China(No.51575307,51225503)the Science and Technology Major Project-Advanced NC Machine Tools & Basic Manufacturing Equipments(No.2013ZX04004021,2014ZX04002051)Top-Notch Young Talents Program of China
文摘A novel symmetrical 3-degree-of-freedom(DOF) parallel kinematic manipulator(PKM) is firstly presented,which is named 3-P(Qu) RU.According to the structure feature,a double closed loop vector method is proposed to investigate this PKM.Based on this method,kinematic,velocity and error models of this manipulator are established respectively.Since3-PRS PKM has been applied successfully in practice and its structure is similar to the 3-P(Qu) RU PKM,corresponding models of a 3-PRS PKM are given and a performance comparison study between them is investigated on workspace,manipulator dexterity,position error and error sensitivity.The comparison results reveal that the 3-P(Qu) RU PKM has the advantage on velocity performance and the disadvantage on accuracy performance.This novel 3-P(Qu) RU PKM is an available selection for a tool head of a hybrid machine tool and the analysis is greatly helpful for the further applications of this manipulator.
文摘SalinityGradient Solar Ponds(SGSPs)offer the potential to capture and store solar energy for use in a range of domestic and industrial activities in regions with high solar insolation.However,the evaporation of water from these ponds is a significant problem that must be overcome for them to be deployed successfully.Thus,two ponds were constructed in the city of Nasiriya,Iraq.The two ponds were cylindrical with a diameter of 1.4 m and a total depth of 1.4 m.The water body in the two ponds was constructed with layer depths of 0.5,0.75 and 0.1 m for the lower convective zone(LCZ),non-convective zone(NCZ)and the upper convective zone(UCZ)respectively.One of the two ponds was covered with a thin liquid paraffin layer(0.5 cm)to eliminate evaporation from the surface of the UCZ.The behavior of the standard SGSP and that of the covered pond with evaporation suppressed can be straightforwardly compared.The experimental units were run for six months from 1st of February to 31st of July 2019.It was shown in the first instance that by covering the pond with a thin layer of paraffin,that evaporation could be suppressed.The results showed that for the conventional SGSP,the temperature of the LCZ reached a maximum of ca.76℃ while in the covered pond the temperature of the LCZ was consistently lower than that in the uncovered pond by approximately 5-6℃.The results also indicated that the temperature of the UCZ in the covered pond was higher than that in the uncovered pond by about 10℃ in the second half of the study period.However,it was noted that on rainy days the paraffin layer was swept away from the surface;and this could hinder the implementation of thin liquid cover in the large SGSP.
文摘Based on the Reddy's theory of plates with the effect of higher-order shear deformations, the governing equations for bending of orthotropic plates with finite deformations were established. The differential quadrature (DQ) method of nonlinear analysis to the problem was presented. New DQ approach, presented by Wang and Bert (DQWB), is extended to handle the multiple boundary conditions of plates. The techniques were also further extended to simplify nonlinear computations. The numerical convergence and comparison of solutions were studied. The results show that the DQ method presented is very reliable and valid. Moreover, the influences of geometric and material parameters as well as the transverse shear deformations on nonlinear bending were investigated. Numerical results show the influence of the shear deformation on the static bending of orthotropic moderately thick plate is significant.
文摘Objective To investigate the relationship between baseline serum uric acid and the severity of coronary artery disease(CAD)in the first-degree relatives or nonfirst-degree relatives of men with type 2 diabetes.Methods Three hundred and eighty-one men with negative coronary angiography for the first time were divided into diabetes and non-diabetes groups and followed-up for
基金the National Natural Science Foundation of China （Grant No. 51375035）, and the Specialized Research Fund for the Doctoral Program of Higher Education of China （Grant No. 20121102110021）.
文摘Bionic jumping robot can cross the obstacles by jumping, and it has a good application prospect in the unstructured com- plex environment. The less Degree of Freedom （DOF） jumping leg, which has the characteristics of simple control and high rigidity, and is very important in research. Based on the experimental observation of leg physiological structure and take-off process of locust, two 1 DOF jumping leg models, which includes four-bar jumping leg model and slider-crank jumping leg model, are established, and multi objective optimization is conducted to deduce the motion law of two 1 DOF jumping leg models and jumping leg of locust is closer. Then the jumping performance evaluation indices are proposed, which include the mechanical property, body attitude, jumping distance and jumping performances of the two jumping leg models environmental effect. According to these evaluation indices, the are analyzed and compared, and the simulation is conducted for further explanations. The analysis results show that the four-bar jumping leg has smaller structural size and its motion law is closer to the hindleg of locust. The slider-crank jumping leg has better mechanical property, stronger energy storage capacity and the rough ground has less effect on it. This study offers a quantitative analysis and comparison for different jumping leg models of bionic locust jumping robot. Furthermore, a theoretical basis for future research and engineering application is established.
