In response to the spread of COVID-19 in Quanzhou on 13th March,2022,a number of schools,including kindergartens,primary schools,junior/senior high schools,and universities,implemented online teaching.In this context,...In response to the spread of COVID-19 in Quanzhou on 13th March,2022,a number of schools,including kindergartens,primary schools,junior/senior high schools,and universities,implemented online teaching.In this context,this study explores the impact of online education on students and their parents in Secondary School S in Quanzhou,Fujian Province,China.Some studies found that online education broke the traditional control model of offline classroom teaching,and that both teachers and students had more autonomy.However,this study shows that online teaching only gives students more autonomy in learning space,but puts more pressure on their long learning time and online tasks submission.The study highlights the impact of online education on students’performance and mental health,as well as the impact on parents.展开更多
We deal with the problem of entire functions sharing one value weakly. Moreover, we improve and generalize some former results obtained by J.-F.Chen, et al. [6], Y.Xu and H.L.Qiu [4], M.L. Fang [5], C.C. Yang, and X.H...We deal with the problem of entire functions sharing one value weakly. Moreover, we improve and generalize some former results obtained by J.-F.Chen, et al. [6], Y.Xu and H.L.Qiu [4], M.L. Fang [5], C.C. Yang, and X.H. Hua [3].展开更多
In this work the thermal transport properties of graphene nanoribbons with randomly distributed vacancy defects are investigated by the reverse non-equilibrium molecular dynamics method. We find that the thermal condu...In this work the thermal transport properties of graphene nanoribbons with randomly distributed vacancy defects are investigated by the reverse non-equilibrium molecular dynamics method. We find that the thermal conductivity of the graphene nanoribbons decreases as the defect coverage increases and is saturated in a high defect ratio range. Further analysis reveals a strong mismatch in the phonon spectrum between the unsaturated carbon atoms in 2-fold coordination around the defects and the saturated carbon atoms in 3-fold coordination, which induces high interfacial thermal resistance in defective graphene and suppresses the thermal conductivity. The defects induce a complicated bonding transform from sp2 to hybrid sp--sp2 network and trigger vibration mode density redistribution, by which the phonon spectrum conversion and strong phonon scattering at defect sites are explained. These results shed new light on the understanding of the thermal transport behavior of graphene-based nanomaterials with new structural configurations and pave the way for future designs of thermal management phononic devices.展开更多
Using first-principles calculations within the generalized gradient approximation (GGA) +U framework, we inves- tigate the effect of C doping on the structural and electronic properties of LiFePO4. The calculated f...Using first-principles calculations within the generalized gradient approximation (GGA) +U framework, we inves- tigate the effect of C doping on the structural and electronic properties of LiFePO4. The calculated formation energies indicate that C doped at O sites is energetically favoured, and that C dopants prefer to occupy 03 sites. The band gap of the C doped material is much narrow than that of the undoped one, indicating better electro- conductive properties. To maintain charge balance, the valence of the Fe nearest to C appears as Fe3+, and it will be helpful to the hopping of electrons.展开更多
Hedges in academic writing are drawn attention by scholars. Hedging devices enable writers to express their uncertainty con-cerning the factuality of their statements or to indicate deference to their readers. In this...Hedges in academic writing are drawn attention by scholars. Hedging devices enable writers to express their uncertainty con-cerning the factuality of their statements or to indicate deference to their readers. In this paper,ten English linguistic academic articles written by Chinese scholars were chosen for the study. Hedges were categorized to four types. The analysis showed the total number of hedges per category in all articles. The results indicated that modals/probabilities and semi-auxiliaries or epistemic verbs were preferred by Chinese linguists. It is suggested that for non-native English speakers mastery of hedging devices is requisite in their graduate programs.展开更多
文摘In response to the spread of COVID-19 in Quanzhou on 13th March,2022,a number of schools,including kindergartens,primary schools,junior/senior high schools,and universities,implemented online teaching.In this context,this study explores the impact of online education on students and their parents in Secondary School S in Quanzhou,Fujian Province,China.Some studies found that online education broke the traditional control model of offline classroom teaching,and that both teachers and students had more autonomy.However,this study shows that online teaching only gives students more autonomy in learning space,but puts more pressure on their long learning time and online tasks submission.The study highlights the impact of online education on students’performance and mental health,as well as the impact on parents.
基金supported by NSF of Fujian Province,China(S0750013),supported by NSF of Fujian Province,China(2008J0190)the Research Foundation of Ningde Normal University(2008J001)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘We deal with the problem of entire functions sharing one value weakly. Moreover, we improve and generalize some former results obtained by J.-F.Chen, et al. [6], Y.Xu and H.L.Qiu [4], M.L. Fang [5], C.C. Yang, and X.H. Hua [3].
基金Project supported by the National Natural Science Foundation of China(Grant No.51202032)the National Key Project for Basic Research of China(Grant No.2011CBA00200)+1 种基金the Natural Science Foundation of Fujian Province,China(Grant Nos.2012J01004 and 2013J01009)the Funds from the Fujian Provincial Education Bureau,China(Grant No.GA12064)
文摘In this work the thermal transport properties of graphene nanoribbons with randomly distributed vacancy defects are investigated by the reverse non-equilibrium molecular dynamics method. We find that the thermal conductivity of the graphene nanoribbons decreases as the defect coverage increases and is saturated in a high defect ratio range. Further analysis reveals a strong mismatch in the phonon spectrum between the unsaturated carbon atoms in 2-fold coordination around the defects and the saturated carbon atoms in 3-fold coordination, which induces high interfacial thermal resistance in defective graphene and suppresses the thermal conductivity. The defects induce a complicated bonding transform from sp2 to hybrid sp--sp2 network and trigger vibration mode density redistribution, by which the phonon spectrum conversion and strong phonon scattering at defect sites are explained. These results shed new light on the understanding of the thermal transport behavior of graphene-based nanomaterials with new structural configurations and pave the way for future designs of thermal management phononic devices.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11074039 and 11004032)the National Basic Research Program of China (Grant No. 2011CBA00200)
文摘Using first-principles calculations within the generalized gradient approximation (GGA) +U framework, we inves- tigate the effect of C doping on the structural and electronic properties of LiFePO4. The calculated formation energies indicate that C doped at O sites is energetically favoured, and that C dopants prefer to occupy 03 sites. The band gap of the C doped material is much narrow than that of the undoped one, indicating better electro- conductive properties. To maintain charge balance, the valence of the Fe nearest to C appears as Fe3+, and it will be helpful to the hopping of electrons.
文摘Hedges in academic writing are drawn attention by scholars. Hedging devices enable writers to express their uncertainty con-cerning the factuality of their statements or to indicate deference to their readers. In this paper,ten English linguistic academic articles written by Chinese scholars were chosen for the study. Hedges were categorized to four types. The analysis showed the total number of hedges per category in all articles. The results indicated that modals/probabilities and semi-auxiliaries or epistemic verbs were preferred by Chinese linguists. It is suggested that for non-native English speakers mastery of hedging devices is requisite in their graduate programs.