Transducing thermal energy into mechanical movements via molecular reconfigurations offers a cutting-edge approach to thermal actuating materials,which could be applied to sensors,energy harvesting and storage devices...Transducing thermal energy into mechanical movements via molecular reconfigurations offers a cutting-edge approach to thermal actuating materials,which could be applied to sensors,energy harvesting and storage devices[1].Thermal expansion is a pivotal aspect in solid state chemistry,intricately intertwined with various factors such as crystal structure,chemical composition,electronic configuration,microstructure,and defects.Most materials undergo isotropic and positive thermal expansion(PTE)because of the disharmonic vibrational amplitudes of their chemical bonds.Moreover,anisotropic thermal expansion(ATE)and negative thermal expansion(NTE)are fascinating physical attributes of solids,which can originate from electronic or magnetic mechanisms,as well as through a transverse phonon mechanism in insulating lattice solids.展开更多
We give a survey on 4-dimensional manifolds with positive isotropic curvature. We will introduce the work of B. L. Chen, S. H. Tang and X. P. Zhu on a complete classification theorem on compact four-manifolds with pos...We give a survey on 4-dimensional manifolds with positive isotropic curvature. We will introduce the work of B. L. Chen, S. H. Tang and X. P. Zhu on a complete classification theorem on compact four-manifolds with positive isotropic curvature （PIC）. Then we review an application of the classification theorem, which is from Chen and Zhu＇s work. Finally, we discuss our recent result on the path-connectedness of the moduli spaces of Riemannian metrics with positive isotropic curvature.展开更多
基金supported by the National Natural Science Foundation of China(22171155)Natural Science Foundation of Shandong Province(ZR2022YQ07)Taishan Scholar Program(tsqn202306166).
文摘Transducing thermal energy into mechanical movements via molecular reconfigurations offers a cutting-edge approach to thermal actuating materials,which could be applied to sensors,energy harvesting and storage devices[1].Thermal expansion is a pivotal aspect in solid state chemistry,intricately intertwined with various factors such as crystal structure,chemical composition,electronic configuration,microstructure,and defects.Most materials undergo isotropic and positive thermal expansion(PTE)because of the disharmonic vibrational amplitudes of their chemical bonds.Moreover,anisotropic thermal expansion(ATE)and negative thermal expansion(NTE)are fascinating physical attributes of solids,which can originate from electronic or magnetic mechanisms,as well as through a transverse phonon mechanism in insulating lattice solids.
基金Acknowledgements The first author was partially supported by the National Natural Science Foundation of China （Grant Nos. 11025107, 11521101） and a grant （No. 141gzd02） from Sun Yat-sen University.
文摘We give a survey on 4-dimensional manifolds with positive isotropic curvature. We will introduce the work of B. L. Chen, S. H. Tang and X. P. Zhu on a complete classification theorem on compact four-manifolds with positive isotropic curvature （PIC）. Then we review an application of the classification theorem, which is from Chen and Zhu＇s work. Finally, we discuss our recent result on the path-connectedness of the moduli spaces of Riemannian metrics with positive isotropic curvature.
