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
Some dynamical properties were discussed for additive cellular automata(CA)over finite abelian groups.These properties include surjection,ergodicity,sensitivity to initial conditions and positive expansivity.Some nece...Some dynamical properties were discussed for additive cellular automata(CA)over finite abelian groups.These properties include surjection,ergodicity,sensitivity to initial conditions and positive expansivity.Some necessary and sufficient conditions of determining ergodicity and sensitivity of the above additive CA were presented,respectively.A necessary condition for the positive expansivity of the above additive CA was given.The positive expansivity was proved to be preserved under the shift mappings for the general CA.The discussion was mainly based on the structure theorem of the finite abelian groups and the matrix associated with the global rule of the additive CA over the finite abelian p-groups.展开更多
We study the space of positively expansive differentiable maps of a compact connected C ∞ Riemannian manifold without boundary. It is proved that （i） the C1-interior of the set of positively expansive differentiabl...We study the space of positively expansive differentiable maps of a compact connected C ∞ Riemannian manifold without boundary. It is proved that （i） the C1-interior of the set of positively expansive differentiable maps coincides with the set of expanding maps, and （ii） Cl-generically, a differentiable map is positively expansive if and only if it is expanding.展开更多
We prove that the existence of positively expansive measures for continuous maps on compact metric spaces implies the existence of e 〉 0 and a sequence of （m, e）-separated sets whose cardinalities go to infinite as...We prove that the existence of positively expansive measures for continuous maps on compact metric spaces implies the existence of e 〉 0 and a sequence of （m, e）-separated sets whose cardinalities go to infinite as m →∞. We then prove that maps exhibiting such a constant e and the positively expansive maps share some properties.展开更多
Over the past decades,two dimensional(2D)-structured materials have attracted considerable interest due to not only their intrinsic aesthetic appeal but also their intriguing physical properties.Herein,a 2D bilayer si...Over the past decades,two dimensional(2D)-structured materials have attracted considerable interest due to not only their intrinsic aesthetic appeal but also their intriguing physical properties.Herein,a 2D bilayer silver squarate was synthesized,which showed combined colossal positive thermal expansion(PTE)along the packing direction and negative thermal expansion(NTE)within the layer.The combined analyses of high resolution synchrotron X-ray powder diffraction,atomic pair distribution function(PDF)and Raman spectra shed light on the anomalous thermal expansion behaviors being closely related to the interlayer argentophilicity and thermal flipping of the ligand.Furthermore,this compound exhibited an intrinsic moderate proton conductivity(1.2×10^(-4) S cm^(-1) at 80℃ under 98% RH).We believe that this work can not only deepen our understanding of the thermal expansion properties of 2D materials but also provide guidance for the design and synthesis of novel functional materials.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National Natural Science Foundation of China(No.11671258)。
文摘Some dynamical properties were discussed for additive cellular automata(CA)over finite abelian groups.These properties include surjection,ergodicity,sensitivity to initial conditions and positive expansivity.Some necessary and sufficient conditions of determining ergodicity and sensitivity of the above additive CA were presented,respectively.A necessary condition for the positive expansivity of the above additive CA was given.The positive expansivity was proved to be preserved under the shift mappings for the general CA.The discussion was mainly based on the structure theorem of the finite abelian groups and the matrix associated with the global rule of the additive CA over the finite abelian p-groups.
基金Supported by JSPD Gtant-in-Aid for Scientific Research (C)(Grant No.19540209)
文摘We study the space of positively expansive differentiable maps of a compact connected C ∞ Riemannian manifold without boundary. It is proved that （i） the C1-interior of the set of positively expansive differentiable maps coincides with the set of expanding maps, and （ii） Cl-generically, a differentiable map is positively expansive if and only if it is expanding.
基金Supported by CNPq,FAPERJ and PRONEX/DS from Brazil
文摘We prove that the existence of positively expansive measures for continuous maps on compact metric spaces implies the existence of e 〉 0 and a sequence of （m, e）-separated sets whose cardinalities go to infinite as m →∞. We then prove that maps exhibiting such a constant e and the positively expansive maps share some properties.
基金supported by the National Natural Science Foundation of China(Grant No.22005340 and 21875285)the Fundamental Research Funds for the Central Universities(20CX06047A)+1 种基金the Taishan Scholar Foundation(ts201511019)the Development Projects of Shandong Province(Grant 2019JZZY010331).
文摘Over the past decades,two dimensional(2D)-structured materials have attracted considerable interest due to not only their intrinsic aesthetic appeal but also their intriguing physical properties.Herein,a 2D bilayer silver squarate was synthesized,which showed combined colossal positive thermal expansion(PTE)along the packing direction and negative thermal expansion(NTE)within the layer.The combined analyses of high resolution synchrotron X-ray powder diffraction,atomic pair distribution function(PDF)and Raman spectra shed light on the anomalous thermal expansion behaviors being closely related to the interlayer argentophilicity and thermal flipping of the ligand.Furthermore,this compound exhibited an intrinsic moderate proton conductivity(1.2×10^(-4) S cm^(-1) at 80℃ under 98% RH).We believe that this work can not only deepen our understanding of the thermal expansion properties of 2D materials but also provide guidance for the design and synthesis of novel functional materials.
