The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from struc...The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from structural degradation during the long-term cycling process,leading to capacity fading.In this study,a Co-doped dMO composite with reduced graphene oxide(GC-dMO)is developed using a simple cost-effective hydrothermal method.The degree of disorderness increases owing to the hetero-atom doping and graphene oxide composites.It is demonstrated that layered dMO and GC-dMO undergo a structural transition from K-birnessite to the Zn-buserite phase upon the first discharge,which enhances the intercalation of Zn^(2+)ions,H_(2)O molecules in the layered structure.The GC-dMO cathode exhibits an excellent capacity of 302 mAh g^(-1)at a current density of 100 mAg^(-1)after 100 cycles as compared with the dMO cathode(159 mAhg^(-1)).The excellent electrochemical performance of the GC-dMO cathode owing to Co-doping and graphene oxide sheets enhances the interlayer gap and disorderness,and maintains structural stability,which facilitates the easy reverse intercalation and de-intercalation of Zn^(2+)ions and H_(2)O molecules.Therefore,GC-dMO is a promising cathode material for large-scale aqueous ZIBs.展开更多
The saddle point equation of Ginzburg-Landau Hamiltonian for the diluted Ising model is developed. The ground state is solved numerically in two dimensions. The result is partly explained by the coarse-grained approxi...The saddle point equation of Ginzburg-Landau Hamiltonian for the diluted Ising model is developed. The ground state is solved numerically in two dimensions. The result is partly explained by the coarse-grained approximation.展开更多
Many membraneless organelles,or biological condensates,form through phase separation,and play key roles in signal sensing and transcriptional regulation.While the functional importance of these condensates has inspire...Many membraneless organelles,or biological condensates,form through phase separation,and play key roles in signal sensing and transcriptional regulation.While the functional importance of these condensates has inspired many studies to characterize their stability and spatial organization,the underlying principles that dictate these emergent properties are still being uncovered.In this review,we examine recent work on biological condensates,especially multicomponent systems.We focus on connecting molecular factors such as binding energy,valency,and stoichiometry with the interfacial tension,explaining the nontrivial interior organization in many condensates.We further discuss mechanisms that arrest condensate coalescence by lowering the surface tension or introducing kinetic barriers to stabilize the multidroplet state.展开更多
A drawn high density polyethylene（HDPE）has been measured by Raman spectroscopy and differential scanning calorimetry （DSC）. The crystalline structure of drawn HDPE is analysed by the Raman internal modes in terms ...A drawn high density polyethylene（HDPE）has been measured by Raman spectroscopy and differential scanning calorimetry （DSC）. The crystalline structure of drawn HDPE is analysed by the Raman internal modes in terms of mass fractions of the crystalline orthorhombic phase, the liquid- like amorphous phase and the disordered anisotropic phase. The mass fractions depend on draw temperature T;and draw ratio R;. The fraction of disordered anisotropic amorphous phase changes very little with, the T;and increases with increasing R;. Sum of the mass fractions of crystalline orthorhombic phase and the disordered anisotropic phase increases linearly as the same slope as the crystallinity W;determined from DSC measurements with increasing T;or R;and it is higher than the W;for all the samples. The results show that the mass fraction of disordered anisotropic phase is partially devoted by the taut tie molecules （TTM s） in the amorphous state. The dependence of the disordered anisotropic phase on T;and R;supports the mechanism of plastic deformation of fibre structure.展开更多
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korean Government(NRF-2021R1A4A1030318,NRF-2022R1C1C1011386,NRF-2020M3H4A1A03084258)supported by the"Regional Innovation Strategy(RIS)"through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(2021RIS-003)
文摘The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from structural degradation during the long-term cycling process,leading to capacity fading.In this study,a Co-doped dMO composite with reduced graphene oxide(GC-dMO)is developed using a simple cost-effective hydrothermal method.The degree of disorderness increases owing to the hetero-atom doping and graphene oxide composites.It is demonstrated that layered dMO and GC-dMO undergo a structural transition from K-birnessite to the Zn-buserite phase upon the first discharge,which enhances the intercalation of Zn^(2+)ions,H_(2)O molecules in the layered structure.The GC-dMO cathode exhibits an excellent capacity of 302 mAh g^(-1)at a current density of 100 mAg^(-1)after 100 cycles as compared with the dMO cathode(159 mAhg^(-1)).The excellent electrochemical performance of the GC-dMO cathode owing to Co-doping and graphene oxide sheets enhances the interlayer gap and disorderness,and maintains structural stability,which facilitates the easy reverse intercalation and de-intercalation of Zn^(2+)ions and H_(2)O molecules.Therefore,GC-dMO is a promising cathode material for large-scale aqueous ZIBs.
基金financially supported by the U. S. national science foundation (NSF) with Grant Nos. DMR-1006557,CHE-1230929,DMR-1310289,and CMMI1333999supported by the Office of Science of the U. S. Department of Energy under contract No. DE-AC02-05CH11231partially on the resources of XSEDE supported by NSF with Grant No. ACI-1053575
文摘第一原理计算一个悬而未决的难题是预测无序相在有限温度下的热力学性能。作者团队指出该难题的最新解决思路是采用可以处理微观组态的配分函数方法,该方法已成为处理只有一种主要微观组态构成的有序相以及有多种明显的微观组态构成的无序相的关键。结合第一原理声子计算和准简谐近似可以有效地预测任意一个给定微观组态的热力学性质。总结了作者团队在第一原理热力学方面的最新研究进展并具体给出了有序相方面的例子:Li2S,hcp Mg和fcc Ni,以及无序相方面的例子:Cu2Zn Sn S4(CZTS)和fcc Ce。同时指出:1从常用的"相"扩展到"微观组态"开辟了一条定量研究材料相变、热膨胀等异常性能的新途径,而这些异常性能的起源可以追溯到"微观组态构型熵";2这些微观组态也可以认为是材料基因组的基本组成模块。
文摘The saddle point equation of Ginzburg-Landau Hamiltonian for the diluted Ising model is developed. The ground state is solved numerically in two dimensions. The result is partly explained by the coarse-grained approximation.
基金National Science Foundation,Grant/Award Number:MCB-2042362National Institute of General Medical Sciences,Grant/Award Number:R35GM133580。
文摘Many membraneless organelles,or biological condensates,form through phase separation,and play key roles in signal sensing and transcriptional regulation.While the functional importance of these condensates has inspired many studies to characterize their stability and spatial organization,the underlying principles that dictate these emergent properties are still being uncovered.In this review,we examine recent work on biological condensates,especially multicomponent systems.We focus on connecting molecular factors such as binding energy,valency,and stoichiometry with the interfacial tension,explaining the nontrivial interior organization in many condensates.We further discuss mechanisms that arrest condensate coalescence by lowering the surface tension or introducing kinetic barriers to stabilize the multidroplet state.
文摘A drawn high density polyethylene（HDPE）has been measured by Raman spectroscopy and differential scanning calorimetry （DSC）. The crystalline structure of drawn HDPE is analysed by the Raman internal modes in terms of mass fractions of the crystalline orthorhombic phase, the liquid- like amorphous phase and the disordered anisotropic phase. The mass fractions depend on draw temperature T;and draw ratio R;. The fraction of disordered anisotropic amorphous phase changes very little with, the T;and increases with increasing R;. Sum of the mass fractions of crystalline orthorhombic phase and the disordered anisotropic phase increases linearly as the same slope as the crystallinity W;determined from DSC measurements with increasing T;or R;and it is higher than the W;for all the samples. The results show that the mass fraction of disordered anisotropic phase is partially devoted by the taut tie molecules （TTM s） in the amorphous state. The dependence of the disordered anisotropic phase on T;and R;supports the mechanism of plastic deformation of fibre structure.
