Topological insulators with localized edge or interface states have been extensively studied,particularly in phononic crystals and related fields;however,their application in seismic metamaterials remains largely unex...Topological insulators with localized edge or interface states have been extensively studied,particularly in phononic crystals and related fields;however,their application in seismic metamaterials remains largely unexplored.To address this gap,we designed a topological seismic metamaterial,where the topological interface is formed by joining the ends of two distinct one-dimensional periodic lattices.The first full-scale field experiment confirms the existence of topological interface states,which exhibit pronounced localization characteristics and induce a resonant amplification effect of 7.2 dB on the total energy of seismic surface waves.This study provides the first experimental validation for the implementation of topological principles in the design of seismic metamaterials,enabling novel approaches to high-sensitivity seismic detection and efficient energy localization for wave control.展开更多
Ultrathin two-dimensional metal-organic framework nanosheets have emerged as a promising kind of heterogeneous catalysts. Herein, we report a new kind of 2D porphyrinic metal-organic framework nanosheets of Rh2-PCN-22...Ultrathin two-dimensional metal-organic framework nanosheets have emerged as a promising kind of heterogeneous catalysts. Herein, we report a new kind of 2D porphyrinic metal-organic framework nanosheets of Rh2-PCN-222, which was prepared from the self-assembly of the metalloporphyrin ligand Rh(TCPP)(DCB)(TCPP = 5,10,15,20-tetrakis(4-methoxycarbonylphenyl)porphyrin;DCB = 3,4-dichlorobenzene) and ZrCl_(4) in the presence of two kinds of monocarboxylic acids as the modulating reagent. The thickness of Rh2-PCN-222 nanosheets was characterized by atomic force microscopy(AFM)and determined to be 5.4-9.6 nm. It was found that the axial aryl dichlorophenyl substituent, which controlled the anisotropic growth of MOFs, was essential for the formation of nanosheets. Catalytic results showed that Rh2-PCN-222 nanosheets were efficient for CO_(2) transformation.展开更多
The intimate host-anion interactions will regulate thermodynamics and kinetics in the self-assembly of cationic cages mimicking biological counterparts.Herein,we report construction and transformation of three Pd(Ⅱ)-...The intimate host-anion interactions will regulate thermodynamics and kinetics in the self-assembly of cationic cages mimicking biological counterparts.Herein,we report construction and transformation of three Pd(Ⅱ)-based metal-organic cages(MOCs)depending on different anions.Stoichiometric conversions of the lantern-shaped MOC-34 into either octahedral MOC-35 or tricapped trigonal prism MOC-36 are induced by BF_(4)^(–)or NO_(3)^(–),respectively.MOC-36 is kinetically favored and can undergo quantitative conversion to the thermodynamically preferred MOC-35 upon heating,accelerated by excess BF_(4)^(–)to motivate dissociative dynamics of Pd-vertices and lower activation barrier of cage transformation.The vip encapsulation behaviors of MOC-35 and MOC-36 have also been tested.These results manifest a significance of host-anion dynamics beyond complementary anion template,shedding light on the understanding of intricate anion recognition in nature.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11974044)。
文摘Topological insulators with localized edge or interface states have been extensively studied,particularly in phononic crystals and related fields;however,their application in seismic metamaterials remains largely unexplored.To address this gap,we designed a topological seismic metamaterial,where the topological interface is formed by joining the ends of two distinct one-dimensional periodic lattices.The first full-scale field experiment confirms the existence of topological interface states,which exhibit pronounced localization characteristics and induce a resonant amplification effect of 7.2 dB on the total energy of seismic surface waves.This study provides the first experimental validation for the implementation of topological principles in the design of seismic metamaterials,enabling novel approaches to high-sensitivity seismic detection and efficient energy localization for wave control.
基金support from the National Natural Science Foundation of China (Nos. 21773314, 21821003 and 21890382)the Guangdong Natural Science Funds for Distinguished Young Scholar (No. 2019B151502017)。
文摘Ultrathin two-dimensional metal-organic framework nanosheets have emerged as a promising kind of heterogeneous catalysts. Herein, we report a new kind of 2D porphyrinic metal-organic framework nanosheets of Rh2-PCN-222, which was prepared from the self-assembly of the metalloporphyrin ligand Rh(TCPP)(DCB)(TCPP = 5,10,15,20-tetrakis(4-methoxycarbonylphenyl)porphyrin;DCB = 3,4-dichlorobenzene) and ZrCl_(4) in the presence of two kinds of monocarboxylic acids as the modulating reagent. The thickness of Rh2-PCN-222 nanosheets was characterized by atomic force microscopy(AFM)and determined to be 5.4-9.6 nm. It was found that the axial aryl dichlorophenyl substituent, which controlled the anisotropic growth of MOFs, was essential for the formation of nanosheets. Catalytic results showed that Rh2-PCN-222 nanosheets were efficient for CO_(2) transformation.
基金supported by the NKRD Program of China(No.2021YFA1500401)the National Natural Science Foundation of China(Nos.21821003,21890380)the LIRTP of Guangdong Pearl River Talents Program(No.2017BT01C161)。
文摘The intimate host-anion interactions will regulate thermodynamics and kinetics in the self-assembly of cationic cages mimicking biological counterparts.Herein,we report construction and transformation of three Pd(Ⅱ)-based metal-organic cages(MOCs)depending on different anions.Stoichiometric conversions of the lantern-shaped MOC-34 into either octahedral MOC-35 or tricapped trigonal prism MOC-36 are induced by BF_(4)^(–)or NO_(3)^(–),respectively.MOC-36 is kinetically favored and can undergo quantitative conversion to the thermodynamically preferred MOC-35 upon heating,accelerated by excess BF_(4)^(–)to motivate dissociative dynamics of Pd-vertices and lower activation barrier of cage transformation.The vip encapsulation behaviors of MOC-35 and MOC-36 have also been tested.These results manifest a significance of host-anion dynamics beyond complementary anion template,shedding light on the understanding of intricate anion recognition in nature.
