The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructi...The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control theory.The vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration control.The paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering applications.The load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of bridges.The vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element method.Using the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency range.The noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.展开更多
A new boroantimonate K2SbB3O8 has been synthesized by high-temperature solidstate reactions, and its crystals have been obtained by the flux method. The crystal structure has been determined from single-crystal X-ray ...A new boroantimonate K2SbB3O8 has been synthesized by high-temperature solidstate reactions, and its crystals have been obtained by the flux method. The crystal structure has been determined from single-crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P21/c with a = 5.8890（2）, b = 11.0512（4）, c = 10.8951（4）A, β =103.200（4）°, V = 690.32（4） A^3, Z = 4, F（000） = 672, ρc = 3.467 g/cm^3, Mr = 360.38 and μ = 5.215mm^-1. Its structure feature is a three-dimensional framework composed of SbO6 octahedra and isolated [B3O8]^7- groups with K＋ cations residing in the one-dimensional tunnels along the a-axis.Interestingly, the isolated [B3O8]^7- groups are distinct from the known [B3O8]^7- groups, which always connect to each other. The UV-vis-NIR absorption, thermal stability and infrared spectrum are also discussed in this paper.展开更多
基金Project(51978585)supported by the National Natural Science Foundation,ChinaProject(2022YFB2603404)supported by the National Key Research and Development Program,China+1 种基金Project(U1734207)supported by the High-speed Rail Joint Fund Key Projects of Basic Research,ChinaProject(2023NSFSC1975)supported by the Sichuan Nature and Science Foundation Innovation Research Group Project,China。
文摘The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control theory.The vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration control.The paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering applications.The load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of bridges.The vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element method.Using the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency range.The noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.
基金Supported by NSFC(21171166,21222102,21301172,21373220,21571178,21525104,51277091,51402296,51502288 and 51502290)Chunmiao Project of Haixi Institute of Chinese Academy of Sciences(CMZX-2015-003)NSF of Fujian Province(2015J01219,2015J05040)
文摘A new boroantimonate K2SbB3O8 has been synthesized by high-temperature solidstate reactions, and its crystals have been obtained by the flux method. The crystal structure has been determined from single-crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P21/c with a = 5.8890（2）, b = 11.0512（4）, c = 10.8951（4）A, β =103.200（4）°, V = 690.32（4） A^3, Z = 4, F（000） = 672, ρc = 3.467 g/cm^3, Mr = 360.38 and μ = 5.215mm^-1. Its structure feature is a three-dimensional framework composed of SbO6 octahedra and isolated [B3O8]^7- groups with K＋ cations residing in the one-dimensional tunnels along the a-axis.Interestingly, the isolated [B3O8]^7- groups are distinct from the known [B3O8]^7- groups, which always connect to each other. The UV-vis-NIR absorption, thermal stability and infrared spectrum are also discussed in this paper.
