Response Spectrum Analysis of 7-story Assembled Frame Structure with Energy Dissipation System

Viscoelastic damper is an effective passive damping device,which can reduce the seismic response of the structure by increasing the damping and dissipating the vibration energy of structures.It has a wide application prospect in actual structural vibration control because of simple device and economical material.In view of the poor seismic behaviors of assembled frame structure connections,various energy dissipation devices are proposed to improve the seismic performance.The finite element numerical analysis method is adopted to analyze relevant energy dissipation structural parameters.The response spectrum of a 7-story assembled frame structure combined the ordinary steel support,ordinary viscoelastic damper,and viscoelastic damper with displacement amplification device is analyzed.The analysis results show that the mechanical behavior of assembled frame structure with ordinary steel supports are not significantly different from those without energy dissipation devices.The assembled frame structure with viscoelastic damper has better seismic performance and energy dissipation,especially for the viscoelastic damper with displacement amplification devices.The maximum value of inter-story displacement angle decreases by 32.24%;the maximum floor displacement decreases by 31.91%,and the base shear decreases by 13.62%compared with the assembled frame structures without energy dissipation devices.The results show that the seismic fortification ability of the structure is significantly improved,and the overall structure is more uniformly stressed.The damping structure with viscoelastic damper mainly reduces the dynamic response of the structure by increasing the damping coefficient,rather than by changing the natural vibration period of the structure.This paper provides an effective theoretical basis and reference for improving the energy dissipation system and the seismic performance of assembled frame structures.

DNA-based nanostructures for RNA delivery

RNA-based therapeutics have emerged as a promising approach for the treatment of various diseases,including cancer,genetic disorders,and infectious diseases.However,the delivery of RNA molecules into target cells has been a major challenge due to their susceptibility to degradation and inefficient cellular uptake.To overcome these hurdles,DNA-based nano technology offers an unprecedented opportunity as a potential delivery platform for RNA therapeutics.Due to its excellent characteristics such as programmability and biocompatibility,these DNA-based nanostructures,composed of DNA molecules assembled into precise and programmable structures,have garnered significant attention as ideal building materials for protecting and delivering RNA payloads to the desired cellular destinations.In this review,we highlight the current progress in the design and application of three DNA-based nanostructures:DNA origami,lipid-nanoparticle(LNP)technology related to frame guided assembly(FGA),and DNA hydrogel for the delivery of RNA molecules.Their biomedical applications are briefly discussed and the challenges and future perspectives in this field are also highlighted.