A Simplified Model for Buckling and Post-Buckling Analysis of Cu Nanobeam Under Compression

Both of Buckling and post-buckling are fundamental problems of geometric nonlinearity in solid mechanics.With the rapid development of nanotechnology in recent years,buckling behaviors in nanobeams receive more attention due to its applications in sensors,actuators,transistors,probes,and resonators in nanoelectromechanical systems(NEMS)and biotechnology.In this work,buckling and post-buckling of copper nanobeam under uniaxial compression are investigated with theoretical analysis and atomistic simulations.Different cross sections are explored for the consideration of surface effects.To avoid complicated high order buckling modes,a stressbased simplified model is proposed to analyze the critical strain for buckling,maximum deflection,and nominal failure strain for post-buckling.Surface effects should be considered regarding critical buckling strain and the maximum post-buckling deflection.The critical strain increases with increasing nanobeam cross section,while themaximumdeflection increases with increasing loading strain but stays nearly the same for different cross sections,and the underlying mechanisms are revealed by our model.The maximum deflection is also influenced by surface effects.The nominal failure strains are captured by our simulations,and they are in good agreement with the simplified model.Our results can be used for helping design strain gauge sensors and nanodevices with self-detecting ability.

Design of functionalized fluorescent ionic liquid and its application for achieving significant improvements in Al^3t detecting

Specific fluorophore was introduced into ionic liquid based on its tunability,thus a kind of novel fluorescent ionic liquid probe[P66614][HQS]was designed,synthesized and characterized.Compared with non-fluorescent HQS,ionic liquid[P66614][HQS]emitted a certain amount of fluorescence,which could be attributed to the well-delocalized frontier orbitals and its charge transfer character,as demonstrated by quantum chemical calculation.Considering the interaction of[P66614][HQS]with metal ions,the application for detecting specific substance as a chemical sensor,such as Al3+was investigated.Compared with the traditional probe HQS,significant improvements in Al^3+detecting was achieved by[P66614][HQS]with stronger binding ability,better sensitivity and selectivity.The better performance of[P66614][HQS]was contributed to the changed charge distribution,leading to the stronger binding interaction.We believe that this new fluorescent ionic liquid exhibited unique properties in detecting Al^3+in aqueous solution,which would broaden the application of ionic liquids.

A succinct enhanced luminescence strategy for fluorescent ionic liquids and the application for detecting CO_(2)

An interesting phenomenon was found that fluorophore was introduced into ionic liquid(IL)to magnify fluorescence signal via the thermally activated delayed fluorescence process;thus up to 15 fold enhancements were achieved.Hence,we reported a succinct enhanced luminescence strategy to reduce single-triplet energy split by the tunability of ILs.This strategy could be extended to more kinds of ILs by the virtue of a preliminary DFT calculation screening.Moreover,the optical feature of IL sensor made it a promising candidate as a gas fluorescence sensor.

固相分子自组装及其材料

分子自组装通常在溶液中发生,形成微纳尺度的分散结构,在纳米医药等领域发挥着重要作用.但基于溶液相分子自组装一般无法形成连续的自支撑材料,使得分子自组装原理无法在更广阔的材料领域发挥理论优势.最近,本课题组在国际上首先提出了分子在固相中自组装的研究思想,并利用沉淀中微纳尺度的聚集体颗粒具有自发融合以降低体系界面能的趋势,实现了分子在固相中的自组装,实现了连续自支撑的分子自组装薄膜的宏量制备,使分子的有序排列方式与宏观材料的性能控制紧密相连.本文总结了本课题组近年来的工作,主要介绍了固相分子自组装的原理、方法及固相分子自组装薄膜材料特有的优异结构性能,包括自修复、抗疲劳、湿度响应的张力、吸油、圆偏振发光、室温磷光、白光荧光等,并展望了固相分子自组装未来的发展空间.