The double-beam system is a crucial foundational structure in industry,with extensive application contexts and significant research value.The double-beam system with damping and gyroscopic effects is termed as the dam...The double-beam system is a crucial foundational structure in industry,with extensive application contexts and significant research value.The double-beam system with damping and gyroscopic effects is termed as the damped gyroscopic double-beam system.In such systems,the orthogonality conditions of the undamped double-beam system are no longer applicable,rendering it impossible to decouple them in modal space using the modal superposition method(MSM) to obtain analytical solutions.Based on the complex modal method and state space method,this paper takes the damped pipe-in-pipe(PIP) system as an example to solve this problem.The concepts of the original system and adjoint system are introduced,and the orthogonality conditions of the damped PIP system are given in the state-space.Based on the derived orthogonality conditions,the transient and steady-state response solutions are obtained.In the numerical discussion section,the convergence and accuracy of the solutions are verified.In addition,the dynamic responses of the system under different excitations and initial conditions are studied,and the forward and reverse synchronous vibrations in the PIP system are discussed.Overall,the method presented in this paper provides a convenient way to analyze the dynamics of the damped gyroscopic double-beam system.展开更多
Two bis-naphthalimide-based supramolecular gelators(NN-3 and NN-4)with a little difference of position of amino groups were designed and synthesized for the detection of oxaloyl chloride and phosgene.Energy transfer c...Two bis-naphthalimide-based supramolecular gelators(NN-3 and NN-4)with a little difference of position of amino groups were designed and synthesized for the detection of oxaloyl chloride and phosgene.Energy transfer could be occurred between two naphthalimide groups in molecules NN-3 and NN-4.Yellow gels NN-3 and NN-4 were formed in some mixed solvents,and nanofibers with different size were obtained in these gels.The self-assembly processes of NN-3 and NN-4 in different solvents were investigated by UV-vis absorption,fluorescent spectra,SEM,FTIR,XRD and NMR.Gelators NN-3 and NN-4 could selectively detect oxaloyl chloride in solution and film states,but detect phosgene only in solution.NN-3exhibited the ratiometric detection ability towards oxaloyl chloride and phosgene with the low limit of detection(LOD)of 210 nmol/L and 90 nmol/L,respectively.NN-4 as the corresponding control sample,it owned the higher LOD towards oxaloyl chloride and phosgene of 12.4μmol/L and 64μmol/L,respectively.Interestingly,films NN-3 and NN-4 could sensitively detect oxaloyl chloride gases with the low LOD of2.0 ppm and 8.34 ppm,respectively.The detection mechanisms of NN-3 and NN-4 were well studied by1H NMR titration,HRMS and theoretical calculation.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 12272323)。
文摘The double-beam system is a crucial foundational structure in industry,with extensive application contexts and significant research value.The double-beam system with damping and gyroscopic effects is termed as the damped gyroscopic double-beam system.In such systems,the orthogonality conditions of the undamped double-beam system are no longer applicable,rendering it impossible to decouple them in modal space using the modal superposition method(MSM) to obtain analytical solutions.Based on the complex modal method and state space method,this paper takes the damped pipe-in-pipe(PIP) system as an example to solve this problem.The concepts of the original system and adjoint system are introduced,and the orthogonality conditions of the damped PIP system are given in the state-space.Based on the derived orthogonality conditions,the transient and steady-state response solutions are obtained.In the numerical discussion section,the convergence and accuracy of the solutions are verified.In addition,the dynamic responses of the system under different excitations and initial conditions are studied,and the forward and reverse synchronous vibrations in the PIP system are discussed.Overall,the method presented in this paper provides a convenient way to analyze the dynamics of the damped gyroscopic double-beam system.
基金financially supported by the National Natural Science Foundation of China(No.U1704164)the Basic Research Project of Henan Provincial Key Scientific Research Project(No.22ZX002)。
文摘Two bis-naphthalimide-based supramolecular gelators(NN-3 and NN-4)with a little difference of position of amino groups were designed and synthesized for the detection of oxaloyl chloride and phosgene.Energy transfer could be occurred between two naphthalimide groups in molecules NN-3 and NN-4.Yellow gels NN-3 and NN-4 were formed in some mixed solvents,and nanofibers with different size were obtained in these gels.The self-assembly processes of NN-3 and NN-4 in different solvents were investigated by UV-vis absorption,fluorescent spectra,SEM,FTIR,XRD and NMR.Gelators NN-3 and NN-4 could selectively detect oxaloyl chloride in solution and film states,but detect phosgene only in solution.NN-3exhibited the ratiometric detection ability towards oxaloyl chloride and phosgene with the low limit of detection(LOD)of 210 nmol/L and 90 nmol/L,respectively.NN-4 as the corresponding control sample,it owned the higher LOD towards oxaloyl chloride and phosgene of 12.4μmol/L and 64μmol/L,respectively.Interestingly,films NN-3 and NN-4 could sensitively detect oxaloyl chloride gases with the low LOD of2.0 ppm and 8.34 ppm,respectively.The detection mechanisms of NN-3 and NN-4 were well studied by1H NMR titration,HRMS and theoretical calculation.
