Seismic mitigation performance of periodic foundations with inertial amplification mechanism considering superstructure-foundation interaction

Author(s):  
Feifei Sun ◽  
Xiaoxin Dai ◽  
Yue Liu ◽  
Lei Xiao
2008 ◽  
Vol 190 (13) ◽  
pp. 4754-4758 ◽  
Author(s):  
E. M. Widenbrant ◽  
Hsiu-Hui Tsai ◽  
Carton W. Chen ◽  
C. M. Kao

ABSTRACT We observed a spontaneous amplification of the Streptomyces coelicolor chromosome, including genes encoding biosynthetic enzymes of the antibiotic actinorhodin. A new junction of two tandem segments has, inserted within it, a third copy of a transposable element existing in two places elsewhere in the chromosome, suggesting its involvement in the amplification mechanism.


Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 581 ◽  
Author(s):  
Quan Zhang ◽  
Jianguo Zhao ◽  
Xin Shen ◽  
Qing Xiao ◽  
Jun Huang ◽  
...  

A novel decoupled XY compliant micro-positioning stage, based on a bridge-type amplification mechanism and parallelogram mechanisms, is designed in this paper. Analytical models of the bridge-type amplification mechanism and parallelogram mechanisms are developed by Castigliano’s second theorem and a Beam constrained model. The amplification ratio, input stiffness, and output stiffness of the stage are further derived, based on the proposed model. In order to verify the theoretical analysis, the finite element method (FEM) is used for simulation and modal analysis, and the simulation results indicate that the errors of the amplification ratio, input stiffness, and output stiffness of the stage between the proposed model and the FEM results are 2.34%, 3.87%, and 2.66%, respectively. Modal analysis results show that the fundamental natural frequency is 44 Hz, and the maximum error between the theoretical model and the FEM is less than 4%, which further validates the proposed modeling method. Finally, the prototype is fabricated to test the amplification ratio, cross-coupling error, and workspace. The experimental results demonstrate that the stage has a relatively large workspace, of 346.1 μm × 357.2 μm, with corresponding amplification ratios of 5.39 in the X-axis and 5.51 in the Y-axis, while the cross-coupling error is less than 1.5%.


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