Nonlinear behavior is important in the vibration test of engineering structures. In this study, a constant response vibration test is proposed for nonlinear element extraction. The method is based on the principle of ...Nonlinear behavior is important in the vibration test of engineering structures. In this study, a constant response vibration test is proposed for nonlinear element extraction. The method is based on the principle of Harmonic Balance Method (HBM). The stiffness or damping can be regarded as constant for particular steady displacement or velocity response. The displacement or velocity is controlled as a constant in the test. Then the measured Frequency Response Function(FRF) is obtained. The equivalent stiffness or damping is estimated using FRFs for a particular vibration response level. The displacement-dependent stiffness and velocity-dependent damping are fitted to describe the unknown non-linearity. The nonlinear spring and damping force can be obtained by combining the fitting results with HBM using first-order expansion. Constant response vibration test is illustrated through experimental setup to verify its effectiveness. Experimental results show that the procedure is capable of achieving an accurate parameter identification of nonlinear damping and stiffness, which is hopeful for industrial application.展开更多
Dear Editor,The information about human civilization has been passed down through texts and images.Owing to its remarkable property,DNA has been suggested as an excellent medium for the long-term storage of texts and ...Dear Editor,The information about human civilization has been passed down through texts and images.Owing to its remarkable property,DNA has been suggested as an excellent medium for the long-term storage of texts and images.Codec systems to convert the data into A/T/C/G sequence and vice versa have become quite critical.The current well-known codec systems(Blawat et al.,2016;Church et al.,2012;Erlich and Zielinski,2017;Goldman et al.,2013;Grass et al.,2015)展开更多
Consciousness lies at the heart of our existence and experience.To probe how perceptual consciousness emerges in the brain,we recorded brainwide intracranial electroencephalography signals from human patients while th...Consciousness lies at the heart of our existence and experience.To probe how perceptual consciousness emerges in the brain,we recorded brainwide intracranial electroencephalography signals from human patients while their perceptual consciousness was effectively manipulated using the continuous flash suppression paradigm.We observed substantial differences in brain activities when visual information gradually enters consciousness.展开更多
文摘Nonlinear behavior is important in the vibration test of engineering structures. In this study, a constant response vibration test is proposed for nonlinear element extraction. The method is based on the principle of Harmonic Balance Method (HBM). The stiffness or damping can be regarded as constant for particular steady displacement or velocity response. The displacement or velocity is controlled as a constant in the test. Then the measured Frequency Response Function(FRF) is obtained. The equivalent stiffness or damping is estimated using FRFs for a particular vibration response level. The displacement-dependent stiffness and velocity-dependent damping are fitted to describe the unknown non-linearity. The nonlinear spring and damping force can be obtained by combining the fitting results with HBM using first-order expansion. Constant response vibration test is illustrated through experimental setup to verify its effectiveness. Experimental results show that the procedure is capable of achieving an accurate parameter identification of nonlinear damping and stiffness, which is hopeful for industrial application.
基金supported by the National Key Research and Development Program (2021YFF1201700,2021YFA0911600,2021YFF1200100)the National Natural Science Foundation of China (31725002,3220120)+1 种基金Shenzhen Science and Technology Program (KQTD20180413181837372)Shenzhen Outstanding Talents Training Fund。
文摘Dear Editor,The information about human civilization has been passed down through texts and images.Owing to its remarkable property,DNA has been suggested as an excellent medium for the long-term storage of texts and images.Codec systems to convert the data into A/T/C/G sequence and vice versa have become quite critical.The current well-known codec systems(Blawat et al.,2016;Church et al.,2012;Erlich and Zielinski,2017;Goldman et al.,2013;Grass et al.,2015)
基金This work was supported by the National Natural Science Foundation of China(U20A2017,31830037)the Science and Technology Funds of Guangdong Province(2020A1515111118,2022A1515010134)+2 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(2017120)the Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions(NYKFKT2019009)the Strategic Priority Research Program of Chinese Academy of Sciences(XDBS01030100,XDB32010300),the Ministry of Science and Technology of the People’s Republic of China(2021ZD0203800),and the Fundamental Research Funds for the Central Universities.
文摘Consciousness lies at the heart of our existence and experience.To probe how perceptual consciousness emerges in the brain,we recorded brainwide intracranial electroencephalography signals from human patients while their perceptual consciousness was effectively manipulated using the continuous flash suppression paradigm.We observed substantial differences in brain activities when visual information gradually enters consciousness.
