This paper concentrates on investigating the mechanical stability of a Beam Position Monitor (BMP)support prototype of the Shanghai Synchrotron Radiation Facility(SSRF)project.Both finite element analysis and vibratio...This paper concentrates on investigating the mechanical stability of a Beam Position Monitor (BMP)support prototype of the Shanghai Synchrotron Radiation Facility(SSRF)project.Both finite element analysis and vibration measurements have been performed.Inconsistent results between the simulations and experiments motivate us to study three connections between the support and the ground:ground bolt(used in the initial design),part grout and full grout(proposed in the later research).After changing the connection, the first eigenfrequency is increased from 20.2Hz to 50.2Hz,and the ratio of the integrated RMS displacement (4—50Hz)is decreased from 4.36 to 1.23 in the lateral direction.The mechanical stability is improved greatly.展开更多
Recently, cavity optomechanics has become a rapidly developing research field exploring the coupling between the optical field and mechanical oscillation. Cavity optomechanical systems were predicted to exhibit rich a...Recently, cavity optomechanics has become a rapidly developing research field exploring the coupling between the optical field and mechanical oscillation. Cavity optomechanical systems were predicted to exhibit rich and nontrivial effects due to the nonlinear optomechanical interaction. However, most progress during the past years have focused on the linearization of the optomechanical interaction, which ignored the intrinsic nonlinear nature of the optomechanical coupling. Exploring nonlinear optomechanical interaction is of growing interest in both classical and quantum mechanisms, and nonlinear optomechanical interaction has emerged as an important new frontier in cavity optomechanics. It enables many applications ranging from single-photon sources to generation of nonclassical states. Here, we give a brief review of these developments and discuss some of the current challenges in this field.展开更多
Vibration signal is an important prerequisite for mechanical fault detection. However, early stage defect of rotating machiner- ies is difficult to identify because their incipient energy is interfered with background...Vibration signal is an important prerequisite for mechanical fault detection. However, early stage defect of rotating machiner- ies is difficult to identify because their incipient energy is interfered with background noises. Multiwavelet is a powerful tool used to conduct non-stationary fault feature extraction. However, the existing predetermined multiwavelet bases are independ- ent of the dynamic response signals. In this paper, a constructing technique of vibration data-driven maximal-overlap adaptive multiwavelet (MOAMW) is proposed for enhancing the extracting performance of fault symptom. It is able to derive an opti- mal multiwavelet basis that best matches the critical non-stationary and transient fault signatures via genetic algorithm. In this technique, two-scale similarity transform (TST) and symmetric lifting (SymLift) scheme are combined to gain high designing freedom for matching the critical faulty vibration contents in vibration signals based on the maximal fitness objective. TST and SymLift can add modifications to the initial multiwavelet by changing the approximation order and vanishing moment of mul- tiwavelet, respectively. Moreover, the beneficial feature of the MOAWM lies in that the maximal-overlap filterbank structure can enhance the periodic and transient characteristics of the sensor signals and preserve the time and frequency analyzing res- olution during the decomposition process. The effectiveness of the proposed technique is validated via a numerical simulation as well as a rolling element beating with an outer race scrape and a gearbox with rub fault.展开更多
文摘This paper concentrates on investigating the mechanical stability of a Beam Position Monitor (BMP)support prototype of the Shanghai Synchrotron Radiation Facility(SSRF)project.Both finite element analysis and vibration measurements have been performed.Inconsistent results between the simulations and experiments motivate us to study three connections between the support and the ground:ground bolt(used in the initial design),part grout and full grout(proposed in the later research).After changing the connection, the first eigenfrequency is increased from 20.2Hz to 50.2Hz,and the ratio of the integrated RMS displacement (4—50Hz)is decreased from 4.36 to 1.23 in the lateral direction.The mechanical stability is improved greatly.
基金supported by the National Natural Fundamental Research Program of China(Grant No.2012CB922103)the National Science Foundation of China(Grant Nos.11375067,11275074,11374116,11204096 and 11405061)the Fundamental Research Funds for the Central Universities HUST(Grant No.2014QN193)
文摘Recently, cavity optomechanics has become a rapidly developing research field exploring the coupling between the optical field and mechanical oscillation. Cavity optomechanical systems were predicted to exhibit rich and nontrivial effects due to the nonlinear optomechanical interaction. However, most progress during the past years have focused on the linearization of the optomechanical interaction, which ignored the intrinsic nonlinear nature of the optomechanical coupling. Exploring nonlinear optomechanical interaction is of growing interest in both classical and quantum mechanisms, and nonlinear optomechanical interaction has emerged as an important new frontier in cavity optomechanics. It enables many applications ranging from single-photon sources to generation of nonclassical states. Here, we give a brief review of these developments and discuss some of the current challenges in this field.
基金supported by the National Natural Science Foundation of China(Grant No.51275384)the Key Project of National Natural Science Foundation of China(Grant No.51035007)+1 种基金the National Basic Research Program of China(Grant No.2009CB724405)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20110201130001)
文摘Vibration signal is an important prerequisite for mechanical fault detection. However, early stage defect of rotating machiner- ies is difficult to identify because their incipient energy is interfered with background noises. Multiwavelet is a powerful tool used to conduct non-stationary fault feature extraction. However, the existing predetermined multiwavelet bases are independ- ent of the dynamic response signals. In this paper, a constructing technique of vibration data-driven maximal-overlap adaptive multiwavelet (MOAMW) is proposed for enhancing the extracting performance of fault symptom. It is able to derive an opti- mal multiwavelet basis that best matches the critical non-stationary and transient fault signatures via genetic algorithm. In this technique, two-scale similarity transform (TST) and symmetric lifting (SymLift) scheme are combined to gain high designing freedom for matching the critical faulty vibration contents in vibration signals based on the maximal fitness objective. TST and SymLift can add modifications to the initial multiwavelet by changing the approximation order and vanishing moment of mul- tiwavelet, respectively. Moreover, the beneficial feature of the MOAWM lies in that the maximal-overlap filterbank structure can enhance the periodic and transient characteristics of the sensor signals and preserve the time and frequency analyzing res- olution during the decomposition process. The effectiveness of the proposed technique is validated via a numerical simulation as well as a rolling element beating with an outer race scrape and a gearbox with rub fault.