心力衰竭(heart failure,HF)是一种复杂的临床综合征,其中,左心衰是HF中最常见的类型,具有较高的患病率和死亡率。但HF病因繁多,明确潜在病因一直是临床上的重大挑战。心脏磁共振(cardiac magnetic resonance,CMR)能够无创评估心脏结构...心力衰竭(heart failure,HF)是一种复杂的临床综合征,其中,左心衰是HF中最常见的类型,具有较高的患病率和死亡率。但HF病因繁多,明确潜在病因一直是临床上的重大挑战。心脏磁共振(cardiac magnetic resonance,CMR)能够无创评估心脏结构、功能及心肌表征等多方面信息,已经成为HF诊断和预后的重要指标。但受空间和时间分辨率的限制,CMR在对心脏细微结构和动态功能的精确评估上仍存在偏差,且对某些特定病理的检测敏感性仍需提高。本文就CMR新技术在HF病因诊断方面的应用进展予以总结,旨在深入探讨不同病因导致的HF在CMR多种序列上的特征表现,以提高早期检出率,为临床诊疗提供影像依据,并有望为将来的研究提供参考。展开更多
Up to present,the problem of the evaluation of fault diagnosability for nonlinear systems has been investigated by many researchers.However,no attempt has been done to evaluate the diagnosability of multiple faults oc...Up to present,the problem of the evaluation of fault diagnosability for nonlinear systems has been investigated by many researchers.However,no attempt has been done to evaluate the diagnosability of multiple faults occurring simultaneously for nonlinear systems.This paper proposes a method based on differential geometry theories to solve this problem.Then the evaluation of fault diagnosability for affine nonlinear systems with multiple faults occurring simultaneously is achieved.To deal with the effect of control laws on the evaluation results of fault diagnosability,a design scheme of the evaluation of fault diagnosability is proposed.Then the influence of uncertainties on the evaluation results of fault diagnosability for affine nonlinear systems with multiple faults occurring simultaneously is analyzed.The numerical simulation results are obtained to show the effectiveness of the proposed evaluation scheme of fault diagnosability.展开更多
Fault diagnose of the roller overrunning clutch is a headache problem in engineering at home and abroad. This paper introduces a new method to solve the problem by using the wavelet transform to separate fault si gnal...Fault diagnose of the roller overrunning clutch is a headache problem in engineering at home and abroad. This paper introduces a new method to solve the problem by using the wavelet transform to separate fault si gnal and further analyzing the impact frequency. The signal local singularities under the wavelet transform are studied. According to the propagation features of modulus maximums of the fault signal and the noise under the wavelet transfor m different on the scales, and by use of the signal wavelet decomposition-recon struction algorithm, the clutch shell vibration acceleration signal is decompose d, denoised, and reconstructed.The signal-to-noise of the monitored signal imp roved greatly.The fault characteristic signal on time domain is positioned.The f ault characteristic frequency is picked up. Experiment shows that it is quite effective.展开更多
文摘心力衰竭(heart failure,HF)是一种复杂的临床综合征,其中,左心衰是HF中最常见的类型,具有较高的患病率和死亡率。但HF病因繁多,明确潜在病因一直是临床上的重大挑战。心脏磁共振(cardiac magnetic resonance,CMR)能够无创评估心脏结构、功能及心肌表征等多方面信息,已经成为HF诊断和预后的重要指标。但受空间和时间分辨率的限制,CMR在对心脏细微结构和动态功能的精确评估上仍存在偏差,且对某些特定病理的检测敏感性仍需提高。本文就CMR新技术在HF病因诊断方面的应用进展予以总结,旨在深入探讨不同病因导致的HF在CMR多种序列上的特征表现,以提高早期检出率,为临床诊疗提供影像依据,并有望为将来的研究提供参考。
基金the Natural Science Foundation of Fujian Province,China(2019J05024)the Education Department Foundation of Fujian Province,China(JAT170091).
文摘Up to present,the problem of the evaluation of fault diagnosability for nonlinear systems has been investigated by many researchers.However,no attempt has been done to evaluate the diagnosability of multiple faults occurring simultaneously for nonlinear systems.This paper proposes a method based on differential geometry theories to solve this problem.Then the evaluation of fault diagnosability for affine nonlinear systems with multiple faults occurring simultaneously is achieved.To deal with the effect of control laws on the evaluation results of fault diagnosability,a design scheme of the evaluation of fault diagnosability is proposed.Then the influence of uncertainties on the evaluation results of fault diagnosability for affine nonlinear systems with multiple faults occurring simultaneously is analyzed.The numerical simulation results are obtained to show the effectiveness of the proposed evaluation scheme of fault diagnosability.
文摘Fault diagnose of the roller overrunning clutch is a headache problem in engineering at home and abroad. This paper introduces a new method to solve the problem by using the wavelet transform to separate fault si gnal and further analyzing the impact frequency. The signal local singularities under the wavelet transform are studied. According to the propagation features of modulus maximums of the fault signal and the noise under the wavelet transfor m different on the scales, and by use of the signal wavelet decomposition-recon struction algorithm, the clutch shell vibration acceleration signal is decompose d, denoised, and reconstructed.The signal-to-noise of the monitored signal imp roved greatly.The fault characteristic signal on time domain is positioned.The f ault characteristic frequency is picked up. Experiment shows that it is quite effective.
