This article studies the fault detection filtering design problem for Roesser type two-dimensional(2-D)nonlinear systems described by uncertain 2-D Takagi-Sugeno(T-S)fuzzy models.Firstly,fuzzy Lyapunov functions are c...This article studies the fault detection filtering design problem for Roesser type two-dimensional(2-D)nonlinear systems described by uncertain 2-D Takagi-Sugeno(T-S)fuzzy models.Firstly,fuzzy Lyapunov functions are constructed and the 2-D Fourier transform is exploited,based on which a finite frequency fault detection filtering design method is proposed such that a residual signal is generated with robustness to external disturbances and sensitivity to faults.It has been shown that the utilization of available frequency spectrum information of faults and disturbances makes the proposed filtering design method more general and less conservative compared with a conventional nonfrequency based filtering design approach.Then,with the proposed evaluation function and its threshold,a novel mixed finite frequency H_(∞)/H_(-)fault detection algorithm is developed,based on which the fault can be immediately detected once the evaluation function exceeds the threshold.Finally,it is verified with simulation studies that the proposed method is effective and less conservative than conventional non-frequency and/or common Lyapunov function based filtering design methods.展开更多
We describe the fabrication of high performance YBa2Cu3O7-δ （YBCO） radio frequency （RF） superconducting quantum interference devices （SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3 （LAO） substrates by ...We describe the fabrication of high performance YBa2Cu3O7-δ （YBCO） radio frequency （RF） superconducting quantum interference devices （SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3 （LAO） substrates by employing stepedge junctions （SEJs） and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47° to 61°, which is steep enough to ensure the formation of grain boundaries （GBs） at the step edges. The YBCO film was deposited using the pulsed laser deposition （PLD） technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH. Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/φ0, a white flux noise of 29 μφ0/√Hz, and the magnetic field sensitivity as high as 80 fT/√Hz. These devices have been applied in magnetocardiography and geological surveys.展开更多
The development of damage detection techniques for offshore jacket structures is vital to prevent catastrophic events. This paper applies a frequency response based method for the purpose of structural health monitori...The development of damage detection techniques for offshore jacket structures is vital to prevent catastrophic events. This paper applies a frequency response based method for the purpose of structural health monitoring. In efforts to fulfill this task, concept of the minimum rank perturbation theory has been utilized. The present article introduces a promising methodology to select frequency points effectively. To achieve this goal, modal strain energy ratio of each member was evaluated at different natural frequencies of structure in order to identify the sensitive frequency domain for damage detection. The proposed methodology opens up the possibility of much greater detection efficiency. In addition, the performance of the proposed method was evaluated in relation to multiple damages. The aforementioned points are illustrated using the numerical study of a two dimensional jacket platform, and the results proved to be satisfactory utilizing the proposed methodology.展开更多
The present paper develops a new method for damage localization and severity estimation based on the employment of modal strain energy. This method is able to determine the damage locations and estimate their severiti...The present paper develops a new method for damage localization and severity estimation based on the employment of modal strain energy. This method is able to determine the damage locations and estimate their severities, requiring only the information about the changes of a few lower natural frequencies. First, a damage quantification method is formulated and iterative approach is adopted for determining the damage extent. Then a damage localization algorithm is proposed, in which a damage indicator is formulated where unity value corresponds to the true damage scenario. Finally, numerical studies and model tests are conducted to demonstrate the effectiveness of the developed algorithm.展开更多
核因子-κB受体活化因子配体(receptor activator of Nuclear factor-kappa B Ligand,RANKL)、核因子-κB受体活化因子(receptor activator of nuclear factor-kappa B,RANK)、骨保护素(osteoprotegerin,OPG)作为肿瘤坏死因子家族的成员...核因子-κB受体活化因子配体(receptor activator of Nuclear factor-kappa B Ligand,RANKL)、核因子-κB受体活化因子(receptor activator of nuclear factor-kappa B,RANK)、骨保护素(osteoprotegerin,OPG)作为肿瘤坏死因子家族的成员,通过RANKL/RANK/OPG信号通路调节破骨细胞发生及成熟,调控骨代谢,其表达水平直接影响骨质代谢与重塑,现被广泛研究。RANKL/RANK/OPG通路在口腔颌面部形成及改建过程中发挥了关键作用,直接或间接反映出口腔骨破坏类疾病的发生与发展状态。该通路的失衡往往伴随RANKL的增加和(或)OPG的减少,RANKL/OPG的比值影响破骨细胞的成熟及功能,但部分疾病中相关因子的表达水平存在争议,且尚无能应用于临床疾病诊疗的阈值。本文就RANKL/RANK/OPG信号通路调节机制及其在牙周炎、种植、牙齿发育、正畸、颌面部骨缺损修复与再生等口腔相关领域的研究现状进行综述,以进一步探讨口腔中骨代谢及骨破坏类疾病的调节机制,并评价相关因子作为生物标志物的诊断和预后潜力,以期指导临床诊疗及探寻可能的免疫调节靶点。展开更多
Using environmental random vibration as the excitation,traditional accelerometer method,non-contact video method and non-contact laser method were employed to determine the natural frequency of Kunyu River footbridge....Using environmental random vibration as the excitation,traditional accelerometer method,non-contact video method and non-contact laser method were employed to determine the natural frequency of Kunyu River footbridge.All the results of these three methods are close to 2.70 Hz,which are concordant with each other and hence credible.展开更多
This paper presents the composition, control scheme and signal processing method of frequency conversion motor speed testing system based on $7-200 PLC, and design the hardware circuit, the trapezoidal chart procedure...This paper presents the composition, control scheme and signal processing method of frequency conversion motor speed testing system based on $7-200 PLC, and design the hardware circuit, the trapezoidal chart procedure and touch screen display program. The debugging test shows that the system is simple, practical, and related design work has laid the foundation for the future.展开更多
基金supported in part by the National Natural Science Foundation of China(62373152,62333005,U21B6001,62073143,62273121)in part by the Natural Science Funds for Excellent Young Scholars of Hebei Province in 2022(F2022202014)+1 种基金in part by Science and Technology Research Project of Colleges and Universities in Hebei Province(BJ2020017)in part by the China Postdoctoral Science Foundation(2022M711639,2023T160320).
文摘This article studies the fault detection filtering design problem for Roesser type two-dimensional(2-D)nonlinear systems described by uncertain 2-D Takagi-Sugeno(T-S)fuzzy models.Firstly,fuzzy Lyapunov functions are constructed and the 2-D Fourier transform is exploited,based on which a finite frequency fault detection filtering design method is proposed such that a residual signal is generated with robustness to external disturbances and sensitivity to faults.It has been shown that the utilization of available frequency spectrum information of faults and disturbances makes the proposed filtering design method more general and less conservative compared with a conventional nonfrequency based filtering design approach.Then,with the proposed evaluation function and its threshold,a novel mixed finite frequency H_(∞)/H_(-)fault detection algorithm is developed,based on which the fault can be immediately detected once the evaluation function exceeds the threshold.Finally,it is verified with simulation studies that the proposed method is effective and less conservative than conventional non-frequency and/or common Lyapunov function based filtering design methods.
基金supported by the National Basic Research Program of China(Grant No.2011CBA00106)the National Natural Science Foundation of China(Grant No.11074008)the Research Fund for the Doctoral Program of Higher Education,China(Grant No.20100001120006)
文摘We describe the fabrication of high performance YBa2Cu3O7-δ （YBCO） radio frequency （RF） superconducting quantum interference devices （SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3 （LAO） substrates by employing stepedge junctions （SEJs） and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47° to 61°, which is steep enough to ensure the formation of grain boundaries （GBs） at the step edges. The YBCO film was deposited using the pulsed laser deposition （PLD） technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH. Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/φ0, a white flux noise of 29 μφ0/√Hz, and the magnetic field sensitivity as high as 80 fT/√Hz. These devices have been applied in magnetocardiography and geological surveys.
基金Financial Support by the Pars Oil and Gas Company(Grant No. 88-065)
文摘The development of damage detection techniques for offshore jacket structures is vital to prevent catastrophic events. This paper applies a frequency response based method for the purpose of structural health monitoring. In efforts to fulfill this task, concept of the minimum rank perturbation theory has been utilized. The present article introduces a promising methodology to select frequency points effectively. To achieve this goal, modal strain energy ratio of each member was evaluated at different natural frequencies of structure in order to identify the sensitive frequency domain for damage detection. The proposed methodology opens up the possibility of much greater detection efficiency. In addition, the performance of the proposed method was evaluated in relation to multiple damages. The aforementioned points are illustrated using the numerical study of a two dimensional jacket platform, and the results proved to be satisfactory utilizing the proposed methodology.
基金supported by the National Natural Science Foundation of China (50909088, 51010009)Science & Technology Development Project of Qingdao (09-1-3-18-jch)Program for New Century Excellent Talents in University (NCET-10-0762)
文摘The present paper develops a new method for damage localization and severity estimation based on the employment of modal strain energy. This method is able to determine the damage locations and estimate their severities, requiring only the information about the changes of a few lower natural frequencies. First, a damage quantification method is formulated and iterative approach is adopted for determining the damage extent. Then a damage localization algorithm is proposed, in which a damage indicator is formulated where unity value corresponds to the true damage scenario. Finally, numerical studies and model tests are conducted to demonstrate the effectiveness of the developed algorithm.
文摘核因子-κB受体活化因子配体(receptor activator of Nuclear factor-kappa B Ligand,RANKL)、核因子-κB受体活化因子(receptor activator of nuclear factor-kappa B,RANK)、骨保护素(osteoprotegerin,OPG)作为肿瘤坏死因子家族的成员,通过RANKL/RANK/OPG信号通路调节破骨细胞发生及成熟,调控骨代谢,其表达水平直接影响骨质代谢与重塑,现被广泛研究。RANKL/RANK/OPG通路在口腔颌面部形成及改建过程中发挥了关键作用,直接或间接反映出口腔骨破坏类疾病的发生与发展状态。该通路的失衡往往伴随RANKL的增加和(或)OPG的减少,RANKL/OPG的比值影响破骨细胞的成熟及功能,但部分疾病中相关因子的表达水平存在争议,且尚无能应用于临床疾病诊疗的阈值。本文就RANKL/RANK/OPG信号通路调节机制及其在牙周炎、种植、牙齿发育、正畸、颌面部骨缺损修复与再生等口腔相关领域的研究现状进行综述,以进一步探讨口腔中骨代谢及骨破坏类疾病的调节机制,并评价相关因子作为生物标志物的诊断和预后潜力,以期指导临床诊疗及探寻可能的免疫调节靶点。
基金Ministry of Science and Technology of China for sponsoring the"Cooperation Research on the Dynamic Safety and Serviceability of Public Structures Servicing for Human"(No.2010DFB74280)between Beijing Institute of Technology and Ruhr-University Bochum
文摘Using environmental random vibration as the excitation,traditional accelerometer method,non-contact video method and non-contact laser method were employed to determine the natural frequency of Kunyu River footbridge.All the results of these three methods are close to 2.70 Hz,which are concordant with each other and hence credible.
文摘This paper presents the composition, control scheme and signal processing method of frequency conversion motor speed testing system based on $7-200 PLC, and design the hardware circuit, the trapezoidal chart procedure and touch screen display program. The debugging test shows that the system is simple, practical, and related design work has laid the foundation for the future.
