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机械信号处理的BSS算法及其比较研究

振动工程学报 2008年第4期21卷 409-416页

作者：张金玉黄先祥谢伟达第二炮兵工程学院陕西西安710025 香港城市大学中国香港

在由多个独立振动构成的复杂机械振动的状态监测和故障诊断中,复杂机械信号的分离和识别的效果往往是其故障诊断成功的关键。为了得到最佳的机械信号分离算法,对5类经典的盲源分离(BSS)算法的特点和性能进行了比较研究,提出了一套评价准... 详细信息

在由多个独立振动构成的复杂机械振动的状态监测和故障诊断中,复杂机械信号的分离和识别的效果往往是其故障诊断成功的关键。为了得到最佳的机械信号分离算法,对5类经典的盲源分离(BSS)算法的特点和性能进行了比较研究,提出了一套评价准则,使用典型的仿真机械信号,对其在机械故障诊断中的典型机械信号的分离效果进行了充分的实验和详细评估。之后,运用两组来自真实工业设备部件的振动数据去检验其结果。研究结果表明不同的BSS算法具有各自的特点,对处理不同类型的机械信号有不同的效果,其结果有指导意义。

关键词：盲信号分离机械信号处理故障诊断二阶统计学高阶统计学

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基于盲均衡理论的弱冲击故障的检测研究

机械科学与技术 2008年第8期27卷 996-999页

作者：张金玉黄先祥谢伟达第二炮兵工程学院西安710025 香港城市大学香港

弱冲击故障检测是故障诊断中既困难又十分重要的研究课题,是实现故障早期诊断的基本手段。本文在分析了现有的冲击检测技术存在问题的基础上,基于盲均衡理论提出一种独特的直接提取和检测弱冲击故障信号的方法。首先根据动力学理论研究... 详细信息

弱冲击故障检测是故障诊断中既困难又十分重要的研究课题,是实现故障早期诊断的基本手段。本文在分析了现有的冲击检测技术存在问题的基础上,基于盲均衡理论提出一种独特的直接提取和检测弱冲击故障信号的方法。首先根据动力学理论研究和建立了机械系统早期冲击响应模型,分析了较小冲击下的振动响应特征;然后根据盲均衡理论研究和建立了提取弱冲击信号的盲均衡模型和算法,并进行改进;最后用两个冲击实验和一个实际工程实例进行实际检验。研究结果表明本方法能够十分有效地从有噪声和干扰中检测期望的信号。

关键词：盲均衡冲击故障故障检测故障诊断

基于EEMD和改进的形态滤波方法的轴承故障诊断研究

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振动与冲击 2013年第2期32卷 39-43,66页

作者：沈长青谢伟达朱忠奎刘方黄伟国孔凡让中国科学技术大学精密机械与精密仪器系合肥230027 香港城市大学系统工程与工程管理系苏州大学城市轨道交通学院江苏苏州215021

轴承故障会导致振动信号中出现冲击响应成分,可通过对冲击响应成分的周期的检测与提取,进行局部故障诊断。但在复杂工况下,故障脉冲易被周围噪声淹没,在分析EEMD和形态学滤波方法的基础上,将EEMD方法与形态学滤波方法相结合,提出结构元... 详细信息

轴承故障会导致振动信号中出现冲击响应成分,可通过对冲击响应成分的周期的检测与提取,进行局部故障诊断。但在复杂工况下,故障脉冲易被周围噪声淹没,在分析EEMD和形态学滤波方法的基础上,将EEMD方法与形态学滤波方法相结合,提出结构元素(SE)选择方法,并用于本征模态信号中冲击响应特征的提取。通过将该方法用于轴承外圈、内圈局部故障状态下的特征的检测,结果表明该方法能有效提取周期性脉冲成分并抑制噪声。

关键词：轴承故障诊断整体平均经验模态分解滤波数学形态学

Limits on light emission from silicon

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Chinese Optics Letters 2009年第4期7卷 268-270页

作者： peter würfel Institut für Angewandte Physik Universitt KarlsruheD-76128 KarlsruheGermany

Although silicon is an indirect semiconductor, light emission from silicon is governed by the same gener- alized Planck＇s radiation law as the emission from direct semiconductors. The emission intensity is given by the absorptance of the volume in which there is a difference of the quasi Fermi energies. A difference of the Fermi energies may result h＇om the absorption of external light （photoluminescence） or from the injection of electrons and holes via selective contacts （electroluminescence）. The quantum efficiency may be larger than 0.5 for carrier densities below 10^15 cm^-3. At larger densities, non-radiative recombination, in particular Auger recombination dominates. At all carrier densities, the relation between emission intensity and difference of the quasi Fermi energies is maintained. Since this difference is equal to the voltage of a properly designed solar cell, luminescence is the key indicator of material quality for solar cells.

关键词： Carrier concentration Fermi level Light Light emission Photoluminescence Semiconducting silicon Silicon

Unfolded p53 in non-neuronal cells supports bacterial etiology of Alzheimer’s disease

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Neural Regeneration Research 2022年第12期17卷 2619-2622页

作者： peter w.French Innlanz Limited SydneyNSWAustralia

Alzheimer’s disease has proven to be largely intractable to treatment,despite years of research,and numerous trials of therapies that target the hallmarks of the disease-amyloid plaques and neurofibrillary *** etiology of Alzheimer’s disease remains *** is a growing body of evidence for an infectious trigger of Alzheimer’s disease,and,in particular,the focus has been on the oral pathogen Porphyromonas gingivalis(***).Reports of the expression of a misfolded form of p53 in non-neuronal cells(fibroblasts,peripheral blood mononuclear cells,and B cells)and serum,which appears several years before clinical symptoms manifest,may provide further support for the role of bacteria in general,and *** in particular,in the initiation of the *** review presents a model of the pathway from initial oral infection with *** to amyloid plaque formation and neuronal degeneration,via the steps of chronic periodontitis;secretion of the inflammagens lipopolysaccharide and gingipains into the bloodstream;induction of an inflammatory response in both peripheral cells and tissues;disruption of the blood-brain barrier,and entry into the central nervous system of the inflammagens and the *** bacteria *** this model,the misfolded p53(or“unfolded p53”;up53)is induced in non-neuronal cells and upregulated in serum as a result of oxidative stress due to lipopolysaccharide from ***53 is therefore a potential biomarker for early diagnosis of the presence of a causative agent of Alzheimer’s *** dental hygiene and aggressive antibiotic treatment may prevent the patient progressing to clinical Alzheimer’s disease if serum up53 is detected at this pre-symptomatic stage.

关键词： Alzheimer’s disease gingipains lipopolysaccharide P.gingivalis periodontitis unfolded p53

High-throughput physical phenotyping of cell differentiation

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Microsystems & Nanoengineering 2017年第1期3卷 316-322页

作者： Jonathan Lin Donghyuk Kim Henry T.tse peter tseng Lillian Peng Manjima Dhar Saravanan Karumbayaram Dino Di Carlo Department of Bioengineering University of CaliforniaLos AngelesCA 90095USA CytoVale Inc. 384 Oyster Point Boulevard#7 SouthSan FranciscoCA 94080USA Department of Biomedical Engineering Tufts UniversityMedfordMA 02155USA Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research Los AngelesCA 90095USA California NanoSystems Institute Los AngelesCA 90095USA Jonsson Comprehensive Cancer Center Los AngelesCA 90095USA Department of Mechanical Engineering University of CaliforniaLos AngelesCA 90095USA

In this report,we present multiparameter deformability cytometry(m-DC),in which we explore a large set of parameters describing the physical phenotypes of pluripotent cells and their derivatives.m-DC utilizes microfluidic inertial focusing and hydrodynamic stretching of single cells in conjunction with high-speed video recording to realize high-throughput characterization of over 20 different cell motion and morphology-derived *** extracted from videos include size,deformability,deformation kinetics,and *** train support vector machines that provide evidence that these additional physical measurements improve classification of induced pluripotent stem cells,mesenchymal stem cells,neural stem cells,and their derivatives compared to size and deformability *** addition,we utilize visual interactive stochastic neighbor embedding to visually map the high-dimensional physical phenotypic spaces occupied by these stem cells and their progeny and the pathways traversed during *** report demonstrates the potential of m-DC for improving understanding of physical differences that arise as cells differentiate and identifying cell subpopulations in a label-free ***,such approaches could broaden our understanding of subtle changes in cell phenotypes and their roles in human biology.

关键词： cell mechanics deformation deformation kinetics morphology physical phenotype stem cells

Differential Kinematic Encoding of Saccades and Smooth-pursuit Eye Movements by Fastigial Neurons

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Neuroscience Bulletin 2022年第8期38卷 927-932页

作者： Zongpeng Sun peter w.Dicke peter Thier School of Psychology Shaanxi Normal UniversityXi’an710062China Department of Cognitive Neurology Hertie Institute for Clinical Brain Research72076TübingenGermany

Dear Editor,Saccades and smooth-pursuit eye movements(SPEMs)are two categories of eye movements with very different kinematics,in particular very different acceleration and velocity ranges,differences that have contributed to the notion of largely segregated underlying neuronal *** instance,it has been suggested that distinct wellsegregated pools of oculomotor vermis(OMV)Purkinje cells(PCs)are specialized for the fine-tuning of the relevant kinematic parameters characterizing each of them.

关键词： pursuit specialized instance

Laser-Based Guided wave Propagation and Mode Decomposition in Detecting the Integrity of Structural I-Beams

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Journal of Computer and Communications 2018年第1期6卷 42-55页

作者： peter tse Faeez Masurkar Smart Engineering Asset Management Laboratory (SEAM) and Croucher Optical Non-Destructive Testing and Quality Inspection Laboratory (CNDT) Department of Systems Engineering and Engineering Management City University of Hong Kong Hong Kong China

This paper addresses the studies carried out on an I-beam to reveal the wave propagation characteristics and tackle the multi-mode propagation of Lamb waves. The experimental setup consisted of a new 3D Scanning Laser Doppler Vibrometer manufactured by Polytec (3D-SLDV) and was used to acquire high resolution time-space Lamb waves that were propagating in the I-beam. A high power and pulsed Nd:YAG laser was used to emit the required Lamb waves. The emission and sensing of the waves were carried out simultaneously. The wave propagation data was recorded by scanning the surface of the I-beam in a sequential manner. The measured data was used to construct the wave patterns that were propagating in the I-beams at different time instants. Furthermore, as the waves in an I-Beam propagate with multiple modes even at low frequency range, filtering was carried out in the frequency-wavenum- ber domain in order to decompose the modes. The results presented thereby confirm that the new 3D-SLDV possesses tremendous capability in revealing the wave propagation characteristics and its interaction with defect. The results could be the first time that the waves propagating in a real I-beam can be visually observed, whilst in the past, it can only be visualized through simulation. The capability of using such totally laser-based 3D inspection system to reveal the characteristics of Lamb wave and its interaction with defects are substantial.

关键词： Laser System I-Beam Lamb waves Mode Decomposition Surface Defect

On the Range of the Common Cycle Time in a Road Network

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Journal of Harbin Institute of Technology(New Series) 2015年第6期22卷 31-36页

作者： Ting Lu Marko wlki peter wagner Institute of Transportation Systems German Aerospace Center (DLR) Faculty of Maritime and Transportation Ningbo University

In a coordinated road network,the optimal common cycle time is determined by evaluating the performance of the network in the given range of cycles. Normally,this range is determined by users 'experience. And a large range of common cycle time,e. g. [30,200] is chosen,which requires long computation time. This study considers that the optimal common cycle time ranges between the minimal and maximal value of intersections' individual optimal cycle time. It is proved mathematically from the convexity condition,that the delay of the network and each individual intersection are convex functions of the cycle time according to webster delay model. Finally,2 000 random cases for the network composed of two intersections and of eight intersections are created to underline the proposed conclusions. The results of all cases confirm the validity,and show up to 90% improvement in computation time to compare with experience range. The signal optimization tool,Synchro,is also used to validate the conclusion by 50 random cases. The results confirm reliability further.

关键词： common cycle traffic signal optimization convexity webster model