Variable step adaptive kurtogram method based on empirical wavelet transform for rolling bearing fault diagnosis

Keqin Zhao,Feng Cheng,Wei-Xi Ji 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6

Envelope analysis is one of the most effective methods in rolling element bearing diagnostics, but finding an optomal frequency band (OFB) has been a challenge for a long time. In this study, a variable-step adaptive kurtogram (VSAK) method based on empirical wavelet transform (EWT) was proposed to select the OFB and apply it in fault detection of rolling element bearings. The VSAK method mainly contains signal reconstruction based on EWT and detection of the appropriate demodulation frequency band based on RK. A new weighted kurtosis-RK was applied in this VSAK method to reduce the influence of high gaussian noise. According to simulation and experimental studies, the results showed that, VSAK was superior over those traditional methods, such as FK and autogram, for the diagnosis of rolling element bearing. It was also concluded that, the sum of amplitude corresponding to the first five fault harmonic frequencies based on VSAK was larger than the sum of amplitude based on FK as well as autogram method.

A Lectin Receptor Kinase Positively Regulates ABA Response During Seed Germination and Is Involved in Salt and Osmotic Stress Response

Keqin Deng,Qiming Wang,Jianxin Zeng,Xinhong Guo,Xiaoying Zhao,Dongying Tang,Xuanming Liu 한국식물학회 2009 Journal of Plant Biology Vol.52 No.6

Lectin receptor-like kinases (LecRK) are widespread in higher plants; however, little is known about their physiological roles. In this study, At1g70130 (designated LecRK-b2), an Arabidopsis LecRK gene, has been investigated. LecRK-b2 was predominantly expressed during seed germination, and its expression was ceased following germination. The expression of LecRK-b2 was induced by abscisic acid (ABA), salt, and osmotic stress. LecRK-b2 lossof- function mutation slightly reduced the ABA sensitivity during seed germination, and this reduced sensitivity was demonstrated not due to lower ABA accumulation level in the seeds. Dual-luciferase transient expression assay confirmed that the transcription factor ABSCISIC ACID INSENSITIVE3 (ABI3) could activate the luciferase under driving of LecRK-b2 promoter. LecRK-b2 transcription level was found to be down-regulated in abi3 during seed germination. Furthermore, LecRK-b2 loss-of-function mutation reduced the salt and osmotic sensitivity during early development stage of Arabidopsis. Taken together, these results suggest that LecRK-b2 functions as a positive regulator of the ABA response during the seed germination and is involved in salt and osmotic stress response in the early development stage.

Association of CDKN2B-AS1 rs1333049 with Brain Diseases: A Case-control Study and a Meta-analysis

Jikuang Zhao,Xizheng Wu,Sheng Nie,Xiang Gao,Jie Sun,Keqin Li,Tiefeng Zhang,Yi Huang 대한정신약물학회 2017 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.15 No.1

Objective: CDKN2B-AS1 polymorphisms were shown to associate with the risk of stroke in European. The goal of this study was to evaluate the contribution of CDKN2B-AS1 rs1333049 to the risk of hemorrhagic stroke (HS) and brain tumor (BT) in Han Chinese. Methods: A total of 142 HSs, 115 BTs, and 494 controls were included in the current association study. The genotyping test was performed using the melting temperature shift method. Results: We failed to validate the association of CDKN2B-AS1 rs1333049 with the risk of brain disease. Significantly higher levels of low-density lipoprotein cholesterol (LDL-C) (p=0.027), high-density lipoprotein cholesterol (HDL-C) (p<0.001) and total cholesterol (TC) (p<0.001) were found in HSs in the genotype GG/GC carriers, but not the genotype CC carriers (p>0.05). The meta-analysis of 10 studies among 133,993 individuals concluded that rs1333049 of CDKN2B-AS1 gene was likely to increase a 16% incidence rate of cerebrovascular disease (CD) among various populations (odds ratio 1.16, 95% confidence interval 1.08-1.25; p<0.0001, random-effect method). Conclusion: Our case-control study identified rs1333049 genotypes showed different association with the concentration of the LDL-C, HDL-C and TC in the HS patients. Meta-analysis supported the association between rs1333049 and CD risk in various populations, although we were unable to observe association between rs1333049 and the risk of HSs in Han Chinese.

Quantitative evaluation of through-thickness rectangular notch in metal plates based on lamb waves

Na Zhao,Bin Wu,Xiucheng Liu,Keqin Ding,Yanan Hu,Mahmoud Bayat 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.71 No.6

Lamb wave technology is a promising technology in the field of structural health monitoring and can be applied in the detection and monitoring of defects in plate structures. Based on the reconstruction algorithm for the probabilistic inspection of damage (RAPID), a Lamb-based detection and evaluation method of through-thickness rectangular notches in metal plates was proposed in this study. The influences of through-thickness rectangular notch length and the angle between sensing path and notch length direction on signals were further explored through simulations and experiments. Then a damage index calculation method which focuses on both phase and amplitude difference between detected signals and baseline signals was proposed. Based on the damage index difference between two vertically crossed sensing paths which pass through the notch in a sensor network, the notch direction identification method was proposed. In addition, the notch length was determined based on the damage index distribution along sensing paths. The experimental results showed that the image reconstructed with the proposed method could reflect the information for the evaluation of notches.

Ginseng polysaccharides: Potential antitumor agents

Ruizhi Tao,Keqin Lu,Gangfan Zong(강사),Yawen Xia,Hongkuan Han,Yang Zhao,Zhonghong Wei,Yin Lu 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.1

Automatic bearing diagnosis based on improved empirical wavelet decomposition and nonparametric test

Hongyan Jiang,Keqin Zhao,Lifei Chen,Dianjun Fang,Feng Cheng,Yong Chen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

The 1/3-binary tree structure bandwidth is fixed, while the bands containing fault information sometimes do not fall equally in the fixed structure. To solve this problem, it is proposed to utilize the power spectrum to replace the Fourier spectrum, and to reconstruct the signal based on the scale space representation for the empirical wavelet decomposition. The fluctuation characteristics of the power spectrum frequency components and the energy distribution within frequency bands are taken full advantage of in this method. A new size parameter updating mechanism is employed to accelerate the signal reconstruction process. At the same time, it is thought that fault frequency is affected by the factor of slippage phenomena in order to realize a self-running diagnosis of bearing failure, and the occurring probability of the bearing fault is introduced to transform the envelope spectrum into a scalar indicator. As a result, without human intervention, the whole failure diagnosis process of the rolling bearing can be achieved by the manner of nonparametric testing. Simulation signal analysis results and experimental analysis results demonstrate the effectiveness and superiority of the proposed method.

A Defect in Zinc Finger Protein Double B-box 1a (DBB1a) Causes Abnormal Floral Development in Arabidopsis

Qiming Wang,Xiaoju Tu,Keqin Deng,Jianxin Zeng,Xiaoying Zhao,Dongying Tang,Xuanming Liu 한국식물학회 2009 Journal of Plant Biology Vol.52 No.6

The double B-box (DBB) type zinc finger protein has thus far been shown to be involved in photomorphegenesis in Arabidopsis thaliana. Here, we show that DBB1a is expressed in the embryo, cytolden, and flower. Misexpression of DBB1a in mutant plants resulted in abnormal numbers and patterns of floral organs. We further show that DBB1a could regulate expression of several floral homeotic genes, including APETALA 2, APETALA 3, PISTILLATA, and AGAMOUS. Interestingly, expression of the microRNA gene MiR172, which is involved in organ boundary establishment, was also misregulated in the dbb1a mutant plants. Our study identified a previously uncharacterized role of DDB1a in regulation of expression of floral homeotic genes and miR172, which is important for understanding of floral pattern formation.