A Novel Vibration Model for Explanation of the Frequency Features in Multistage Wind Turbine Gearboxes Considering the Effects of Inter-stage Meshing Frequency Modulation

Yanyan Nie,Fangyi Li,Liming Wang,Jianfeng Li,Yanle Li,Mingshuai Sun,Mengyao Wang,Guoyan Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.1

As a kind of green energy, wind energy has become cost-competitive mainstream energy in the world. The gearbox is one of the most important and vulnerable components in the wind turbine (WT), which suffers a high failure rate and downtime. It is of great significance to the condition monitoring and fault diagnosis of the WT gearbox. However, in the multistage WT gearbox, the vibrations generated from different stages are coupled, which leads to a complex vibration spectral structure and brings difficulties in condition monitoring and fault diagnosis. Aiming to understand the vibration frequency features of multistage WT gearboxes, a novel phenomenological vibration model is established and the spectral structure is deduced by using the Fourier series analysis. In the vibration model, the phenomenon of inter-stage meshing frequency modulation (ISMFM) is considered, which is clearly proposed for the first time. The theoretical derivations are validated by both simulation and engineering tests using a 2.0 MW industrial WT gearbox. The results show that under healthy conditions, in addition to the meshing frequencies and their harmonics of each stage, there are also ISMFM sidebands in the vibration spectrum of the multistage WT gearbox, and the amplitude of the sidebands will change with the health status of the gearbox. The findings are not only applicable to the WT gearbox studied in this paper, but also to other similar multistage gearbox systems, which can provide a priori spectral structure for a multistage gear transmission system to assist its condition monitoring and fault diagnosis.

Wear Resistance of Different Bionic Structure Manufactured by Laser Cladding on Ti6Al4V

Mengyao Wu,Xiaohong Zhan,Hengchang Bu,Lijun Liu,Yuanzeng Song,Yaping Li 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

In this study, the laser cladding system with an IPG YLS-6000 fber laser was used, and the WC–Ti6Al4V powder reinforcedcomposite coatings on Ti6Al4V titanium alloy with various bionic structures were innovatively fabricated. The microstructures and surface damage behavior of the coatings were characterized by scanning electron microscopy, energy dispersivespectroscopy, and X-ray difraction. Additionally, the wear resistance of diferent bionic structures was evaluated, which hadnot been comprehensively explored in the published literature. The results indicated that the un-melted WC particles in thecoatings act as a hard reinforcement, avoiding serious wear of the coating. In addition, the hard coatings exhibit excellentdeformation resistance and the soft substrate cushion the shear stress. So when the “Ratio”, which refers to the laser cladding area to sample area, is between 0.25 and 0.3, the sample has the highest wear resistance. Furthermore, the “Dot+Line”bionic structure has the best wear resistance compared with other structures. The separated line units and the addition of dotunits can improve the stress concentration state of bionic structure are conducive to release the stress to the substrate underthe cladding layer.

Research on vibration control of a transmission tower-line system using SMA-BTMD subjected to wind load

Li Tian,Jingyu Luo,Mengyao Zhou,Wenzhe Bi,Yuping Liu 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.82 No.5

As a vital component of power grids, long-span transmission tower-line systems are vulnerable to wind load excitation due to their high flexibility and low structural damping. Therefore, it is essential to reduce wind-induced responses of tower-line coupling systems to ensure their safe and reliable operation. To this end, a shape memory alloy-bidirectional tuned mass damper (SMA-BTMD) is proposed in this study to reduce wind-induced vibrations of long-span transmission tower-line systems. A 1220 m Songhua River long-span transmission system is selected as the primary structure and modeled using ANSYS software. The vibration suppression performance of an optimized SMA-BTMD attached to the transmission tower is evaluated and compared with the effects of a conventional bidirectional tuned mass damper. Furthermore, the impacts of frequency ratios and SMA composition on the vibration reduction performance of the SMA-BTMD are evaluated. The results show that the SMA-BTMD provides superior vibration control of the long-span transmission tower-line system. In addition, changes in frequency ratios and SMA composition have a substantial impact on the vibration suppression effects of the SMABTMD. This research can provide a reference for the practical engineering application of the SMA-BTMD developed in this study.

Seismic response control of transmission tower-line system using SMA-based TMD

Li Tian,Mengyao Zhou,Canxing Qiu,Haiyang Pan,Kunjie Rong 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.1

This study proposes a new shape memory alloy-tuned mass damper (SMA-TMD) and investigates the effectiveness of this damper in reducing and controlling the vibrations of a transmission tower-line system under various seismic excitations. Based on a practical transmission line system and considering the geometric nonlinearity of this system, the finite element (FE) software ANSYS is used to create an FE model of the transmission tower-line system and simulate the proposed SMA-TMD. Additionally, the parameters of the SMA springs are optimized. The effectiveness of a conventional TMD and the proposed SMA-TMD in reducing and controlling the vibrations of the transmission tower-line system under seismic excitations is investigated. Moreover, the effects of the ground motion intensity and frequency ratio on the reduction ratio (η) of the SMA-TMD are studied. The vibration reduction effect of the SMA-TMD under various seismic excitations is superior to that of the conventional TMD. Changes in the ground motion intensity and frequency ratio have a significant impact on the η of the SMA-TMD. As the ground motion intensity and frequency ratio increase, the η values of the SMA-TMD first increase and then decrease. Studying the vibration reduction effects of the SMA-TMD can provide a reference for the practical engineering application of this damper.

Moving Object Detection Using Sparse Approximation and Sparse Coding Migration

( Shufang Li ),( Zhengping Hu ),( Mengyao Zhao ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.5

In order to meet the requirements of background change, illumination variation, moving shadow interference and high accuracy in object detection of moving camera, and strive for real-time and high efficiency, this paper presents an object detection algorithm based on sparse approximation recursion and sparse coding migration in subspace. First, low-rank sparse decomposition is used to reduce the dimension of the data. Combining with dictionary sparse representation, the computational model is established by the recursive formula of sparse approximation with the video sequences taken as subspace sets. And the moving object is calculated by the background difference method, which effectively reduces the computational complexity and running time. According to the idea of sparse coding migration, the above operations are carried out in the down-sampling space to further reduce the requirements of computational complexity and memory storage, and this will be adapt to multi-scale target objects and overcome the impact of large anomaly areas. Finally, experiments are carried out on VDAO datasets containing 59 sets of videos. The experimental results show that the algorithm can detect moving object effectively in the moving camera with uniform speed, not only in terms of low computational complexity but also in terms of low storage requirements, so that our proposed algorithm is suitable for detection systems with high real-time requirements.

Albumin-binding photosensitizer capable of targeting glioma via the SPARC pathway

Xingshu Li,Jae Sang Oh,이윤지,Eun Chae Lee,Mengyao Yang,Nahyun Kwon,Tae Won Ha,Dong‑Yong Hong,Yena Song,Hyun Kyu Kim,Byung Hoo Song,최선,Man-Ryul Lee,윤주영 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background : Malignant glioma is among the most lethal and frequently occurring brain tumors, and the average survival period is 15 months. Existing chemotherapy has low tolerance and low blood-brain barrier (BBB) permeability; therefore, the required drug dose cannot be accurately delivered to the tumor site, resulting in an insufcient drug efect. Methods : Herein, we demonstrate a precision photodynamic tumor therapy using a photosensitizer (ZnPcS) capable of binding to albumin in situ, which can increase the permeability of the BBB and accurately target glioma. Albuminbinding ZnPcS was designed to pass through the BBB and bind to secreted protein acidic and rich in cysteine (SPARC), which is abundant in the glioma plasma membrane. Results : When the upper part of a mouse brain was irradiated using a laser (0.2 W cm−2) after transplantation of glioma and injection of ZnPcS, tumor growth was inhibited by approximately 83.6%, and the 50% survival rate of the treatment group increased by 14 days compared to the control group. In glioma with knockout SPARC, the amount of ZnPcS entering the glioma was reduced by 63.1%, indicating that it can target glioma through the SPARC pathway. Conclusion : This study showed that the use of albumin-binding photosensitizers is promising for the treatment of malignant gliomas.

The Properties of Planck Galactic Cold Clumps in the L1495 Dark Cloud

Tang, Mengyao,Liu, Tie,Qin, Sheng-Li,Kim, Kee-Tae,Wu, Yuefang,Tatematsu, Ken’ichi,Yuan, Jinghua,Wang, Ke,Parsons, Harriet,Koch, Patrick M.,Sanhueza, Patricio,Ward-Thompson, D.,Tó,th, L. Viktor,S American Astronomical Society 2018 The Astrophysical journal Vol.856 No.2

매드 - 창사 문화 공원_창사, 중국

Yu Kui,Li Guo Jin,Shen Jun,Florian Pucher,Yi Wen Zhen,Li Juan,Zhao Fan,Hao Yi,Yao Mengyao 현대건축사 2006 월간 CONCEPT Vol.- No.86

Recent progress on photodynamic therapy and photothermal therapy

김희정,YANG MENGYAO,권나현,조문연,HAN JINGJING,Wang Rui,Qi Sujie,Li Haidong,Nguyen Van‐Nghia,Li Xingshu,Cheng Hong‐Bo,윤주영 대한화학회 2023 Bulletin of the Korean Chemical Society Vol.44 No.3

Noninvasive treatments for terminal cancer patients constitute a new trend in tumor treatment. Therefore, phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), has attracted considerable interest. Light and a photosensitizer (PS) are employed in both treatment methods. For PDT, the PS generates reactive oxygen species (ROS) when exposed to light, whereas for PTT, the PS generates heat. In this regard, the systematic design of new PSs has become an active area of phototherapy research in an effort to solve the problems associated with conventional PSs. In the past decade, acti- vatable and heavy-atom-free PSs have become significant research areas. Therefore, we discuss our recent contributions to the PDT and PTT in this account.

Developing the Symptoms and Functional Impairment Rating Scale: A Multi-Dimensional ADHD Scale

Yasong Du,Mengyao Li,Wenqing Jiang,Yan Li,David. R. Coghill 대한신경정신의학회 2018 PSYCHIATRY INVESTIGATION Vol.15 No.1

ObjectiveaaThis research developed a practical, multi-dimensional attention deficit hyperactivity disorder (ADHD) rating scale (i.e., the Symptoms and Functional Impairment Rating Scale, SFIRS) for Chinese children, aged 6–12 years, with ADHD. MethodsaaThe structural validity, criterion validity, internal consistency, and test-retest reliability of the scale were evaluated. Item screening was conducted with 412 ADHD patients and 322 developmentally typical controls. ResultsaaThe scale includes 44 items, divided among Hyperactivity-Impulsivity, Self-Control, Inattention, Self-Management, Academic Performance, and Social Interaction. The six-factor model showed good data fit, with each factor significantly correlated with its corresponding criterion (r=0.690–0.841). The Cronbach’s α of the full scale was 0.976. Total score test-retest reliability was r=0.816 (p<0.01). ConclusionaaThe SFIRS thus demonstrated good reliability and validity and may be used to assess ADHD among children aged 6–12 years in China.