Parameter identification of the Bouc-Wen model for the magnetorheological damper using fireworks algorithm

Xiaoliang Chen,Liyou Xu,Shuai Zhang,Sixia Zhao,Kui Liu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

To solve the problems of low identification accuracy and complex identification methods in the Bouc-Wen model of the magnetorheological (MR) damper, a new parameter identification method using the fireworks algorithm (FWA) is proposed. According to the experimental results of the dynamic characteristics of the MR damper and the simulation data of the Bouc-Wen model, the FWA is used to identify the seven parameters of the Bouc-Wen model. On the basis of the relationship between the identification results and the command current, the current-controlled Bouc-Wen model (I-Bouc-Wen model) is constructed and compared with the experimental results under different sinusoidal excitation frequencies. Compared with the genetic algorithm (GA), differential evolution (DE) algorithm, and particle swarm optimization (PSO) algorithm, the FWA has the advantage of faster convergence, shorter calculation time, and higher stability in solving the parameter identification problem of the highly nonlinear hysteretic model. Under three harmonic excitations, the average calculation accuracies of the IBouc-Wen model reache 88.64 %, 90.45 %, and 81.28 %, respectively, and the dynamic characteristic curve of the model is in basic agreement with the experimental results. It can be used for the subsequent controller design and simulation research and lay a foundation for applying the parameterized model of the MR damper in vibration reduction control.

MiR-200c-3p inhibits LPS-induced M1 polarization of BV2 cells by targeting RIP2

Zhao Lei,Liu Xiaosong,Yang Jiankai,Wang Xiaoliang,Liu Xiaomeng,Wu Jianliang,Li Chen,Xu Donggang,Hu Yuhua 한국유전학회 2022 Genes & Genomics Vol.44 No.4

Background: Microglia are important immune cells, which can be induced by lipopolysaccharide (LPS) into M1 phenotype that express pro-inflammatory cytokines. Some studies have shown that microRNAs play critical roles in microglial activation. Objective: This study was designed to investigate the role of miR-200c-3p in regulating inflammatory responses of LPS-treated BV2 cells. Methods: The expression of miR-200c-3p in BV2 cells was detected by real-time PCR. Receptor-interacting protein 2 (RIP2) was predicted as a target gene of miR-200c-3p. Their relationship was verified by dual-luciferase reporter assay. The function of miR-200c-3p and RIP2 in microglial polarization and NF-κB signaling was further evaluated. Results: LPS treatment reduced miR-200c-3p expression in a dose-dependent and time-dependent manner in BV2 cells. LPS treatment increased the expression of M1 phenotype markers inducible nitric oxide synthase (iNOS) and major histocompatibility complex class (MHC)-II, promoted the release of pro-inflammatory cytokines interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α, and enhanced the nuclear translocation and phosphorylation of nuclear factor-kappaB (NF-κB) p65. Reversely, miR-200c-3p mimics down-regulated the levels of these inflammatory factors. Furthermore, RIP2 was identified to be a direct target of miR-200c-3p. RIP2 knockdown had a similar effect to miR-200c-3p mimics. Overexpression of RIP2 eliminated the inhibitory effect of miR-200c-3p on LPS-induced M1 polarization and NF-κB activation in BV2 cells. Conclusions: MiR-200c-3p mimics suppressed LPS-induced microglial M1 polarization and NF-κB activation by targeting RIP2. MiR-200c-3p/RIP2 might be a potential therapeutic target for the treatment of neuroinflammation-associated diseases.

RUNX1 Ameliorates Rheumatoid Arthritis Progression through Epigenetic Inhibition of LRRC15

Jian-ning Zhao,Hao Ding,Xiaoliang Mei,Lintao Li,Peng Fang,Ting Guo 한국분자세포생물학회 2023 Molecules and cells Vol.46 No.4

Leucine-rich repeat containing 15 (LRRC15) has been identified as a contributing factor for cartilage damage in osteoarthritis; however, its involvement in rheumatoid arthritis (RA) and the underlying mechanisms have not been well characterized. The purpose of this study was to explore the function of LRRC15 in RA-associated fibroblastlike synoviocytes (RA-FLS) and in mice with collagen-induced arthritis (CIA) and to dissect the epigenetic mechanisms involved. LRRC15 was overexpressed in the synovial tissues of patients with RA, and LRRC15 overexpression was associated with increased proliferative, migratory, invasive, and angiogenic capacities of RA-FLS and accelerated release of pro-inflammatory cytokines. LRRC15 knockdown significantly inhibited synovial proliferation and reduced bone invasion and destruction in CIA mice. Runt-related transcription factor 1 (RUNX1) transcriptionally represses LRRC15 by binding to core-binding factor subunit beta (CBF-β). Overexpression of RUNX1 significantly inhibited the invasive phenotype of RA-FLS and suppressed the expression of proinflammatory cytokines. Conversely, the effects of RUNX1 were significantly reversed after overexpression of LRRC15 or inhibition of RUNX1-CBF-β interactions. Therefore, we demonstrated that RUNX1-mediated transcriptional repression of LRRC15 inhibited the development of RA, which may have therapeutic effects for RA patients.

A Hybrid PWM Scheme for Stator Loss Reduction of Two Parallel Interleaved Inverter-Fed PMSM Drive with a Minimized Switching Loss

Liu Shengfu,Jin Xiaoliang,Shi Wen,Yang Huan,Zhao Rongxiang 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.1

The modulation’s eff ects on the stator losses have been explored by previous studies. It confi rms that the voltage vector error introduced by the PWM schemes dominants the PWM-related harmonic eddy-current loss and the PWM-related harmonic copper loss. However, the existing PWM schemes of two parallel inverter focus on the ZSCC peak reductions. They do not explore the reductions of the voltage vector error by the optimal vector sequences to suppress the stator loss. This paper aims to reduce the stator loss of the permanent magnet synchronous motor (PMSM) drive systems fed by the two parallel interleaved inverter with an optimal PWM scheme. First, this paper investigates the eff ects of the instantaneous voltage vector error, resulting from a PWM inverter, on the eddy-current loss and stator copper loss and reveals that a reduced voltage error reduces the eddy-current loss and stator copper loss. Then, this paper divides each 60° sector into six subsectors to minimize the voltage vector error, and with the proposed sector division, it further elects the optimal vector sequences for the subsectors, applying the minimum switching times per carrier period. Besides, the proposed optimal vector sequences are implemented through a simplifi ed carrier-based method. The presented analysis confi rms that the proposed PWM scheme can reduce the eddy-current loss, stator copper loss, and switching loss of the existing methods. Finally, the experimental results verify the theoretical analysis and optimal performance of the proposed modulation strategy.

Distribution characteristics and processes along flow paths of shallow groundwater in the Tan-Lu fault zone in Anhui province, China

Dejian Wang,Jiazhong Qian,Weidong Zhao,Xiaoliang Hou,Wei Wang,Lei Ma 한국지질과학협의회 2022 Geosciences Journal Vol.26 No.4

To disclose the distribution characteristics, the situation of flow and storage, and processes along flow paths of shallow groundwater in Tan-Lu fault zones, nine hundred and seven groundwater table elevations data and one hundred hydrochemical samples of shallow groundwater were taken from the Tan-Lu fault zone in Anhui province to analyze the characteristic of groundwater distribution. The geographic information system (GIS) method was used to analyze the spatial distribution characteristics of groundwater tables, total dissolved solids (TDS) and chloride ion (Cl−). Geophysical prospecting, drilling material and regional hydrogeological survey were utilized to disclose groundwater storage and flow regime in the fault zone. The results show that the Tan-Lu fault zone in Anhui province has controlled groundwater flow into the Jiashan basin, Hefei basin, Chaohu area and Qianshan basin, which developed from north to south in this area. Groundwater in theses basins have recharged from surrounding areas to form a water storage space. Geophysical prospecting and drilling technology revealed that the Tan-Lu fault zone provided a flow channel and storage space for groundwater. Faults provide preferential channels in some areas for the groundwater flow and circulation, eventually deep hot-water flows upward and discharges in the form of hot-springs. The identification of the groundwater flow pathway can help to provide a reliable scientific basis for regional spatial development and utilization of groundwater resources.

Full speed range position‑sensorless compound control scheme for PMSMs

Pu Liu,Di Liu,Yongpeng Shen,Ankang Liu,Xiaoliang Yang,Jun Zhao 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.8

At low speeds, a high frequency signal injection method for the position-sensorless control of permanent magnet synchronous motors (PMSMs) produces additional power loss and position estimation delay. Meanwhile, at high speeds, the sliding mode observer (SMO) method has a chattering problem. With a focus on these problems, a full speed range position-sensorless compound control approach is proposed in this paper. First, the phase relationship between the different coordinate systems of the I/F control, and the mechanism of the chattering phenomenon of a sliding mode observer are analyzed. Then the full speed range position-sensorless control approach based on a combination of I/F control and an extended sliding mode observer is constructed. Through feeding back the estimated back electromotive force to the calculation of the stator current observer and using the rotated influence immune phase-locked loop, the innovative extended-SMO effectively improves the chattering phenomenon. Furthermore, the smooth transition between the two control schemes is achieved by a current slope decrement switching controller. Finally, the effectiveness of the proposed full speed range position-sensorless compound control approach for PMSMs is validated on a surface PMSM experimental bench.

The Role of Neutrophil-to-Lymphocyte Ratio in Predicting Pathological Response for Resectable Non–Small Cell Lung Cancer Treated with Neoadjuvant Chemotherapy Combined with PD-1 Checkpoint Inhibitors

Xiaoyan Sun,Yingnan Feng,Bin Zhang,Wuhao Huang,Xiaoliang Zhao,Hua Zhang,Dongsheng Yue,Changli Wang 대한암학회 2022 Cancer Research and Treatment Vol.54 No.4

Purpose The aim of our study was to investigate the value of baseline and preoperative neutrophil-to-lymphocyte ratio (NLR) in predicting the pathological response and disease-free survival (DFS) of neoadjuvant chemotherapy alone or combined with programmed cell death-1 (PD-1) checkpoint inhibitors in patients with resectable non–small cell lung cancer (NSCLC). Materials and Methods Resectable NSCLC patients who underwent neoadjuvant chemotherapy alone or combined with PD-1 checkpoint inhibitors between January 2018 and January 2020 were included. Peripheral venous blood samples of the patients were collected within 3 days prior to the first neoadjuvant treatment and within 3 days prior to surgery. Results A total of 79 patients in neoadjuvant chemotherapy combined with PD-1 checkpoint inhibitors group and 89 patients in neoadjuvant chemotherapy alone group were included. Thirty-five point four percent of the patients achieved pathological complete response (pCR) in neoadjuvant chemotherapy combined with PD-1 checkpoint inhibitors group, whereas only 9.0% reached pCR in the group of neoadjuvant chemotherapy. High NLR level were correlated with poor pathological response and DFS in neoadjuvant chemotherapy or combined with PD-1 checkpoint inhibitors group. Multivariate analysis revealed that baseline NLR could independently predict pathological response and DFS in the neoadjuvant chemotherapy combined with PD-1 checkpoint inhibitors group. Conclusion High NLR level were correlated with poor pathological response and shorter DFS in patients with NSCLC undergoing neoadjuvant chemotherapy or combined with PD-1 checkpoint inhibitors. Meanwhile, baseline NLR could independently predict response to pathological response and DFS, revealing its potential as a screening tool in NSCLC patients who received neoadjuvant chemotherapy combined with PD-1 checkpoint inhibitors.