Design and Numerical Study of Hybrid Magnetic Source Disc-type Magnetorheological Valve

Xiaolong Yang,Yan Li,Youming Zhou,Shiying Zhou,Jiehong Zhu 한국자기학회 2023 Journal of Magnetics Vol.28 No.2

Magnetorheological valves are important components in hydraulic systems that provide precise position control. At present, the low-pressure drop performance of magnetorheological valves is the main problem limiting their application. To improve the pressure drop performance of magnetorheological valves, a hybrid magnetic source disc magnetorheological valve is proposed. The magnetic pressure drop model and viscous pressure drop model of the hybrid magnet source disc type magnetorheological valve based on the Bingham model are Derived. Magnetic field distributions in the damping channel of the hybrid magnet source disc type magnetorheological valve are obtained by using ANSYS finite element analysis software. The mathematical model of the relationship between pressure drop and magnetic induction intensity was established using Matlab software, and the effects of parameters such as effective current, axial damping gap, radial damping gap, and coil width on the pressure drop performance of disc-type magnetorheological valves with hybrid magnetic sources were numerically analyzed. The results show that the pressure drop of the disc magnetorheological valve with a hybrid magnetic source can reach 10.9935 MPa at the current I=3A, axial damping gap ga=1 mm, and radial damping gap gr=1.5 mm. Compared with the conventional disc magnetorheological valve, the pressure drop performance of the hybrid magnetic source disc magnetorheological valve is improved by 28 %, which provides ideas on how to improve the pressure drop performance of the magnetorheological valve.

Optimization of Nutrients for Dinactin Production by a Marine Streptomyces sp. from the High Latitude Arctic

Jiao Zhou,Hao He,Xiaolong Wang,Jian Lu,Xiangshan Zhou,Menghao Cai,YuanXingZhang 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4

Streptomyces sp. R-527F, which produces the macrotetrolide antibiotic dinactin, was isolated from the sediments of the Arctic Ocean. In this work, optimization of the nutrients required for dinactin production including medium development and precursor stimulation, were investigated. Optimization of the medium and replacement of polar sea water were achieved using a one factor at a time experiment in conjunction with statistical analysis using methods covering Plackett–Burman design, the steepest descent method and central composite design. Dinactin production in the optimized medium was 160.8 mg/L, which was 47 fold higher than the control. Supplementation of the fermentation with exogenous acetate (1.5 mmol/L), succinate (6 mmol/L), malonate (24 mmol/L) and citrate (6 mmol/L) further enhanced dinactin biosynthesis by 42.7, 122.3, 66.7, and 62.1%, respectively. The precursors, in particular succinate, facilitated sugar use and also increased pH levels. Furthermore, a six-pulse feeding of total 6 mmol/L succinate in a 5 L bioreactor fermentation yielded a maximal production of 279.0 mg/L dinactin, 124.1% higher than that without precursor stimulation. This nutritional regulation process is easy to scale up and holds the potential for adaptation to industrial use. Keywords: arctic actinomycete, fermentation, dinactin

Enhancing densification and electrical properties of KNN-based lead-free ceramics via two-step sintering

Zhou Yu,Fang Bijun,Zhang Shuai,Lu Xiaolong,Ding Jianning 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.5

0.95(Li 0.02 Na 0.50 K 0.48 )(Nb 0.95 Sb 0.05 )O 3 -0.05AgTaO 3 (0.95LNKNS-0.05AT) lead-free piezoelectric ceramics were prepared by conventional ceramic processing via the two-step sintering process (abbreviated as TSS). The influences of sintering condi- tions in the first stage of the TSS process on densification, dielectric and piezoelectric properties of the 0.95LNKNS-0.05AT ceramics prepared by the TSS were deeply studied. By introducing TSS for preparing the 0.95LNKNS-0.05AT ceramics, the volatilization of alkali metal elements can be decreased and all the 0.95LNKNS-0.05AT ceramics show high densifica- tion. By optimizing the T 1 sintering temperature and t 1 holding time in the first stage of the TSS, the relative permittivity of the 0.95LNKNS-0.05AT ceramics sintered at 1140 °C for 0.5 h and 1050 °C for 8 h is increased to 5957 at 1 kHz, while the relative permittivity of the 0.95LNKNS-0.05AT ceramics prepared by the conventional sintering method (abbreviated as CS) is only 5205. The d 33 , g 33 , and K p values are increased from 134 pC/N, 14.6 × 10 –3  Vm/N, and 17.4% to 224 pC/N, 25.5 × 10 –3  Vm/N, and 31.9%, respectively. The 0.95LNKNS-0.05AT ceramics exhibit thermal activation relaxation behav- ior, and the high-temperature Cole–Cole impedance performance can be fitted well by the equivalent circuit (RQC) and equivalent circuit (RC) connected in series. The space charge effect conforms to the Arrhenius relationship, which presents a thermally activated hopping type process and relates to the oxygen vacancies generated by the evaporation of alkali metals during the TSS process.

Emergent constraints on future projections of the western North Pacific Subtropical High

Xiaolong Chen,Tianjun Zhou,Peili Wu,Zhun Guo,Minghuai Wang 한국기상학회 2023 한국기상학회 학술대회 논문집 Vol.2023 No.4

Fluctuation Power Control Strategy for MMC-based SST to Reduce the Submodule Capacitor Voltage Oscillation

Xiaolong Cai,Jianwen Zhang,Gang Shi,Xu Cai,Jianqiao Zhou,Zhuyong Li,Jiacheng Wang,Jiajie Zang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

In the future AC-DC hybrid distribution system, solid state transformer (SST) will take place of conventional transformer, as it could reduce the weight and volume of transformer, and achieve voltage and current regulation, power flow control, power quality enhancement. MMC-based SST is a novel SST topology, which could provide the MVDC port. However, the excessive bulky submodule capacitors limits this topology into practical application. This paper proposes a fluctuation power control strategy for MMC-based SST to reduce the submodule capacitor voltage oscillation, which could optimize the capacitance and reduce the volume and cost of capacitor. The feasibility of this proposed method is verified by MATLAB simulation.

MiR-126-3p inhibits apoptosis and promotes proliferation by targeting phosphatidylinositol 3-kinase regulatory subunit 2 in porcine ovarian granulosa cells

Zhou, Xiaofeng,He, Yingting,Jiang, Yao,He, Bo,Deng, Xi,Zhang, Zhe,Yuan, Xiaolong,Li, Jiaqi Asian Australasian Association of Animal Productio 2020 Animal Bioscience Vol.33 No.6

Objective: Numerous studies have indicated that the apoptosis and proliferation of granulosa cells (GCs) are closely related to the normal growth and development of follicles and ovaries. Previous evidence has suggested that miR-126-3p might get involved in the apoptosis and proliferation of GCs, and phosphatidylinositol 3-kinase regulatory subunit 2 (PIK3R2) gene has been predicted as one target of miR-126-3p. However, the molecular regulation of miR-126-3p on PIK3R2 and the effects of PIK3R2 on porcine GCs apoptosis and proliferation remain virtually unexplored. Methods: In this study, using porcine GCs as a cellular model, luciferase report assay, mutation and deletion were applied to verify the targeting relationship between miR-126-3p and PIK3R2. Annexin-V/PI staining and 5-ethynyl-2'-deoxyuridine assay were applied to explore the effect of PIK3R2 on GCs apoptosis and proliferation, respectively. Real-time quantitative polymerase chain reaction and Western Blot were applied to explore the regulation of miR-126-3p on PIK3R2 expression. Results: We found that miR-126-3p targeted at PIK3R2 and inhibited its mRNA and protein expression. Knockdown of PIK3R2 significantly inhibited the apoptosis and promoted the proliferation of porcine GCs, and significantly down-regulated the mRNA expression of several key genes of PI3K pathway such as insulin-like growth factor 1 receptor (IGF1R), insulin receptor (INSR), pyruvate dehydrogenase kinase 1 (PDK1), and serine/threonine kinase 1 (AKT1). Conclusion: MiR-126-3p might target and inhibit the mRNA and protein expressions of PIK3R2, thereby inhibiting GC apoptosis and promoting GC proliferation by down-regulating several key genes of the PI3K pathway, IGF1R, INSR, PDK1, and AKT1. These findings would provide great insight into further exploring the molecular regulation of miR-126-3p and PIK3R2 on the functions of GCs during the folliculogenesis in female mammals.

Glial and Vascular Cell Regulation of the Blood-Brain Barrier in Diabetes

Xiaolong Li,Yan Cai,Zuo Zhang,Jiyin Zhou 대한당뇨병학회 2022 Diabetes and Metabolism Journal Vol.46 No.2

As a structural barrier, the blood-brain barrier (BBB) is located at the interface between the brain parenchyma and blood, and modulates communication between the brain and blood microenvironment to maintain homeostasis. The BBB is composed of endothelial cells, basement membrane, pericytes, and astrocytic end feet. BBB impairment is a distinguishing and pathogenic factor in diabetic encephalopathy. Diabetes causes leakage of the BBB through downregulation of tight junction proteins, resulting in impaired functioning of endothelial cells, pericytes, astrocytes, microglia, nerve/glial antigen 2-glia, and oligodendrocytes. However, the temporal regulation, mechanisms of molecular and signaling pathways, and consequences of BBB impairment in diabetes are not well understood. Consequently, the efficacy of therapies diabetes targeting BBB leakage still lags behind the requirements. This review summarizes the recent research on the effects of diabetes on BBB composition and the potential roles of glial and vascular cells as therapeutic targets for BBB disruption in diabetic encephalopathy.

Liquid crystal lens with a concave polyimide layer

Zhou, Zuowei,Li, Xiaolong,Ren, Hongwen SPIE - International Society for Optical Engineeri 2017 Optical engineering Vol.56 No.7

Preparation and Self-Healing Behaviors of Poly(acrylic acid)/Cerium Ions Double Network Hydrogels

Hongwei Zhou,Guohe Xu,Jie Li,Shihao Zeng,Xiaolong Zhang,Zhaohui Zheng,Xiaobin Ding,Weixing Chen,Qiguan Wang,Wenzhi Zhang 한국고분자학회 2015 Macromolecular Research Vol.23 No.12

This work aims at developing an approach to poly(acrylic acid)/cerium ions (PAA/cerium ions) double network hydrogels and exploring the self-healing properties of the hydrogels, with expectation to provide some clues for constructing new healable gel actuators and enrich the family of self-healable hydrogels. The hydrogel is covalently crosslinked by a traditional crosslinking agent N,N'-methylene bis-acrylamide to form the first network and further physically crosslinked by the ionic interaction between cerium ions and the carboxyl groups in the hydrogel network. The preparation method and self-healing behaviors of the hydrogels are investigated.

Research on the Performance of Magnetorheological Semi-Active Suspension with Stepped By-Pass Valve based on Fuzzy PID Control

Chenguang Yang,Xiaolong Yang,Youming Zhou 한국자기학회 2023 Journal of Magnetics Vol.28 No.3

At present, most of the seat suspensions of heavy-duty trucks use passive suspension and active suspension. The passive suspension has gradually failed to meet people's needs in terms of vibration reduction performance, and the active suspension will consume too much energy. In this paper, a stepped by-pass valve magnetorheological semi-active suspension based on fuzzy PID control is proposed. The Simulink is used to simulate the system. In the case of sinusoidal excitation, the results show that this semi-active suspension reduces the vertical acceleration by 44.36%, the dynamic deflection of the suspension by 29.63% and the dynamic deformation of the tire by 43.78% compared with the passive suspension. Under the condition of C-level road surface input, the vertical acceleration of the suspension is reduced by 35.14%, the dynamic deflection of the suspension is reduced by 31.93%, and the dynamic deformation of the tire is reduced by 27.65%.