Effect of Solid Particles on Cavitation and Lubrication Characteristics of Upstream Pumping Mechanical Seal Liquid Membrane

Chen, Huilong,Sun, Dongdong,Wu, Yuanzheng,Chen, Miaomiao,Zhang, Peilin Korean Society for Fluid machinery 2017 International journal of fluid machinery and syste Vol.10 No.4

In order to investigate the effect of solid particles on the cavitation characteristics and lubricating properties of the micro-gap liquid film in Upstream pumping mechanical seals,the Eulerian multiphase flow model was used to simulate the liquid film with different diameter and volume fraction of solid particles to analyze the influence of the particles on the distribution of vacuole, opening force and friction torque of the film under different working conditions. The results showed that the particles have an inhibitory effect on the cavitation, and the cavitation area and the volume fraction of the bubbles were both decreased.The cavitation area increased with the increase of particle diameter, which indicated that the inhibition of cavitation was weakened with the increase of particle diameter. The cavitation area decreased with the increase of the particle volume fraction, and the volume fraction increased the cavitation inhibition effect. The presence of particles improved the opening force of liquid film to a certain extent and increased with the increase of particle volume fraction, but the effect of particle diameter on opening force was different under different rotating speed and different medium pressure.The friction torque did not change obviously with the particle diameter,and decreased only slightly with the increase of the particle volume fraction.In the working condition range, the cavitation degree is not related to the pressure of the medium, but increases with the increase of the rotational speed, and the cavitation area and volume fraction of bubbles Were significantly decreased when there were solid particles.

Effect of Solid Particles on Cavitation and Lubrication Characteristics of Upstream Pumping Mechanical Seal Liquid Membrane

Huilong Chen,Dongdong Sun,Yuanzheng Wu,Miaomiao Chen,Peilin Zhang 한국유체기계학회 2017 International journal of fluid machinery and syste Vol.10 No.4

In order to investigate the effect of solid particles on the cavitation characteristics and lubricating properties of the micro-gap liquid film in Upstream pumping mechanical seals, the Eulerian multiphase flow model was used to simulate the liquid film with different diameter and volume fraction of solid particles to analyze the influence of the particles on the distribution of vacuole, opening force and friction torque of the film under different working conditions. The results showed that the particles have an inhibitory effect on the cavitation, and the cavitation area and the volume fraction of the bubbles were both decreased. The cavitation area increased with the increase of particle diameter, which indicated that the inhibition of cavitation was weakened with the increase of particle diameter. The cavitation area decreased with the increase of the particle volume fraction, and the volume fraction increased the cavitation inhibition effect. The presence of particles improved the opening force of liquid film to a certain extent and increased with the increase of particle volume fraction, but the effect of particle diameter on opening force was different under different rotating speed and different medium pressure. The friction torque did not change obviously with the particle diameter, and decreased only slightly with the increase of the particle volume fraction. In the working condition range, the cavitation degree is not related to the pressure of the medium, but increases with the increase of the rotational speed, and the cavitation area and volume fraction of bubbles Were significantly decreased when there were solid particles.

Investigate the Effect of Potassium on Nodule Symbiosis and Uncover an HAK/KUP/KT Member, GmHAK5, Strongly Responsive to Root Nodulation in Soybean

Liu Jianjian,Liu Jinhui,Cui Miaomiao,Chen Xiao,Liu Junli,Chen Jiadong,Chen Aiqun,Xu Guohua 한국식물학회 2022 Journal of Plant Biology Vol.65 No.6

Leguminous plants form root nodule organs with soil rhizobia bacteria, which can fix atmospheric nitrogen (N2) and supply ammonia to the host plant. It is established that the symbiotic N fixation efficiency is substantially influenced by plant nutrients, such as molybdenum (Mo), phosphorus (P), copper (Cu), and zinc (Zn). Potassium (K+) is the most abundant cation in plant cells; however, little evidence regarding the potential link between K nutrition and symbiotic N fixation efficiency is available to date. Here, we showed that K+ deficiency reduced the efficiency of symbiotic nitrogen fixation, and inoculated with rhizobia strain USDA110 could improve plant K+ acquisition. Furthermore, we identified a potassium transporter gene (GmHAK5) that was highly expressed in the root steles and in the vasculature cells of nodules. The GmHAK5 protein was localized at the plasma membrane and could rescue the growth phenotype of yeast K+ uptake-defective mutant. The results obtained from this study provides new insights for the understanding of the potential role of K+ nutrition in modulating symbiotic N fixation in soybean.

Adiponectin induced AMP-activated protein kinase impairment mediates insulin resistance in Bama mini-pig fed high-fat and high-sucrose diet

Miaomiao Niu,Lei Xiang,Yaqian Liu,Yuqiong Zhao,Jifang Yuan,Xin Dai,Hua Chen 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.8

Objective: Adipose tissue is no longer considered as an inert storage organ for lipid, but instead is thought to play an active role in regulating insulin effects via secretion adipokines. However, conflicting reports have emerged regarding the effects of adipokines. In this study, we investigated the role of adipokines in glucose metabolism and insulin sensitivity in obese Bama mini-pigs. Methods: An obesity model was established in Bama mini-pigs, by feeding with high-fat and high-sucrose diet for 30 weeks. Plasma glucose and blood biochemistry levels were measured, and intravenous glucose tolerance test was performed. Adipokines, including adiponectin, interleukin-6 (IL-6), resistin and tumor necrosis factor alpha (TNF-α), and glucose-induced insulin secretion were also examined by radioimmunoassay. AMP-activated protein kinase (AMPK) phosphorylation in skeletal muscle, which is a useful insulin resistance marker, was examined by immunoblotting. Additionally, associations of AMPK phosphorylation with plasma adipokines and homeostasis model assessment of insulin resistance (HOMA-IR) index were assessed by Pearce's correlation analysis. Results: Obese pigs showed hyperglycemia, high triglycerides, and insulin resistance. Adiponectin levels were significantly decreased (p<0.05) and IL-6 amounts dramatically increased (p<0.05) in obese pigs both in serum and adipose tissue, corroborating data from obese mice and humans. However, circulating resistin and TNF-α showed no difference, while the values of TNF-α in adipose tissue were significantly higher in obese pigs, also in agreement with data from obese humans but not rodent models. Moreover, strong associations of skeletal muscle AMPK phosphorylation with plasma adiponectin and HOMA-IR index were obtained. Conclusion: AMPK impairment induced by adiponectin decrease mediates insulin resistance in high-fat and high-sucrose diet induction. In addition, Bama mini-pig has the possibility of a conformable model for human metabolic diseases.

Community Discovery in Weighted Networks Based on the Similarity of Common Neighbors

Miaomiao Liu,Jingfeng Guo,Jing Chen 한국정보처리학회 2019 Journal of information processing systems Vol.15 No.5

In view of the deficiencies of existing weighted similarity indexes, a hierarchical clustering method initializeexpand-merge (IEM) is proposed based on the similarity of common neighbors for community discovery inweighted networks. Firstly, the similarity of the node pair is defined based on the attributes of their commonneighbors. Secondly, the most closely related nodes are fast clustered according to their similarity to form initialcommunities and expand the communities. Finally, communities are merged through maximizing themodularity so as to optimize division results. Experiments are carried out on many weighted networks, whichhave verified the effectiveness of the proposed algorithm. And results show that IEM is superior to weightedcommon neighbor (CN), weighted Adamic-Adar (AA) and weighted resources allocation (RA) when usingthe weighted modularity as evaluation index. Moreover, the proposed algorithm can achieve more reasonablecommunity division for weighted networks compared with cluster-recluster-merge-algorithm (CRMA)algorithm.

Differential Hrd1 Expression and B-Cell Accumulation in Eosinophilic and Non-eosinophilic Chronic Rhinosinusitis With Nasal Polyps

Kun Chen,Miaomiao Han,Mengyao Tang,Yadong Xie,Yuting Lai,Xianting Hu,Jia Zhang,Jun Yang,Huabin Li 대한천식알레르기학회 2018 Allergy, Asthma & Immunology Research Vol.10 No.6

Purpose: Hrd1 has recently emerged as a critical regulator of B-cells in autoimmune diseases. However, its role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) remains largely unexplored. This study aimed to examine Hrd1 expression and B-cell accumulation and their possible roles in CRSwNP. Methods: Quantitative real-time polymerase chain reaction, immunohistochemistry, enzyme-linked immunosorbent assay and Western blotting were used to assess gene and protein expression in nasal tissue extracts. Cells isolated from nasal tissues and peripheral blood mononuclear cells were characterized by flow cytometry. Local antibody production was measured in tissue extracts with a Bio-Plex assay. Additionally, changes in Hrd1 expression in response to specific inflammatory stimuli were measured in cultured dispersed polyp cells. Results: Nasal polyps (NPs) from patients with eosinophilic CRSwNP (ECRS) had increased levels of Hrd1, B-cells and plasma cells compared with NPs from patients with non-eosinophilic CRSwNP (non-ECRS) or other control subjects (P < 0.05). The average Hrd1 levels in B-cells in NPs from ECRS patients were significantly higher than those from non-ECRS patients and control subjects (P < 0.05). NPs also contained significantly increased levels of several antibody isotypes compared with normal controls (P < 0.05). Interestingly, Hrd1 expression in cultured polyp cells from ECRS patients, but not non-ECRS patients, was significantly increased by interleukin-1β, lipopolysaccharide and Poly(I:C) stimulation, and inhibited by dexamethasone treatment (P < 0.05). Conclusions: Differential Hrd1 expression and B-cell accumulation between the ECRS and non-ECRS subsets suggests that they can exhibit distinct pathogenic mechanisms and play important roles in NP.

Community Discovery in Weighted Networks Based on the Similarity of Common Neighbors

Liu, Miaomiao,Guo, Jingfeng,Chen, Jing Korea Information Processing Society 2019 Journal of information processing systems Vol.15 No.5

In view of the deficiencies of existing weighted similarity indexes, a hierarchical clustering method initialize-expand-merge (IEM) is proposed based on the similarity of common neighbors for community discovery in weighted networks. Firstly, the similarity of the node pair is defined based on the attributes of their common neighbors. Secondly, the most closely related nodes are fast clustered according to their similarity to form initial communities and expand the communities. Finally, communities are merged through maximizing the modularity so as to optimize division results. Experiments are carried out on many weighted networks, which have verified the effectiveness of the proposed algorithm. And results show that IEM is superior to weighted common neighbor (CN), weighted Adamic-Adar (AA) and weighted resources allocation (RA) when using the weighted modularity as evaluation index. Moreover, the proposed algorithm can achieve more reasonable community division for weighted networks compared with cluster-recluster-merge-algorithm (CRMA) algorithm.

Adaptive Fixed Time Parameter Estimation and Synchronization Control for Multiple Robotic Manipulators

Qiang Chen,Miaomiao Gao,Liang Tao,Yurong Nan 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.9

In this paper, an adaptive fixed time parameter estimation and synchronization control scheme is proposedfor multiple robotic manipulators with unknown parameters and lumped disturbances. A mean coupling synchronization error is defined by averaging all the tracking errors of multiple robotic manipulators, and an adaptive fixed time synchronization control scheme is proposed to guarantee that both the tracking error and the synchronization error can simultaneously converge to zero within a fixed time, which means that the upper bound of the settling time is independent of the initial conditions. Moreover, an adaptive parameter estimation law is developed through constructing auxiliary filtered variables to achieve the accurate estimation of the unknown system parameters. Comparative simulations are provided to validate the effectiveness of the proposed scheme.

Effect of Revolution on Inhomogeneous Deformation of IF Steel in High Pressure Torsion

Song, Yuepeng,Chen, Miaomiao,Xu, Baoyan,Gao, Dongsheng,Kim, Hyoung Seop 'Scientific Research Publishing, Inc.' 2016 Materials sciences and applications Vol.7 No.11

Effects of Friction and Anvil Design on Plastic Deformation during the Compression Stage of High-Pressure Torsion

( Yuepeng Song ),( Miaomiao Chen ),( Baoyan Xu ),( Dongsheng Gao ),( Jing Guo ),( Lingfeng Xu ),( Zheng Wang ),( Hyoung Seop Kim ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.11

Herein, we report the results of our investigation on the effect of friction and anvil design on the heterogeneous plastic-deformation characteristics of copper during the compressive stage of high-pressure torsion (HPT), using the finite element method. The results indicate that the friction and anvil geometry play important roles in the homogeneity of the deformation. These variables affect the heterogeneous level of strain in the HPT compressed disks, as well as the flash in the disk edge region. The heterogeneous plastic deformation of the disks becomes more severe with the increasing depth of the cavity, as anvil angle and friction coefficient increase. However, the homogeneity increases with increases in the wall angle. The length of flash and the area of the dead metal zone increase with the depth of the cavity, while they decrease at a wall angle of 180°. (Received March 17, 2016; Accepted May 25, 2016)