Predicting fatigue life for finite roller contacts based on a mixed EHL model using realistic surface roughness

Mingyong Liu,Chenhui Wu,Chunai Yan 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.7

Surface contact fatigue is a major failure mode of many mechanical components, such as various gear pairs, bearings, cam-follower systems, and so on. The present study aims to develop a fatigue life prediction approach for finite line contact model using machined surface topography. Based on the developed model, the effect of working conditions and lubrication parameters on the lubrication performance and fatigue life are investigated. The obtained results show that, by introducing the realistic roughness, the distribution of pressure, film thickness and stress field is significant fluctuations. Meanwhile, the location of maximum stress tends to move to subsurface. The effect of load on fatigue life is significant. Yet, the speed does not seem to have a great influence on the fatigue life in various load ranges. It is also indicated that the high ambient viscosity is beneficial to the lubrication performance and fatigue life.

Parametric studies of lubrication performance of a helical gear pair with non-Newtonian fluids

Mingyong Liu,Caichao Zhu,Hua iju Liu,Chenhui Wu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.1

In this paper, Thermal elastohydrodynamic lubrication (TEHL) model of a helical gear pair is proposed to study contact performanceduring the whole meshing period. Effects of working conditions and design parameters on lubrication performance, i.e. film thickness,pressure, temperature, friction coefficient, etc. are investigated. Influence of thermal effect and non-Newtonian effect are evaluatedthrough a detailed study on three characteristic meshing positions. Results show that, the thermal effects and non-Newtonian fluid bothhave significant effects on the lubrication performance of the helical gear pair, especially in high speed, heavy load cases. The effects ofnormal pressure angle, helix angle and module on lubrication performance along the line of action are discussed.

Robust Vehicle-Infrastructure Localization Using Factor Graph and Probability Data Association

Feihu Zhang,Mingyong Liu,Dhiraj Gulati,Alois Knoll 한국통신학회 2018 Journal of communications and networks Vol.20 No.4

This paper presents a robust graph-based optimizationframework for vehicle-infrastructure cooperative localization. Compared to the state-of-the-art approaches, the proposed solutionkeeps high performance in presence of unknown data associationenvironments. In this paper, the association probability of eachmeasurement is calculated, and then assigned to the correspondingedges on the graph, in which the nonlinear least square method isutilized to optimize the state. Thus the proposed approach presentsa robust framework in the presence of high association uncertaintyduring vehicle-infrastructure cooperative localization, in which thecorresponding weights from outliers are lower than the true vehicles. The experimental results demonstrate the good robustness insimulated data.

A Novel Control Algorithm for the Self-organized Fission Behavior of Flocking System with Time Delay

Panpan Yang,Mingyong Liu,Xiaokang Lei,Cheng Song 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.4

This paper studies the self-organized fission control problem for flocking system with time delay. Bothconstant and time-varying time delay cases are considered. Firstly, a novel information coupling degree (ICD) basedfission control algorithm, which is able to split a coherent flock into multiple sub-groups under conflict externalstimuli, is proposed. Then, for the case of constant time delay, the sufficient conditions for the fission controlalgorithm is derived using Lyapunov-Razumikhin theorem. For the case of time-varying time delay, Lyapunov-Krasovskii functional method is adopted to obtain the sufficient conditions for the fission control algorithm in termsof linear matrix inequalities (LMIs). Finally, numerical simulations are provided to illustrate the effectiveness ofthe theoretical results.

SVQL: A SQL Extended Query Language for Video Databases

Chenglang Lu,Mingyong Liu,Zongda Wu 보안공학연구지원센터 2015 International Journal of Database Theory and Appli Vol.8 No.3

With the rapid increasing of video data, video queries are becoming increasingly important. To better describe users’ video query requirements, developing a functional video query language has become a promising and interesting task. In this paper, we present a novel query language called SVQL for video databases, which is developed based on an extension of the traditional database query language SQL. In SVQL, we remain the clear and concise grammatical framework of SQL, thereby making SVQL easy to learn and use for traditional users, i.e., making SVQL with a user-friendly interface. Moreover, we extend the WHERE clause of SQL to introduce new conditional expressions, such as variable declaration, structure specification, feature specification and spatial-temporal specification, thereby, making SVQL with powerful expressiveness. In this paper, we first present the formal definitions of SVQL and illustrate its basic query capabilities using examples. Then, we discuss the SVQL query processing techniques. Finally, we evaluate SVQL through the comparison with other existing video query languages, and the evaluation results demonstrate the practicality and effectiveness of our proposed query language for video databases

Oil film stiffness and damping in an elastohydrodynamic lubrication line contact-vibration

Yuanyuan Zhang,Hua iju Liu,Caichao Zhu,Mingyong Liu,Chaosheng Song 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7

An elastohydrodynamic lubrication line contact-vibration model is proposed to study the stiffness and damping of the oil film existed in the EHL contact region. An initial mutual approach between interacting surfaces, which deviates from the steady-state balanced position, is assumed under the free contact-vibration to predict the response of the mutual approach. An inertia term, which represents the acceleration of the gap motion, is added to the classical force balance equation to form the equation of motion of the mutual approach. Response of the mutual approach is solved based upon the solving of the contact-dynamic model. The oil stiffness is calculated according to the natural frequency of the response under damped and non-damped conditions, the latter of which represents dry contact conditions. The oil film damping is calculated in terms of the principle of the energy conservation which utilizes the whole history of response compared with the log decrement method. Effect of the normal load, the rolling speed and the amplitude of the regular sinusoidal surface waviness on the oil film stiffness, the contact stiffness and the oil film damping are studied. The study provides an insight on the oil film dynamic characteristics of lubricated contact-vibration problems which appear in gears, bearings, etc. The results show that the oil film damping factor decreases with the increasing normal load as well as the increasing rolling speed. The oil film stiffness increases with the normal load and decreases with the rolling speed. Also, compared to the contact stiffness, the oil film stiffness makes less contribution to the total stiffness. The surface waviness amplitude has little effect on the oil film stiffness and the oil film damping.

Dietary Supplementation with Acanthopanax senticosus Extract Modulates Cellular and Humoral Immunity in Weaned Piglets

Kong, Xiangfeng,Yin, Yulong,Wu, Guoyao,Liu, Hejun,Yin, Fugui,Li, Tiejun,Huang, Ruilin,Ruan, Zheng,Xiong, Hua,Deng, Zeyuan,Xie, Mingyong,Liao, Yiping,Kim, Sungwoo Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.9

This study was conducted to test the hypothesis that dietary supplementation with an herbal extract of Acanthopanax senticosus (AS) enhances the immune response in weaned piglets. Sixty piglets weaned at 21 days of age were randomly assigned to 3 treatment groups representing the addition of 0 or 1 g/kg of the AS extract or 0.2 g/kg of colistin (an antibiotic) to maize- and soybean meal-based diets (n = 20 per group). On days 7, 14 and 28 after initiation of the addition, total and differential counts of leucocytes, proliferating activity of peripheral lymphocytes, serum levels of immunoglobulins (Ig) and cytokines and the spleen index were determined. The AS extract decreased (p<0.05) the number of neutrophils on days 7 and 28 in comparison with the control group and reduced (p<0.05) serum interleukin-$1{\beta}$ level on day 28 compared with the other 2 groups. Dietary supplementation with the AS extract increased (p<0.05) the lymphocyte/leukocyte ratio on day 28 compared with the control group and increased the proliferating activity of lymphocytes on days 14 and 28 compared with the other 2 groups. The AS extract increased (p<0.05) the serum content of IgG on day 7 and of IgG and IgM on day 28 compared with the other 2 groups, as well as increasing the serum content of tumor necrosis factor on day 7 and spleen index on days 7 and 28 compared with the control group. Collectively, these findings suggest that the AS extract as a dietary additive enhances the cellular and humoral immune responses of weaned piglets by modulating the production of immunocytes, cytokines and antibodies.

Pim-1 Protects Retinal Ganglion Cells by Enhancing Their Regenerative Ability Following Optic Nerve Crush

Shoumei Zhang,Li Shuai,Dong Wang,Tingting Huang,Shengsheng Yang,Mingyong Miao,Fang Liu,Jiajun Xu 한국뇌신경과학회 2020 Experimental Neurobiology Vol.29 No.3

Provirus integration site Moloney murine leukemia virus (Pim-1) is a proto-oncogene reported to be associated with cell proliferation, differentiation and survival. This study was to explore the neuroprotective role of Pim-1 in a rat model subjected to optic nerve crush (ONC), and discuss its related molecules in improving the intrinsic regeneration ability of retinal ganglion cells (RGCs). Immunofluorescence staining showed that AAV2- Pim-1 infected 71% RGCs and some amacrine cells in the retina. Real-time PCR and Western blotting showed that retina infection with AAV2- Pim-1 up-regulated the Pim-1 mRNA and protein expressions compared with AAV2-GFP group. Hematoxylin-Eosin (HE) staining, γ-synuclein immunohistochemistry, Cholera toxin B (CTB) tracing and TUNEL showed that RGCs transduction with AAV2-Pim-1 prior to ONC promoted the survival of damaged RGCs and decreased cell apoptosis. RITC anterograde labeling showed that Pim-1 overexpression increased axon regeneration and promoted the recovery of visual function by pupillary light reflex and flash visual evoked potential. Western blotting showed that Pim- 1 overexpression up-regulated the expression of Stat3, p-Stat3, Akt1, p-Akt1, Akt2 and p-Akt2, as well as βIII-tubulin, GAP-43 and 4E-BP1, and downregulated the expression of SOCS1 and SOCS3, Cleaved caspase 3, Bad and Bax. These results demonstrate that Pim-1 exerted a neuroprotective effect by promoting nerve regeneration and functional recovery of RGCs. In addition, it enhanced the intrinsic regeneration capacity of RGCs after ONC by activating Stat3, Akt1 and Akt2 pathways, and inhibiting the mitochondrial apoptosis pathways. These findings suggest that Pim-1 may prove to be a potential therapeutic target for the clinical treatment of optic nerve injury