The influence of lateral shock absorber valve parameters on vehicle dynamic performance

Xiao Qian,Li Qinghua,Chang Chao 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.5

The shock absorber is important for improving train dynamics characteristics, and its valve parameters determine its performance andalso directly affect the train dynamics characteristics. Hydraulic control model of lateral shock absorber is established by using parametricmodeling method in Easy5, and CRH2 trailer model is constructed in VI-Rail. Calculation result of shock absorber model’s speedcharacteristic is embedded into the vehicle model. The accuracy of the vehicle model is verified by a real track-test, and numerical analysisis done about the influence of various parameters on vehicle dynamics performance. The research results show that critical velocityand stability index increase with the increase of damping aperture and through-flow aperture. One-way valve aperture of bottom valveand one-way valve aperture of piston have little influence on those performance. As spring stiffness increases in the range of 800-2000N/cm, critical velocity increases and stability index decreases, and its influence is little if spring stiffness is beyond this scope. As preloadforce of spring increases in the range of 100-250 N, critical velocity increases and stability index decreases, and its influence is also littleif the preload force of spring is beyond this scope.

Analysis of the wheel/rail rolling contact fatigue of a high-speed train under the transient mechanism

Qian Xiao,Jifeng Zheng,Jihua Liu,Jun Fang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5

The Rolling contact fatigue (RCF) damage of high-speed wheels is a main factor that affects railway safety. This paper presents a Finite element model (FEM) of high-speed transient rolling contact that considers kinetic parameters as initial conditions. This model is used to calculate wheel/rail RCF. With a CRH2 high-speed train as the research object, a head car model is established with the multibody dynamics software UM. The train is driven on a straight track at a speed of 300 km/h. Different contact geometric parameters, such as lateral displacement and attack angle, are obtained. A 3D high-speed transient elastic-plastic FEM of wheel/rail rolling contact is then developed by using ABAQUS with the initial dynamic contact geometric parameters. The actual geometries of the wheel tread and rail head as well as the elastic-plastic properties are considered in this model. This consideration makes the model highly suitable for solving 3D transient rolling contact behavior. The normal force, creep force, and contact area in the contact patch are solved and used in the fatigue model. Owing to the hunting movement of wheels, the wheel/rail force and lateral displacement change significantly at 0.2 and 0.5 s. The longitudinal and lateral creep force increase sharply with the increase in shear stress. The work states of the wheel/rail at 0.2 and 0.5 s easily reach the ratchet effect zone, and the fatigue index is large. The fatigue damage of the wheels is generally near the nominal rolling circle.

Cinnamaldehyde Derivatives Inhibit Coxsackievirus B3-Induced Viral Myocarditis

( Xiao-qiang Li ),( Xiao-xiao Liu ),( Xue-ying Wang ),( Yan-hua Xie ),( Qian Yang ),( Xin-xin Liu ),( Yuan-yuan Ding ),( Wei Cao ),( Si-wang Wang ) 한국응용약물학회 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.3

The chemical property of cinnamaldehyde is unstable in vivo, although early experiments have shown its obvious therapeutic effects on viral myocarditis (VMC). To overcome this problem, we used cinnamaldehyde as a leading compound to synthesize derivatives. Five derivatives of cinnamaldehyde were synthesized: 4-methylcinnamaldehyde (1), 4-chlorocinnamaldehyde (2), 4-methoxycinnamaldehyde (3), α-bromo-4-methylcinnamaldehyde (4), and α-bromo-4-chlorocinnamaldehyde (5). Neonatal rat cardiomyocytes and HeLa cells infected by coxsackievirus B3 (CVB3) were used to evaluate their antiviral and cytotoxic effects. In vivo BALB/c mice were infected with CVB3 for establishing VMC models. Among the derivatives, compound 4 and 5 inhibited the CVB3 in HeLa cells with the half-maximal inhibitory concentrations values of 11.38 ± 2.22 μM and 2.12 ± 0.37 μM, respectively. The 50% toxic concentrations of compound 4 and 5-treated cells were 39-fold and 87-fold higher than in the cinnamaldehyde group. Compound 4 and 5 effectively reduced the viral titers and cardiac pathological changes in a dose-dependent manner. In addition, compound 4 and 5 significantly inhibited the secretion, mRNA and protein expressions of inflammatory cytokines TNF-α, IL-1β and IL-6 in CVB3-infected cardiomyocytes, indicating that brominated cinnamaldehyde not only improved the anti-vital activities for VMC, but also had potent anti-inflammatory effects in cardiomyocytes induced by CVB3.

Halitosis: an underestimated but important extraintestinal manifestation in inflammatory bowel disease

Xiao Xian Qian 대한장연구학회 2024 Intestinal Research Vol.22 No.3

Relationship Between the SER Treatment Period and Prognosis of Patients with Small Cell Lung Cancer

Xiao, Xiao-Guang,Wang, Shu-Jing,Hu, Li-Ya,Chu, Qian,Wei, Yao,Li, Yang,Mei, Qi,Chen, Yuan Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.15

Purpose: To explore the relationship between SER (time between the start of any treatment and the end of radiation therapy) and the survival of patients with limited-stage small cell lung cancer. Materials and Methods: Between 2008 and 2013, 135 cases of limited-stage small cell lung cancer (LS-SCLC) treated with consecutively curative chemoradiotherapy were included in this retrospective analysis. In terms of SER, patients were divided into early radiotherapy group (SER<30 days, n=76) and late radiotherapy group ($SER{\geq}30$ days, n=59) with a cut-off of SER 30 days. Outcomes of the two groups were compared for overall survival. Results: For all analyzable patients, median follow-up time was 23.8 months and median overall survival time was 16.8 months. Although there was no significant differences in distant metastasis free survival between the two groups, patients in early radiotherapy group had a significantly better PFS (p=0.003) and OS (p=0.000). Conclusions: A short SER may be a good prognostic factor for LD-SCLC patients treated with concurrent chemoradiotherapy.

The role of the apoptosis-related protein BCL-B in the regulation of mitophagy in hepatic stellate cells during the regression of liver fibrosis

Qian Ding,Xiao-Li Xie,Miao-Miao Wang,Jie Yin,Jin-Mei Tian,Xiao-Yu Jiang,Di Zhang,Jing Han,Yun Bai,Zi-Jin Cui,Hui-Qing Jiang 생화학분자생물학회 2019 Experimental and molecular medicine Vol.51 No.-

The clearance of activated hepatic stellate cells (HSCs) by apoptosis is critical for the reversibility of hepatic fibrosis. Mitochondrial homeostasis is regulated by mitophagy, which is an efficient way of clearing injured mitochondria that plays an important role in apoptosis. However, the role of mitophagy in apoptosis in HSCs and hepatic fibrosis is still unclear. Here, we show that mitophagy is enhanced in parallel with increased apoptosis in hepatic stellate cells during the reversal of hepatic fibrosis. The inhibition of mitophagy suppressed apoptosis in HSCs and aggravated hepatic fibrosis in mice. In contrast, the activation of mitophagy induced apoptosis in HSCs. Furthermore, we confirmed that BCL-B, which is a member of the BCL-2 family, is a regulator mediating mitophagy-related apoptosis. The knockdown of BCL-B resulted in increased apoptosis and mitophagy in HSCs, while the overexpression of BCL-B caused the opposite effects. BCL-B inhibited the phosphorylation of Parkin (a key regulator of mitophagy) and directly bound phospho-Parkin. Altogether, enhanced mitophagy promotes apoptosis in HSCs during the reversal of hepatic fibrosis. BCL-B suppresses mitophagy in HSCs by binding and suppressing phospho-Parkin, thereby inhibiting apoptosis. BCLB- dependent mitophagy is a new pathway for the regulation of apoptosis in HSCs during the regression of hepatic fibrosis

The XPD Lys751Gln Polymorphism has Predictive Value in Colorectal Cancer Patients Receiving Oxaliplatin-Based Chemotherapy: a Systemic Review and Meta-analysis

Qian, Ying-Ying,Liu, Xin-You,Pei, Dong,Xu, Jia-Li,Shen, Hua,Chen, Xiao-Feng,Liu, Yi-Qian,Shen, Li-Zong,Shu, Yong-Qian Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Background: The predictive value of the xeroderma pigmentosum group D (XPD) Lys751Gln polymorphism regarding clinical outcomes of patients with colorectal cancer (CRC) receiving oxaliplatin-based chemotherapy has been evaluated in numerous published studies, but the results remain inconclusive. Therefore, we performed a meta-analysis to determine the precise role of the XPD Lys751Gln polymorphism in this clinical situation and optimize individual chemotherapy. Materials and Methods: A multiple search strategy was used to identify eligible studies. Pooled odds ratios (ORs), generalized odds ratio (ORG) and their 95% confidence intervals (CIs) were used to estimate the objective response, while hazard ratios (HRs) with 95%CIs were used for progression-free survival (PFS) and overall survival (OS). Results: A total of 17 studies including 2,286 patients met the inclusion criteria. Overall, the XPD 751Gln allele was associated with a non-significant reduced objective response to oxaliplatin-based chemotherapy in all patients or in the Asian and Caucasian subgroups. However, poor PFS and OS of CRC patients treated with oxaliplatin-based regimens were significantly related to the XPD 751Gln allele in the dominant model (PFS: HR=2.10, 95%CI: 1.65-2.67; OS: HR=3.18, 95%CI: 1.57-6.47). On stratified analysis by ethnicity, these relationships were more pronounced in Asians (PFS: HR=2.49, 95%CI: 1.79-3.47; OS: HR=5.25, 95%CI: 3.46-7.94) than in Caucasians (PFS: HR=1.73, 95%CI: 1.22-2.46; OS: HR=1.78, 95%CI: 1.06-2.99). Conclusions: The XPD Lys751Gln polymorphism may have prognostic value in patients with CRC undergoing oxaliplatin-based chemotherapy.

Weighted FP-Tree Mining Algorithms for Conversion Time Data Flow

Xiao-jun Chen,Jia Ke,Qian-qian Zhang,Xin-ping Song,Xiao-ming Jiang 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.1

The data distribution in the data streams usually changes dynamically with time. Traditional mining algorithms based on transaction are difficult to establish the correlation between time characteristics and relationship features, thus making the results inaccurate. By analyzing the problems in the processing of time data stream, we put forward the concept of time gap degrees and design a mining algorithms based on weighted FP-Tree. We introduce the concept of FP-Tree node weights to transform the time data dynamically and excavate the data stream association rules. The experiments performed on the actual data set show that the algorithm can improve the recall and precision while consumes comparable computational time.

Correlation between Intravoxel Incoherent Motion Magnetic Resonance Imaging Derived Metrics and Serum Soluble CD40 Ligand Level in an Embolic Canine Stroke Model

Xiao-Quan Xu,Chen-Jiang Wu,Shan-Shan Lu,Qian-Qian Gao,Qing-Quan Zu,Xing-Long Liu,Hai-Bin Shi,Sheng Liu 대한영상의학회 2017 Korean Journal of Radiology Vol.18 No.5

Objective: To determine the relationship between intravoxel incoherent motion (IVIM) imaging derived quantitative metrics and serum soluble CD40 ligand (sCD40L) level in an embolic canine stroke model. Materials and Methods: A middle cerebral artery occlusion model was established in 24 beagle dogs. Experimental dogs were divided into low- and high-sCD40L group according to serum sCD40L level at 4.5 hours after establishing the model. IVIM imaging was scanned at 4.5 hours after model establishment using 10 b values ranging from 0 to 900 s/mm2. Quantitative metrics diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) of ischemic lesions were calculated. Quantitative metrics of ischemic lesions were normalized by contralateral hemisphere using the following formula: normalized D = Dstroke / Dcontralateral. Differences in IVIM metrics between the low- and high-sCD40L groups were compared using t test. Pearson’s correlation analyses were performed to determine the relationship between IVIM metrics and serum sCD40L level. Results: The high-sCD40L group showed significantly lower f and normalized f values than the low-sCD40L group (f, p < 0.001; normalized f, p < 0.001). There was no significant difference in D*, normalized D*, D, or normalized D value between the two groups (All p > 0.05). Both f and normalized f values were negatively correlated with serum sCD40L level (f, r = -0.789, p < 0.001; normalized f, r = -0.823, p < 0.001). However, serum sCD40L level had no significant correlation with D*, normalized D*, D, or normalized D (All p > 0.05). Conclusion: The f value derived from IVIM imaging was negatively correlated with serum sCD40L level. f value might serve as a potential imaging biomarker to assess the formation of microvascular thrombosis in hyperacute period of ischemic stroke.

Research on influence of harmonic wear wheel on wheel/rail contact geometry of high-speed train

Qian Xiao,Zhixiang Luo,Xu Xu,Jifeng Zheng,Shu Cheng 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2

Harmonic wear is one of the common wear phenomena of high-speed train wheels. The change of wheel/rail rolling contact geometry leads to unstable characteristics of wheel/rail contact, which directly affects the quality and safety of high-speed train operation. Because wheelset lateral displacement directly affected the wheel/rail contact geometry, in this paper, the UM software was used to establish a high-speed train vehicle-track coupled dynamics simulation model of the CRH2 (China Railway High-speed 2) head car. Lateral displacement of harmonic wear wheel was calculated under different wear condition to analyze the influence of harmonic wear wheels on wheelset lateral displacement. Then according to macroscopic dimension change of the wheel profile from lateral and radial directions of high-speed train induced by harmonic wear wheels, wheel profiles under different wear condition were selected. And wheel/rail contact geometry under different harmonic wear stages was calculated to discuss the influence of harmonic wear wheel on wheel/rail contact geometry. The results show that harmonic order and wave depth of harmonic wear wheel have small influence on the lateral displacement of wheelset, but the influence of wave depth is greater than harmonic order. The average difference of lateral displacement between harmonic wear wheel and no harmonic wear wheel increases with the increase of wave depth and order. In a harmonic wave length, the maximum value of both equivalent conicity and contact angle appear in deepest wave depth. The greater the wave depth, the more obvious the fluctuations, and equivalent conicity changes are less obvious.