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The objective of this study is to investigate the safety of high temperature superconducting (HTS) high-speed maglev trains operating in an open environment subjected to strong crosswinds. Therefore, a full-size numerical model of the HTS high-speed maglev engineering prototype is developed based on the 3-D, steady RANS method and SST k-ω turbulence model. Then, the aerodynamic loads are added to the simplified aerodynamic loading center of the train, and a dynamic vehicle model on basis of the special nonlinear magnetic-track relationship is established to study the variation of safety indexes of the HTS maglev train under different crosswinds and operation speeds. It is found that the safety indexes of the maglev train meet the requirements under different crosswind scenarios, indicating that the HTS maglev engineering prototype has great stability against crosswinds. It is expected to adapt to high-speed operation and withstand at least 20.7 m/s crosswind speed under 600 km/h operation speed, to provide a reference for future engineering applications of the HTS maglev train.

Damage identification of axle-box bearings is essential to ensure the safe operation of railway trains. The envelope spectrums generated by spectral coherence are effective bearing damage identification tools, but the traditional spectral coherence-based envelope spectrums cannot effectively reveal the bearing damage features under strong interference noise or cannot fully extract the damage information distributed in multiple spectral frequency bands. To solve these problems, a weighted combined envelope spectrum (WCES) based on spectral coherence is proposed as an enhanced bearing damage detector in this paper. First, the frequency domain signal-to-noise ratio (FDSNR) is devised to measure the damage information in each spectral frequency component of spectral coherence. Then, an information threshold is introduced into the estimated FDSNR to construct a weighting function to enhance the informative spectral frequency components and eliminate the interference components. Eventually, the spectral coherence normalized by the weighting function is integrated to generate WCES for bearing damage identification. The simulation and experimental results indicate that the proposed method can effectively excavate the fault-related information and detect railway axle-box bearing damages, and the comparisons with the state-of-the-art methods demonstrate the superiority of the proposed method.

Based on one-dimensional inviscid isentropic theory, the equations of flow parameters around a subsonic evacuated tube train are derived. In choked condition, the flow of tube throat reach the speed of sound and mass flow will not increase for a fixed upstream pressure and temperature. The flow around the subsonic evacuated tube train is a non-choked or a choked flow, under different operating speeds and blockage ratios. The flow parameters inside the tube can be solved. The theoretical results are compared and verified by numerical simulation using the overset mesh technique. The results show that the error between the theoretical and numerical results in the non-choked condition is within 2%. The maximum relative error in the choked state is 6.6%. When using the overset mesh technique for transient simulations, the initial speed of the train in the numerical simulation causes a higher intensity of shock and expansion waves inside the tube, but does not affect the results in other regions. In summary, the theoretical equation can predict the characteristics of compressible flow around a subsonic evacuated tube train.

High-temperature superconducting (HTS) maglev has excellent potential in high-speed transportation due to its capability of passive stabilization levitation. However, in applications, the vibration of maglev vehicle with a large amplitude will be triggered for some external incentives or interference owing to its weak damping characteristics. Hence, it is preferable and necessary to find a way to reduce the vibration without mechanical contact. In terms of mechanical structure, the HTS maglev system mainly consists of HTS bulks and permanent magnets guideway (PMG). Utilizing the magnetic field provided by PMG, we designed and assessed an electromagnetic shunt damper (EMSD) for the HTS maglev system, by which the vibrations can be attenuated without contact. At first, the parameters of EMSD were theoretically optimized, respectively. Second, according to the structure of the Halbach PMG, the experimental EMSD was presented. In this damper, two groups of coils in reverse series were set above the two magnetic poles of the PMG to get a large induced electromotive force. Eventually, the experimental results show that the vibrations of the HTS maglev model vehicle can be attenuated more than 80% in the resonance region when the designed EMSD was employed in the system. Namely, this non-contacting damper will highly enhance the dynamic characteristics of HTS maglev systems.

To achieve the running control of the all-wheel-driving and active-steering articulated vehicles (AWDASAVs) with n-units, an adaptive tracking control method is proposed in this paper, which includes a real-time target trajectory generation and an adaptive tracking control system. Firstly, the AWDASAV kinematics model is derived, and then the front-axle trace as the target trajectory is computed for all rear-axle steering by using data compressing and filtering, coordinate transformation, and local spline differences, which has small data storage and high computational efficiency and makes it easier to use in AWDASAV. Secondly, an adaptive tracking control system composed of an adaptive active steering controller and a differential distribution controller is designed to achieve accurate trajectory tracking and coordinated movement for AWDASAV. Finally, the AWDASAV simulation model with five-units was built in ADAMS by code development for cross-validation simulation, and the simulations with two cases at various speeds are carried out to verify the simulation model and control method. To further investigate the proposed method, the influence of three parameters on the tracking control performance and comparison with different control methods are carried out. The results exhibit excellent tracking control performance.

It is a practical engineering problem to lift the pantograph during train operation. In this paper, a pantograph-catenary (PAC) model is established, which can realize pantograph lifting during train operation. In this model, the contact model between contact piece and contact wire is established using the polygon contact model (PCM). The PAC collision test rig is established, and the simulation model at low speed is verified by comparing the contact force and vertical acceleration of contact piece obtained from simulation and test. The factors influencing the process of pantograph lifting are analyzed. The simulation results show that the position where the dropper and contact wire are connected is the most disadvantageous position for pantograph lifting. The maximum impact force increases with the increase of pantograph lifting speed, and the relationship between them is linear. In addition, if the influence of aerodynamic force is not considered, the running speed of vehicle will not affect the pantograph lifting process.

To realize the running control of distributed-drive and active-steering articulated virtual rail trains travelling on urban roads under non-contact virtual rail constraints, target trajectory generation and active-steering control are crucial issues. In this article, a novel tracking control method is proposed, which includes a dynamic target trajectory generation and a new active-steering tracking control system. First, a distributed-drive and active-steering articulated virtual rail train kinematics model with n-sections is derived, and then a new target trajectory generation method is proposed using data filtering and compression, coordinate transformation and spline difference, and the simulation comparison shows that the proposed method has less data storage space and high computational efficiency. Second, a new active-steering tracking control system composed of a rear axle preview active-steering controller, a front axle coordinated steering controller, and a differential-distribution controller is designed to achieve tracking control and coordinated movement of distributed-drive and active-steering articulated virtual rail train. Finally, a distributed-drive and active-steering articulated virtual rail train simulation model was constructed in ADAMS, and then simulations are performed under three rail conditions and compared with the other two methods, which show that the proposed method has good tracking control accuracy, adaptability, and superiority under various rails and different speeds.

Due to urbanisation and the economic challenges of traffic, it is urgently necessary to develop an environmentally friendly virtual-track train with suitable speed, high load capacity and low construction cost in China. To guide the design and evaluate this train’s dynamic behaviour, a spatial-dynamics model has been developed based on the dynamics theory and tyre-road interaction. The proposed dynamics model comprises mechanical vehicle systems, traction and braking characteristics and tyre-road dynamic interactions. The coupling effects amongst those systems of virtual track train are derived theoretically for the first time. The nonlinear characteristics of the tyre are modelled by the transit tyre-magic formula with consideration of road irregularities. Based on a designed PID controller and the comprehensive dynamics model, the dynamic performance of the system can be revealed considering motion coupling effects and complicated excitations, especially under traction and braking conditions. The dynamic responses of whole virtual track train can be obtained by numerical integration under different conditions. The vibration characteristics of such train are assessed under running at a constant speed and during the traction/braking process. The results show that the vibrations of the vehicle system are significantly influenced by road irregularities, especially at high speed ranges. The motions and vibrations of different components are intensive coupled, which should not to be neglected in the dynamics assessment of the virtual track train. Besides, the dynamics model can also be applied to dynamics-related assessment (fatigue, strength and some damage conditions, et al.) and parameter optimisation of the virtual-track train.

An extended pantograph-catenary (PAC) contact collision model is presented in this paper. The catenary is described by a finite element model while the pantograph is described by a multi-body model. The normal collision model is established by using the Hertzian contact theory. A 1:1 PAC collision contact test rig is built to validate the pantograph-lifting model. The dynamic responses of the PAC system during lifting the pantograph with different velocities and positions are studied. The research results show that the velocity and position of lifting the pantograph will affect the pantograph-lifting time, acceleration of collector piece, vertical displacement and contact force in the process of lifting pantograph. When the velocity of lifting the pantograph exceeds 0.5 m/s, the contact force between the pantograph and the contact wire will exceed 250 N, which is the allowed value set in the provisions of EN50367. It is essential to control the velocity of lifting the pantograph below 0.4 m/s to prevent the catenary or contact piece from being damaged due to the excessive impact force. The distribution of the droppers also affects the collision force between the PAC system.

The Gini index (GI), GI II, and GI III are proven to be effective sparsity measures in the fields of machine condition monitoring and fault diagnosis, and they can be reformulated as the ratio of different quasi-arithmetic means (RQAM). Under this framework, generalized Gini indices (GGIs) have been developed for sparse quantification by applying nonlinear weights to GI, and another generalized form of GI, referred to here as power function-based Gini indices I (PFGI1s), has been introduced by using power function as the generator of quasi-arithmetic means. The GGIs with different weight parameters exhibit reliable sparse quantization capability for repetitive transient features, while their repetitive transient discriminability is lower than kurtosis and negentropy under noise contamination. PFGI1 achieves enhanced repetitive transient discriminability with increasing power exponent, showing the advantage of the generalization approach. In this paper, based on RQAM, a single-parameter generalization method for generating PFGI1s is introduced into GI II and GI III from the perspective of the quasi-arithmetic mean generator, which leads to the power function-based Gini indices II and III (PFGI2s and PFGI3s) constructed from GI II and GI III, respectively. Mathematical derivation proves that PFGI2s and PFGI3s satisfy at least five of six typical attributes of sparsity measures and are two new families of sparsity measures. Simulation analysis shows that, similar to PFGI1s, PFGI2s and PFGI3s can monotonically estimate the sparsity of the data sequence and can simultaneously achieve strong random transient resistibility and high repetitive transient discriminability compared with traditional sparsity measures. The experimental results of bearing run-to-failure demonstrate that PFGI1s, PFGI2s, and PFGI3s with appropriate power exponents can effectively quantify the repetitive transient features caused by bearing faults and can accurately characterize the bearing degradation status compared with the state-of-the-art sparsity measures.

A sparse squared envelope is crucial for efficient and accurate diagnosis of bearing faults. Blind deconvolution (BD) is a well-established sparse feature enhancement method for the diagnostics of rolling bearings. Traditional BD methods, such as minimum entropy deconvolution (MED), are susceptible to random transients, making it difficult to enhance fault features of rolling bearings subject to strong random shocks. Deconvolution methods that take the fault characteristic frequency (or fault impulse period) of interest as an algorithm input parameter, such as maximum second-order cyclostationarity blind deconvolution (CYCBD), can alleviate this deficiency. However, bearing fault features are difficult to be enhanced by these methods when the specified characteristic frequency deviates from the actual value greatly. To overcome these problems, the modified smoothness index (MSI) of the squared envelope is proposed as the objective function of the deconvolution method, and a new BD method is developed to achieve a sparse squared envelope for fault diagnosis of rolling bearings. Furthermore, the methodology is extended to the frequency domain, and another new BD method that utilizes the MSI of the squared envelope spectrum as the objective function is established to achieve a sparse squared envelope spectrum for bearing diagnostics. These two proposed BD methods are robust to random transients and do not require characteristic frequency or impulse period as an input parameter for feature enhancement. The performance of the two proposed BD methods is verified on experimental datasets from two different railway axle bearing test rigs and compared with the state-of-the-art deconvolution methods. The results show that the two proposed methods can effectively enhance repetitive transient features in noisy vibration signals and accurately diagnose different faults of railway axle bearings.

In this paper, an articulated virtual rail train running on an urban road with N-unit is introduced, and a new tracking control system is designed to realize the tracking control of the articulated virtual rail train. First, a dynamic model for the articulated virtual rail train with N-unit is derived with 11N degrees of freedom. Second, based on the dynamic model, a steering control system is designed, which includes the following sub-controllers: a unit 1 front-axle steering controller and a unit 1∼N rear-axle steering controller for approaching the virtual target path, a unit 2∼N front-axle steering controller for coordinating the movement of adjacent units, and a four-wheel-steering (4WS) controller for each unit. Finally, a numerical simulation model of the train with five units is built in MATLAB, and a cross-validation model is built in ADAMS software. The simulation and verification results show that the tracking errors are within 50 mm, and the lateral articulation forces are less than 2 kN, which indicates that the designed control system has a good tracking performance.

The operating temperature plays a key role in the service reliability of ball bearings used in the traction motor of high-speed trains. Studies on the heat generation and temperature distributions of the bearing under the vehicle vibration environment are critical for designing the high-speed train traction motor bearing and to monitor its operation. In this paper, an SKF friction torque model that considers the inlet shear heating reduction and kinematic replenishment/starvation reduction was used to calculate the power loss of the bearing operating in a high-speed train. A thermal analysis model of the bearing, which takes into account the vehicle vibration due to track irregularities, was developed to study the thermal characteristics of the bearing operating in a high-speed train. Experiments were conducted on a service high-speed train (i.e. CRH380B) to validate the proposed bearing thermal analysis model. The thermal characteristics of the bearing and the influence of key factors on the operating temperature of the bearing under vehicle vibration due to track irregularities were studied with the proposed bearing thermal analysis model. The results show that the thermal failure of the bearing subassemblies most likely occurs at the balls region owing to the highest temperature in that region, compared to the inner and outer raceway of the bearing. The method of applying grease with appropriate kinematic viscosity should be adopted to reduce the power loss of bearing while meeting the lubrication requirement. The vehicle vibration due to track irregularities significantly influences the thermal characteristics of high-speed train motor bearings, which cannot be ignored in the thermal analysis of bearings operating in a high-speed train.

Hydraulic dampers are mainly used to maintain high-speed trains in a stable state when running at high speed. In this paper, an equivalent method for the lifetime of dampers is proposed to establish the relationship between the long-term loading test and the mileage in service condition. The performance degradation of the damper at different temperatures is calculated using the long-term loading test carried out under the corresponding temperature conditions. Arrhenius model is applied to convert the degradation under different temperatures, and the sensitive parameter is selected for the conversion of the damper’s performance degradation under different temperatures. An energy method is proposed to solve the problem of the damper lifetime under different loads, so as to achieve the equivalent of the damper between the long-term load test and the mileage in service condition. Finally, taking the anti-yaw damper of a certain type of high-speed train in China as the research object, the lifetime equivalent method proposed in this paper is applied and the result showed that the anti-yaw damper had remaining service life after 2.4 million kilometers of service.

To analyse and simulate the dynamic responses of the gearbox in a vehicle–track system, a three-dimensional vehicle–track coupled dynamics model for high-speed trains has been developed in this study with a comprehensive consideration of the transmission system. Using this dynamics model, the coupling effects between the gearbox housing and its connected components were analysed. Based on the dynamic results, the dynamic stress field of the gearbox housing can be obtained using the finite element methods. The model outputs were successfully validated through comparisons with field test data. Following model validation, the dynamic stress and its distribution throughout the gearbox housing were further investigated under different excitations, including track irregularities, wheel polygonal wear and flatness. The results demonstrate a significant increase in the stress levels of the oil level window aperture and the bottom face of the housing, which coincides with the location of cracks that are formed in the gearbox housing during frequent vehicle operation. While a specific case has been studied here, the proposed dynamics model can be applied to related dynamic assessments, such as vibration or suspension parameter analyses, as well as to stress analyses of any rail vehicle transmission system to guide the maintenance and design.

There is likely to be a demand to run high-speed trains in extreme cold weather conditions in the near future; therefore, it is important to study the change in the characteristics of the materials and components in an extreme cold environment and their effects on the vehicle system dynamics. Experimental research into the low temperature characteristics of a pantograph hydraulic damper was carried out in this study. The results show that low temperature causes an increase in damping forces, and when the temperature is above the boundary temperature range, most indices of the damping capability increase with the decrease of temperature; when the temperature is below the boundary temperature range, most indices decrease with the decrease of temperature. Key parameters are identified to obtain the theoretical description of low-temperature damping characteristics using a simplified-parametric damper model and the experimental data. A mathematical model of the pantograph–catenary system incorporating the pantograph damper model is then established to calculate the effect of the damper performance on the pantograph dynamics low temperatures. Simulation results show that the lowering performance of the pantograph deteriorates noticeably due to the unstable low-temperature damping characteristics, but the deterioration of the raising performance and contact quality of the pantograph due to the low-temperature characteristics of the damper are less obvious. The results obtained in this study are valuable for understanding the low-temperature characteristics of a hydraulic damper, and instructive in the optimal specification of the pantograph damper for high-speed trains running in cold weather conditions.

Solitary fibrous tumours are unusual neoplasms that develop from mesenchymal cells, usually originating from the pleura. A pericardial solitary fibrous tumour is an extremely rare occurrence. We report a 64-year-old woman who presented to the hospital with chief complaints of dyspnoea and abdominal distension. Echocardiography and enhanced computed tomography revealed an intrapericardial tumour with local invasion to the right atrium. Histopathological examination of a biopsy specimen showed a patternless distribution of spindle-shaped cells in a collagen stroma, with a high mitosis rate. Immunohistochemistry was positive for vimentin, CD34, and Bcl-2. The final diagnosis was a pericardial malignant solitary fibrous tumour with right atrial invasion. Surgical resection of the tumour was not performed because of its invasion into the myocardium. We systematically reviewed the literature on cardiac solitary fibrous tumours up to 2019.

The gear transmission system of a high-speed train is the key component, which delivers the traction torque from the motor to the wheelset. It couples with the vehicle system via the suspension system, gear meshing and the wheel–rail interface. The dynamic performance of the transmission system directly affects the operational reliability or even the running safety of high-speed trains. In this study, the effects of wheel polygonalisation and wheel flat on the dynamic responses of the transmission system are investigated through simulations of a novel vehicle dynamics model. This model integrates the flexible gearbox housing, the time-varying mesh stiffness and the nonlinear gear tooth backlash, and the track irregularities to obtain more realistic responses of the traction transmission systems in a vehicle vibration environment, from motors to wheelsets, under the effects of the wheel flat and polygonal wear. The field experimental tests are implemented for a vehicle running along a main high-speed railway line in China. Subsequently, the developed dynamics model is validated with good agreement between the experimental and the theoretical results. The calculated results revealed that wheel flat and wheel polygonal wear caused a high-frequency fluctuation of both the longitudinal creep force and the gear mesh force, causing a violent and complex torsional vibration of the gear transmission system. Moreover, the flexible deformation of the gearbox housing, especially its resonance due to the wheel polygonal wear, contributed to the torsional vibration of the gear transmission system.

Wheel damage of high-speed trains has received great attention since it is detrimental to safety and reliability and consumes huge maintenance costs. However, the mixed operation mode of electric multiple units (EMUs) in China induces great challenges in distinguishing the influence of different railway lines on wheel damage. This paper develops a data-driven approach to quantify the influence of different railway lines on wheel damage and further applies it to damage risk prediction. First, under several fundamental assumptions, linear discriminant analysis and the proposed data padding strategy are used to quantify the influence on wheel damage due to per unit mileage of running on each railway section. The result shows that the influence on wheel damage varies significantly for different railway sections. Then, a route-based predictor is defined to represent the cumulative influence of an EMU’s routes on its wheel damage. Further, a wheel damage prediction model is developed based on a support vector machine using the route-based predictor and three other predictors from the operational data. Validation and test results demonstrate that the actual damage rate is higher for wheelsets predicted with higher damage probabilities. The proposed methodology has the potential to be applied to the risk-based operation and maintenance of high-speed trains.

Optical sensors based on fiber Bragg gratings have become an important type of sensing element for strain measurements. In this study, fiber Bragg grating strain sensors and corresponding reference temperature sensors were integrated into a pantograph strip. The results of an online test indicated that the temperature of the pantograph strip impacting the strain measurement reaches about 80 ℃ while the vehicle was running. In addition, Fourier analysis showed that the energies of the temperature measurement signals dominated the relatively low-frequency band (less than 0.02 Hz), whereas the strain signals prevailed in the relatively high-frequency band. Thus, a novel method based on a digital filtering technique was proposed for temperature compensation in fiber Bragg grating sensor systems for monitoring the conditions in electrified pantograph–catenary systems. A Butterworth high-pass filter was designed to reject the temperature-related signal component with a stopband and to capture the real strain in the passband in frequency domain. To achieve this filtering, the cutoff frequencies and the filter order were calculated adaptively according to the frequency-domain characteristics of the measured temperature signal. With the designed filter, the temperature effect to the strain signals can be eliminated so that the strain can be estimated accurately. In comparison with the traditional temperature compensation technique, the proposed method is more effective in terms of estimating the real strain of the pantograph strip in practical applications. Compensated by the proposed method, the time-domain and frequency-domain analyses of the contact force denote the frequencies corresponding to the support span, and the dropper can be distinguished. Further, the first-order (4 Hz) and second-order (8.3 Hz) natural frequencies of the pantograph are visible in the measurements from catenary sections, which demonstrates the sufficiency and rationality of the proposed temperature compensation method for fiber Bragg grating sensor systems.

Objectives The purpose of this study was to compare the efficacy and safety of drug-eluting beads transarterial chemoembolization plus camrelizumab (D-TACE-C) with conventional transarterial chemoembolization plus camrelizumab (C-TACE-C) in the treatment of patients with unresectable hepatocellular carcinoma (HCC). Materials and Methods This was a retrospective study that evaluated the consecutive medical records of patients with unresectable HCC who had undergone D-TACE-C or C-TACE-C from April 2020 to August 2021. Efficacy of treatment was evaluated using tumor response, progression-free survival (PFS) and survival rates. The adverse events were recorded. Results A total of 54 patients were included in this study, including 27 patients who had received D-TACE-C treatment, and 27 patients who had received C-TACE-C treatment. The median PFS and DCR in the D-TACE-C group were significantly longer than those for the C-TACE-C group (PFS: 10 vs. 3 months, P=.017; DCR: 70.4% vs. 40.7%, P = .028). Cox regression analysis showed that D-TACE-C was the only protective factor for PFS. The 6-month and 12-month survival rates in D-TACE-C group and C-TACE-C group were 85.2% versus 79.4% (P = .646) and 65.2% versus 65.1% (P = .903), respectively. Reactive cutaneous capillary endothelial proliferation was the most common adverse event associated with the treatment. There was no significant difference in the adverse events related to TACE and camrelizumab between the two groups. No treatment-related deaths occurred in this study. Conclusions D-TACE-C is a safe and well-tolerated treatment, and may produce better PFS and tumor response in patients with unresectable HCC than C-TACE-C.

This study investigates the effects of polygonal wear of wheels on the dynamic performance of the gearbox housing of high-speed trains. First, a dynamics model of the driving system is developed considering gear meshing and flexible deformation of the gearbox housing. Responses of the gearbox housing are calculated using the modal superposition method. Then, a multibody dynamics model of a railway motor car is established considering the driving system. Rig tests in the laboratory and field experiments on the Beijing–Shanghai high-speed rail line are, respectively, performed. Based on the simulation and experiments, the dynamic characteristics of the gearbox housing of the motor car are analysed. The results of the analysis show that polygonal wear can significantly influence the vibration of the gearbox housing, and the maximum amplitude of the acceleration of vibration is more than 200 g. In addition, resonance of the gearbox housing occurs due to the 20th-order polygonal wear. In the resonance region, the oil level sight glass of the gearbox housing vibrates severely, contributing immensely to its cracking.

This study aimed to explore the mechanisms of bridging integrator-3 dysregulation, its prognostic value, and related signaling pathways in colorectal cancer . Bioinformatic analysis was performed based on the data from The Cancer Genome Atlas–colorectal cancer and Human Protein Atlas. Colorectal cancer cell lines, LoVo and HT29 cells, were used as in vitro cell model to assess the effect of demethylation on bridging integrator-3 expression. Results showed that bridging integrator-3 was downregulated in colorectal cancer tissues compared to normal colon and rectum tissues. Heatmap of bridging integrator-3 messenger RNA expression, exon expression, and DNA methylation indicated a negative correlation between bridging integrator-3 expression and methylation of some CpG sites within the coding sequence. Demethylation treatment significantly increased bridging integrator-3 expression in LoVo and HT29 cells. Low bridging integrator-3 messenger RNA and exon expression were associated with significantly worse overall survival (P = .015 and .013, respectively). Multivariate analysis confirmed that low bridging integrator-3 messenger RNA expression was an independent prognostic factor of unfavorable overall survival (Hazard Ratio (HR) = 1.596, 95% confidence interval: 1.024-2.486; P = .039). High bridging integrator-3 DNA methylation was also associated with significantly worse overall survival (P = .013). Kyoto Encyclopedia of Genes and Genomes analysis indicated that the genes correlated with bridging integrator-3 (absolute Pearson r ≥ 0.3, n = 121) were enriched in sphingolipid signaling pathway, natural killer cell-mediated cytotoxicity, p53 signaling pathway, and apoptosis. Based on these findings, we infer that DNA hypermethylation might be an important mechanism of suppressed bridging integrator-3 expression in colorectal cancer . Its low expression is an independent predictor of unfavorable survival in patients with primary colorectal cancer . Bridging integrator-3 might act as a tumor suppressor via modulating natural killer cell-mediated cytotoxicity, p53 signaling pathway, and apoptosis.

An efficient surrogate-based aerodynamic shape optimization method is developed to improve the optimization efficiency. In this method, the field approximate model is presented firstly to predict the flow field parameters of interest for specific aerodynamic optimization problems with respect to the design variables and sequentially updated. The differential evolution is used to locate the optimum of field approximate model coupled with the analytical post-processing to calculate the objective and constraints for aerodynamic optimization. This optimal point is calculated by time-consuming computational fluid dynamics simulation and the result is added to the sampling set to update the sampling points and field approximate model. The proposed method is compared with conventional sequential approximate optimization and shows great advantages in accuracy and efficiency. Two shape optimization test cases are provided to verify the efficacy and efficiency of the proposed method.

Illegal behavior such as casually parking or traveling in the highway emergency lane have negative effects on public traffic safety. The Highway Emergency Lane Illegal Occupancy Scale was developed for Chinese drivers, and psychometric properties and influencing factors were assessed. Three hundred drivers submitted questionnaires; after incomplete questionnaires were excluded, 239 complete questionnaires remained for study. Exploratory factor analysis was used to determine the factor structure, which showed that all factors were internally reliable. Demographic variables were found to have significant negative correlations with occupancy behaviors. Additional analysis indicated that drivers between 41 and 55 years old or with more than 10 years of driving experience had significantly fewer total points than drivers in other age groups, indicating that they were less inclined to occupy the highway emergency lane. Drivers with a postgraduate education or higher were especially aware of the traffic rules to be obeyed to ensure safety. A significant positive correlation was found between traffic violation variables and occupancy behaviors. The average score of legal consciousness was highest among all factors, indicating that Chinese drivers lack an understanding of traffic laws and regulations. Insufficient institutions, indifferent management, and poor education compound this illegal occupancy phenomenon in the highway emergency lane.

The influence of contact surface upon the dynamic performance of a pantograph–catenary system is a question that has been highlighted by the increasing use of high speed railways. Using the mode-superposition method, we establish a pantograph–catenary-coupled dynamics model with consideration of the contact surface; we analyse the characteristics of the contact surface based on a large amount of measured data; and we determine the characteristic parameters according to their influence upon the system dynamic performance. The results show that the contact wire irregularity contains a periodic component formed by gravity and a random component formed by wear, local assembly errors, hardpoints and the like. Periodic and low-frequency random irregularities mainly lead to the increase in contact force amplitude at peak points with wavelengths submultiple of the tension length, span or dropper spacing. On the contrary, high-frequency random irregularity has a great influence upon the amplitude of all frequencies and is the main factor leading to the deterioration of the system dynamic performance. The contact strip wear surface achieves quadratic function fitting, and we propose two characteristic quantities of this surface, namely, shape parameter A, and wear depth B. The wear surface of contact strip enhances the periodic characteristics of pantograph–catenary system of each span, leading to the amplitude increase of the contact force in frequency with span submultiple wavelength. The bigger the absolute value of the shape parameter, the poorer the dynamic performance. According to the criteria of the contact force eigenvalues, we determine the threshold value of the contact strip shape parameter A, and the contact wire irregularity amplitude of each frequency. The threshold given in this paper can be used in the condition assessment of parts, and make judgements on whether a servicing is needed, which is part of the technologies for informationisation and intelligent high-speed train health management.

This study investigates the effect of an internal dynamic excitation of the traction system on the dynamic performance of a high-speed train. First, a dynamic model of the traction system is developed that considers various complex factors such as the time-varying stiffness of meshing teeth pairs and the gear transmission error. The internal exciting force of the gear is taken to be the result of multiplying its meshing stiffness by its transmission error. Then a multi-body dynamics model of the motor car that includes the driving system is established. Furthermore, a field experiment at a high-speed rail line is performed. Based on the test data, the dynamic characteristics of a high-speed train are analyzed. The obtained results show that the internal dynamic excitation of the traction system can significantly influence the vertical vibration of the frame and gearbox; however, it has little effect on their lateral vibration. The sampling frequency has a major effect on the vibration amplitude of the gearbox; frequency spectrum results show that when the train runs at a high speed, the main vibration frequencies of the gearbox are the meshing frequency and its harmonic frequencies. It is demonstrated that it is necessary to take the internal dynamic excitation into account when assessing the dynamic performance of the gear transmission system.

Aerodynamics of trains running inside tunnels change more significantly in comparison with open air scenarios. It has been confirmed that the lateral vibration as well as the aerodynamic drag of the trains is increased and the micro-pressure wave is produced at the tunnel exit when the trains are passing through tunnels. The aim of this article is to explore the impact of a high-speed train passing through a tunnel on the pantograph aerodynamics and the dynamic behavior of the pantograph–catenary interaction. The aerodynamic forces acting on the pantograph are investigated thoroughly by extensive numerical simulations as well as systematic field tests. To investigate the effects of the aerodynamic forces of pantograph on the quality of current collection, the numerical simulations of the pantograph–catenary dynamic interaction are conducted with our proposed model, taking into consideration the action of the aerodynamic uplift forces obtained by the numerical simulations on the pantograph. Then, a series of numerical simulations are also carried out to analyze the effects of the train speed and the blockage ratio on the aerodynamic uplift forces of the pantograph, on the contact forces, as well as on the displacement of the contact wire, while the train is passing through a tunnel. The results reveal that compared with the open air scenarios, the aerodynamic drag and uplift forces of the pantograph, the mean value of the contact force and the displacement level of the registration arm can considerably increase as the train runs inside a tunnel. Moreover, the statistical values of the contact forces and the displacement level of the contact wire become larger while the train is passing through the tunnel at different speeds. On the other hand, the quality of current collection decreases with the increasing of the blockage ratio.

The objective of this effort is to numerically investigate the effect of the fire-in-the-hole staging event on the start-up flow separation and side loads of a conical nozzle during flight. The axisymmetric transient flow structure in nozzle was examined by time-accurate numerical method with time-varying chamber pressure and separation gap width. Three-dimensional time-accurate computations to examine the side loads due to non-nominal staging movement were conducted for two particular cases: misalignment between two stages and the angle of the nozzle thrust vector direction. Each asymmetry case comprised several specific staging state points which determined the corresponding chamber pressure and staging gap width. As presented by the simulation results, the flow separation in nozzle is significantly prolonged and intensified by the obstruction of the lower stage dome. When the flow separation location moves close to the nozzle exit, a strenuously axial oscillation of the separation shock appears and lasts for a period of time. In the three-dimensional asymmetric computations, in spite of strenuous oscillation, the time-average of nozzle side loads indicate that the asymmetric staging situation could lead to large sustained lateral disturbance forces. An essential ingredient driving the flow unsteadiness and asymmetry is related to the deflected and reversed supersonic flow by the dome and interstage wall corner of lower stage.

The paper presents an autonomous navigation method for a spacecraft formation flying in the proximity of an asteroid. The measurements from an onboard high resolution camera and a LIDAR are used to estimate the relative position and velocity of the spacecraft with respect to the asteroid. The main innovation is the inclusion of inter-spacecraft measurements provided by the same sensors to evaluate the improvement of navigation performance. Several schemes are constructed to quantify the navigation performance affected by different combinations of measurements, which are obtained from each spacecraft within a 2-spacecraft formation. Unscented Kalman Filter (UKF) is then proposed to simultaneously estimate the position and velocity of each spacecraft with respect to the asteroid. Some examples demonstrate that a significant improvement of the navigation accuracy can be obtained by fusing the inter-spacecraft measurements with the spacecraft-to-asteroid measurements. The robustness of the proposed navigation strategy is then assessed by considering a range of different magnitudes of the noise in measurements and process.

A high-order extended state observer-enhanced controller is proposed to address the problem of velocity and altitude tracking for a hypersonic flight vehicle with strong nonlinearity, parameter uncertainty, and external disturbance. First, the feedback linearization-based control is introduced as the baseline controller, and the nonlinear multi-input/multi-output system is transformed into two integral-chain single-input/single-output systems. And then, the lumped disturbance is extended as a new system state to represent the total effect of the unknown part of nonlinearity, parameter uncertainties, and external disturbances. Consequently, a high-order extended state observer is proposed to estimate all the states of the extended system for each channel of the longitudinal dynamics. With the compensation of the estimated disturbance, a high-order extended state observer-enhance control is investigated to improve the control tracking performance and robustness. Moreover, all the control parameters are associated with the bandwidth, and the stability of the closed-loop system is analyzed. Due to the concise form of the proposed enhanced controller, all of the vehicle information except for the system outputs is not necessary to be obtained. Therefore, a simplification of the control system framework could be accomplished, which reveals an enormous potential in the engineering practice. Simulation results demonstrate the high effectivity and strong robustness of the proposed method for the hypersonic flight vehicle compared with the other controllers.

The conventional crosswind stability analysis of high-speed trains is based on a deterministic approach with the final output being a characteristic wind curve (CWC). The CWC only provides the dividing line between the safe state and failure state of vehicles, thus it cannot be used to evaluate the overturning probability of vehicles subjected to strong winds. To overcome this shortcoming of the conventional CWC, a fuzzy stochastic approach is proposed that can make an effective assessment of the operational safety of high-speed trains exposed to stochastic winds. According to this methodology, the uncertain parameters existing in the system such as stochastic winds and aerodynamic coefficients are modelled as basic random variables, and the failure of the structure is considered as a fuzzy random event. An algorithm for computing the unsteady aerodynamic loads of high-speed trains exposed to stochastic winds is created and then the aerodynamic loads are applied to a dynamic model of the vehicle system in order to investigate the dynamic response. Importance sampling is used to conduct an analysis of the crosswind stability of high-speed trains based on fuzzy random reliability theory. This finally leads to the substitution of the conventional CWC by probabilistic characteristic wind curves (PCWCs). The conventional CWC is shown to be over-conservative, while the PCWCs can provide more significant reference for the safe operation of high-speed trains.

A series of tests were conducted to study the effect of the strip inclination angle on the friction and wear behavior of a contact strip rubbing against a contact wire with electric current using a ring-block-type test machine. The arc voltage and electric current were measured throughout the tests to evaluate the scaled accumulated arc energy. The variations of the wear rate of the carbon strip and the scaled accumulated arc energy with strip inclination angle were obtained. Experimental results show that the strip inclination angle has an effect on the friction and wear behavior of contact strip against contact wire with electric current, and an appropriate strip inclination angle can decrease wear of the contact strip.

Adipose-derived stem cells demonstrate promising effects in promoting cutaneous wound healing, but the mechanisms are still not well defined and contradictory views are still debatable. In the present research, we established a mouse cutaneous wound model and investigated the effects of adipose-derived stem cells in wound healing. Adipocyte, adipose-derived stem cells, and epidermal keratinocyte stem cells were isolated from younger and aged donors according to the standard protocol. The conditioned medium either from adipose-derived stem cells or from adipocytes was used to treat epidermal keratinocyte cells. The results showed that adipocytes or adipose-derived stem cells isolated from younger donors demonstrated mild advantage over those cells isolated from aging donors. Adipose-derived stem cells showed stronger stimuli than adipocytes, and the adipose-derived stem cells or adipocytes from younger donors enabled to support higher growth rate of keratinocyte stem cells. The invasion of vasculature was observed at day 10 after posttransplantation in the mice bearing the keratinocyte stem cells or combination of keratinocyte stem cells with adipose-derived stem cells; however, simply inoculating keratinocyte stem cells from aging donors did not result in vasculature formation. Adipose-derived stem cells isolated from younger donors were able to inspire the host’s self-healing capabilities, and age-associated factors should be taken into consideration when designing a feasible therapeutic treatment for skin regeneration.

Diverging diamond interchange (DDI) is a form of diamond interchange attracting growing interest from traffic engineers and researchers. Conventional control delay calculation models are not effective when applied to DDI because of the possible internal queue spillback. This paper describes a method to calculate control delay at DDI using a new analytical model. The model was first developed for control delay calculations of external movements at conventional diamond interchanges. Through the addition of a function to calculate delay of internal movements, the model was successfully used at a DDI to calculate control delay of both internal movements and external movements. Simulation studies are also conducted to validate the new model. This study can be used either as a stand-alone delay calculation model or as a supplement to existing simulation methods. The model also shows promise for use in other signalized interchange configurations with two or more adjacent intersections.

The activities and protein content of extracellular signal-regulated kinase (ERK)1/2 in the heart were measured in rats at 4 and 16 weeks after volume overload due to aortocaval shunt. Protein content of phosphorylated ERK1/2 was increased at both 4 and 16 weeks, whereas protein content of total ERK1/2 was increased only at 16 weeks of inducing volume overload. The ERK1/2 activities, estimated as phospho-Elk-1 content, were also increased at 4 and 16 weeks of inducing volume overload. The increased phosphorylated ERK1/2 and E-26-like (Elk)-1 protein content in 16 weeks failing hearts was much greater than that in 4 weeks hypertrophied hearts. These changes in phosphorylated ERK1/2 and Elk-1 protein content in both 4 and 16 weeks volume overloaded animals were attenuated by treatment with enalapril and/or losartan. The results indicate that activation of ERK1/2 may be involved in the development of cardiac hypertrophy and heart failure due to volume overload, and these changes are partially prevented by blockade of the renin—angiotensin system (RAS).

Yttria-stabilized tetragonal zirconia/20 wt% alumina (TZP-3Y20A) composites were fabricated by spark plasma sintering at various sintering temperatures over the range of 1000—1400°C. Hydroxyapatite (HA) additive was added in volume fractions of 10—50% in order to increase the biocompatibility of the composite. The densification behavior of the TZP-3Y20A composite and that of the composites with HA were investigated. In the case of TZP-3Y20A composites, the density increases steadily with temperature and reaches a maximum value of 97.8% of the theoretical density at 1400°C. The solution interface formed between zirconia (ZrO2) and alumina (Al 2O3) strengthens the bond between ZrO2 and Al 2O3 grains and facilitates densification. In the case of TZP-3Y20A/HA composites, sintering at 1400°C led to the formation of tricalcium phosphate in the samples, which resulted from the decomposition of HA due to its limited thermal stability at high temperature; no reaction was observed between ZrO2 and HA. The addition of HA imposes a barrier effect on the diffusion between ZrO2 and Al2O3 grains, thus limiting the grain growth of ZrO2 and Al2O 3.

Signal losses and fluctuating carbon contamination bands are “bottlenecks” in the application of surface-enhanced Raman spectroscopy (SERS) for reliable chemical analysis. They originate mainly from prolonged laser irradiation of the sample during data collection, which causes analyte decomposition and/or loss of the enhancing capabilities of the adsorption site. In this work, a laser illumination/signal collection technique, the “multiple points collection” (MPC) method is introduced to circumvent these problems. The MPC method is based on the use of a pair of galvanic mirrors to scan the laser beam rapidly and steadily across the sample surface. Each position is irradiated for

Inflammation and its subsequent endothelial dysfunction have been reported to play a pivotal role in the initiation and progression of chronic vascular diseases. Inhibiting the attachment of monocytes to endothelium is a potential therapeutic strategy for vascular diseases treatment. α-Melanocyte stimulating hormone is generated from a precursor hormone called proopiomelanocortin by post-translational processing. However, whether α-melanocyte stimulating hormone plays a role in regulating endothelial inflammation is still unknown. In this study, the effects of α-melanocyte stimulating hormone on endothelial inflammation in human umbilical vein endothelial cell lines were investigated. And the result indicated that α-melanocyte stimulating hormone inhibits the expression of endothelial adhesion molecules, including vascular adhesion molecule-1 and E-selectin, thereby attenuating the adhesion of THP-1 cells to the surface of endothelial cells. Mechanistically, α-melanocyte stimulating hormone was found to inhibit NF-κB transcriptional activity. Finally, we found that the effect of α-melanocyte stimulating hormone on endothelial inflammation is dependent on its receptor melanocortin receptor 1.

Silver coated SiN and SiO2 tips have been fabricated for use with a bottom-illumination tip-enhanced Raman spectroscopy (TERS) setup with a 488 nm laser excitation. SiN tips with 50–60 nm of deposited Ag give the best TERS enhancements for brilliant cresyl blue test analyte spin-coated on a glass slide. Ag nanoparticles on SiN or SiO2 rather than Si tips are better for TERS because of the proximity of the wavelengths of their surface plasmon resonance to 488 nm. Adjustments of tilt angle of the metallized tip with respect to the surface plane is shown to considerably raise the intensities of the TERS signals, even from tips that initially appear to be rather non-enhancing. This work helps to enable the more frequent use of the 488 nm laser for nanoscale chemical analysis with both TERS and fluorescence imaging in the same setup.

This study uses a hybrid simulation method to investigate the dynamic behavior of pantographs. A special test facility, which is used to simulate the dynamic performance of a pantograph when it runs through the overhead line, is established and described. As the catenary is difficult to model in an indoor hardware test facility, a mixed theoretical-experimental technique is used. On the basis of the set-up of hybrid simulation test device of the pantograph-catenary system, the dynamic behaviors of four types of pantographs running along the overhead equipment at different running speeds are examined and compared. Meanwhile, the dynamic parameters such as mass, stiffness, and damping of four pantographs are measured using the hybrid simulation test facility. On the basis of these parameters, the dynamic behaviors of the four pantographs are analyzed. The dynamic behavior of the four pantographs is carried out under the CH160-0 catenary, which is used for 160 km/h rail line in China. The dynamic behavior may be different for other kinds of catenary.

The experiment on the adhesion coefficient of a wheel-rail system has been carried out by means of a full-scale test facility under the condition of different axle loads and rolling speeds. The effects of the condition of the wheel-rail contact surfaces, such as a clean and dry surface, water and oil contamination and slip, on the adhesion coefficient have been investigated in the experiment. The experimental results show that, when the rolling speed of the wheelset increases, the adhesion coefficient decreases under the condition of the constant creepage and water contamination on the contact surfaces, but it increases for oil contamination. Using the data obtained by statistics and analysis of the experimental results and Kalker's rolling contact theory with Hertzian form modified by the present authors, a numerical analysis concerning the effect of wheelset rolling speed on the adhesion coefficient and the distribution of the stick-slip area in the contact area has been made. The numerical results are in good agreement with those obtained by experiment. They are very useful in designing the traction power of a locomotive at higher speeds.

The Finite Element Method is a powerful method that can be used to describe the dynamic behavior of mechanical systems. The most crucial problem to use this method is the large degree of freedom in FE-models. It is very difficult or even impossible to design controllers. Consequently, it is necessary to reduce the model. However, the model reduction deals only with the state variables, therefore the model reduction is not sufficient for the shape control, because a great number of reference and measured data are needed for the shape description and control. In [Zhang, W. and Michaelis, B. 2000. “Shape Control with Karhunen-Loève-Decomposition,” 11th Int. Conference on Adaptive Structures and Technologies, Nagoya, Japan, October 23-26, pp. 119-126.], we have developed a new method using the Karhunen-Loève-Decomposition to realize the shape control. In this paper, we will first give the theory briefly and then the experimental results.

This article focuses on the missile integrated guidance and autopilot design in the end-game phase with control input saturation. First, the nonlinear integrated guidance and autopilot model is developed with third actuator dynamics, where the control surface deflection has magnitude constraint. Second, three nonlinear extended state observers are used to estimate the aerodynamics coefficients’ uncertainties and unmatched time-varying disturbances. Third, a command filtered controller is designed step by step with linear and nonlinear sliding surfaces to improve the terminal performance. In the process, different command filters are implemented to avoid the influences of disturbances and repetitive derivation and solve the problem of unknown control direction. The stability of closed-loop system is proved by Lyapunov theory, and the principles abided by the controller parameters are concluded through the proof. Finally, 6-degree-of-freedom numerical simulations are presented to show the feasibility and validity of the proposed controller.