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The fracture phenomenon of fastener clips occurs frequently in the sections with serious rail corrugation of high-speed railway, which brings huge potential safety hazards to track service and driving safety. In order to prevent the vibration fatigue fracture of fastener clips in high-speed railway, a dynamic vibration absorber (DVA) for clips is proposed in this paper to suppress the primary sensitive frequency of the corresponding resonant of clips. Firstly, based on the optimal design theory of DVA, a parameters design method of ring-shaped DVA suitable for clips is proposed. Secondly, the vibration characteristics of the high-speed railway fastener system are investigated, and the main reason for the fastener clips fracture is analyzed by simulation analysis combined with filed test. Then, focusing on the primary resonant frequency of clips, the vibration reduction effect of the ring-shaped DVA is analyzed. The results show that the ring-shaped DVA can change the natural frequency of the clip system, reduce the vibration response in the range of the original resonant frequency, and avoid the resonance phenomenon. Finally, the influences of mass ratio, frequency ratio, and damping ratio on the vibration reduction effect are analyzed, and the effectiveness of the parameters design method of ring-shaped DVA proposed in this paper is further proved. The research results can provide methodological support for the anti-breakage design of high-speed railway fastener clips.

This paper analytically investigates the dynamic interaction of two neighboring tunnels in the saturated soil. The twin tunnels are simulated using the Flugge shell theory, and the surrounding soil is modelled by the Biot’s theory. The solution for cylindrical waves in saturated porous media is derived by applying the potential decomposition. The addition theorem is subsequently introduced to translate cylindrical waves, thereby satisfying the boundary conditions at the interfaces between the twin tunnels and saturated soil. Numerical examples are presented to analyze soil vibrations under different loading conditions calculated by different tunnel models. The neighboring tunnels have strong dynamic interaction, resulting in the insertion gain up to ± 20 dB. It is recommended to account for the interaction between neighboring tunnels when calculating the vibrations from underground railways.

A stochastic micromechanical framework is proposed to quantitatively characterize the probabilistic behavior of the saturated concrete healed by the electrochemical deposition method (EDM). Multiphase micromechanical representation for the healed saturated concrete is presented based on the material’s microstructures. Differential scheme-based multilevel homogenization procedures are proposed to quantitatively predict the effective properties of the repaired concrete. The material microstructures are characterized by the non-stationary random process and random variables. The probabilistic behavior for the repaired concrete is reached with high computational efficiency by incorporating the dimensional decomposition method and Newton interpolations. The predictions obtained by the proposed stochastic micromechanical framework are then compared with the available experimental data, existing models, and direct Monte Carlo simulations, which indicates that the presented stochastic micromechanical framework is computationally efficient and capable of characterizing for the probabilistic behavior of saturated concrete repaired by EDM considering the inherent randomness. Finally, the influences of the deposition products and healing degrees on the probabilistic behavior of repaired concrete are discussed based on the proposed models.

In order to evaluate the vibration response of the slab track with damage more efficiently in high speed railway, a periodic nonlinear dynamic model with implicit solving method for damaged slab track is proposed involving the damage constitutive relationship of concrete under uniaxial tension. The vibration equations of the nonlinear model are discretized via the periodic spectral method in space domain, and subsequently based on the Newmark-β method and the Newton-Raphson method, the implicit dynamic integration scheme is constructed in time domain. The detailed solving procedure of the implicit dynamic integration scheme with Newton-Raphson iteration for the periodic nonlinear model is illustrated ultimately. By comparing the implicit and explicit solutions of the periodic model, the correctness and efficiency of the periodic model are verified. Furthermore, the vibration response and the evolutional rules of structural damage for the slab track of high speed railway with different strength grades for concrete slab are investigated respectively via employing the periodic model with implicit solving method.

A discretization is applied to the continuous field-based pedestrian model to derive a discrete version. The concept of walk period is introduced so that pedestrians’ varied walking velocities can be studied without introducing any modification to the underlying logic. This further allows the discrete model to analyze a flow of randomly mixed population. Next, starting from the discrete model, a high performance GPU model targeting at the OpenCL heterogeneous parallel framework is developed. Advanced techniques are developed to allow efficient access to stored field strength, avoid atomic operations, and so on. Numerical experiments disclose that the GPU model can bring a as high as 30.8x performance improvement, with contrast to the previously developed CPU model. Thus, when equipped with proper functional modules such as a macroscopic/mesoscopic route selection and so on, the GPU model can act as a core engine for simulation of a large/very-large population.

For evaluating the vibration response of the damaged slab track efficiently, a novel explicit periodic nonlinear model for the damaged slab track in high speed railway involving material nonlinearity of damage is presented based on the theory of continuum damage mechanics and the constitutive relationship of concrete under uniaxial tension, where the infinite periodically supported composite beam for the track on the elastic foundation is truncated into a beam section with the length of a single vehicle by introducing periodic boundary conditions. The vibration equations of the nonlinear model are discretized into ordinary differential equations (ODEs) in space domain by the periodic spectral method, and then by applying the explicit central difference method these ODEs are solved with time-domain difference ultimately. The validity of the model is verified by the comparison of the results from the periodic model, finite element method (FEM) and the field test, and the reasonable values of the key computational parameters are recommended. Moreover, the influence of track structural parameters on the vibration response and damage evolution of CRTS II slab track of China’s high speed railway is investigated with the periodic nonlinear model. And some practical conclusions for design and construction are acquired.

This paper investigates the influence of non-uniform corrosion of the mild steel reinforcement on the cracking propagation of the concrete cover. Partial surface of the reinforcement was coated by an epoxy resin in order to prevent the covered surface of the steel from corrosion. As a result, the reinforcement was corroded partially along the surface by an impressed current in this way. The corrosion propagation of the steel reinforcement and the corrosion-induced cracking process was investigated during different corrosion periods. The width and the cracking paths were observed carefully. The results showed that two cracking paths would happen to the concrete cover due to the non-uniform corrosion of the steel reinforcement, including the corrosion-induced crack along the radius direction of the concrete cover and two branches in the secant direction of the corrosion zone. The aggregate of the concrete could also influence the propagation of the cracking path significantly.

Wheel/rail contact modelling is essential in railway vehicle dynamic simulation, wheel/rail wear and fatigue. For this purpose, the tiny contact area at wheel/rail interface needs to be carefully investigated. In this paper a Partition Model (P_M) method is proposed to solve the wheel/rail normal contact problem. In the model, the contact region is divided into zones according to different curvature radii of wheel/rail profiles, and each zone is modified by the principle (the normal gaps of contact patch boundaries being equal to each other). For the sake of accuracy, both the iterative algorithms of wheel/rail normal force and elastic compression are also introduced in this model. Three typical test cases are designed to verify the feasibility and accuracy of the proposed method, and the results are compared to those provided by Kalker׳s CONTACT program and Finite Element (FE) method. The results show that the P_M method is fast and accurate for calculating normal contact problems in non-Hertzian cases. The good agreement with CONTACT and finite element method indicates that the capability of P_M method in railway vehicle simulation, wheel/rail wear and fatigue.

A revised Fourier pseudo-spectral method is applied to quickly solve the dynamic response of the railway ballastless track structure with damage. Considering the nonlinearity of the material damage of the track slab and the base, the pseudo-spectral method (PSM) of collocation format is used to discretize the vibration equation of the track slab and the base in spatial domain. Since the convergence and solution precision of the collocation method are greatly related to the collocation scheme, in order to ensure the quasi-convergence of the pseudo-spectral method, the Fourier-Galerkin spectral method is used to obtain the elastic convergence solution of the periodic dynamic model of the ballastless track, which is used as the criterion for quasi-convergence of the approximate solution of PSM. In order to reduce the number of collocation points and improve the accuracy of the approximate solution of PSM, the ballastless track model with discrete point support is replaced by the ballastless track model with uniformly continuous support. The optimal number of collocation points for the quasi-convergence of the PSM is obtained. Then, the interpolation basis function of the PSM is regularized, and the modified PSM is proposed, with which the model can achieve quasi-convergence under given collocation point number. In this paper, the accuracy of the pseudo-spectral method is improved, and the principle of collocation point selection is established, which makes it feasible for the nonlinear periodic spectral method to be applied to the damage evolution analysis, life prediction and structural dynamic optimization of the ballastless track.

Slab tracks are common track structures in high-speed railways. In this study, a vehicle/slab track interaction model is developed based on vehicle–track coupling dynamics theory, and composite track elements are used to rapidly model the finite element equations of the slab track based on the stationary value theory of total potential energy. In the model, the rail is represented as a discretely-supported infinite beam, the slab and the base are considered as continuously-supported free beams, and the connections of the track structure are modelled as viscoelastic spring–damping elements. The composite track element method effectively derives the equations of motion with high or low degrees of freedom by increasing or decreasing the number of track elements; therefore, it can be applied to the dynamic analysis of the track and to investigate the dynamic responses of the slab track system, including the rail, pad, slab, Cement asphalt mortar (CA mortar) and base. The equations of motion of the vehicle system are also proposed using the finite element method. The vehicle system and the slab track system interact through the vertical wheel/rail force, which is approximated using Hertz contact theory. The dynamic responses of a slab track subjected to moving vehicle loads are analysed using dynamic simulations and are compared with another classic simulation method. The effects of random track irregularity and vehicle velocity on the dynamic responses of the slab track system are discussed.

A model based on the theory of train-track-bridge coupling dynamics is built in the article to investigate how high-speed railway bridge pier differential settlement can affect various railway performance-related criteria. The performance of the model compares favorably with that of a 3D finite element model and train-track-bridge numerical model. The analysis of the study demonstrates that all the dynamic response for a span of 24 m is slightly larger than that for a span of 32 m. The wheel unloading rate increases with pier differential settlement for all of the calculation conditions considered, and its maximum value of 0.695 is well below the allowable limit. Meanwhile, the vertical acceleration increases with pier differential settlement and train speed, respectively, and the values for a pier differential settlement of 10 mm and speed of 350 km/h exceed the maximum allowable limit stipulated in the Chinese standards. On this basis, a speed limit for the exceeding pier differential settlement is determined for comfort consideration. Fasteners that had an initial tensile force due to pier differential settlement experience both compressive and tensile forces as the train passes through and are likely to have a lower service life than those which solely experience compressive forces.

Wheel-rail contact stress is foundation of the relationship between wheel and rail, and also an important basis for investigating further wear, surface damage and other problems of wheel and rail system. A three dimension elastic-plastic wheel/rail contact model is established using non-linear finite element method. The changes of wheel/rail normal contact stress, Mises stress and elastic-plastic deformations are analyzed under different conditions in heavy haul railway. A method is provided for a foundation of the future study of wheel-rail contact wear, fatigue and cracks germination and development in this paper.

Most underground railway lines are constructed by the shield method, resulting in the periodic jointed characteristic of tunnel structure in the longitudinal direction. This paper presents a new semi-analytical method to predict the three-dimensional dynamic response of a periodic jointed tunnel in the soil. The tunnel rings are conceptualized as cylindrical shells, and the tunnel ring joints are modelled as a series of springs with continuous supports around the circumference. The soil surrounding the tunnel is simulated using the elastic continuum theory. By applying the periodic-infinite structure theory, the solution for a harmonic moving load applied to the periodic jointed tunnel is obtained. The tunnel is subsequently coupled with the surrounding soil via the boundary conditions on the tunnel-soil interface. The accuracy of the proposed method is verified via comparisons with the existing methods and model test results. The numerical results show that the existence of the tunnel ring joint has a significant effect on the soil vibrations, resulting in an increase in soil vibration levels of 5–10 dB.

The effect of high-speed train head shape on its aerodynamic performance is very important. In order to prove the effect of longitudinal profile shape of train head on aerodynamic performance, using CFD method, a two dimension model is developed to investigate outer flow field of high speed train head. Three types of train head profile schemes are calculated. The effects of longitudinal profile shape of high speed train head on aerodynamic performance are analyzed. The results show that different head profile curves cause different surface pressure distributions of body, different airflow velocities of outer flow field and different turbulent distributions. If the longitudinal profile shape of train head is spindle and streamline length of train head is 8m, aerodynamic drag of the train will well reduce.

Based on vehicle-track coupled dynamic theory, a three-dimensional asymmetric vehicle-track coupling vibration model is developed to investigate the effect of voided elastic two-block sleepers on vehicle and track system dynamic responses. For the vehicle system, one car body, two frames, and four wheel sets are assumed to be rigid, with 35 degrees of freedom (DOF). For the track system, the rails and the concrete two-block sleepers are the main vibration components. The rails are modelled as Timoshenko beams, and the concrete two-block sleepers are assumed to be rigid mass with vertical and lateral movement. The pads under the rails and the rubber boots under the sleepers provide greater vertical and lateral elasticity for the track. The Hertz nonlinear elastic contact theory is used to calculate the normal wheel/rail force. The wheel/rail tangent creep force is first calculated using Kalker’s linear creep theory and then modified by the Shen-Hedrick-Elkins theory. The results show that the asymmetric voided elastic two-block sleepers have greater effects on the dynamic responses for fasteners and sleepers than on the car body and the wheel/rail forces under measured geometric irregularity and random irregularity. Two or more voided sleepers will greatly affect the vehicle running safety.

The aim is to clearly delineate the upper thoracic sympathetic chains and neural connections between the chains and ventral rami of the thoracic nerves, and to provide an anatomical foundation for successful upper thoracic sympathicotomy for treating upper essential hyperhidrosis. The upper thoracic sympathetic chains, upper five intercostal nerves, and neural connections between them in 50 halves of 25 adult cadavers have been dissected, measured, and mapped. The stellate ganglion had an incidence of 80%. The second to the fourth thoracic sympathetic ganglia were commonly located in the corresponding intercostal spaces with the presence of 92%, 68%, and 50%, respectively. The incidence of the first and second intercostal rami was 40% and 6%, and that of the ascending or descending rami from the second, third and fourth ganglia was 54%, 24%, and 14%, respectively. Additional rami communicantes joined the ventral ramus of the 1st thoracic nerve proximal to the point where the latter gave a branch to the brachial plexus. The farthest horizontal distance from the sympathetic chain to the junction between the additional rami communicantes and the second to the fourth intercostal nerves was 29.1 mm. Only 16% of cadavers had similar anatomy bilaterally. Anatomical variations of the upper thoracic sympathetic trunk in relation to intercostal nerves, which may be one of the causes resulting in surgical failures and recurrences, were striking. Attention should be given to such anatomical variations when planning thoracic sympathicotomy.

Due to growing concerns on the low-frequency box bridge structure vibration-born noise, the noise and vibration reduction design becomes a research focus at present. In this paper, based on the slab ballastless track- box bridge coupling dynamic model developed by the finite element method, the influences of stiffness and damping of the cement asphalt mortar (CAM) layer on the elevated box bridge structure vibration and noise radiation are studied. The results show that: the effect of stiffness of the CAM layer on the sound pressure level (SPL) caused by the box bridge structure vibration is not obvious, but the radiation scope of the box bridge structure noise is expanded by the greater stiffness of the CAM layer; with the damping of CAM layer increasing, the sound pressure of vertical acoustic field decreases, and the radiation scopes above and below the box bridge are also smaller, but the sound pressures of the noise concentration areas near the box bridge increases.

According to the CRTSII bi-block ballastless track structure commonly used in high-speed railway, a 3D finite element model of CRTSII bi-block ballastless track structure on viaduct is established. Then characteristics of vertical displacement of the rail in frequency domain and dynamic responses of the ballastless track structure can be obtained by transient dynamic analysis, based on the finite element software (the speed of the train are 200, 250, 300 and 350 km/h respectively). Analysis results show that: (1) Without considering track irregularity, the frequencies corresponding to the peak of the vertical displacement of rail are approximately equal to the multiples of v/La, so the peak frequency can be adjusted by changing the speed when the length of a train is certain; (2) The vertical displacement of the track slab is less than 60% of the rail, and its vertical acceleration is only 2.1%, showing that fasteners play a good effect on reducing vibration; (3) Without other damping measures except fasteners, the vertical displacements of the track slab, supporting layer and viaduct are very close, but their vertical accelerations are some different; (4) The speed of the train has a great impact on the vertical acceleration, and the maximum vertical accelerations of the rail, track slab, supporting layer and viaduct at 350 km/h are 1.68, 1.82, 1.96, 1.65 times of 200 km/h respectively; (5) The vertical compressive stress of the track structure has a turning point.

In order to relief railway transportation pressure in China, the load-raising reform of existing railway lines is paid much more attention. In load-raising reform of existing railway lines process, the most obvious improvement is the increase of vehicle axle load. Using the theory of wheel-track dynamics, The vertical dynamic model for the ballast rail track and heavy haul train interaction could be built. In this model, the heavy haul train is regarded as a subsystem with 10 degrees of freedom, and the ballast track structure is built using finite element method. The two subsystems are coupled using via non-linear Hertz contact mechanism considering the influence caused by track irregularity. This paper analyzes the dynamic response between train and track using the combination method of new rapid explicit integration method and Newmark integration method. And the dynamic response of existing ballast track under heavy haul train of different loads which are 25 t, 27 t and 30 t is specialized analyzed. During the analysis process, the dynamic performance indexes include: rate of wheel load reduction, wheel-rail vertical force, dynamic displacement of the ballast track, vibration acceleration of ballast track, and dynamic stress distribution of ballast track. The research results show that: 1). When heavy haul train are running on ballast track, every dynamic performance index is still within the national standards, and it can meet the dynamic requirement for running heavy haul train. 2). The trends of the dynamic displacement of the track structure under different loads are similar to one another. And the dynamic displacements of the rail under 27 t-axle-load and 30 t-axle-load increase 16% and 22% respectively, compared with the 25 t-axle-load. 3). In general it can be concluded that the growth proportion of the dynamic stress of the track structure is similar to the dynamic displacement. And the dynamic stresses of the rail under 27 t-axle-load and 30 t-axle-load increase 15% and 22% respectively, compared with the 25 t-axle-load.

To understand the characteristics of head check (HC) propagation, the methods for reconstruction and modelling HCs in the rail were presented by realizing the geometry morphology and spatial position of HCs with the help of some creative technologies: X-ray computed tomography (CT) was applied to detect the rail specimens taken from a curve in a heavy-haul railway and the three dimensional (3D) internal information of HC was extracted and digitalized to the point cloud data with 3D coordinate by thresholding of the grey level. For splicing HCs in different rail specimens, removing the abnormal points, extracting and fitting the edges of HCs, the algorithms for investigating the geometry characteristics, including geometry morphology and spatial angle were designed and programmed. Therefore, the reconstruction of 3D HCs in rail was realized by reconfiguration of geometry morphology and spatial position. By defining the contact property, the fitted 3D HCs were assembled and coupled with a 3D rail model for further crack propagation analysis with the eXtended finite element method (XFEM). The reconstruction results can provide an accurate method for reconstruct HC and a reliable model for study the HCs propagation in the rails of the heavy-haul railway.

Polyphenols are important bioactive substances in apple. To explore the profiles of the nine representative polyphenols in this fruit, a high-performance liquid chromatography method has been established and validated. The validated method was successfully applied for the simultaneous characterization and quantification of these nine apple polyphenols in 11 apple extracts, which were obtained from six cultivars from Shaanxi Province, China. The results showed that only abscission of the Fuji apple sample was rich in the nine apple polyphenols, and the polyphenol contents of other samples varied. Although all the samples were collected in the same region, the contents of nine polyphenols were different. The proposed method could serve as a prerequisite for quality control of Malus products.

Ubiquitin inhibitors act at many levels to enhance apoptosis signaling. For TNF-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis signaling, there are at least five mechanisms by which apoptosis are regulated by the ubiquitin-proteasome pathway. First, proteasome inhibitors can decrease Fas-like inhibitor protein (FLIP) protein levels in tumors, resulting in increased apoptosis signaling due to increased caspase-8 activation. This appears to involve the ubiquitin ligase TNF receptor activation factor-2 (TRAF2) and acts indirectly by causing cell-cycle arrest at a stage where there is high degradation of the FLIP-TRAF2 complex. Second, the regulation of the proapoptotic Bcl-2 family member BAX occurs indirectly. Apoptosis signaling and caspase activation results in a confirmation change in the normally monomeric BAX, which exposes the BH3 domain of BAX, leading to dimerization and resistance to ubiquitin degradation. BAX then translocates into the mitochondria, resulting in the release of proapoptotic mitochondrial factors such as cytochrome c and second mitochondria-derived activator of caspase (SMAC). This results in the activation of caspase-9 and formation of the apoptosome and efficient apoptosis signaling. A third mechanism of the regulation of TRAIL signaling in the ubiquitin-proteasome pathway is mediated by the inhibitor of apoptosis proteins (IAP) E3 ligases. These IAPs can directly bind to caspases but also can act as ubiquitin ligases for caspases, resulting in the degradation of these caspases. IAP binding to caspases can be inhibited by SMAC, which exhibits a caspase-9 homology domain. The fourth mechanism for apoptosis activation by proteasome inhibitors is through the stabilization of the inhibitor of the kappaB (IkappaB)/NF-kappaB complex and prevention of nuclear translocation of the antiapoptosis transcription factor NF-kappaB. During TRAIL-DR4, DR5 signaling, this pathway is activated by interactions of activated Fas-associated death domain with activated receptor-interacting protein (RIP), which in turn activates NF-kappaB-inducing kinase and phosphorylates IkappaB. Therefore, the inhibition of IkappaB degradation blocks this RIP-mediated antiapoptosis signaling event. Last, p53 protein levels, and susceptibility to apoptosis, can be deregulated by the human homolog Hdm2 (Mdm2) E3 ligase. This process is inhibited by p53 phosphorylation and by sequestration of Mdm2 by ARF. Better mechanisms to inhibit the ubiquitin-proteasome pathway targeted at the ubiquitin-proteasome degradation process itself, or more specifically at the E3 ligases known to modulate and downregulate proapoptosis pathways will lead to the enhancement of TRAIL apoptosis signaling and better cancer therapeutic outcomes act through this pathway.

In high-speed railway, the slab and the box bridge are the important noise-radiated components. Because the stiffness of the bridge is not well-distributed along bridge longitudinal direction, when a train passes through the elevated bridge, the wheel load position has a certain influence on the box bridge structure's noise emission. In order to probe the influence of wheel load position on structure acoustic radiation characteristics of the box bridge, modal acoustic transfer vector method (MATV) is used. The results show that, the shell element can better than solid element in simulation of bridge noise emission. The method of modal acoustic transfer vector can better combine with box bridge modal, so the bridge itself sound characteristics can more accurately be reflected. The acoustic field under the bridge changes randomly with different frequency. With the distance increase 15m in the range of 15~45m horizontally, the noise radiation pressure level of the box bridge averagely decreases 8dB; but then in the range of 45~50m, it becomes high. For a single box bridge, the sound pressure of double lines is higher 6dB than that of single one at 0~280Hz. In different loading modes, the noise emission caused by the box bridge is very different.

Compared with the ballasted track, the ballastless tracks of high-speed railway have higher environmental noise emissions caused by a train running. To predict and control wheel/rail noise radiation due to roughness of wheel and rail running surface on slab track, a model is used to calculate and analyze the influences of railway slab structure parameters on wheel/rail rolling noise. The result shows that the weights of the slab have more influence on emissions of the slab, but have little impact on noise emission of the wheel and rail. Below 500Hz, the greater the weight of the slab, the greater is the noise emission of the slab, but above 500Hz, the greater the weight of the slab, the lower the noise emission of the slab is. The cement-asphalt (CA) mortar elastic modulus under the slab has more influence on noise emissions of the slab, but has little impact on noise emission of the wheel and rail. The greater the elastic modulus of CA mortar is under the slab, the less is the noise emission of the slab. The rubber pads installed under the slab have little influence on wheel and rail noise emissions, but have more influence on noise emissions of the slab. On the whole, the rubber pads under the slab are set to reduce wheel-rail noise, which is beneficial.

Noise radiated from the elevated bridge structure in high-speed railway is a great concern. In order to analyze the noise radiation characteristics of box bridge structure, two couples of steady-state load are applied at the center of box bridge with double lines, and then using the modal of box bridge structure and the acoustic transfer vector the linear relationship between bridge surface vibration velocity and sound pressure is established in frequency domain by the direct boundary element method. Then the modal displacement is transformed into a vibration velocity vector for the calculation of the noise radiation characteristics of arbitrary points in the acoustic field with the modal acoustic transfer vector. The study results show that modal acoustic transfer vector method can adequately be combined with vibration characteristics of the box bridge itself, so it can more accurately reflect the influence of the box bridge's own structural characteristics on structure noise radiation. In addition, it can reduce the computation time. With the distance increasing horizontally from the bridge center, the box bridge noise radiation will decrease in some positions, but it will increase in other places. The sound pressure distribution of vertical direction away from the bridge surface at the distance 30m horizontally fluctuates obviously with frequency. With the distance increasing vertically above the bridge, sound pressure will decrease gradually. Overall, the sound pressure above the bridge is lower than under the bridge.

A dynamics model of high-speed train system is developed using multi-body dynamics theory to calculate and analyze the effect of the second suspension damper parameters on ride comfort. In this model, car body, bogies, and wheelsets are modelled as rigid bodies. Primary and second suspension systems are regarded as a spring-damping element. FASTSIM algorithm is used to simulate wheel-rail contact. The study results show that the reasonable values of second vertical damper and second anti-snaking damper make the vehicle obtain a better ride comfort index. The appropriate damping value increased in second lateral damper can effectively improve the ride comfort, but the damping value of the second lateral damper in the suspension system needs to match the damping value of second anti-snaking damper reasonably. In order to obtain better ride comforts, damping values of second vertical damper and lateral damper should not be too high.

To investigate the condition of microwave radiation pollution from mobile phone base station built in populated area.Random selected 18 residential districts where had base station and 10 residential districts where had no base stations. A TES-92 electromagnetic radiation monitor were used to measure the intensity of microwave radiation in external and internal living environment.The intensities of microwave radiation in the exposure residential districts were more higher than those of the control residential districts (p0.05). There was a intensity peak at about 10 m from the station, it would gradually weaken with the increase of the distance. The level of microwave radiation in antenna main lobe region is not certainly more higher than the side lobe direction, and the side lobe direction also is not more lower. At the same district, where there were two base stations, the electromagnetic field nestification would take place in someplace. The intensities of microwave radiation outside the exposure windows in the resident room not only changed with distance but also with the height of the floor. The intensities of microwave radiation inside the aluminum alloys security net were more lower than those of outside the aluminum alloys security net (p0.05), but the inside or outside of glass-window appears almost no change (p0.05).Although all the measure dates on the ground around the base station could be below the primary standard in "environment electromagnetic wave hygienic standard" (GB9175-88), there were still a minorities of windows which exposed to the base station were higher, and the outside or inside of a few window was even higher beyond the primary safe level defined standard. The aluminum alloys security net can partly shield the microwave radiation from the mobile phone base station.