Abstract:The aerodynamic performances of a long-span cable-stayed bridge in its completion state, which has a deck girder of open cross section, were investigated with sectional model tests in wind tunnel. Experiment results have shown that the deck of the bridge concerned suffers remarkable vortex-induced resonances within the designed wind velocity, both vertical and torsional. Parametric experiment study has shown that this vortex-induced resonance exists in an extensive scope of structural damping ratios, with amplitudes overstepping the permitted value based on recognized standard even if both the vertical and torsional damping ratios of the section model increase up to 1%. In order to suppress the vortex-induced deck oscillation, an effective vibration control scheme has been brought forward in virtue of wind tunnel tests. Model tests have shown that the adopted mitigation measure can eliminate the vortex-induced resonance effectively. Aerodynamic measure put forward will be helpful to the wind-resistance design of analogous bridges.

Abstract:CFD technique was employed to investigate the effect of surface roughness on the mean pressure coefficients of a full-scale cooling tower. Six kinds of surface roughness with smooth surface and varying roughness heights, as covered by the design code, were studied for a full-scale cooling tower. The numerical results were compared with the wind tunnel and full-scale measurement results from published works. It has been shown that, when full-scale-based CFD simulation successfully circumvents the Reynolds similitude, the smooth tower section has a large mean wind pressure coefficient than the rougher tower sections. It is therefore concluded that the real surface roughness must be reproduced in the evaluation of the mean wind pressure coefficient of cooling towers.

Abstract:The bending load performance of flange-plate connections in steel tubular structures was studied. By using experimental methods and related bolt strain measurement device, four specimens containing different types of flange-plate connections were four-point bended with loading instruments. The mechanic features of bolts and flange-plates were monitored. The yield loading capacity and ultimate loading capacity of the connections were found and compared with the results obtained in the FEM method. It has been proved that they are identical with each other. The experiment results have revealed that the prying forces in the tensile region of flange-plate connections do exist, and the prying action of connections with a stiffener is stronger than that of connections without a stiffener. The safety margin of the connections is approximately 1.2.

Abstract:order to study the effect of compressive stress and shape factors on the vertical stiffness of square laminated rubber bearings, serial compression tests were conducted on four 400×400 mm2 full scale square laminated rubber bearings at stresses of 10 MPa，12.5 MPa and 15 MPa. The relation between the vertical stiffness, shape factors and compressive stress of the four bearings was studied and an experimental expression was obtained. The tests and analysis results have shown that the vertical stiffness of the laminated rubber bearing is compressive stress dependent, the vertical stiffness increases when the compressive stress increases; at constant compressive stress, the increase of the second shape factors will lead to the increase of vertical stiffness; and the compressive stress has more influence on vertical stiffness when the bearing has a large second shape factor value.

Abstract:Some provisions in the technical specification for steel structure of light-weight buildings with gabled frames（CECS 102:2002） have been improved, especially those about stability analysis. Through sufficient and systematic finite element analysis, the defects of the above issues in the existing specification were pointed out and the improvement proposals were suggested: 1）modifiying and extending the values of the effective length coefficient of tapered column ; 2）modifying the formula of the amplification factor for the effective length of the tapered column in light-weight steel structure with gabled frames with leaning column ; 3）modifying the formulas for the web effective width of members with I-section ; 4）new stability design formulas on cold-formed purlins under wind uplift load. The above work has provided a theoretical basis for revising Shanghai Technical Specification for steel structure of light-weight buildings with gabled frames.

Abstract:In HEDG process with ELID for advanced engineering ceramics, due to the great increase of the wheel speeds and the depths of cutting, there is no dense and continuous oxide films on the wheel surface and ELID process cannot be controlled adaptively. On some rational hypotheses, we built a geometrical model for the ideal distributions of grits on the wheel surface, and on this basis, by combining the wear characteristics of the grits with Faraday's law of electrolysis, and aiming to keep the protruded height of abrasives constant, the mathematical models for controlling ELID process in HEDG of engineering ceramics were established, and strategies for controlling ELID progress were concluded from this model. In order to validate them, HEDG with ELID for ZrO2 ceramics with different electrolysis parameters was carried out, and their grinding forces and surface roughness were compared. Experiment results have shown that these strategies can solve problems of ELID controlling in HEDG of engineering ceramics, and realize continuous and stable grinding process.

Abstract:Based on the large project analysis software MSC.Marc, a 3D finite element model was designed to simulate the rolling process of Fi stand. Simulation of the strip's steering state was done under asymmetrical variations and the high temperature constitutive equations of 1235 aluminum were obtained from experiments. The asymmetry of the rolling force, strip trajectory and other rolling parameters were studied under asymmetric distribution of incoming thickness, asymmetric shape of rolling gap and incoming un-centering. Then the relevance between the strip steering and the horizontal distribution of rolling parameters, such as the rolling force and the reduction rate, was discussed. The result has shown that the relationship between the strip steering direction under various disturbances and the difference on both sides of rolling force cannot determine the steering direction of the strip according to the difference under the rolling force. The difference of reduction rate is consistent with the steering direction, and strip steering is always from the larger reduction rate side to the smaller side. This result provides a theoretical reference for strip correcting strategies when the variations are uncertain.

Abstract:The general interface and the programs for the multi-physical analysis of the traction transformer were designed, which combined the advantages of the interface design of VB with the secondary development of ANSYS. The research staff needs only to input the structure parameters and electrical parameters, and all the parameters were automatically matching with the ANSYS APDL programs. The finite element model of the traction transformer was established through VB calling ANSYS, and calling the different physical programs and post-processing programs. The multi-physical analysis and calculation were completed by avoiding fussy program input and shortening the design cycle of new products, which indicates that the analytical interface will be valuable in engineering application.

Abstract:In order to solve the problem of surveying the magnetic head's lubricating thickness repeatedly in the production process, the dynamic tests were done repeatedly by using Atomic Force Microscope (AFM) . The results have shown that, below 25 angstroms, where the head reads and writes data, were carried out the relationship between the lubricant thickness and the distance of the point from the disk center is linear. From 25 angstroms to the edge of the disk, by using the improved Euler method to process the data, the relationship between the difference of the calculated value and the actual value was found, and the distance of the point from the disk center is linear.The theoretical analysis and actual confirmation of the experiment errors were carried out, with indicated that, because of the air current pressure release and the partial magnetism releases caused by the magnetic head gap in the diskette edge, the magnetic head edge lubricating thickness is very difficult to forecast.

Abstract:The problems of phenolic resin/graphite composite bipolar plates are their brittleness and poor mechanical strength. In this study, coupling agent was used to enhance the interfacial adhesion of composite and thus improve the flexural strength. The influence of the types, treating methods and content of coupling agent on the properties of bipolar plates were investigated. Results have shown that a sharp increase of flexural strength was observed for bipolar plates prepared by graphite modification, while the conductivity decreased modestly. Meanwhile, the bipolar plates prepared by resin modification offer high conductivity and excellent flexural strength. Therefore, it can be concluded that resin modification is more suitable for the fabrication of composite bipolar plates. When 0.7wt% of the coupling agent is added to the composite by resin modification, the composite bipolar plate modified by silane coupling agent has a conductivity of 70.3 S·cm-1 and a flexural strength of 33.3 MPa. And for the composite bipolar plate modified by titanate coupling agent, the conductivity and flexural strength are 73.8 S·cm-1 and 32.1 MPa, respectively. These values well satisfy the requirements of composite bipolar plates.

Abstract:The surface of Al flake powder was modified with aluminum zirconium organic metal coupling agent. The resulting flakes were incorporated into epoxy coatings as anticorrosive pigments. The energy dispersive x-ray (EDS) tests and scanning electron microscopy (SEM) tests indicated that the coupling agent improved the dispersion of Al flake powder, so that the flatness, adherent and shielding effect of the coatings was greatly enhanced. The electrochemical impedance spectroscopy (EIS) results of coatings in 3.5% NaCl solution showed that, in the initial immersion stage the coatings exhibited larger impedance values and better corrosion resistance after modification. In addition, after 52 days of immersion, the coatings before modification had no corrosion resistance, the coatings after modification still displayed good corrosion protection with an impedance value of 106 Ω cm2, and the epoxy coatings exhibited the highest protective performance when 2.5% of the coupling agent was used.

Abstract:The influence on the variation characteristics of aquifer parameters, induced by groundwater source heat pump (GWSHP) operation under constant flow and constant pressure difference, was theoretically analyzed by case study. The present study, compared with the constant flow operation, indicates that the porosity and hydraulic conductivity increase by 0.45% and 2.07% respectively under constant pressure difference operation. The influence on the variation characteristics of aquifer parameters, under constant pressure difference operation, is greater than constant flow operation. For the full penetrating well, the influence on the variation characteristics of aquifer parameters decreases gradually with the increase of the borehole diameter and aquifer thickness under different operation modes.

Abstract:By establishing a mathematical model of triple-sleeve energy storage exchangers according to enthalpy method， the dynamic characteristics was simulated, and the impact of different phase-change layers, fluid flow and fluid inlet temperature on the storage characteristics was investigated. It laid a theoretical foundation for energy storage devices, integrated system development and optimization design.

Abstract:In order to solve the problem of video memory limitation during GPU-based visualization of large scale volume data, a compressing and rendering strategy was proposed. Volume data was compressed by combining wavelet transform with vector quantization algorithm, and then transferred to GPU totally. When rendering, a GPU-based ray casting algorithm was adopted and only few current needed data was decompressed and transformed. In order to realize real-time interactive visualization, a multi-resolution rendering method was designed. Experimental results based on CUDA show that this strategy can decrease the video memory consumption effectively and obtain better image quality while ensuring interactive rendering frame rate.

Abstract:Through the process of resource distribution and user request, this paper proposed a user utility function for tasks in the cloud computing environment. In this model, the risk is invoked to quantize the loss of the services and resources in the un- authorization access. Based on risk, this paper proposed a user expected utility function. Finally, the simulation experiment demonstrates the relation among the tasks quantity and the users' request, time, and cost. Through the experiment, a perfect value exists for the task quantity, and near this perfect value, the users' utility can be optimized.

Abstract:Because the second-order partial differential equations (PDE) have the staircase effect and the fourth-order PDEs can　alleviate this effect, a model based on the fourth-order PDEs was proposed for multiplicative noise removal. An alternating minimization algorithm was established to find the solution of the model. Some experimental examples were given to prove the effectiveness of the proposed model.

Abstract:Based on the basic functions of futures markets, the SVAR model was used to analyze futures market and spot market's response to their respective impulse factors. The results show that futures market has active and effective impacts on spot market, while spot market is negative and weak to futures market. Variance decomposition of the two markets' reaction to the price fluctuations indicates that 94% of the variance derives from itself and 6% from the spot market. When spot market reaches strong sustainability, only 10% comes from itself and 90% from the futures market. The investigation outcome will provide an important theoretical basis for the selection of arbitrage spot.