Abstract:The hydration heat was tested to investigate the early crack in the web of a long-span PC box girder bridge. Based on the mechanical properties of specimens cured at the construction site, the temperature and stress fields were simulated in time varying model by finite element method. The prestress tension was analyzed with construction stage considered as well.The results demonstrated that the calculated results of hydration heat agreed well with the measured ones. The hydration heat is one of the main reasons for the early cracks in the web of box girder, while the stress of the concrete box girder is at a very low level during prestress tension.

Abstract:A U.L formulation was proposed for the nonlinear analysis of plane beam element with rigid arms. According to the characteristics of the motion and the deformation of a rigid-ended plane beam element, an explicit expression of non-linear tangent stiffness matrix was derived by U.L procedure. The deficiency of the reference that neglects the effects of element inner-force on additional term of the tangent stiffness matrix was improved to solve the divergence for strong nonlinear problems. An accurate deformation algorithm was presented,and a detailed calculation procedure was provided. A computer program was developed to analyze the geometrical nonlinear behavior of the plane beam with and without rigid arm. The results have demonstrated that the proposed innovative element and algorithm are efficient and accurate with satisfied convergence, and have promising applications in practical engineering projects.

Abstract:The removal of phosphate from aqueous solution using the anion-exchange membrane was investigated without supplying electrical potential based on Donnan dialysis principle. The results showed that the removal efficiency of phosphate achieved 70.0 % under the conditions of influent phosphate of 2.0 mg/L(0.064 5 mmol/L), the NaCl concentration of 0.1 mol/L in the receiver solution, the flow rate of the feed solution of 5.0 mL/min. Decreasing the initial pH of the feed solution to 3.0, the phosphate concentration outlet in the feed solution was much higher than that with the initial pH of 5.0~9.0,and the removal efficiency of phosphate was only 43.5 %. In the tested concentration range, the accompanying anions (Cl-，HCO-3 and SO2-4) had little effect on the removal of phosphate. Using Na2SO4 solution as the receiver phase, the removal of phosphate greatly reduced. Decreasing the NaCl concentration in the receiver solution had little influence on the transport of phosphate, but the concentration of phosphate in the receiver solution decreased significantly. Increasing the flow rate of the feed solution from 2.5 mL/min to 10.0 mL/min , the removal efficiency of phosphate decreased obviously from 84.3 % to 61.1 %.

Abstract:By taking “26 ℃ air conditioning energy conservation motion” as the research background, this paper analyzed the comfort and energy-saving performance of temperature control air-conditioning system. Then, a comparison of the Predicted Mean Vote (PMV) values of two connected rooms in different orientations revealed that, at the same temperature, different average radiation temperatures caused different comfort indexes. The same temperature control standard usually resulted in uncomfortable environment. The energy-saving differences between the temperature and the comfort index control of air conditioning system in summer and winter were analyzed, which illustrated that the temperature control embodied neither heat comfort nor energy-consumption, and comfort index control, like PMV index control, is one of the effective methods which ensures comfort and considers the energy-saving requirement of air conditioning system.

Abstract:A calculation method for night ventilation was presented by considering the air flow rate as piecewise function and utilizing the calculation method of natural ventilation. A night ventilation experiment was done to compare the effect of ventilation time and air flow rate, and the temperature of experimented rooms was calculated by the model. The results of experimental and mathematical calculations were compared. It has been shown that they are in good agreement, so the calculation method on night ventilation can be used in engineering.

Abstract:This paper was concerned with the validity and applicability of local approaches used for the fatigue assessment of welded joints. The equivalent stress was introduced according to Taylor's critic distance theory classified as local approaches，and determined in the finite element method. The fatigue data of both steel and aluminium cruciform joints were analyzed. The fatigue failure might originate from weld toes and roots in load-carrying cruciform joints. The analysis results have shown that the equivalent stress can be used to predict the position where fatigue failures occur. The data of fatigue strength and stress-life were examined in terms of equivalent stress. It has been shown that the data scattering is remarkably reduced for cruciform joints with fatigue failure originating from weld toes. Then, the unified strength and S-N curve can be expected to be determined, but it is not the same for cruciform joints with fatigue failure originating from weld roots. The data scattering is high and comparable with the case where fatigue strength is expressed in terms of nominal stress. The latter indicates that the validity of local approaches is absent and its applicability needs further studies.

Abstract:The effect of throttle（the effect of shape and location of the orifice, the effect of clearance）on the performance of shock absorber was analyzed according to a new torsion damp shock absorber of vehicle. Some design ideas were proposed in two aspects:considering the orifice and the clearance,or considering the clearance only. According to fluid mechanics, a model of calculating the shock absorber was established. The velocity characteristic curve was obtained. The different characteristics of the two ideas can be used in the design of different torsion damp shock absorbers.

Abstract:When the rolling bearing works in fault condition, the complexity of the vibration signal will change. Sample entropy (SE) is defined to measure the complexity of time series in single scale, while multiscale entropy (MSE) is used to measure the complexity of time series in different scales, which contains much more information. Based on this, a new rolling bearing fault diagnosis approach based on MSE and SVM was put forward. In this paper, the concepts of SE and MSE were introduced, then MSE was applied to extract the feature information from bearing vibration signals and SVM was used to identify the rolling bearing fault categories. Finally the proposed approach was applied to the experimental data, and the analysis results indicate that the proposed approach can fulfill the rolling bearing fault classification effectively.

Abstract:According to the particularity of the rhombic bus chassis layout, two degrees of freedom (2-DOF) handling model were established based on front/rear wheel linkage steering. Based on the model, the stability factor was deduced, and the condition satisfying under steering was determined. At the same time, the vehicle handling stability was analyzed, and the effect on the handling stability caused by the vibration of vehicle parameters was analyzed. The analysis results have shown that the influence caused by the mass of the vehicle is very small on the vehicle handling stability, but the influence caused by the wheelbase and the position of center of mass is greater. The condition satisfying under steering and the influence caused by the changes of parameters on the vehicle handling stability will contribute to the overall design of the rhombic bus, and will have better reference value for engineering.

Abstract:This paper proposed a system for the conditional monitor and fault diagnosis of tamping machine, which can collect the information of monitoring tamping machine's working condition on line in real-time. The information was processed and analyzed with an expert system, and this system can combine with the condition of monitoring railway maintenance to make reasonable judgments for the operational state of the tamping machine in order to ensure the operational quality,and can offer reliable basis for follow-up maintenance. Currently, this system has been put into operation. It improves the operating quality and speed of the tamping machine and brings better economic benefits.

Abstract:In order to simplify the Microgrid small signal model, only the dynamics of the power allocation loop of the droop generators and the dynamics of the DC voltage and reactive power output control loop of the PQ generator were considered. Normally, the filter reactance of the PQ generator is much larger than the Microgrids line impedance and the output power of the PQ generator is approximately controlled by the magnitude and phase of the inverter bridge voltage. By this approximation, the small signal model of the PQ generator can be in accordance with the droop generator by defining the small signals of the magnitude and phase of the output voltage as the model states. And in order to overcome the adverse impact of the big droop coefficients on the stability of the Microgrid, a feed forward path on the real power allocation loop was added to improve the stability. Lastly, time domain simulation confirmed the above analysis.

Abstract:For the real-time and objective measurement of the risk caused by on-line power transformer, a power transformer risk assessment method was put forward based on Fuzzy Analytic Hierarchy Process (FAHP) and Artificial Neural Network (ANN) from the perspective of the accuracy and quickness of risk assessment. An analytic hierarchy process model for transformer risk assessment was built by analyzing risk factors affecting transformer risk level. In this model, a risk index system was established and index weights were quantified. The weight relation of each risk factor in transformer risk calculation was analyzed by applying fuzzy consistency judgment matrix. It took major risk factors as the input of the neutral network by making use of adaptive ability and nonlinear mapping ability of the ANN, thus realizing the intelligent quantitative assessment of transformer risks. Simulation results have shown that this method increases the speed and result accuracy of risk assessment and can provide feasible decision basis for transformer risk management and maintenance decisions.

Abstract:Based on the rectangular resonator metal-insulator-metal (MIM ) waveguide structure, we have presented and proven a new type of surface plasmon band-stop filter using the two-dimensional finite-difference time-domain method (2-D FDTD). This structure consists of a waveguide channel and a column of rectangular cavity resonator,which is parallel to the waveguide. When F-P conditions are met between the length of the rectangular cavity and the wavelength, the surface Plasmon (Surface Plasmon Polaritons, SPPs) of the wavelength will be restricted in the cavity, which results in the filtering effect. By adjusting the length and the number of the resonator, we can easily filter out one or more specific single wavelength. Compared with other structures of SPPs filter, this structure is more concise and can filter narrower wavelengths with smaller energy loss. It can be applied to optical equipments in high integrated circuit devices.

Abstract:4-tert-butyl-2- (α-methylbenzyl) phenol（t-BAMBP）was synthesized from tert-butylphenol and styrene catalyzed by concentrated phosphoric acid. The optimal synthesis conditions were as follows: a reaction temperature of 150 ℃, a reaction time of 150 min, a reactant ratio of 1∶1.8, and a catalyst dosage equal to 1.5% of the feed stock. Under such conditions, the conversion percent of tert-butyl phenol was 81.29%, and the yield of t-BAMBP was 81.04%. The synthetic products were separated and purified by vacuum distillation. The proper distillation temperature was 156~157 ℃, and the absolute pressure was 400Pa. The purity of t-BAMBP was higher than 98.79%. The tert-butyl group removing mechanism in the t-BAMBP synthesis process was analyzed, and the by-products forming routes were deduced.

Abstract:The aqueous ethanolic extract of Eucalyptus leaves were used as the antioxidant in food additives, but it was not all clear of antioxidative components. In this paper, two tautomerizing gallotannins with strong antioxidant activity were isolated from the eucalyptus leaves extract. The antioxidant activities of the two components were more than two times that of the standant antioxidant Trolox (ORAC index). The chemical structures were determined by HPLC, H-NMR and 13C-NMR. The results have shown that one is 3-galloyl-4,6-HHDP-D-glucose (Gemin D), and the other is 2，3，4，6-two-HHDP-D-glucose（Pedunculagin）, and the former component is the first to be isolated from this plant.

Abstract:A modified AFSA (artificial fish swarm algorithm) with parameters dynamic adjusting was proposed to solve the problem of standard AFSA algorithm trapped in local optimal solution and low convergence precision. The advanced algorithm was modified with the following strategies: adjusting the parameters dynamically in the visual field and the congestion factor to improve the searching efficiency, modifying the removing crossover operator to find the crossing point and eliminate it, and designing a further optimizing operator to find the current optimal value again in the current path. The improved AFSA was applied to the TSP problem, and the experiment result has shown that the proposed algorithm has better convergence effect and can improve search performance.

Abstract:Taking the coordinated development of energy, economy and environment into account, we use the concept of environmental DEA technology and measure efficiency by expanding the traditional DDF model and use the expanded DDF model to analyze China's energy efficiency. The result has shown that different regions show different energy efficiency. The highest energy efficiency region is the three major cities, while inefficiency concentrates in the western region. Meanwhile, the cost of environmental regulations in the western region with a lower energy efficiency shows a shape of W.

Abstract:Applying housing feature pricing theory, the housing estate's average price in Nanjing was selected as a dependent variable in Sep.2011,and 8 factors affecting housing prices as an independent variable is quantized. Then geographically weighted regression was processed. Compared with the traditional OLS estimation, GWR model has a better fit. At the same time, it has been found that all significant factors influencing housing prices in the spatial distribution are different and the characteristics of this difference are revealed.