Abstract:An experiment study was conducted on the flexural behavior of reinforced concrete beam strengthened by Polyvinyl Alcohol-Engineered Cementitious Composite (PVA-ECC) mortar subjected to secondary load. Based on the comparison between test results of seven beams reinforced by PVA-ECC steel mesh and one general beam, the effect of once-loading extent and height of reinforcement at the side of RC beam on the flexural strength and deflections capacity was investigated. Beams were reinforced with U-shape, and the crack distribution, load-max deflection, strain development of concrete and steel, etc. were measured. Test results have indicated that PVA-ECC steel mesh technology is an efficient method to reinforce RC beam, which can markedly increase the load-bearing capacity, section stiffness and crack-resisting behavior. In addition，when the height of reinforcement at the side of RC beam is half of the beam's height，the load-capability of reinforced RC beam changes slightly compared with the full height of reinforcement R

Abstract:When calculating high-strength bolted bearing-type joint controlled by member strength, the consideration of friction force directly affects the carrying capacity. This process was analyzed in this paper according to the mechanism of high-strength bolted bearing-type joint, and FEM was used to simulate the loading process, in which the cooling method was used to simulate the prestress of high-strength bolt. The results have shown that, when connection capacity is controlled by member strength and the friction force is not considered for high-strength bolted bearing-type joint, the carrying capacity will be reduced. A proper calculation method based on analysis was proposed.

Abstract:There is uncertainty in the analysis of the stability of karst roof under pile tip. The interval numbers were used to express the calculation parameters. And the method to determine the interval numbers was proposed by the comprehensive application of interval mathematical theory, rock mass rating index (RMR) and Hoek-Brown empirical strength criterion. Secondly, the limit equilibrium analysis model of karst roof under pile tip was presented on the basis of the present study. The model can consider the action of punching shear, shearing and bending at the same time. Thirdly, the performance function was proposed to evaluate the reliability of the stability of karst roof under pile tip. The non-probabilistic reliability analysis method for stability of karst roof under pile tip was finally founded. This method is proved to be rational and feasible with engineering case analysis, and it provides a new uncertain analysis method for the stability evaluation of karst roof under pile tip.

Abstract:This study is concerned with a new reverse-cycle hot gas method using phase change thermal energy storage (TES) to eliminate frost in an air-source heat pump (ASHP), which can effectively solve the shortage of defrosting energy. The feasibility of defrosting was investigated through experiments and the modes' performances were compared with a nominal 850 W capacity ASHP system conventional reverse-cycle hot gas defrosting method. The results have indicated that thermal energy storage based reverse-cycle hot gas method can improve the discharge and suction pressure and shorten defrosting time in defrosting. In defrosting operation, the TES defrosting method can improve discharge and suction pressure by 0.25 MPa and 0.15 MPa respectively, and shorten defrosting time by 60% in the tested environment, relative to the conventional reverse-cycle hot gas defrosting method.

Abstract:Based on the occupant injury severity in side pole impact, this paper conducted a computer simulation study on the side pole impact of a passenger car. The injury criterion and parameters of dummy, the side structure deformation and acceleration of the car body were thoroughly analyzed in terms of the crash characteristics of the car in side pole impact. The countermeasures for improving the strength of the door-sill-beam and the floor cross member were presented. Simulation results have shown that the side pole impact increases occupant injury risk and makes more intrusion on the side structure of the body, compared with car to barrier side impact. The passenger car safety performance can be improved in side pole impact by strengthening the door-sill-beam and the floor cross member. 

Abstract:Unsteady, massive separation and complex vortex structures are the typical features of vehicle external flow field. The numerical simulation of the external flow field around a car was carried out by using DES methods. The results such as pressure distribution, skin friction coefficient distribution, velocity and turbulence kinetic energy distribution in the wake were compared with the results by using the RANS methods. It has been indicated that it has few differences between RANS and DES in obtaining the time-average results, but DES methods are particularly suited and clearly superior to RANS methods for unsteady flows and in capturing the structures which contain energy. Hence, DES methods are more suitable to calculating the complex flow field around a car. In contrast to RANS, computational cost is more expensive for DES, and RANS is economical for obtaining the time-average information of flow field.

Abstract:To predict the heating and pressing parameters of a micro aspheric lens molding process, a molding process model was established and all the boundary conditions were set. Based on the finite element software numerical simulation, mold filling condition of glass D-ZK3 at 540~590 ℃ was analyzed, and the optimum molding temperature was about 580 ℃.The results have shown that the higher the molding temperature, the smaller the residual stress, and the minimum heating time for this model is about 155 s at 580 ℃ molding temperature. Residual stress after molding is larger at the edge of lens than at the center, and the strain is larger at the top than at the bottom. Finally, three different molding velocities were analyzed, and the results have shown that the average residual stress of the lens increases with the increase of molding velocity.

Abstract:This paper proposed a method to accomplish scan test low-power optimization through voltage control. This method is named voltage-control method for short. It controls the power supply of combination logical units mainly through gating transistor insertion. It effectively solves the problem of the useless propagation to combination logic from test signals in the process of the shift-in of scan test. The power supply of combination logic is controlled, thus the voltage-control method not only effectively reduces useless dynamic power, but also substantially reduces the leakage current static power caused by power supply. Also the insertion of gating transistor has little influence on the designed area and timing sequence. The experiment result has shown that the voltage-control method has much less influence on the area and delay than the logic gate insertion method, and also, the power optimization is improved by nearly 32%.

Abstract:Carbon nanotubes embedded in cuprous oxide (Cu2O/MWNTs) particles composites superflue spheres were fabricated in situ in the solution method. The products were characterized through scanning electron microscope (SEM), transmission electron microscope (TEM) and UV-visible photometer. The results have shown that the MWNTs are embedded in cuprous oxide spheres homogeneously. The size of compound spheres is influenced by the reaction temperature, the concentration ration of the reactant and the titration speed of sodium hydroxide. By comparing the photocatalytic effect of cuprous oxide on the p-nitrophenol with that of the compound spheres which consist of carbon nanotubes embedded in cuprous oxide, the results have shown that the degradation rate is about 10% higher than cuprous oxide.

Abstract:Multimodal WC-12Co coating was deposited on low carbon steel substrate by using JP-8000 HVOF spraying system. The properties of bond strength，microhardness， porosity and abrasive wear of the coating were investigated. The phases of the feedstock powder and the coating were analyzed by XRD. The characterizations of spraying feedstock powder， microstructure and surface micrograph wear surfaces were analyzed by SEM. The results have indicated that the WC does not decompose obviously during spraying and the coating exhibits high bond strength，microhardness and compact structure. Compared with the 316L stainless steel，multimodal WC-12Co coating exhibits excellent abrasive wear resistance.

Abstract:This paper presented a meshless local Petrov-Galerkin method based on the natural neighbour interpolation for a plate described by the Reissner-Mindlin theory. The natural neighbour interpolation shape functions have Kronecker Delta function property, which facilitates the imposition of essential boundary conditions. The local weak forms of the equilibrium equations and the boundary conditions are satisfied in local polygonal sub-domains in the mean surface of the plate. These sub-domains were constructed with Delaunay tessellations and domain integrals were evaluated over included Delaunay triangles by using the Gaussian quadrature scheme. The present method combines the advantage of easy imposition of essential boundary conditions of NEM with some prominent features of the MLPG. The numerical results have shown that the proposed method is easy to implement and very effective for these problems.

Abstract:A series of KNO3 modified zeolite catalysts（K/Zeo，Zeo = ZSM-5 , Y）were prepared in impregnation method and employed in the conversion of lactic acid to 2, 3-Pentanedione(PDO). The characterizations of XRD and low-temperature N2-physisorption indicated that the process of KNO3 modification damaged to some extent the framework of zeolites, resulting in the decrease of specific surface area and pore volume but the increase of the pore size of the zeolites. The catalytic performance evaluation and carbon balance examination have shown that, compared with those over the unmodified zeolite catalysts, both PDO yield and carbon balance are greatly improved, due to the generation of new active sites and the adjustment of pore sizes, over the modified ones. Among various modified catalysts, a K/NaZSM-5(60), which possesses a micro-mesoporous structure, exhibits the best performance, providing 52.4% lactic acid conversion and 48% PDO selectivity at 280 ℃. The high performance of this catalyst may be the result of its large specific surface area.

Abstract:Polymers bearing a single formoxyl acrylic group at the chain end were synthesized by reacting between poly(styryl)lithium and maleic anhydride（MAH）. The functionalized polymer was characterized by GPC, IR and Raman. The end-capping mechanism was figured, including the possible coupling reaction of dimmer. According to kinetic study, the reaction behavior could be explained by SN2 mechanism. Specifically, various factors related to functionalized efficiency, such as temperature, time of end-capping reaction, MAH/PSLi molar ratio (cMAH/cPSLi) etc., were investigated. The result has shown that the reaction efficiency was obviously affected by reaction time and polar addition. The functionalized efficiency at the optimism conditions can be up to 83.3%.

Abstract:To study the chemical composition characteristics of dry deposition is very important to the understanding of their influence on forest ecosystem. They are the key factors to grasp the formation, transportation and deposition mechanisms of the acidic matters in the air and the aerosol. This paper studied the chemical composition characteristics of air and aerosol based on the monitor data of three typical acidic catchments, including Cai Jia Tang (CJT) in Hunan, Lei Gong Shan (LGS) in Guizhou and Tie Shan Ping (TSP) in Chongqing. The research results have indicated that the dominant acidic materials are SO2,SO42-,and NO2, and the dominant basic ones are NH+4，Ca2+，K+ and NH3. The dry deposition ratio of SO2 has a close relationship with the local sources of sulfur (S) and has seasonal variations as well. The mean seasonal concentration of (NH3+NH+4)-N is higher than (HNO3+NO-3)-N in all of the three areas. The order of annual mean concentration of NO2-N and NH3-N in the three sections are TSP>CJT>LGS. Furthermore, the gas/particle ratio for the ammonia compounds is less than 1∶1 in the three areas, and that for the nitrogen compounds is close to 1∶1 at CJT, more than 1∶1 at LGS, and less than 1∶1 in TSP.

Abstract:The comprehensive index assessment method based on the state-pressure-response index systems was applied to establish the eco-security assessment index systems of the water environment of Changsha-Zhuzhou-Xiangtan district, and through the index system, the eco-security of the water environment was evaluated according to 2004-2008 statistical data. The assessment results have shown that the synthetical index value for the security assessment of the water environment in Changsha-Zhuzhou-Xiangtan district presented a low level except in 2006, and it was in the warning condition, and the assessment value of the state has been decreasing in these years, which indicated that the eco-system of the water environment in Changsha-Zhuzhou-Xiangtan district has been damaged continuously and the proportion of response index was the smallest among the researched indexes. Therefore, the efforts on the eco-system construction of the water environment should be intensified in the coming years.

Abstract:A kind of gesture segmentation method based on monocular vision was built for the analysis of the skin color information characteristics and gesture movements features, with which a meaningful gesture region could be obtained from the video image sequence. For the identified background image, the skin color region of gestures was captured through the analysis of the skin color information characteristics with a sampling interval of 10 frames. At the same time, the movement region of gestures was captured through the difference method, and then the initial gesture region could be obtained after the fusion of the skin color region and the movement region. The erosion and dilation algorithm of mathematical morphology were further studied, and the gestures segmentation and positioning of the video image sequence were realized. The experiment results have shown that the method has a good gesture segmentation results and higher positioning accuracy.

Abstract:Particle Swarm Optimization algorithm easily gets stuck at local optimal solution and shows premature convergence. An improved Particle Swarm Optimization algorithm based on two-subpopulation(TS-IPSO) was proposed. The search range of the algorithm was extended through main subpopulation particle swarm and assistant subpopulation particle swarm, whose search direction was inversed completely. It also adopts the crossbreeding mechanism in genetic algorithm, and uses non-linear inertia weight reduction strategy to accelerate the optimization convergence and improve the search capabilities of particles, then effectively decrease the risk of trapping into local optima. Experiment results have shown that the TS-IPSO can greatly improve the global convergence ability and enhance the rate of convergence, compared with SPSO.

Abstract:DSmT can solve the problems of high conflict evidence combination, but it has the disadvantage that the calculation is too large and the mass value of main element is difficult to converge. In order to solve this problem, a fast mass function convergence algorithm was proposed, which just calculates the basic belief of the single element in the frame of discernment to normalize them, and then rebuild the mass value, thus it can greatly reduce the calculation and make the mass function quickly converge to a certain threshold, which is convenient to quickly and exactly recognize and sort the targets. The comparison and simulation computation example have proved the validity of this algorithm.