Abstract:The Split Hopkinson Pressure Bar (Split Hopkinson Pressure Bar, SHPB) test was done to investigate the dynamic properties of crumb rubber modified asphalt concrete under impact loading. Test results and analyses have indicated that the addition of rubber can notably increase the plasticity of asphalt concrete. Both dynamic strength and impact toughness are functions of temperature and strain rate. The strength and toughness have higher values at 25 ℃ than those at -20 ℃ and 60 ℃ while increasing monotonically with the increase of strain rate. The addition of rubber can enhance the strength and toughness of the material by more than 200% and nearly 200%, respectively. The superior performance of rubber modified asphalt concrete under impact loading comes from the "stone-rubber-stone", i.e., rigid-flexible- rigid, contact made in asphalt concrete. There exists an optimized rubber with respect to the anti-impact performance of the material, which is about 20% by the mass of asphalt binder.

Abstract:In order to investigate the contact-hardening mechanism of the mortar component of demolished concrete, the mortars were separated and ground. One group of the power was directly molded at a certain compression, and the other group was molded after hydro-thermal synthesis at the temperature of 120 ℃ with a water solid ration of 5 by adding ground lime and quartz sand to adjust Ca/Si morel ratio. The apparent density, compressive strength, flexural strength and softening coefficient of the molded specimens were measured immediately. The results have shown that the ground mortar has a contact-hardening property to some extent and after hydro-thermal reaction, this property is obviously improved. The reacting production is amorphous silicate calcium hydration by XRD analysis. The maximum flexible strength and compressive strength are up to 5.7 MPa and 16.8 MPa respectively, and the specimen has a certain water resistance property, of which the softening coefficient can be 0.7. The property of contact-hardening is affected by the styles of the coarse aggregates of the demolished concretes and the constant time of temperature.

Abstract:Based on the fact that China's current research on the advanced analysis of steel frame focuses on capacity limit state, this paper uses traditional first order calculation method, second-order simplified calculation method and second-order accurate calculation method to calculate the lateral deformation of a 2-bay 15-story steel frame and obtains the peak drift and inter-story drift of the steel frame in the three methods. The drift results were compared, the study was carry out on the influence of the lateral deformation and the drift limit of steel frame under serviceability limit state when considering second-order effect. The results have shown that, for the steel frame considering second-order effect, the lateral deformation of the structure increased significantly, and the peak drift and the inter-story drift when considering second-order effect,are much bigger than those in traditional first order calculation method. For the structure design considering second-order effect, if we still use the drift limit of our country's current design code, the amount of steel will increase significantly. Compared with second-order accurate calculation method, the second-order simplified calculation method has good accuracy and can be used to calculate the second-order drift of the steel frame.

Abstract:Groups of tensile tests on architectural coated fabrics were carried out. Based on the current design specifications and experiment statistics, the main mechanical properties were analyzed to provide data for accurate partial coefficients. Then, the current design specifications for membrane structures were summarized and the safety factors in domestic specification were analyzed. Finally, the calibration method was adopted to determine the failure probability of membrane structures. The results have shown that the safety factors for the two load combinations are safe.

Abstract:Following the hertz contact and raceway control theory of the ball screw and considering the centrifugal force and gyroscopic moment acting on the ball screw, the dynamic model of high-speed ball screw was set up with consideration of pretension. The effects of different working conditions, such as the running speed and the axial preload, on the mechanical properties of the ball screw were studied and solved through numerical analysis. The result has shown that these factors affect the dynamic characteristic of ball screw dramatically, and the dynamic characteristic of ball screw at high speed is greatly different from that of ball screw at low speed.

Abstract:In order to adapt to fast-changing consumer needs and minimize design and modeling work, this study employs theme matching method to discuss the theme matching model and sanitary ware product design and to take the specific case of shower design in order to create the software of 3-D shape design system for sanitary ware products based on theme matching model and computer-aided design as well. Production practice has shown that the system has successfully completed rapid industrialization and improved the efficiency of sanitary ware product design and development.

Abstract:In order to solve the serious harmonic contamination and transformers' vibration and noises of the existing high-power industrial rectifier system, harmonic magnetic flux suppression technology of transformer core based on inductive filtering method was proposed. Firstly, the new rectifier transformer and filtering device were analyzed and designed. Based on the harmonic suppressing principle of the new converter transformer and the view of harmonic magnetic flux suppression in transformer core, the inherent distinction and characteristics of the inductive filtering method on the harmonic suppression and the reduction of the transformers' vibration and noises were revealed. Then, this paper achieves the normal tuning of the filtering devices by measuring the phase differences between harmonic voltages and currents. A new DC power supply system was also established. In addition, the practical test results of the new DC power system have shown that the harmonics generated by rectifiers and loads are well suppressed and the vibration and noises of the transformers are greatly reduced.

Abstract:By using impulse theorem, we have analyzed the mechanism of trigger thyristor by high-frequency pulse instead of width pulse .Through the establishment of an excitation circuit and a trigger thyristor circuit mathematical model and with the thyristor switch time, latching current, perceptual load and pulse transformer model parameters, we have calculated the thyristor conduction of minimum pulse width，cycle and pulse-width of equivalent high-frequency pulse column. Accordingly, we have designed thyristor "double narrow pulse triggering" program based on microcomputer control high-frequency pulse column. A prototype test waveforms and data of trigger microcomputer excitation system have shown that high-frequency pulse column and the excitation voltage waveform of three-phase controlled thyristor rectifier bridge rostrum are stable and have good symmetry. Also, the excitation voltage is stable and continuously adjustable. It has satisfied the requirements of wide pulse triggering.

Abstract:Hot compression tests of a new type of AM80-0.2Sr-1.5Ca magnesium alloy were performed on Gleeble-1 500 at a strain rate of 0.01~1 s-1 and a deformation temperature of 300~450 ℃. The true stress-true strain curves and the strain hardening rate were obtained. The parameters of the modified L-J microstructure model, including the hardening parameter and recovery parameter, were calculated by combining the L-J model with K-M model. The evolution of the microstructure and dislocation density of the AM80-0.2Sr-1.5Ca magnesium alloy during the hot compression at 450 ℃ were simulated by using DEFORM-3D software. The results have shown that the recrystallized grains are larger and distribute non-uniformly when the strain rates are low, and the recrystallized grain size decreases with the increase of strain rate. The simulation results agree well with the experiments, which prove the accuracy of the L-J modeling for predicting the DRX process during hot compression.

Abstract:The microstructure and tensile properties of 5A90 aluminum-lithium alloy rolled plate after heat treatment were studied with optical microscope, scanning electron microscope and transmission electron microscope. The results showed that the microstructure of the as-rolled plate presented anisotropy. Equiaxed grain appeared in the rolling plane. The microstructure in the longitudinal section and cross section presented a rolling streamline. There were a small number of recrystallized grains within the alloy. With the ageing heat treatment at 130 ℃ after the solid solution of 460 ℃/20 min, the hardness of the alloy increased continuously with ageing time until 20 hour peak-ageing, then the hardness dropped slowly. The main precipitate strengthening phase of 5A90 alloy was δ'(Al3Li) phase, and there was a good coherent relationship between δ′ phase and the matrix at peak-ageing. The ultimate tensile strength, yield strength and elongation were 512 MPa, 437 MPa and 7.5%, respectively. The main fracture manner of 5A90 aluminum-lithium alloy was dimple fracture, delamination cracking and cracking along the sub-boundaries. Tensile fracture surfaces showed the mixed characteristics of ductile fracture and brittle fracture.

Abstract:The microstructures and phase compositions of the WC reinforced Ni-based self-fluxing alloy composite coatings prepared by oxy-acetylene flame spray-welding were investigated with optics microscope（OM）and X-ray diffraction ( XRD) . The wear performance of the spray-welding coatings was tested by a MLS-225 wet sand rubber wheel abrasive wearing tester. The micrograph of the sprayed powders and the worn surfaces of the coatings were examined with scanning electron microscopy (SEM). The results have shown that the microstructures of the spray-welding coating are composed of γ-Ni solid solution，with large amounts of fine carbide grains such as Cr7C3，Cr23C6, Cr2B, CrB2 and WC particles. The hardness of the spray and fused Ni base WC composite coatings firstly increased and then decreased with the added content of WC，and the WC content for the highest hardness and abrasive resistance of coating is 25%.

Abstract:A new method of image character fuse was used to analyze and mine a mass of information of image. The mapping between the image character and its meaning was established by using neural network learning to mine the meaning of image. The image of cultural heritage was taken as the object of this study, and the images of 100 ancient buildings were selected. Their image characters and semantic information were extracted, and learning base of neural network was established. The 6 test images were selected and validated the validity and practicability of this method.

Abstract:In bilateral negotiation procedures, there often exist a number of issues. Models based on agenda, similarity or cases, ignore in most cases the interdependence of values of each issue. This paper proposes an interdependence-oriented bilateral multi-issue negotiation model. Firstly, the model adopts the thoughts of sequential procedure and local acceptance strategy for multi-issues negotiation. Secondly, it introduces off-line learning mechanism to partition the successful historical records of learning and uses these association rules and neural networks, which are generated from off-line learning to predict the acceptable values of interdependent issues. Lastly, this model presents a segmentation time strategy, which is based on the interdependent predicted value. The experiment results have shown that this model can improve the overall utility and efficiency to some extent.

Abstract:A definition of edge-matrix was given. And two algorithms for determining perfect matching Mi were proposed， of which the algorithm A is determined by using Δ（G）-edge coloring of edge-matrix K′2n, and the algorithm B to perfectly match Mi is determined by partitioning edge-matrix K′v into 2×2 sub matrix and also by solving n-1 perfect matching M′i of a complete graph Kn .The procedures of constructing round-robin tournament K(i)20 by using the algorithm A and using algorithm B were presented respectively.

Abstract:This paper studied the continuity of a multi-linear commutator generated by littlewood-Paley operator and Lipschitz functions on Triebel-Lizorkin space, Hardy space and Herz-Hardy space.

Abstract:Prepayment option and default option are implied in the housing mortgage loan, but whether they will be carried out depends on two risk factors, which are interest rate and housing price. Traditional structured option pricing theory usually overestimates the option value of housing mortgage loan. The double binomial tree quid pricing model makes it better adaptive by taking multi-step jumping cases into account on the basis of model Wei, combining HST model to remove state variables' correlation and by introducing social cost as a variable. The empirical analysis indicates that the option value increases sharply when housing price fluctuates to a certain extent, and interest rate fluctuation influences the option value directly or indirectly by affecting housing price. Therefore, it is necessary to pay great attention to the impact of interest rate on real estate market, and to strengthen the macro-control on real estate market in order to maintain its healthy development.

Abstract:The order parameter of Duffing-Holms model is analyzed and found out. Existence conditions of Duffing-Holms model's periodic solutions are put forward, which indicates that we can control financial chaos in OGY method and nonlinear synchronous method. One periodic solution is set out before numerical simulation of OGY is done. The conclusion has demonstrated that, to control effectively chaos in Chinese financial market, the government must prepare fully and adjust slowly. Finally, the conclusion of numerical simulation of nonlinear synchronous controlling has demonstrated that the government can control stock markets of Shanghai and Shenzhen by indentifying one market as the driven system and the other as the controlled response system.