Abstract:Based on the test of steel-concrete composite frame, the refined 3-D finite element (FE) modeling of steel-concrete composite frame was proposed by using Msc.Marc to gain a better understanding of the structural behavior of the composite frames. A number of material nonlinearities and contact nonlinearities, as well as geometry nonlinearities, were taken into account. Strain-based fracture criterion was adopted in the FE model to simulate the fracture of beam flange. The global and local behavior of the FE analysis models agreed well with those of the test specimens. Parametric studies were conducted on the basis of the refined FE model. The analyzed parameters included slab width, shear connection degree, axial force ratio, etc. The influences of these parameters on the behavior of the composite frame in terms of stiffness, strength and ductility were studied. It was suggested that the concrete slab width should be taken at least as a quarter of the beam span in the 3D FE model or in the test specimen to accurately evaluate the impact of the slab action. The axial force ratio had a great impact on the ductility of composite frame, while the thickness of the slab and shear connection degree had little effect on the seismic behavior of the composite frame. And some ideas for the corresponding design provisions were proposed.

Abstract:The flow field around a rectangular cylinder with an aspect ratio of 4 was simulated with Reynolds-averaged Navier-Stokes equations combined with SST k-ω turbulent models, which helped to represent its flow structures and aerodynamic characteristics. The results obtained, including drag coefficient, Strouhal number, mean and fluctuating pressure distribution on cylinder surfaces, averaged vortex shedding location and reattachment length, agreed well with available reports. Through the application of the Principle Component Analysis (PCA) to records of fluctuating pressure on the surfaces, it is found that the first principle component shares the same trends with the RMS distribution of fluctuating pressure, which may be an alternative way to characterize the fluctuating pressure. Based on the configuration of the first principle component, the vortex shedding location on the side surface can be readily located, and the vortex shedding frequency can also be obtained from the coefficients of the first principle. It is highlighted that the main vortex shedding on the side surfaces dominates the features of the fluctuating pressure.

Abstract:Based on computer-aided geometric design, the surface was reconstructed according to the given data points by means of non-uniform rational B-spline technique. With the aim of finding an optimum surface that meets the architectural intent data points, an adjustment method was presented, which takes minimum structural deformation under gravity as the objective function and data point's position as design variables. Gradient method was employed to modify the free form surface by adjusting design variables. The surface shape was modified iteratively according to data points' changes. The approach has been implemented into two projects and the feasibility of the approach was demonstrated.

Abstract:Based on the site selection of Hunan rural housing with hilly terrain, the northern vegetation can shelter the house in flat area from cold wind in winter, and the natural ventilation in summer will not be influenced. It is useful for rural housing to improve the indoor thermal environment. The influence of different distances between the vegetation and the house were simulated in the section by CFD, and the optimal distance was obtained on the basis of the zero dimension pressure distribution on southern and northern wall surfaces. Then, the different widths of vegetation were also simulated in plane in the same way, and the optimal width was obtained. At last, the optimal design model of rural housing with vegetation was obtained, and the different requirements of natural ventilation in winter and summer can be satisfied simultaneously.

Abstract:Parking trajectory characteristics were analyzed, and an approach for trajectory planning was proposed on the basis of the B spline theory, and the parking path was realized by adjusting the control points. Potential collision points were analyzed,and the constraint equations were established accordingly. The orientation constraints at the start point,the location constraints at the parking point,and the restriction of vehicle were considered, and the constraint equations were established respectively. Parking kinematic function was presented on the basis of Ackerman steering theory, and parking trajectory optimization function was presented to minimize the max trajectory curvature in parking process with the restrictions mentioned above. The approach was used to plan parking path for general parking space and tight parking space, and the trajectory function was solved in Matlab. The simulation results have shown that the car can reverse into parking set safely in general parking space, with the trajectory curvature changing continuously and the car paralleling the parking set at the parking point. The car can reverse into parking set without collision in tight parking space by adjusting steering angle repeatedly, with the trajectory curvature changing continuously. It is proved that the approach proposed can find a collision-free path in different parking spaces and meets the demand of continuous trajectory curvature, so the problem of shutting down to steer the wheel in parking process has been solved.

Abstract:The traditional mean shift algorithm uses the tracking window of fixed size, so it is not efficient to track target vehicle, which continuously changes in size. To solve this problem, this paper presented a new vehicle tracking algorithm according to the characteristic of tracked vehicle. The new algorithm is based on the combination of mean shift and C-V model. Firstly, the initial tracking window was obtained with traditional mean shift tracking algorithm, then the tracking window was shifted and reshaped according to the shape information of target vehicle obtained by C-V model. In the tracking process, the shape and color information were both considered. Meanwhile, an improved C-V model was proposed, which used a new level set initialization function. Experiment results have shown that the tracking algorithm improves vehicle tracking accuracy greatly and guarantees real-time tracking.

Abstract:In order to improve the system robustness and adaptive ability in the permanent magnet synchronous motor (PMSM) sensorless control system, a new active-disturbance rejection controller (ADRC) was presented. In practice, the ADRC parameters are difficult to operate and adjust, so we introduced the fuzzy control.Combined with their own characteristics, and a self-adapted active disturbance rejection controller with fuzzy control theory was designed. The inside and outside of the system disturbance were considered as the unknown disturbances, with the new ADRC to implement the PMSM sensorless control. Simulation results have shown that the system has strong adaptive ability of disturbance and robust at different speed conditions, and it has high accurate speed estimation. The feasibility and advantages of the control strategy have been validated in the field of permanent magnet synchronous motor control.

Abstract:This paper designed an eight-axis control system by adopting ASIC as the central core, and using the PCI multi-axis controller to control the stepper motor movement through state feedback. Combining the advantages of Hopfield neural network and the genetic algorithm, the control system adopted GA-Hopfield neural network to optimize the path of Chinese sculpture. This method solved the perplexity sculpture process problem and shortened the total sculpture path. This paper presented the hardware structure of the system, the GA-Hopfield neural network optimization algorithm and its simulation. The application has shown that the multi-axis motion control system has good stability and control accuracy.

Abstract:This paper presented a 3.1~10.6 GHz ultra-wideband (UWB) low noise amplifier (LNA) in a 0.18 μm CMOS process. The circuit was designed with current-reuse and impedance feedback technology, so it has the characteristics of low power dissipation and flat gain. Simulation results have shown that, across the frequency band of interest, the LNA achieves 17.5 dB of average gain, the input and output return loss is lower than -8 dB, respectively, the minimum NF is about 2.8 dB, and the power dissipation is about 11.35 mW under the power supply of 1.5 V.

Abstract:There are a lot of power quality problems such as a large number of harmonics and voltage fluctuations, caused by quickly changing diverse types of loads and power resources in microgrid. An optimizing control method based on robust H2/H∞ controllers was proposed by establishing a unified math model of UPQC in micorgrid. The state equation contains the uncertain parameters of the structure, and all allowable uncertainties can meet both the H∞ disturbance attenuation and the optimal H2 performances of the closed-loop control system. The design of robust H2/H∞ controller was transformed into an optimal problem with constraints of linear matrix inequalities, from which the robust H2/H∞ output feedback controllers can be derived. The simulation and experiment results show this method can obtain preferable control effect, fast dynamic response and good robustness.

Abstract:In order to realize direct electroless nickel plating on aluminum alloy under the middle temperature of 70 ℃, an activator (fluoride) was added and the main complexing agent was adjusted in the chemical bath. Appropriate concentration of activator can accelerate the electroless nickel plating and improve the comprehensive performance of coatings. When citric acid was replaced by aminoacetic acid as the main complex agent, the corrosion resistance of coating was obviously improved. The corrosion potential increased, the corrosion current decreased and the resistance of color degeneration was also obviously enhanced. The Ni-P coatings with good comprehensive performance were produced in the bath containing 2 g·dm-3 KF and 8 g·dm-3 aminoacetic acids.

Abstract:This paper aims to investigating the effects of fresh frozen plasma (FFP) on the release of nitric oxide (NO) in normal human lung microvascular endothelial cell. NO/Nitrite/Nitrate assay showed a much higher NO production in the conditioned media of FFP-treated human pulmonary microvascular endothelial cells (HPMECs). Phospho-kinase array and Western blotting revealed that FFP significantly increased the activation of AMPK 1, Akt1 and eNOS in HPMECs. Pretreatment with Compound C (AMPK inhibitor), LY294002 (PI3K/Akt inhibitor) or L-NAME (NOS inhibitor) inhibited AMPK 1/ Akt1/ eNOS cell signaling，FFP-induced eNOS activation and NO production in HPMECs. This study reveals a new mechanism in which FFP exerts its vasoprotective effect.

Abstract:The microstructure evolution of the Fe-20Mn-2.6Al-2.6Si TRIP/TWIP steel with different deformation levels was studied with optical microscopy, X-ray diffraction and transmission electron microscopy. The results indicated that stacking faults and dislocation cells were primarily formed at the initial stage of deformation. The contents of the α martensite and ε martensite were gradually increasing with the strain increasing. At the last stage, the α martensite becomes the main phase. So, the tensile deformation mechanism of the Fe-20Mn-2.6Al-2.6Si steel was the phase transformation inducing the deformation (TRIP). The optical microscopy morphology showed that many lamellas appeared when the deformation level was up to 6.5%, and these lamellas were usually mistaken for deformation twins. But the transmission electron microscope (TEM) analysis indicated that deformation twins were hardly found at any of the deformation levels. Actually, the lamellas observed in the optical microscopy or low magnification TEM images were ε phase, which further confirms that the deformation mechanism of the Fe-20Mn-2.6Al-2.6Si TRIP/TWIP steel was the TRIP mechanism.

Abstract:ZnS and La-doped ZnS thin films were successfully synthesized by using chemical bath deposition on conductive glass substrates. The effects of La doping on the surface morphology of the films were investigated with SEM, and the deposition process of ZnS thin films was analyzed with CHI660B electrochemical comprehensive analysis. The prepared ZnS thin films were nearly spherical and compact. The electrode potential shifted negatively, deposition rate decreased and the particle size increased with La doping into the ZnS films due to the adsorption of low electronegative La on the electrode surface. It is suggested that electrochemical investigation is an effective tool in studying ZnS deposition process by chemical bath deposition.

Abstract:For the research on the fluid flow in the porous medium of graphite, the law of non-Darcy flow was revealed through the seepage flow of single-phase water in the saturated carbon-graphite with the whole Core Flow System.The experiment results indicate that the flow of water deviates from Darcy's law, the flow curve is nonlinear, and it can be described in a quadratic equation. The fitting precision is higher, and the correlation coefficient is more than 0.99. The flow has minimum starting pressure gradient in the seepage process and its value decreases rapidly with increasing porosity.Graphite materials can be divided into three categories according to the minimum starting pressure gradient with the change in porosity, namely “easy infiltration category”, “difficult seepage category” and “transition category”. Their porosity is greater than 18%, less than 11% and in 11%~18%. The nonlinear seepage law of water is verified through Reynolds number criterion and it agrees well with the experimental phenomena.

Abstract:Based on the sample data of China from 1960 to 2008, this paper used Toda-Yamamoto test program to carry out quantitative research on China's energy consumption, carbon emission and economic growth in the causal relationship between the three. The results show that economic growth and energy consumption are the cause of CO2 emission Granger causality. It means that economic growth and the increase in energy consumption will lead to increased CO2 emissions, and vice versa. Energy consumption and economic growth have two-way Granger causality. The results show that China's energy consumption and the corresponding carbon dioxide emission in the coming decades will continue to grow. Therefore, China should actively formulate and implement policies to reduce carbon dioxide emission.

Abstract:As a newly emerging financing method, BT (Build-Transfer) Mode has demonstrated its extensive application in infrastructure construction. In allusion to the principle of BT project risk allocation, this paper first provided an analysis on two kinds of risks within BT Mode: the risk as common construction mode does and certain particular risks of its own. And then, based on the principle of “risk sharing and benefit sharing”, it established the mathematical model of risk sharing. The model result shows that the project's maximum overall efficiency will be achieved when the participant who has the largest risk preference coefficient bears the project risk. Finally, according to the conclusion, it puts forward specific principles of the apportionment of risks and benefits, which can serve as practical guidelines for each participant during BT project negotiation.