Advanced Materials Research Vols. 468-471

Abstract: Commercial transfemoral prostheses remain limited to energetically passive devices. Intelligent prostheses still do not replace the power generation capabilities of the missing limb. Active Transfemoral Prosthesis is designed to compensate the movements of transfemoral amputees. Base on the function and principle of huaman lower limb, Active transfemoral prosthesis is designed. Virtual prototype of active transfemoral prosthesis 3D model is built through Solidworks. A dynamical system is used to generate a position trajectory to control a linear motor replacing the missing joint. Hopf oscillator is used to construct a central pattern generator (CPG), which makes up the dynamical system.

Abstract: The paper researches on the behavior of particles in the PSO, and improves the situation of easily falling into local optimum by the right combination of simulated annealing and PSO. In the paper, the author compared the original PSO and the improved SAPSO algorithms in neural network training. The empirical research shows that the improved algorithm performed better than the PSO algorithm in global search ability, and the prediction accuracy is greatly increased.

Abstract: This paper direct to security and real-time requirements in high-speed network transmission processing, based on SOPC technology, design a High throughput AES encryption/ decryption processing unit with pipelining. The design goal is to optimize the hardware structure and improve the throughput, S-box design and parallel processing structure. Compared with traditional AES crypto-chip has faster rate with encryption and less consumption of resources advantages. This design adopts VHDL hardware description language, use Quartus II 8.0 for the synthesis and routing, and this processing unit is packaged an independent IP core, attached to the Altera provided the Nios II system, finally download and test validation on the DE2 development platform.

Abstract: Based on Density Functional Theory (DFT) first-principles plane-wave ultra-soft pseudo-potential method, we calculated the electronic structure of wurtzite ZnO, Ag-doped ZnO and Ag-Al co-doped ZnO. And we anglicized of energy band structure, electron density of states of Ag-doped and Ag- Al co-doped ZnO crystal. The results indicated: Ag-doped ZnO introduced the deep accepter level in the energy gap, carrier (hole) located near the top of the valence band. And when we add active donor Al to the Ag-Al doped ZnO, the main level moved to low-energy, forming a shallow acceptor level. Meanwhile, the acceptor level got wider, non-localized features got significantly, improving the doping concentration and stability of the system.

Abstract: A novel controller based on the fuzzy B-spline neural network is presented, which combines the advantages of qualitative defining capability of fuzzy logic, quantitative learning ability of neural networks and excellent local controlling ability of B-spline basis functions, which are being used as fuzzy functions. A hybrid learning algorithm of the controller is proposed as well. The results show that it is feasible to design the fuzzy neural network control of autonomous underwater vehicle by the hybrid learning algorithm.

Abstract: The calculation of fluctuating pressure is necessary during the progress of trip in the managed pressure drilling, because the bottomhole pressure should be constant during the progress of trip. The prediction model of the fluctuating pressure during the progress of trip was established based on the unsteady flowing theory. The actual application state of the prediction model was presented through a computational example. By the comparison between the computational result and the field test result, the computational result matches the field test result very well, which indicates the rationality and the accuracy of the model.

Abstract: According to the characteristics of the elevator fault vibration signals, proposing a Based on analysis of time series AR bi-spectrum elevator fault diagnosis. When the zero-mean, non-Gaussian white noise elevator device, the vibration signal using sampling to establish time series autoregressive model (AR model), resulting in AR bi-spectrum. Bi-spectrum signal processing is a new, powerful signal processing technology, which can be described the nonlinear coupling, suppression Gaussian noise and retention of phase information, you can get the elevator working status of the different dynamic characteristics. The results show that bi-spectral analysis with AR elevator failure is feasible and effective.

Abstract: This article uses the flow field numerical simulation technology, it does simulation research for the flow field of the whole pneumatic conveying cotton trunk, through studying different types of jet orifice of the conveying trunk of comb—type cotton picker, finding out the influence of jet orifice width on pressure and velocity field, further understanding flow field distribution characteristics of the internal pneumatic cotton conveyance system, and providing necessary basis for the machine.

Abstract: Although meeting the regulations of the time, early buildings are prone to fire hazards, such as damages to the fire zones, changes of floor entrances and exits, locked emergency exit doors, blocking of entrances and exits by vehicles, increased fire sources, dense population in the buildings, due to insufficient professional knowledge and technology in fire prevention. Once a fire occurs, it can result in major casualties, serious loss of social costs, as well as environmental and social issues. This study investigated 17 major fire cases occurring in residential-commercial composite buildings in the last 20 years in Taiwan. The fire hazard factors were determined based on expert review. The findings can serve as a reference for fire agencies in promoting fire prevention.

Abstract: In this study, the fatigue crack growth rates (FCGRs) of Ti-15V-3Cr-3Al-3Sn alloy aged in the temperature ranges from 426 to 593 oC for 8 hrs was determined at stress ration of 0.1 or 0.5. The results of fatigue crack growth tests revealed the FCGRs decreased with increasing aging temperature. Generally, the 426oC aged specimen had the highest FCGRs among the specimens being tested, regardless of stress ratio. It was noted obvious increase in FCGRs occurred for the 482oC aged specimen at stress ratio of 0.5. Fatigue fracture appearance of various specimens tested in air exhibited predominantly transgranular fatigue fracture with coarse stripes for the specimens aged at/above 538oC. Intergranular fracture was more likely to be found in the 426oC aged specimen, and for the A482 specimen tested at high stress ratio.