Abstract. Wireless and mobile communication networks are becoming more and more fashionable in today's mobile world. In wireless communications, Mobile Ad hoc Networks play crucial role. Ad hoc network is an infrastructureless and self -organized collection of autonomous nodes. In mobile ad hoc network, routing is one of the thrust areas. There are no committed routers in MANETs; every network node should contribute to routing. Simulation tools are used to analyze the performance of routing protocols in MANETs. Propagation models show strong impact on the performance of routing protocols during simulations. This paper investigates the impact of familiar propagation models Two-ray and Shadowing on the performance of AODV and DSR routing protocols using NS-2. Experimental results found that both AODV and DSR show better throughput in two-ray ground model.

In this paper, based on the composite laminated plate theory and a strain energy model, the damping capacity of a Carbon Fiber Reinforced Plastics (CFRP) raft frame was studied. According to the finite element analysis (FEA) and damping ratio prediction model, the influences of different layups on the damping capacity of the raft frame and its components (top/bottom plate and I-support) were discussed. Comparing the FEA results with the test results, it can be figured out that the CFRP laminate layup has a great influence on the damping ratio of the raft frame, and the maximum error of the first-order natural frequency and damping ratio of the top/bottom plate were 5.6% and 15.1%, respectively. The maximum error of the first-order natural frequency of the I-support between the FEA result and the test result was 7.5%, suggesting that because of the stress concentration, the error of the damping ratio was relatively large. As for the raft frame, the damping performance was affected by the I-support arrangement and the simulation analysis was in good agreement with the experimental results. This study can provide a useful reference for improving the damping performance of CFRP raft frames.

Based on the thick-wall cylinder theory and composite material mechanics, the stress distribution model of the CFRP shaft tube and metal shaft head has been established, and the relationship between the layup parameters and the value of interference on the maximum assembly force and failure torque in the interference fit joints of the CFRP shaft tube and the metal shaft head is deduced. Combining the three-dimensional finite element analysis model with experimental data, the result shows that the layup angles of the CFRP shaft tube have a greater influence on the joint connection performance than the layup sequence, and the larger the layup angle, the better the joint assembly performance while keeping the value of interference constant. The maximum assembly force and failure torque of the interference fit joints increase linearly while the value of the interference amount increases when the layup parameters are constant.

Network load is balanced and energy is in stable and sustainable is the important guarantee for the stability of the network. Traditional clustering algorithm for ad hoc network can effectively achieve a single point of network stability, and there is no efficient algorithm for long-term stability. Improvements have been made in this context traditional network clustering algorithm, based on efficient cluster head node using residual energy and communications networking sensor networks nodes remaining weaknesses in the energy networks and strengthening, improving the overall balance and effectiveness of the network, and ultimately to improve the long-term stability in wireless ad hoc networks sensor networks.

Punch variety of drives, hydraulic, motor type is also commonly used. Conventional press drives both in terms of simplicity of the structure also in terms of effectiveness of control are present many problems. As is a background on the background of press drive innovative design, research on pulsed electric-magnetic field driven punch. Thanks to electro-magnetic direct drive, the system structure is simple, convenient control flexible, changing the timing and amplitude of excitation pulse, can change the speed and direction of movement of permanent magnet ring and have the output force of significant features. From the design on the effect of pulse electromagnetic drive punch, its index relative to the mechanical structure has improved, such as stamping frequencies up to 300 times/min, noise less than 80dB, volume reduction of cent, reduce the weight of 60%. This structure can greatly improve the working speed of the punch, while simplifying punch drive mechanical structure.