[en] In order to solve the problem of the inverse kinematics of general robot, such as slow speed in problem-solving and lower accuracy of the solution, a high precision MPGA-RBFNN algorithm is proposed, which introduce the Multiple Population Genetic Algorithm (MPGA) into Radial Basis Functions Neural Network (RBFNN). Combining with the positive kinematics model of general robots, the RBFNN with three-layers is used to solve the inverse kinematics of general robots and the MPGA is adopted to optimize the network structure and connection weights of RBFNN. By using the way of hybrid coding and simultaneous evolutionary, the non-linear mapping from the posture of the robot in the working space to the angle of the joint is realized, avoiding the complicated formula derivation and improving the speed of solving. Finally, the experimental are tested on the 6R robot, the results show that the MPGA-RBFNN algorithm is not only improves the speed of the solving, but also enhances the training success rate and the calculation accuracy. (paper)

[en] In order to improve the joint's properties, local heat treatment of TC4 titanium alloy with electron beam was conducted. After electron beam local heat treatment, residual stresses of weld were tested by the X-ray method. Compared with EBW, the martensite grains of weld become finer after electron beam local heat treatment, and residual stress distribution of TC4 titanium alloy joints is improved. (authors)

No abstract available

[en] A simple strategy for the one-step synthesis of polyaniline/AgCl nanocomposites at the water/magnetic ionic liquid interface was reported. By controlling the reactive conditions, highly dispersed polyaniline/AgCl nanocomposites with their size ranging around 50–80 nm were obtained with magnetic ionic liquid as the oxidant. Transmission electron microscopy was used to show the morphology of the nanocomposites. The nanocomposites were also characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Moreover, polyaniline/AgCl nanocomposites on a glassy carbon electrode showed strong electrocatalytic activity for H₂O₂ and could be used to construct a H₂O₂ biosensor.

[en] Measuring the conductivity changes of sensing materials to detect a wide range of radiation energy and dosage is one of the major sensing mechanisms of radiation sensors. Carbon nanotube (CNT) filled composites are suitable for sensing radiation because of the extraordinary electrical properties of CNTs and the CNT-network formed inside the polymer matrix. Although the use of CNT-based nanocomposites as potential radiation sensing materials has been widely studied, there is still a lack of theoretical models to analyze the relationship between electrical conductivity and radiation dosages. In this article, we propose a 3D model to describe the electrical conductivity of CNT-based nanocomposites when being irradiated by ionizing radiation. The Monte Carlo method has been employed to calculate radiation intensity, CNT concentration and alignment’s influence on the electrical conductivity. Our simulation shows a better agreement when CNT loading is between the percolation threshold and 3% volume fraction. Radiation experiments have been performed to verify the reliability of our model to illustrate a power function relationship between the electrical conductivity of a CNT-filled polymer and radiation intensity. In addition, the predicted alignment to obtain the best sensitivity for radiation sensing has been discussed to help with CNT-network building in the fabrication process. (paper)

[en] Highlights: • An electron beam welding with multi-beam preheating method is proposed to reduce welding buckling distortion. • Thermal tensioning effect caused by multi-beam preheating can effectively reduce the compressing stress in welding zone. • Reduction of the plastic compressing stress by multi-beam preheating can reduce buckling distortion by up to 80%. In order to decrease the buckling distortion of thin-walled structures, a new electron beam welding method with simultaneous multi-beam preheating on both sides of the weld is proposed. Compared with traditional electron beam welding, this method can effectively reduce welding distortion, without the use of auxiliary clamping fixtures or post-weld heat treatment. In the finite element analysis, the conical Gaussian heat source model was selected as the heat source for welding and the rectangle uniform plane heat source model was selected as the heat source for multi-beam preheating. The temperature distribution, thermal stress and welding distortion of welded SUS304 stainless steel sheets were simulated and a series of experiments were conducted to verify the feasibility of electron beam welding with multi-beam preheating. Experiment and simulation results show that the temperature distribution with multi-beam preheating is more uniform and thermal tensioning effect caused by multi-beam preheating can reduce the compressing stress in the welding zone. Therefore, the application of multi-beam preheating method can reduce the plastic compressing deformation and final buckling distortion of thin-walled structures. Using this method, maximal 80% reduction of the buckling distortion can be achieved.