We reported a novel hydrogelator with L-lysine as a linker to connect 7-carboxyl methoxycoumarin and hydrazine as lipophilic and water-soluble moieties. Ultrasound accelerated the gelation and induced homogenous self-assembly of fibrils into entangled 3D networks. The hydrogel exhibits great potential for future biomedical applications.

The structural components of high speed trains are usually made of aluminum alloys, for example, 6082. The dynamic mechanical behavior of the material is one of key factors considered in structural design and safety assessment. In this paper, dynamic mechanical experiments were conducted with strain rate ranging from 0.001 s −1 to 100 s −1 using Instron tensile testing machine. The true stress-strain curves were fitted based on experimental data. Johnson-Cook model of 6082-T6 aluminum alloy was built to investigate the effect of strain and strain rate on flow stress. It has shown that the flow stress was sensitive to the strain rate. Yield strength and tensile strength increased with a high strain rate, which showed strain rate effect to some extent. Fracture analysis was carried out by using Backscattered Electron imaging (BSE). As strain rate increased, more precipitates were generated in fracture.

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Abstract. Precision of ball screw had a great impact on the positioning accuracy of NC positioning platform. The lead error and backlash of ball screw, which could be accurately measured by laser interferometer, were two key factors affecting the positioning accuracy of NC positioning platform. By setting the compensation data in the numerical control system, significant improvement of the positioning accuracy of NC positioning platform could be achieved. A method for measuring lead error and backlash of ball screw by laser interferometer was introduced and another method for calculating compensation data basing on the results of measurement was putted forward. Experiments were carried out on a multi-mode industrial CT scanning platform to verify these two methods. And the positioning accuracy of multi-mode industrial CT scanning platform was advanced obviously by compensating ball screw lead error and backlash with the compensation data measuring by laser interferometer.

Cable-driven parallel robots (CDPR) with spatial configuration are widely used while ones with plannar configuration are rarely applied. Therefore, this paper studies the modeling and control characteristics of a three degree-of-freedom cable-driven planar parallel robot with great application prospects. Aiming at the shortcomings of the existing control methods towards CDPR, a new method based on fuzzy adaptive PD computing torque control is proposed which contains a reasonable optimal distribution of cable forces. To validate the method, the tracking control simulation research and analysis are carried out for the trajectory of high-order interpolation planning, the results of which show that the control method has favorable dynamic tracking accuracy and mechanical properties. Moreover, compared with the fixed-gain computed torque control, the proposed control method can overcome the influence of model inaccuracy more effectively.