The excessive pesticide residues in cereals, fruit and vegetables is a big threat to human health, and it is necessary to develop a portable, low-cost and high-precision pesticide residue detection scheme to replace the large-scale laboratory testing equipment for rapid detection of pesticide residues. In this study, a colorimetric device for rapid detection of organophosphorus pesticide residues with high precision based on a microfluidic mixer chip was proposed. The microchannel structure with high mixing efficiency was determined by fluid dynamics simulation, while the corresponding microfluidic mixer chip was designed. The microfluidic mixer chip was prepared by a self-developed liquid crystal display (LCD) mask photo-curing machine. The influence of printing parameters on the accuracy of the prepared chip was investigated. The light source with the optimal wavelength of the device was determined by absorption spectrum measurement, and the relationship between the liquid reservoir depth and detection limit was studied by experiments. The correspondence between pesticide concentration and induced voltage was derived. The minimum detection concentration of the device could reach 0.045 mg·L⁻¹ and the average detection time was reduced to 60 s. The results provide a theoretical and experimental basis for portable and high-precision detection of pesticide residues.

This paper proposed a rapid design and additive manufacturing method of customized bionic sports sole with high performance for the elderly. A parametric modeling software of human foot is developed, which can realize the rapid measurement and modeling of the elderly's foot and corresponding sole structure with specific characteristics. A self-developed material extrusion equipment is adopted to fabricate thermoplastic polyurethanes (TPU) material parts. The influence of extrusion temperature on the tensile properties of fabricated TPU parts is investigated, the hyperelastic model is applied to simulate the mechanical response of TPU, the sole shape is designed and optimized by finite element method (FEM). The leopard paw bionic sole pattern is designed and the antiskid performance is tested by friction experiment. Customized bionic sports sole made of TPU material is successfully manufactured by the self-developed material extrusion equipment. The results indicate that the personalized customization of sports sole for the elderly can be quickly designed and manufactured by the combination of parametric modeling software and material extrusion equipment.

This research proposed a vibration monitoring device based on a piezoresistive flexible sensor with microstructured surfaces to achieve a simple acquisition of vibration information in the driver’s cabin of automobiles. The shape, size and arrangement mode of microstructures on the piezoresistive flexible sensor performance were investigated by finite element simulation. The polydimethylsiloxane/hydroxylated multi walled carbon nanotubes (PDMS/MWCNTs-COOH) composite membranes were prepared by the combination of high-pressure spraying and spinning coating method. The electromechanical response curves of the piezoresistive flexible sensor composed of a double-layer PDMS/MWCNTs-COOH composite membranes based on a dual-height cylindrical microstructure were tested. A vibration monitoring device was developed to process the signals obtained by the fabricated piezoresistive flexible sensor, and the vibration response of the car cab under different driving conditions was investigated. The results indicated that the cylindrical microstructure with small size can improve the sensitivity of the fabricated piezoresistive flexible sensor. Compared with the single-height and dual-height cylindrical microstructure, the piezoresistive flexible sensor with dual-height cylindrical microstructure can expand the detection range, and improve the linearity and sensitivity. The piezoresistive flexible sensor exhibits excellent performance, with a sensitivity of 1.774 kPa⁻¹ and a detection range is 0–0.5 kPa. The above advances can improve the authenticity of the collected data, and provide a basis for the processing and analysis of the vibration signal before improving the noise, vibration and harshness performance of the vehicle.

Simulation and experimental study on drag reduction and anti-adhesion of subsoiler with bionic surface