Magnetic nanorobotic swarms can mimic collective functions of organisms in nature and be programmed for flexible spatiotemporal control. In this work, different assemblies of magnetic nanoparticle (MNP) swarms were constructed. Temperature-sensitive hydrogels were used as carriers to fix the distribution and ensure the stability of the swarm structure and the biocompatibility of the microrobot. Under three different outfield assembly strategies (gravitational field, gradient magnetic field, and uniform magnetic field), six different assembly modes of MNP are encapsulated (three unilateral unfolding assemblies with different microsphere profiles, unilateral chain assembly, and two symmetric chain assemblies with different magnetic chain positions). Their differences in the execution of motion, magnetothermal effects, and release of loaded DOX drugs were explored. The results showed that the symmetrical chain assembly with the magnetic chain distributed on the outside showed the best performance due to the advantage of the magnetic moment. It has a speed of up to 600 μm/s and a temperature rise rate of up to 1.5 °C/ min. The present work provides an excellent solution to the poor MNP cluster distribution stability problem and enriches the assembly control scheme of microrobots in medical, catalytic, and three-dimensional-printing fields.

We propose a modified generalized Harvey–Shack model by adding the empirical correction factor related to the scattering angle on the basis of the original theory. The result shows that the modified model reduces the root mean square error (RMSE) from less than 2% to less than 1%, and the relative peak error from less than 50% to less than 20%, which significantly improves the accuracy of scattering prediction. The prediction of the Rayleigh–Rice model is not as good as the Harvey–Shack model. The RMSE of the Rayleigh–Rice model is within 2.5%, and the relative peak error is within 60%.

No abstract

We propose a full-band model to quantitatively calculate terrestrial atmospheric scattering in stray light testing based on the Monte Carlo algorithm. Measurements are conducted using two classifications of air cleanliness at off-axis angles from 35° to 90°. Corresponding simulations of Mie scattering and Rayleigh scattering are used for a comparison with the measured values. The relative root mean square deviation of the simulation from the measurement result is 3.72% and 24.1% for Mie scattering and Rayleigh scattering, respectively. This exhibits excellent agreement between the measured and predicted values for a 26° full-angle baffle when illuminated by a 550 mm diameter collimated beam.