Magnetic-driven micro-robotic devices have shown promising potential in enabling applications in micromanipulation, biosensing, targeted drug delivery, and minimally invasive surgery. However, the fabrication of miniaturized magnetic structures with complex geometries has remained the major technical obstacle. In this study, we report the development of a new magnetically-active photopolymerizable resin comprises poly (ethylene glycol) diacrylate monomer, Fe3O4 magnetic nanoparticles, photoinitiator, and other functional additives. Micro-continuous liquid interface production (micro-CLIP) 3D printing process was employed to realize high-resolution and high-speed fabrication of complex structures. The key characteristic properties of resin along with the matching process conditions were investigated experimentally, which allows for establishing the set of optimal fabrication conditions in fabricating magnetic microactuators towards potential applications.
In this paper, a tunable metamaterial consisting of periodic layers of steel, polyurea and piezoelectric ceramic transducer
(PZT) was presented. The PZT layer in this structure was connected to an inductor L. Transfer matrix method was used
to calculate the band structure of the sample. It was observed that an extremely narrow stop band was induced by the
PZT layer with inductor L. This narrow stop band was attributed to the resonance circuit constituted by the piezoelectric
layer, for the piezoelectric layer with electrodes could be seen as a capacitor. Further, homogenization was used to
calculate the effective elastic constants of the sample. Results showed that the effective parameters of this structure
behaved negative in the narrow stop band. The location of the narrow stop band was in the charge of inductor L, which
could be used to design acoustic filters or noise insulators by changing the parameters of structure.
Microcantilever sensors have been widely used in designing force, strain and biochemical sensors. The fast-growing applications in nanoelectromechanical systems (NEMS) lead to strong demands to downsize the sensing elements to nanometer scale. In this paper, the detected environment on the performance of this photonic crystal sensor is investigated. The nanocavity, which can be used to localize the electromagnetic field in a low refractive index region, is a new sensing method to measure nano-scaled deformation. Through numerical simulation, we demonstrate that the range of the force sensor in each component force in X and Y directions are 0-1μN. In X direction, the minimum detectable applied forces are about 0.057μN and 0.070μN for the microcantilever operated in the water and air, respectively. And these in Y direction are 0.043μN and 0.053μN, respectively. Hence, it shows that a better resolution of applied force can be achieved in water than in air.
The chemically powered nanowire model consisting of a catalytic and a noncatalytic nanowire confined in a cubic box is investigated. The interactions between nanowire and solvent are simulated using hybrid molecular dynamics/ multiparticle collision dynamics. The motion of the nanowire is analyzed using rigid body dynamic. The effect of temperature and solvent concentration on the center-of-mass velocity of motor are provided. The center-of-mass velocity of the nanomotor along its axis increases with an increase of temperature and solvent concentration. The results are also compared with existed nanodimer model.
With advantages of ultra-compact size, high resolution, and easy integration, nano-scaled force sensors based on photonic crystal are widely used in microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS). The performances of these nano-scaled force sensors are mainly determined by the shape nanocavity. The principle of the sensor is that the output wavelength of the force sensor using photonic crystal varies as a function of force and pressure. In this work, a novel three dimensional nano-scaled force sensor based on silicon photonic crystal, in which a nanocavity is embedded in an S-shaped elastic body, is provided and studied numerically. The advantage of this force sensor is that it can be used in the NEMS to measure the component force in the X direction, Y direction and Z direction, simultaneously. The relationship between the force and the output wavelength is determined using finite element method (FEM) and finite difference time-domain method (FDTD).