The continuous expansion of smart microelectronics has put forward higher requirements for energy conversion, mechanical performance, and biocompatibility of micro-energy storage devices (MESDs). Unique porosity, superior flexibility and comfortable breathability make the textile-based structure a great potential in wearable MESDs. Herein, a timely and comprehensive review of this field is provided according to recent research advances. The following aspects, device construction of textile-based MESDs (TMESDs), fabric processing of textile components and smart functionalization (e.g., mechanical reliability, energy harvesting, sensing, self-charging and self-healing, etc.) are discussed and summarized thoroughly. Also, the perspectives on the microfabrication processes and multiple applications of TMESDs are elaborated.
The emergence of smart headlights with reconfigurable light distributions that provide optimal illumination, highlight road objects, and project symbols to communicate with traffic participants further enhances road safety. Integrating all these functions in a single headlight usually suffers from issues of bulky multi-functional add-on modules with high cost or the use of conventional spatial light modulators with low optical efficiency and complex thermal design requirements. This paper presents a novel laser headlight prototype based on biaxially resonant microelectromechanical systems (MEMS) mirror light modulator for mapping blue laser patterns on phosphor plate to create structured white illumination and tunable road projection. The proposed headlight prototype system enables reconfigurable light distribution by leveraging laser beam scanning with fewer back-end lens and simple thermal design requirements. Built with thin-film lead zirconate titanate oxide (PbZrTiO3) actuators, the MEMS mirror achieved high-frequency biaxial resonance of 17.328 kHz, 4.81 kHz, and optical scan angle of 12.9°. The large mirror design of 2.0 mm facilitates more refined resolvable projection pixels, delivers more optical power, and provides moderate optical aperture to possibly serve as the common spatial light modulator of headlight and the light detection and ranging (LiDAR) towards all-in-one integration. The carefully designed bi-axial resonant frequency improves the device’s robustness by offsetting the lowest eigenmode away from the vehicle vibration. By establishing the laser headlight prototype systems of both 1D and 2D scanning modes, a mathematical model of laser modulation and MEMS electrical control principles of Lissajous scanning are proposed to tune the projection pattern density and shapes. It laid the foundation for developing a laser scanning control system with more complex project functions and prompting the application of MEMS for compact headlight system that addresses night driving visibility, eliminates glare effect, and renders interactive projection capabilities.
Dynamic errors of the stylus-based probing system seriously affect the measurement accuracy in surface quality detection on microstructures. A method, which is focused on measuring the surface form of microgears, microholes on the injector nozzle, and so forth, is proposed to control dynamic errors of the stylus-based probing system. Firstly, two kinematical models were built to systematically investigate the dynamic performance of the stylus-based probing system, and the relationship between the measuring force, scanning speed, fidelity, and dynamic errors was described. Then, numerical simulations of the surface form measurement, in which a sine-shaped microstructure was taken as a target surface, were carried out. Results of the numerical simulations reveal that the dynamic errors were affected by the scanning speed and the initial position of the measured specimen. Lastly, a method to control dynamic errors by properly setting up the scanning speed and the initial position of the specimen was proposed for the surface form measurement of microstructures.
5 December 2022 in Optics and Lasers in Engineering
Microstructure-based function components are widely used in precision engineering. Surface profile measurement is an essential tool to verify the manufacturing quality of microstructures and to enhance the working performance of the device employing microstructures as function components. However, highly accurate surface profile measurements are difficult to perform for microstructures owing to their complex surface topographies. In this paper, a measurement system is proposed for the surface profile measurement of microstructures. The main components of the measurement system are a precision displacement stage to move the workpiece, a homemade probing system with a diamond microstylus to sense the surface profile variation of the microstructures on the workpiece, and a vibration isolation table to reduce the disturbance of the measurement environment. In addition, the stability of the measurement was experimentally investigated. Microstructures with shape of equilateral right triangle were employed as the measurement specimen, and the surface profile of triangular microstructures was measured by employing two methods to correct errors caused by the specimen inclination and the radius of the stylus tip. The shape, depth, and period of the measured microstructures were also detected based on the results of the surface profile measurement. Experimental results demonstrate the feasibility of the proposed surface profile measurement for microstructures with complex surface topographies.
1 November 2015 in Desalination and Water Treatment
At present, a high-temperature steam requirement is the main problem in the recovery of furfural. In this work, D141 macroporous resin was selected to separate and enrich furfural from the hydrolysate, and ethanol was selected as the desorption reagent. The adsorption selectivity of furfural and acetic acid made it possible to obtain acetic acid simultaneously. Adsorption kinetics revealed that the rate was rapid and fitted by a pseudo-second-order model. Then the breakthrough curve and optimal operation conditions were systematically investigated. The optimized process of adsorption was a 3 bed volume (BV) solution loaded on the fixed bed of the D141 resin with a velocity of 1 BV/h, then eluted by 1 BV ethanol with a velocity of 1 BV/h. As a result, 96.97% of final recovery yield of furfural was obtained. Compared with the previous studies, the D141 macroporous resin was found to be more favorable for the adsorption of furfural in the hydrolysate.