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Abstract The cone photoreceptors in our eyes selectively transduce the natural light into spiking representations, which endows the brain with high energy-efficiency color vision. However, the cone-like device with color-selectivity and spike-encoding capability remains challenging. Here, we propose a metal oxide-based vertically integrated spiking cone photoreceptor array, which can directly transduce persistent lights into spike trains at a certain rate according to the input wavelengths. Such spiking cone photoreceptors have an ultralow power consumption of less than 400 picowatts per spike in visible light, which is very close to biological cones. In this work, lights with three wavelengths were exploited as pseudo-three-primary colors to form ‘colorful’ images for recognition tasks, and the device with the ability to discriminate mixed colors shows better accuracy. Our results would enable hardware spiking neural networks with biologically plausible visual perception and provide great potential for the development of dynamic vision sensors.

Magnetorheological elastomer (MRE) is a magnetically controlled intelligent material, whose mechanical properties (such as stiffness, elastic modulus, intrinsic frequency, damping capacity, etc.) can be continuously and reversibly controlled by adjusting the strength of the applied magnetic field. It is now widely studied and applied in the fields of vibration control, mechanical engineering, civil engineering, etc. When MRE is made into grinding or polishing tools, the mechanical removal of the process can be controlled by changing the stiffness and other properties of MRE in a magnetic field, which is expected to be widely used in the field of precision machining. In this paper, the materials, the methods and the processes to prepare MRE are introduced, and the influencing rules of external field (including magnetic and temperature fields) on the performance of MRE are analyzed. The intrinsic structure model is described based on magnetic dipole theory and macromechanics, which provides guidance for MRE preparation and practical engineering applications. Besides, the application status and future development direction of MRE in the field of precision machining are reviewed. The variation of magnetically controlled properties using MRE can be better applied to precision machining and has a good development prospect.

The doubly fed induction generator with super capacitor is helpful to enhance the system inertia. At the same time, its structural characteristics are more suitable for the power grid topology without communication lines. However, the change of its topology also brings some problems. In this article, when SCESS-DFIG is participating in frequency regulation, DC bus voltage fluctuation caused by power imbalance of multiple converters is studied. The dynamic power response of super capacitor with DC-DC converter is a step load for grid side converter. The load of DC bus is nonlinear and random, so the balance and stability of the original system will change accordingly. Because of the complex topology and system composition of the doubly fed induction generator with super capacitor, the conventional feed-forward compensation control strategy can not be used to improve its dynamic response speed. Therefore, this article designs a control strategy which is applied for DC bus voltage fluctuation of the doubly fed induction generator with super capacitor. The theory proposed in this article is verified by simulation model and experiment.

The enhanced phase-locked loop (EPLL) adds an amplitude estimate to the conventional phase-locked loop (PLL), which solves the problem of double-frequency disturbance in the Phase-Locked Loop mathematical model at steady state. However, there are few researches on disturbance resistance design of EPLL in complicated grid environment. Therefore, periodic disturbances of different frequencies are introduced into frequency estimation and amplitude estimation of EPLL when the grid voltage has DC offset, three-phase unbalance, high-order harmonic disturbance and sub-synchronous oscillation (SSO). This will interfere with the frequency and amplitude estimation performance of the EPLL, and then affect the closed-loop control and frequency tracking of the converter. In order to improve disturbance rejection of the EPLL. Firstly, the mathematical model of the disturbance in the frequency and amplitude loop is deduced and analyzed. Then the active disturbance rejection control (ADRC) is used to improve the EPLL. Through the simulation model of MATLAB/Simulink, the parameters of the ADRC and the ESO are compared and validated. The proposed EPLL based on ADRC is verified experimentally for the tracking performance under the frequency stability or drop in complicated power grid environment.

Nano-manipulation technology, as a kind of “bottom-up” tool, has exhibited an excellent capacity in the field of measurement and fabrication on the nanoscale. Although variety manipulation methods based on probes and microscopes were proposed and widely used due to locating and imaging with high resolution, the development of non-contacted schemes for these methods is still indispensable to operate small objects without damage. However, optical manipulation, especially near-field trapping, is a perfect candidate for establishing brilliant manipulation systems. This paper reports about simulations on the electric and force fields at the tips of metallic probes irradiated by polarized laser outputted coming from a scanning near-field optical microscope probe. Distributions of electric and force field at the tip of a probe have proven that the polarized laser can induce nanoscale evanescent fields with high intensity, which arouse effective force to move nanoparticles. Moreover, schemes with dual probes are also presented and discussed in this paper. Simulation results indicate that different combinations of metallic probes and polarized lasers will provide diverse near-field and corresponding optical force. With the suitable direction of probes and polarization direction, the dual probe exhibits higher trapping force and wider effective wavelength range than a single probe. So, these results give more novel and promising selections for realizing optical manipulation in experiments, so that distinguished multi-functional manipulation systems can be developed.