Amorphous urchin-like copper@nanosilica hybrid for efficient CO_(2) electroreduction to C2+ products

Currently most of research efforts for selective electrocatalysis CO_(2) reduction to C2+products have relied on crystalline Cu-based catalysts;amorphous Cu with abundant low-coordinated atoms holds greater promise for this conversion yet remains relatively underexplored.Here we report an amorphous urchin-like Cu@nanosilica hybrid synthesized by electrostatic coupling Si polyanions with Cu salt in hydrothermal processes.The Cu@nanosilica electrocatalyst displays excellent CO_(2) electroreduction activity and selectivity with a Faradic efficiency of 70.5%for C2+product production,and higher stability compared to the crystalline Cu counterpart.The solar-driven CO_(2) electrolysis yields an energy efficiency of 20%for C2+product production.Mechanism study reveals that the urchin-like Cu@nanosilica catalyst with amorphous Cu/Cu^(+)dispersion enhances CO_(2) adsorption and activation to facilitate generation of CO_(2)^(-)*and possible CO^(*)intermediates,and suppresses hydrogen evolution concurrently.The combined effects of both aspects promote efficient C2+product production from CO_(2) electroreduction.

A solution using only electromagnetic coils for relative pose control in satellite docking

This paper proposes an electromagnetic coil topology and its control strategy,which can be incorporated into the electromagnetic docking device to achieve relative pose control in satellite docking.The target satellite has a main coil;the chaser satellite possesses a main coil of the same size accompanied by six and four evenly arranged secondary coils inside and outside the main coil,respectively.The coil on the target satellite is DC energized,while the currents in the coils of the chaser satellite are regulated.To remove the coupling between the pitch/yaw torque and translational force,the internal and external secondary coils of the chaser satellite interact with the main coil of the target satellite to perform the control of relative pitch/yaw and relative translation,respectively,so relative pose control can be achieved.The torque and force vectors exerted by the secondary coils of the chaser satellite are synthesized onto the pitch and yaw axes of the body frame.According to their spatial composition relationship,the formulas are proposed,which obtain the magnetic moment vectors of the coils from the set torques and forces.The controllers regulating pitch/yaw,translation,and distance utilize a three-loop cascaded structure that consists of an outer position loop,a middle velocity loop and an inner current loop.The control strategy is verified by dynamics simulation.

Relative roll control of satellite docking using electromagnetic coils

An electromagnetic coil topology and its control strategy,which can be incorporated into the electromagnetic docking device,have been proposed for the relative roll control of two satellites in space.The target satellite and the chaser satellite are respectively embarked with four and six coils evenly arranged around the docking axis.All the coils on the target satellite are Direct Current(DC)energized,while the currents in the coils of the chaser satellite are regulated to achieve the relative roll control.The electromagnetic force/torque model is built by utilizing the frequentlyused far field model.Based on the fundamental components extracted from that model,this paper proposes a real-time magnetic moment vector distribution formula that simply generates a constant roll torque.This paper not only presents an equation for calculating the relative roll angle through the Euler angles of two satellites,but also an equation that converts the roll torque setpoint to the setpoints of the coil currents.A 3-closed-loop positioning controller composed of angle,angular velocity,and current loop is developed.The proposed topology is verified by finite element simulation,and the control strategy is validated by dynamics simulation and ground-based tests.

Lightweight structure of a phase-change thermal controller based on lattice cells manufactured by SLM

Thermal controllers equipped with phase-change materials are widely used for maintaining the moderate temperatures of various electric devices used in spacecraft. Yet, the structures of amounts of thermal controllers add up to such a large value that restricts the employment of scientific devices due to the limit of rocket capacity. A lightweight structure of phase-change thermal controllers has been one of the main focuses of spacecraft design engineering. In this work, we design a lightweight phase-change thermal controller structure based on lattice cells. The structure is manufactured entirely with AlSi10 Mg by direct metal laser melting. The dimensions of the structure are 230 mm × 170 mm × 15 mm, and the mass is 190 g, which is 60% lighter than most traditional structures(500–600 g) with the same dimensions. The 3 D-printed structure can reduce the risk of leakage at soldering manufacture by a welding process. Whether the strength of the designed structure is sufficient is determined through mechanical analysis and experiments. Thermal test results show that the thermal capacity of the lattice-based thermal controller is increased by50% compared to that of traditional controllers with the same volume.

N-doped defective carbon with trace Co for efficient rechargeable liquid electrolyte-/all-solid-state Zn-air batteries

Simple synthesis of multifunctional electrocatalysts with plentiful active sites from earth-abundant materials is especially fascinating. Here, N-doped defective carbon with trace Co(1.5 wt%) was prepared via a scalable one pot solid pyrolysis process. The sample exhibits efficient bifunctional OER/ORR activity in alkaline, mainly ascribed to the unique micro-mesoporous structure(1–3 nm), high population of graphitic-N doping(up to 49.0%), abundant defects and the encapsulated Co nanoparticles with graphitized carbon. The according rechargeable liquid Zn-air batteries showed excellent performance(maximum power density of 154.0 mW cm^(-2); energy density of 773 Wh kg^(-1) at 5 mA cm^(-2) and charging-discharging cycling stability over 100 cycles). As a proof-of-concept, the flexible, rechargeable all-solid-state Zn-air batteries were constructed, and displayed a maximum power density as high as 45.9 mW cm^(-2), among the top level of those reported previously.

A New Recursive Composite Adaptive Controller for Robot Manipulators

In this paper,a new recursive implementation of composite adaptive control for robot manipulators is proposed.We investigate the recursive composite adaptive algorithm and prove the stability directly based on the Newton-Euler equations in matrix form,which,to our knowledge,is the first result on this point in the literature.The proposed algorithm has an amount of computation O(n),which is less than any existing similar algorithms and can satisfy the computation need of the complicated multidegree manipulators.The manipulator of the Chinese Space Station is employed as a simulation example,and the results verify the effectiveness of this proposed recursive algorithm.