Ampere-level CO electroreduction with single-pass conversion exceeding 85% in acid over silver penetration electrodes.

Synthesis of valuable chemicals from CO electroreduction in acidic media is highly desirable to overcome carbonation. However, suppressing the hydrogen evolution reaction in such proton-rich environments remains a considerable challenge. The current study demonstrates the use of a hollow fiber silver penetration electrode with hierarchical micro/nanostructures to enable CO reduction to CO in strong acids via balanced coordination of CO and K/H supplies.

Tensile-Strained Cu Penetration Electrode Boosts Asymmetric C-C Coupling for Ampere-Level CO-to-C Reduction in Acid.

The synthesis of multicarbon (C) products remains a substantial challenge in sustainable CO electroreduction owing to the need for sufficient current density and faradaic efficiency alongside carbon efficiency. Herein, we demonstrate ampere-level high-efficiency CO electroreduction to C products in both neutral and strongly acidic (pH=1) electrolytes using a hierarchical Cu hollow-fiber penetration electrode (HPE). High concentration of K could concurrently suppress hydrogen evolution reaction and facilitate C-C coupling, thereby promoting C production in strong acid.

Fatigue Life Data Fusion Method of Different Stress Ratios Based on Strain Energy Density.

To accurately evaluate the probabilistic characteristics of the fatigue properties of materials with small sample data under different stress ratios, a data fusion method for torsional fatigue life under different stress ratios is proposed based on the energy method. A finite element numerical modeling method is used to calculate the fatigue strain energy density during fatigue damage. Torsional fatigue tests under different stresses and stress ratios are carried out to obtain a database for research.

Explicit stability condition for delta fractional order systems with α∈(0,+∞).

This paper delves into the stability of time-advance delta fractional order systems, with a specific emphasis on the order range (0,+∞) rather than the conventional range (0,1). The delta Laplace transform is used to investigate the stability of the suggested system, and a mapping relation ρ=ss+1 is introduced. The explicit stability condition is provided, articulated in relation to a specific distribution of eigenvalues of the system matrix.

Electrochemical Epoxidation of Propylene to Propylene Oxide via Halogen-Mediated Systems.

As one of the most important derivatives of propylene, the production of propylene oxide (PO) is severely restricted. The traditional chlorohydrin process is being eliminated due to environmental concerns, while processes such as Halcon and hydrogen peroxide epoxidation are limited by cost and efficiency, making it difficult to meet market demand. Therefore, achieving PO production through clean and efficient technologies has received extensive attention, and halogen-mediated electrochemical epoxidation of alkene is considered to be a desirable technology for the production of alkylene oxide.

Memristors based on NdNiO nanocrystals film as sensory neurons for neuromorphic computing.

By mimicking the behavior of the human brain, artificial neural systems offer the possibility to further improve computing efficiency and solve the von Neumann bottleneck. In particular, neural systems with perceptual capability expand the application field and lay a good foundation for the construction of perceptual storage and computational systems. However, research on neurons with perceptual functions is still relatively scarce, with most works focusing on optoelectronic synapses.

Highly Efficient CO Reduction at Steady 2 A cm by Surface Reconstruction of Silver Penetration Electrode.

Electroreduction of CO to CO is a promising route for greenhouse gas resource utilization, but it still suffers from impractical current density and poor durability. Here, a nanosheet shell (NS) vertically standing on the Ag hollow fiber (NS@Ag HF) surface formed by electrochemical surface reconstruction is reported. As-prepared NS@Ag HF as a gas penetration electrode exhibited a high CO faradaic efficiency of 97% at an ultra-high current density of 2.

A SmNiO memristor with artificial synapse function properties and the implementation of Boolean logic circuits.

Recently, with the improvement of the requirements for fast and efficient data processing in the era of artificial intelligence, new forms of computing have come into being. Developing memristor devices that can simulate the brain's computing neutral network is particularly important for applications in the field of artificial intelligence. However, there are still some challenges in their biological function simulation and related circuit design.

Lyapunov stability criteria in terms of class K functions for Riemann-Liouville nabla fractional order systems.

This paper focuses on the problem of stability analysis for Riemann-Liouville nabla fractional order systems. On one hand, a useful comparison principle is built and then a rigorous proof is constructed for the well-known Lyapunov stability criterion in terms of class K functions. On the other hand, the constraint of the Lyapunov function is refined using a positive constant γ or a sequence h(k), resulting two practical theorems.

Interval estimation for nabla fractional order linear time-invariant systems.

In this paper, we provide a framework to achieve interval estimation for nabla Caputo fractional order linear time-invariant (LTI) systems in the presence of bounded model uncertainties. Interval observers based on fractional order positive systems theory are designed by possessing desired stable and positive error dynamics. Specifically, the basic concepts and conditions for guaranteeing stability and positivity of the considered systems are derived systematically by finding the system responses.

Time-varying Lyapunov functions for nonautonomous nabla fractional order systems.

The classical Leibniz rule for the integer difference cannot be easily applicable for the fractional counterpart. It further leads to a great difficulty in the calculation of the Lyapunov functions with product form. To overcome such a challenge, several fractional difference inequalities are developed for Lyapunov functions which are the product of a time sequence and a function regarding to system state.

A numerical approximation method for fractional order systems with new distributions of zeros and poles.

A multiple-zero-pole (MZP) method is proposed for general SISO fractional order dynamic systems in this paper. Based on amplitude-frequency curve, a new rational approach to fractional differentiator is designed. There are three advantages of MZP method.

Lyapunov functions for nabla discrete fractional order systems.

This paper focuses on the fractional difference of Lyapunov functions related to Riemann-Liouville, Caputo and Grünwald-Letnikov definitions. A new way of building Lyapunov functions is introduced and then five inequalities are derived for each definition. With the help of the developed inequalities, the sufficient conditions can be obtained to guarantee the asymptotic stability of the nabla discrete fractional order nonlinear systems.

Fixed pole based modeling and simulation schemes for fractional order systems.

This paper mainly investigates the numerical implementation issue of fractional order systems. First, a pattern of fixed pole schemes are developed to approximate fractional integrator/differentiator, whose common is that the poles keep constant for different α. Then, two solutions are proposed to improve the approximation performance around α=0.

An innovative parameter estimation for fractional order systems with impulse noise.

This paper investigates the problem of parameter estimation for fractional order linear systems when the output signal is polluted by impulse noise. The conventional least square error objective function is replaced by a new approximate least absolute error (ALAE) function to restrain the influence of impulse noise. Then a novel parameter estimation approach is designed based on the stochastic gradient method, the fractional order parameter update law and the ALAE criterion, which improves estimation accuracy and enhances robustness at the same time.

Observer-based adaptive backstepping control for fractional order systems with input saturation.

An observer-based fractional order anti-saturation adaptive backstepping control scheme is proposed for incommensurate fractional order systems with input saturation and partial measurable state in this paper. On the basis of stability analysis, a novel state observer is established first since the only information we could acquire is the system output. In order to compensate the saturation, a series of virtual signals are generated via the construction of fractional order auxiliary system.

The output feedback control synthesis for a class of singular fractional order systems.

This paper investigates the output feedback normalization and stabilization for singular fractional order systems with the fractional commensurate order α belonging to (0,2). Firstly, an effective criterion for the normalization of singular fractional order systems is given with output differential feedback. Afterwards, both static and dynamic output feedback stabilization of such normalized fractional order systems are derived.

Robust fast controller design via nonlinear fractional differential equations.

A new method for linear system controller design is proposed whereby the closed-loop system achieves both robustness and fast response. The robustness performance considered here means the damping ratio of closed-loop system can keep its desired value under system parameter perturbation, while the fast response, represented by rise time of system output, can be improved by tuning the controller parameter. We exploit techniques from both the nonlinear systems control and the fractional order systems control to derive a novel nonlinear fractional order controller.

A universal modified LMS algorithm with iteration order hybrid switching.

This paper presents a fractional order modified least square algorithm(FOMLMS), which involves an iteration order switch strategy. A FOMLMS scheme whose iteration order can be extended into α∈(0,2) is investigated. The performance of FOMLMS with the iteration order in different interval (0<α<1or1<α<2) is separately analyzed.

An innovative fixed-pole numerical approximation for fractional order systems.

A novel numerical approximation scheme is proposed for fractional order systems by the concept of identification. An identical equation is derived firstly, from which one can obtain the exact state space model of fractional order systems. It reveals the nature of the approximation problem, and then provides an effective scheme to obtain the desired model.