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This article investigates a class of multi-agent systems (MASs) with known dynamics external disturbances, where the communication graph is directed, and the followers have undirected connections. To eliminate the impacts of external disturbance, the technologies of disturbance observer-based control are introduced into the containment control problems. Additionally, to save communication costs and energy consumption, a distributed disturbance observer-based event-triggered controller is employed to achieve containment control and reject disturbance. Furthermore, designing the event-triggered function using an exponential function is beneficial for a time-dependent term while ensuring the exclusion of Zeno behavior. Finally, a numerical simulation is provided to validate the effectiveness of the theoretical analysis.

This paper uses the adaptive dynamic programming (ADP) method to achieve optimal trajectory tracking control for quadrotors. Relying on an established mathematical model of a quadrotor, the approximate optimal trajectory tracking control, which consists of the steady-state control input and the approximate optimal feedback control input, is designed for a nominal system. Considering the compound disturbances in position and attitude dynamic models, disturbance observers are introduced. The estimated values are used to design robust compensation inputs to suppress the effect of the compound disturbances for good trajectory tracking performance. Theoretically, the Lyapunov theorem demonstrates the stability of a closed-loop system. The robustness and effectiveness of the proposed controller are confirmed by the simulation results.

This paper presents a practical study on how to improve the ℋ∞ performance and meet the input–output constraints of the two-degrees-of-freedom (DOF) flexible-joint manipulator system (FJMS) with parameter uncertainties and external disturbances. For this reason, a robust constrained moving-horizon ℋ∞ controller is designed to improve the system ℋ∞ performance while still satisfying the input–output constraints of the uncertain system. First, the uncertain controlled system model of the two-DOF FJMS is established via the Lagrange equation method, Spong’s assumption, and the linear fractional transformation (LFT) technique. Then, the control requirements and input–output constraints of the uncertain system are transformed into the linear matrix inequality (LMI) via the theory of ℋ∞ control and the full-block multiplier technique. Next, the LMI optimization problem refreshed by the current state is addressed at each sample moment with the idea of the moving-horizon control of the model predictive control (MPC), and the calculated gain is implemented to the nonlinear closed-loop system under the state feedback structure. The validity and feasibility of the designed control scheme is finally verified via the results of simulation experiments.

The metallic molybdenum disulfide exhibits large interlayer spacing, high electrical conductivity and abundant active sites, which shows wildly application prospects in the field of energy storage and conversion. The recent progress of metallic molybdenum disulfide in energy storage and conversion was reviewed. Firstly, the crystal and electronic structure of the metallic molybdenum disulfide were introduced, and the synthesis methods such as top-down (lithium intercalation stripping) and bottom-up (solvent/hydrothermal) were included. Then, the progress of metallic molybdenum disulfide and its composites in the fields such as hydrogen evolution reaction, lithium (sodium) ion batteries and supercapacitors were summarized. Finally, it is pointed out that the current challenges of metallic molybdenum disulfide are uncontrollable synthesis process and poor structural stability. The in-depth study on the structure and properties of metallic molybdenum disulfide is expected to fundamentally improve its performance and practical application in the field of energy storage and conversion.

This paper studies the containment control problem of linear multi-agent systems (MASs) subject to external disturbances, where the communication graph is a directed graph with the followers being undirected connections. In order to save communication costs and energy consumption, a distributed disturbance observer-based event-triggered controller is employed based on the relative outputs of neighboring followers. Compared with conventional controllers, our observer-based controller utilizes the relative outputs of neighboring followers at the same triggered instant. Furthermore, it is shown that Zeno behavior can be avoided. Finally, the validity of our proposed methodology is demonstrated by a simulation example.

On the basis of the dam monitoring data,we analyze and evaluate dam deformation and dislocation distribution laws of spillway drain channels during operation upon the impounding of the face dam with crest overflow in Feigu Reservoir.The correlation analysis of environmental variables such as the reservoir water level,air temperature,and water temperature is carried out by means of mathematical statistics and spatiotemporal distribution analysis.It is concluded that the horizontal deformation and settlement of the dam crest are less than the safety warning values.Air temperature and the reservoir water level are the main environmental factors affecting dam deformation.The dislocation magnitude of the spillway drain channel is highly sensitive to temperature,but with coordinated deformation,adjacent drain channels have small disjunction momentum,and thus the spillway drain channel is in a safe state.We can reduce the uneven settlement of the spillway on the dam crest by mixing the main stone pile with a small amount of buried stone concrete.

Lithium-air batteries(LABs) are among the most promising electrochemical energy storage technologies in the future due to extremely high theoretical energy density. The performance of LABs is mainly governed by the electrochemical reactions that occur on the surface of the cathode. Therefore, the rational design of a cathode with high stability and reversibility is the key to commercially viable LABs. However, the side reactions are caused by the instability of traditional carbon-based electrodes can limit capacity and cycle performance of LABs, therefore, alternative carbon-based electrode materials are required. Based on the structure and the principle of cathode reaction of LABs, the current challenges of LABs were presented. Then based on the analysis of the instability of carbon-based cathode, the design of a stable and reversible cathode for LABs was summarized. Finally, a perspective that the rational design of the cathode catalyst and the in-depth understanding of the catalytic mechanism play a decisive role in the performance improvement of LABS was provided.

Recently, the alternating direction method of multipliers (ADMM) has been used effectively to solve the multi-agent unconstrained optimization problems, where the objective function is the sum of privately known local objective functions of agents. In this paper, first, with the help of the edge-node incidence matrix, an unconstrained optimization problem is transformed into an equivalent optimization problem with only equality constraint and, thus, can be dealt with the ADMM conveniently. Second, a novel distributed inexact consensus ADMM is proposed to enable the agents to reach consensus on the optimal solution of the optimization problem. At the same time, the analysis of the linear convergence of the proposed algorithm is also provided under some mild conditions. Finally, some simulation results are presented to demonstrate the better effectiveness of the proposed algorithm than the standard consensus-based ADMM algorithm.

Iron and steel enterprises are facing difficult problems such as increasing inventory, excess capacity, and poor profitability. It is urgent to solve them through the development of green and intelligent manufacturing technology for iron and steel enterprises to address the current critical situation. Based on the analysis of the characteristics of manufacturing processes in iron and steel enterprises, the materials flow (with a core of iron element flow) and its corresponding energy flow network, as well as the deficiencies of the synergy between materials flow and energy flow in existing enterprise information systems, synergetic optimization methods between materials flow and energy flow in the iron and steel manufacturing process were investigated in this paper. It revealed that the coupling between materials flow and energy flow should be planned, designed and implemented for both the unit manufacturing equipment and the overall manufacturing process. The synergetic optimization can be achieved by three approaches, including perfecting information monitoring, synergizing planning and synergizing scheduling. Based on the analysis, a schematic resolution on top of the existing information system architecture was proposed towards the optimization of production, resource and energy. The synergetic optimization between materials flow and energy flow in the iron and steel manufacturing process can be realized by improving the corresponding functions of the existing manufacturing execution system, enterprise resource planning and energy management system, facilitated by a newly proposed information subsystem handling the synergetic optimization with the support of digitization and modelling of the relevant information in materials flow and energy flow.

Tumor interstitial fluid pressure (TIFP), is a physiological parameter with demonstrated predictive value for a tumor's aggressiveness, drug delivery, as well as response to treatments such as radiotherapy and chemotherapy. Despite its utility, measurement of TIFP has been limited by the need for invasive procedures. In this work, the theoretical basis for approaching the absolute value of TIFP and the experimental method for noninvasively measuring TIFP are presented. Given specific boundary and continuity conditions, we convert theoretical variables into measurable variables by applying MRI technology. The work shows that TIFP in the central region of the tumor can be estimated by an analysis of the variation of tissue fluid motion in the tumor rim and surrounding tissue. It is determined from three noninvasive measurable parameters: i) an estimate of the velocity of the tumor interstitial fluid at the tumor surface, which is maximal, ii) a measurement of the distance from the tumor surface to where the tumor exudates are absorbed (or normalized), and iii) an estimate of the hydraulic conductivity of the interstitium through which the tumor exudate travels. We experimentally show that the fluid flow within the tumor rim is not uniform, even for a round shaped tumor, and demonstrate the procedures for the noninvasive measurement of TIFP.

We give a characterization of trace-preserving and positive linear maps preserving trace distance partially, that is, preservers of trace distance of quantum states or pure states rather than all matrices. Applying such results, we give a characterization of quantum channels leaving Helstrom's measure of distinguishability of quantum states or pure states invariant and show that such quantum channels are fully reversible, which are unitary transformations.