Finite-time stabilization with extended dissipativity via a mixed control strategy for MJSs with hierarchical sensor failures

Nonlinear Dynamics - Based on a mixed control strategy, this study addresses the finite-time stabilization with extended dissipativity for Markov jump systems (MJSs) with unreliable...     

Platinum nanoparticle-doped multiwalled carbon-nanotube-modified glassy carbon electrode as a sensor for simultaneous determination of atenolol and propranolol in neutral solution

Ionics - In this paper, the simultaneous determination of β-blockers (atenolol (ATN) and propranolol (PRO)) was investigated using cyclic voltammetry (CV) and differential pulse voltammetry...     

Adaptive stabilization of high order nonholonomic systems with strong nonlinear drifts

This paper investigates the problem of adaptive stabilization control design for a class of high order nonholonomic systems in power chained form with strong nonlinear drifts, including unmodeled dynamics, and dynamics modeled with unknown nonlinear parameters. A parameter separation technique is introduced to transform the nonlinear parameterized system into a linear-like parameterized system. Then, by the use of input-state scaling technique and adding a power integrator backstepping approach, an adaptive state feedback controller is obtained. The adaptive control based switching strategy is proposed to eliminate the phenomenon of uncontrollability. Global asymptotic regulation of the closed-loop system states and the boundedness of other signals are guaranteed. Simulation examples demonstrate the effectiveness of the proposed scheme.     

Syntheses and characterizations of three low-dimensional chloride-rich zincophosphates assembled about [d-Co(en)(3)](3+) and [dl-Co(en)(3)](3+) complex cations

Three new chloride-rich zincophosphates including two zero-dimensional (0D) clusters [dl-Co(en)3]2[Zn4(H2PO4)2(HPO4)2Cl8] (denoted ZnPO-CJ33) and [d-Co(en)3]2[Zn4(H2PO4)2(HPO4)2Cl8] (denoted ZnPO-CJ34), and one-dimensional (1D) zincophosphate chain [dl-Co(en)3][Zn2(H2PO4)(HPO4)2Cl2] (denoted ZnPO-CJ35) have been solvothermally prepared. ZnPO-CJ33 and ZnPO-CJ34 possess the same cluster structure as the macroanionic [Zn4H6P4O16Cl8]6- unit formed by alternation of ZnOCl3/ZnO3Cl and HPO4/H2PO4 tetrahedra but differ in the countercations. The racemic [dl-Co(en)3]3+ cations are located among the clusters of ZnPO-CJ33, whereas chiral [d-Co(en)3]3+ cations are located among the clusters of ZnPO-CJ34. ZnPO-CJ34 templated by the optically pure chiral [d-Co(en)3]3+ cations is the first chiral monomeric zincophosphate. ZnPO-CJ35 templated by the racemic [dl-Co(en)3]3+ cations possesses a 1D infinite chain structure formed by the alternation of ZnO3Cl and HPO4/H2PO4 tetrahedra. The 1D chain structure of ZnPO-CJ35 can also be viewed as generated from the condensation of 0D clusters of ZnPO-CJ33, with the terminal Cl ions replaced by HPO4 groups. Experimentally, the structural transformation from ZnPO-CJ33 to ZnPO-CJ35 has been investigated.     

莲(Nelumbo nucifera)叶片结构的光镜和扫描电镜的观察

本文报道了莲的浮叶和立叶两种不同生态型叶的表面特征及解剖结构。莲的气孔器主要分布在上表皮,下表皮的则为零星分布。莲的气孔器类型多,表面结构复杂,有形态相近的六种类型,但孔口普遍呈开放状态。集中在莲鼻位置及散生在叶缘的排水器,其水孔形状与气孔器的孔口极为类似,彼     

Divergent Chemistry Paths for 3D and 1D Metallo-Covalent Organic Frameworks (COFs)

The marriage of dynamic covalent chemistry (DCC) and coordination chemistry is a powerful tool for assembling complex architectures from simple building units. Recently, the synthesis of woven covalent organic frameworks (COFs) with topologically fascinating structures has been achieved using this approach. However, the scope is highly limited and there is a need to discover new pathways that can assemble covalently linked organic threads into crystalline frameworks. Herein, we have identified branching pathways leading to the assembly of three-dimensional (3D) woven COFs or one-dimensional (1D) metallo-COFs (mCOFs), where the mechanism is underpinned by the absence or presence of ligand exchange.     

Barrier Lyapunov functions-based fixed-time stabilization of nonholonomic systems with unmatched uncertainties and time-varying output constraints

The fixed-time stabilization problem is addressed in this paper for a kind of nonholonomic systems in chained form with unmatched uncertainties and time-varying output constraints. A novel tan-type barrier Lyapunov function is introduced to deal with time-varying output constraints. Under the unified framework of the considered system with and without output constraints, a state feedback controller is designed with the aid of adding a power integrator technique and switching control strategy. It is shown that the suggested controller ensures the states of closed-loop system to zero in a given fixed time without disobeying the constraints. Finally, simulation results are given to confirm the efficacy of the presented control scheme.

     

Robust Adaptive Finite-Time Stabilization of Nonlinearly Parameterized Nonholonomic Systems

This paper investigates the problem of adaptive finite-time stabilization of nonlinearly parameterized nonholonomic systems. By skilly using the parameter separation, input-state-scaling, and adding a power integrator techniques, an adaptive state feedback controller is obtained. Based on switching strategy to eliminate the phenomenon of uncontrollability, the proposed controller can guarantee that the system states globally finite-time converge to the origin, while other signals remain bounded. Simulation examples demonstrate the effectiveness and the robust features of the proposed approach.     

Photonic generation of millimeter-wave ultra-wideband signal using microfiber ring resonator

The photonic generation of millimeter-wave (MMW) ultra-wideband (UWB) signal using microfiber ring resonator (MRR) is proposed. The central frequency and 10-dB bandwidth of generated MMW-UWB signal varying with Q factor of MRR are analyzed. We successfully demonstrate a generation of 24-GHz MMW-UWB signal by utilizing a microfiber ring resonator with free spectrum range of 20 GHz and Q factor of 19,000. The generated MMW-UWB signal has a power spectrum density complying with Federal Communication Committee requirements.