Delay-dependent guaranteed-cost control based on combination of Smith predictor and equivalent-input-disturbance approach

This paper presents a new system configuration and a design method to improve control performance for a system with an input time delay and disturbances. The equivalent-input-disturbance approach is extended to handle a time-delay system. It is combined with the Smith predictor to reject disturbances. A delay-dependent stability condition is devised in terms of a matrix inequality by using the free-weighting matrix approach. The gain of the observer is designed by applying the cone complementary linearization method to the matrix inequality. A numerical example demonstrates the validity of the method.     

Two new 2D organic–inorganic hybrids assembled by lanthanide-substituted polyoxotungstate dimers and copper–complex linkers

Two new organic–inorganic hybrid copper–lanthanide heterometallic polyoxometalates (POMs), [Cu(dap)₂]_3.5[Cu(dap)₂(H₂O)]₃[La(α-SiW₁₁O₃₉)₂]·5H₂O (1) and H[Cu(dap)₂(H₂O)][Cu(dap)₂]₄[Eu(α-PW₁₁O₃₉)₂]·13H₂O (2) (dap = 1,2-diaminopropane), have been made under hydrothermal conditions and characterized by elemental analyses, IR spectra, XRD, thermogravimetric (TG) analyses and X-ray single-crystal diffraction. They both display interesting 2D organic-inorganic hybrid POMs containing 3d-4f cations and organic dap ligands. To the best of knowledge, 1 represents the first 2D Cu–Ln heterometallic silicotungstate assembled by [La(α-SiW₁₁O₃₉)₂]^13 − dimers and [Cu(dap)₂]^2 + linkers, while 2 is a new 2D Cu-Eu heterometallic Keggin-type phosphotungstate with dap ligands. Furthermore, the variable-temperature magnetic susceptibility of 2 has been investigated.     

A digital-twin visualized architecture for Flexible Manufacturing System

The new generation of industrial 4.0 intelligent manufacturing system consists of Human-Cyber-Physical System (HCPS), integrating human with cyber and physical systems. In manufacturing, a digital-twin visualization architecture is to solve the human-machine interaction problem that concerns digital-twin modeling on the Cyber-Physical (C-P) side and on the Human-Cyber side. Although there are many related research and applications, there lacks attention in terms of full life cycle functional services and lightweight architecture. This paper presents a general architecture of digital-twin visualization for flexible manufacturing systems (FMS). How the digital-twin C-P modeling of multi-source heterogeneous information can be described is investigated and how the 3D visualized human-machine interaction with digital-twin scenario information is explored in the proposed architecture. Besides, the visualization method of high-value information, relating to the life cycle planning, design, debugging and service stages, is studied and discussed thoroughly. Also, a digital-twin modeling concept of "Geometric information (G)-Historical samples (H)-Object attribute (O)-Snapshot collection (S)-Topology constraint (T)" (GHOST) is proposed, and methods for developing virtual digital-twin scenes architecture are presented. Based on the proposed modeling concept of GHOST for digital-twin, prototypes have been developed for the general platform of digital-twin RESTful services and the cross-platform general visual mock-up software. Experimental results show that this method is effective in the FMS lifecycle in various aspects.     

Synthesis of composite of graphene and UO3 composite via one-step solution chemical reaction and its application to UO2-based accident tolerant fuel

In this paper, two kinds of composites constructed by UO₃ nanoflakes (which is UO₃·yNH₃·xH₂O, precisely) and different graphene oxide (GO) nanosheets (homemade GO, GO-h, and commercial GO, GO-c) were prepared via solution chemical reaction. The two kinds of GO share similar morphology and possess the same species of functional groups. Nevertheless, GO-h possesses higher oxidization degree and thus could adsorb more uranyl ions, and the corresponding composite shows a much more regular shape: UO₃ nanoflakes and GO nanosheets cross each other, which would help overcome the disadvantage of graphene aggregation. As a result, homemade reduced graphene oxide (RGO-h) sheets inside the final UO₂ pellets (named as UO₂/GO-h) could construct a well-bulit thermally conductive network to enhance its thermal conductivity. However, similar RGO-c network cannot be observed in the UO₂/GO-c pellest originated from GO-c. Therefore, only the thermal conductivity of UO₂/GO-h pellet acquires a dramatic increase, 37.30% relative to UO₂ pellet at 1200 °C, showing that UO₂/GO-h possesses great potential for the development of novel UO₂-based ATF fuels.     

Special Z-scheme CdS@WO3 hetero-junction modified with CoP for efficient hydrogen evolution

In order to explore new materials capable of producing the new energy hydrogen, co-catalyst CoP was successfully modified Z-scheme hetero-junction CdS@WO₃ to achieve efficient splitting of water under visible light. With the lactic acid solution as sacrificial agent, the H₂ production was 736.89 μmol corresponding the apparent quantum yield of 1.72%, which was 20.2 and 24.5 times than pure CdS and WO₃, respectively. The results of XRD, TEM and FESEM characterization showed that the catalyst has obvious micro-morphology and high crystallinity. The valence distribution and composition of elements in the catalyst were measured by XPS. UV-vis, PL and electrochemical detection showed that the catalyst has excellent optical and electrical properties such as rapidly photo-generated charge transfer efficiency. Not only the energy band structure of the catalyst was calculated and analyzed, simultaneously the charge transfer mechanism and HER mechanism were explored and proposed.     

Stabilization of uncertain linear distributed delay systems with dissipativity constraints

This paper examines the problem of stabilizing linear distributed delay systems with nonlinear distributed delay kernels and dissipativity constraints. Specifically, the nonlinear distributed kernel includes functions such as polynomials, trigonometric and exponential functions. By constructing a Liapunov–Krasovskii functional related to the distributed kernels, sufficient conditions for the existence of a state feedback controller which stabilizes the uncertain distributed delay systems with dissipativity constraints are given in terms of linear matrix inequalities (LMIs). In contrast to existing methods, the proposed scenario is less conservative or requiring less number of decision variables based on the application of a new derived integral inequality. Finally, numerical examples are presented to demonstrate the validity and effectiveness of the proposed methodology.     

Several variants of Kalman Filter algorithm for power system harmonic estimation

This paper presents the maiden application of a variant of Kalman Filter algorithm known as Local Ensemble Transform based Kalman Filter (LET-KF) for power system harmonic estimation. The proposed algorithm is applied for estimating the harmonic parameters of a power signal containing harmonics, sub-harmonics, inter-harmonics in presence of white Gaussian noise. These algorithms are applied and tested for both stationary as well as dynamic signals containing harmonics. The LET-KF algorithm reported in this paper is compared with the earlier reported Kalman Filter based algorithms like Kalman Filter (KF) and Ensemble Kalman Filter (EnKF) algorithms for harmonic estimation. The proposed algorithm is found superior than the reported algorithm for its improved efficiency and accuracy in terms of simplicity and computational features, since there are less multiplicative operations, which reduces the rounding errors. It is also less expensive as it reduces the requirement of storing large matrices, such as the Kalman gain matrix used in other KF based methods. Practical validation is carried out with experimentation of the algorithms with the real time data obtained from a large paper industry. Comparison of the results obtained with KF, EnKF and LET-KF algorithms reveals that the proposed LET-KF algorithm is the best in terms of accuracy and computational efficiency for harmonic estimation.     

Vanadium based zinc spinel oxides: Potential materials as photoanode for water oxidation and optoelectronic devices

In the recent past, layered zinc-based vanadium spinel oxides (ZnVOs) have shown an intriguing way to accomplish the challenges of energy conversion, storage, and utilization issues. Here, through first-principles calculations, a comprehensive study has been carried out to investigate the AV₂M (where A = Zn, Zn₂, Zn₃, Zn_4, and M = O₄, O₆, O₇, O₈, O₉ respectively) electronic, photocatalytic, and optical properties. Formation energies with a negative sign express that the final compounds from the pure elements are possible and cohesive energies revealed that compounds are energetically stable. Spin-polarized calculations are also taken into account for better approximation of the electronic properties (band structure and density of states). All layered structures show indirect bandgap for spin-up calculations in range 0.3 eV–2.4 eV, while spin-down calculations show mix trends in range 2.3 eV–3.50 eV. An appropriate band edge with large enough kinetic over-potentials of the oxygen evolution reaction (ΔE_V ≥ 1.244 eV) makes them potential candidates as photoanode for water splitting. ZnV₂O₄ is more suitable for OER as it has small kinetic overpotential as compared to the oxidation potential of water. Interestingly, all ZnVOs display a dramatically large coefficient (~10⁵ cm⁻¹) for optical absorption. Photogenerated electrons and holes on the layered zinc-based vanadium spinel oxide surfaces could make these spinel oxides promising materials for photocatalytic water splitting and solar energy conversion.     

求解约束优化问题的自适应人工蜂群算法

针对约束优化问题，提出一种自适应人工蜂群算法。算法采用反学习初始化方法使初始种群均匀分布于搜索空间。为了平衡搜索过程中可行个体和不可行个体的数量，算法使用自适应选择策略。在跟随蜂阶段，采用最优引导搜索方程来增强算法的开采能力。通过对13个标准测试问题进行实验并与其他算法比较，发现自适应人工蜂群算法具有较强的寻优能力和较好的稳定性。     

中国古代鞋履风尚变迁史研究

采用文献资料搜集法和实地考察法,按照历史进程的先后,以图文并茂的方式梳理了鞋履雏形、鞋履与礼制、鞋履与时尚、鞋履与变革等中国古代历史悠久的鞋履风尚。伴随着鞋履材料的日趋精细,鞋履制作工艺的巨大进步,中国古代鞋履的发展从早期注重功能性为前提的裹脚物,到被纳入"礼治"范畴,到兼容并蓄的多元化式样,再到守旧与变革的斗争,经历了漫长的历史岁月。通过中国古代鞋履风尚变迁史研究,可以较为全面和真实地了解当时人们的鞋履生活,有助于人们从时尚文化的角度审视古代鞋履艺术的审美及发展。