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关键词： Lithium-ion batteries   Battery health prognostics   Differential thermal voltammetry   Particle filter   Gaussian process regression  

摘要： Battery state foretasting and health management are significant tasks for ensuring safety and stability of battery systems. Accurate state estimation can not only provide valuable parameters for energy man-agement but also may prolong battery usage lifespan. Comprehensive theoretical analysis and practical application, differential thermal voltammetry analysis method has great potentials in actual operation. This paper proposes a closed-loop battery capacity estimation framework, Gaussian process regression and multi-output Gaussian process regression for constructing battery dynamic state-space function, to improve the accuracy and robustness of battery SOH estimation. Firstly, a time-series model of battery capacity degradation is established as the state equation using Gaussian process regression. Secondly, two strong correlation indicators are treated as observed parameters to construct an observation equation through multi-output Gaussian process regression, where the health indicators are extracted from the partial smoothed curves by two filter methods. Thirdly, particle filter algorithm is employed to correct the prior estimated capacity and suppress noise perturbations for achieving closed-loop control. Additionally, the performances of particle filter algorithm with different particle sizes are discussed and analyzed from accuracy and computational time aspects. Verification of three types of batteries indicates that the proposed method has an excellent capability for battery capacity estimation. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Offshore wind turbine   Wave energy converter   Differential evolution   GPU-Acceleration   Layout optimization   Wake model  

摘要： Offshore wind turbines (OWTs) are used to harvest wind energy on the seas. Their foundations must bear wind and wave loads simultaneously, resulting in greater cost than onshore wind turbines. To harvest more energy and reduce the total cost, a wind-wave hybrid energy system is proposed in this study. Oscillating wave surge converters (OWSCs) are used to harvest wave energy and protect OWTs from waves. The reduced wave impact on the wind turbine foundation reduces the total cost. Wind turbines and converters are independent;even existing wind farms can convert to hybrid farms. An analytical wave wake model for the converter is presented to optimize the layout of the devices. The wave wake of the wind turbine foundations is also examined. An innovative GPU-accelerated multi-objective differ-ential evolution algorithm is used to globally optimize the device layout in actual environmental con-ditions. The optimized hybrid farm has 37.75% greater energy output and 43.65% less wave loads on the wind turbine foundations than wind-only farms. The wave wake model for the converter has an accuracy of 94.73%. The GPU-accelerated codes can run 1136 times faster than the CPU-based codes, and are available to other researchers. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Sterigmatocystin   Magnetic molecularly imprinted polymer   Functional monomers   Triallyl isocyanurate   Reverse prediction method  

摘要： A novel magnetic molecularly imprinted polymers (MMIPs) with a new functional monomer Triallyl isocyanurate was synthesized successfully to enrich and detect sterigmatocystin (STG) in wheat samples. The differential UV-vis spectra and the reverse prediction method were selected to achieve the optimal synthesis conditions of the MMIPs, which were characterized well. The adsorption experiment showed that MMIPs have high selectivity and sensitivity. A magnetic solid phase extraction combined with high performance liquid chromatography (MSPE-HPLC) method based on the MMIPs was successfully established with the optimal extraction condition. The linear range and RSD were 1.8-25 ng.g(-1) and 2.6-4.1%, respectively. The recovery of this method was 87.6-96.9% and the limit of detection (LOD) was 0.63 ng.g(-1). The excellent sensitivity and selectivity of this method were confirmed by experiment of the extraction and detection of STG in wheat extracts. This work extends the use of molecular imprinting in mycotoxins applications.

关键词： Fuzzy valued function   Fractional calculus   Fuzzy Mellin transform   Riemann-Liouville fractional derivative and integral operator   Fuzzy fractional differential equations  

摘要： This paper deals with the application of fuzzy Mellin transform for fuzzy valued functions. It is an attempt to investigate fuzzy Mellin transform in fractional sense and is called fuzzy fractional Mellin transform. Some techniques are proposed for the solution of fuzzy fractional order differential equations by using left-sided Riemann-Liouville fractional derivative. Moreover, some illustrative examples are solved to show the capability and effectiveness of fuzzy Mellin transforms method by converting it into a general solution for an analogous equation with the left-sided Riemann-Liouville derivative and then presenting its explicit representation. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Uniform stability   Boundedness of solutions   Converse Lyapunov theorem   Generalized ordinary differential equations   Measure functional differential equations   Asymptotic controllability  

摘要： Generalized ordinary differential equations (we write generalized ODEs), introduced by J. Kurzweil in 1957, are known to encompass several other types of equations as measure functional differential equations, for instance. In this paper, we obtain converse Lyapunov theorems for generalized ODEs and, in particular, for measure functional differential equations which, in turn, encompass impulsive functionals differential equations as well as functional dynamic equations on time scales. We also relate uniform stability to boundedness of solutions. As an application, we establish necessary and sufficient conditions for a system of non-homogeneous nonlinear generalized ODEs defined in a Banach space and for a system of non-homogeneous measure functional differential equations to be asymptotically controllable. We include an example which illustrates the main results. (c) 2021 Elsevier Inc. All rights reserved.

关键词： Digital PCR   Direct detection   Microfluidics chip   EGFR T790M  

摘要： Nucleic acid extraction and purification before amplification is considered an essential step for nucleic acid amplification testing. However, this may cause losses or introduce errors that can lead to inaccurate results, especially when using samples with a small nucleic acid concentration. Here, we developed a direct digital chip that enabled us to detect nucleic acid without DNA extraction and purification. We have developed a self-priming liquid-dispensing digital PCR chip that does not require any external power. This is a robust anti-evaporation digital PCR chip with fast sampling and accurate quantification performance. Using this chip, we have estab-lished an on-chip direct nucleic acid amplification method that does not require nucleic acid extraction and purification for liquid biopsy samples. In order to verify the feasibility of this chip for clinical samples, we detected the EGFR T790M mutation from plasma. Results showed that EGFR T790M mutation could be detected with an accuracy of 100% and a sensitivity of 0.01%. Without nucleic acid extraction and purification, the assay avoids complex pre-processing, thus saving time and achieving precise quantification. We expect our direct digital PCR chip to have practical applications in diagnosis, screening, and research, especially in resource-deprived regions.

关键词： Water lily (Nymphaea)   Eutrophication   Phosphorus   Nitrogen   Phytoremediation  

摘要： Excessive inputs of phosphorus (P) and nitrogen (N) trigger eutrophication of the water bodies, which promotes the undesirable growth of algal bloom and deterioration of the water quality, and aquatic biodiversity. Macrophytes provide an environmentally benign and economically viable paradigm for the ecological restoration of eutrophic aquatic ecosystems. Water lily (Nymphaea) is largely used as ornamental plant for landscaping, and it has been documented that water lily possesses the potentiality in mitigating polluted aquatic environments. In the present study, water lily cultivars Nymphaea Texas Dawn (NTD), Nymphaea Colorado (NC), Nymphaea Madame Wilfron Gonne`re (NMWG), and Nymphaea Sunshine Princess (NSP) were investigated for their potency in alleviating the eutrophication. The concentrations of total P and total N were significantly higher in the leaves of NC and NSP compared with NTD and NMWG. Therefore, NC and NSP were selected for subsequent studies to decipher their recuperation efficacy on eutrophic waters at different growth stages. NC and NSP significantly reduced the concentrations of eutrophication indicators i.e., total P, NH4+-N, and chemical oxygen demand in different gradients of the simulated eutrophic water in a growth-dependent manner. On the contrary, NC and NSP triggered a significant increase in the concentration of dissolved oxygen particularly at the seedling stage. Notably, the concentrations of total P (shoot and root) and total N (root) were relatively higher in NSP than NC. The study thus revealed a growth-dependent differential efficacy of NSP and NC in mitigating the different eutrophic waters.

关键词： Partial integro-differential equation   Caputo fractional derivative   L1 scheme   Error analysis  

摘要： The main purpose of this work is to study the numerical solution of a time fractional partial integro-differential equation of Volterra type, where the time derivative is defined in Caputo sense. Our method is a combination of the classical L1 scheme for temporal derivative, the general second order central difference approximation for spatial derivative and the repeated quadrature rule for integral part. The error analysis is carried out and it is shown that the approximate solution converges to the exact solution. Several examples are given in support of the theoretical findings. In addition, we have shown that the order of convergence is more high on any subdomain away from the origin compared to the entire domain. (C) 2021 Elsevier B.V. All rights reserved.