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•Hydrophilic Ce@SCA were designed and synthesized through facile method.•The hydrophilicity of the carbon aerogel microspheres was improved.•Ce@SCA possesses excellent adsorption ...properties and selectivity for Sb(III) in water.•Redox and complexation processes are involved in the removal mechanisms of Sb(III).•DFT calculations confirm the positive effect of sulfur doping on the adsorption process.
Antimony pollution is well recognized to induce cancer and deformity. By polymerization technique, a carbon aerogel microsphere (Ce@SCA) modified by Ce and S with micron size, well-developed pore structure, and large specific surface area was created. Ce@SCA exhibited the advantages of efficient selectivity and high adsorption capacity for Sb(III) in water. The highest adsorption capacity derived using the Sips isothermal model was 345.18 mg∙g−1, and the Sb (III) adsorption process was thermodynamically estimated as spontaneous, exothermic, and entropy-decreasing chemisorption. Meanwhile, Ce@SCA can convert highly toxic Sb(Ⅲ) into Sb(Ⅴ), which is suitable for the remediation of antimony-contaminated water bodies. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) were analyzed to elucidate the adsorption mechanism and to propose optimized adsorption configurations. A considerable number of –OH and -SH on the surface may increase the binding site of Sb, and the creation of S-Sb, O-Sb, and Ce-O-Sb covalent bonds was the key to Sb adsorption. This research provides a simple method for preparing cerium oxide-loaded and sulfur-doped carbon aerogel (Ce@SCA) with mild conditions and no hazardous waste, which also has superior adsorption properties for Sb (III) and high reusability.
The family Hepeviridae includes several positive-stranded RNA viruses, which infect a wide range of mammalian species, chicken, and trout. However, few hepatitis E viruses (HEVs) have been ...characterized from invertebrates. In this study, a hepevirus, tentatively named Crustacea hepe-like virus 1 (CHEV1), from the economically important crustacean, the giant freshwater prawn
, was characterized. The complete genome consisted of 7750 nucleotides and had a similar structure to known hepatitis E virus genomes. Phylogenetic analyses suggested it might be a novel hepe-like virus within the family Hepeviridae. To our knowledge, this is the first hepe-like virus characterized from crustaceans.
Most reported catalysts for lithium‐sulfur battery can work for only one of the multiple elementary reactions, thereby resulting in the gradual enrichment of unconverted polysulfides at the catalytic ...centers and aggravating the shuttle effect. Herein, the concept of cascade catalysis based on a ternary heterostructure, which divides sulfur redox reactions into distinct steps by multiple catalytic centers, is proposed to realize the tandem reduction of Li2S8 to Li2S. As a proof of concept, the ternary heterostructure Na0.67Ni0.25Mn0.75O2(NNMO)‐MnS2‐Ni3S4 achieved by in situ non‐topotactic electrochemical reconstruction successfully integrates three types of active centers into one structure to achieve cascade catalysis. More specifically, NNMO acts as an adsorption mediator to effectively capture polysulfides, MnS2 functions better in catalyzing the conversion of polysulfides into Li2S4 and Ni3S4 demonstrates an enhanced catalytic effect for Li2S precipitation. This synergistic cascade catalysis originates primarily from the dynamic energy‐level matching between the metal d‐band center and the lowest unoccupied molecular orbital of the polysulfides, affording appropriate molecular orbital hybridization and facile interfacial electron transition and thus endowing favorable sulfur reduction kinetics. Eventually, the NNMO‐MnS2‐Ni3S4/S composite electrode exhibits excellent rate performance and high restraining ability toward the polysulfide shuttle under long cycling, high sulfur loading and low electrolyte conditions.
The ternary heterostructure achieved by in situ non‐topotactic reconstruction of Na0.67Ni0.25Mn0.75O2 successfully integrates three types of active centers into one structure to achieve cascade catalysis for Li‐S batteries. Such synergistic cascade catalysis is derived from the dynamic evolution of the energy‐level difference between the metal d‐band center and lowest unoccupied molecular orbital of polysulfides, endowing favorable sulfur reduction kinetics.
Model‐guided extremum seeking–case studies Tan, Ying; Chen, Xiang; Hua, Youying ...
International journal of adaptive control and signal processing,
March 2022, 2022-03-00, 20220301, Volume:
36, Issue:
3
Journal Article
Peer reviewed
Summary
In practice, data‐driven control and optimization techniques are applied to address problems in engineering systems of which the model is either unavailable or so complicated that a ...model‐based analytic design can be hardly carried. Among them, the extremum seeking (ES) is a popular model‐free or data‐driven optimization method that has been effectively applied to provide optimal solutions to various industrial control systems. In this article, a new design philosophy, called the model‐guided ES, which is a special case of model‐guided data‐driven (MGDD) optimization, is presented and demonstrated with two successful case studies. In particular, it is shown that, in these two cases, how models of physical systems, even if imperfect or developed in a data‐driven way instead of the first‐principle based approach, could be integrated together with the conventional ES algorithm to deliver much improved and guaranteed convergence performance and the ultimate bound. It is noted that the first case is for the automotive diesel engine optimization and the second case for the automated regulation of LiDAR detection range. Both cases are successfully validated with experiments.
Researches on agricultural land use would help the stakeholders to make better decisions about agricultural resources. However, studies on agricultural land have been lacking. In this context, ...Xiangxi was chosen as a typical region, and five indicators (Kernel Density, change importance, etc.) and two models (gray forecasting model and GeoSoS-FLUS) were used, to explore the spatio-temporal evolution trends and simulate the future scenarios of agricultural land use. The results were as follows: (1) Xiangxi was dominated by agricultural land, and nearly 50% of total extent was forestry land. Extent of agricultural land decreased by about 56.89 km2 or 3.74% from 2000 to 2018; (2) The density of each agricultural land in the study area had considerable spatial heterogeneity, and showed a main trend of shrinkage, especially in the south regions; (3) In 2030, the spatial pattern and composition of agricultural land in Xiangxi will maintain the existing status, while both of the area and proportion of agricultural land will decline, with a loss of 241.34 km2 or 2.85% decrease from 2000. Nevertheless, the study believed that the slight shrinkage of the agricultural land in Xiangxi is in line with the objective law. At the same time, the study suggested to strengthen the scientific management and rational utilization of agricultural land, with emphasis on arable land and fishery land in the south, especially the administrative center.
•miR-223-3p expression is downregulated in the serum of EAM mice.•miR-223-3p overexpression favors a switch of LPS-stimulated DCs toward a tolerant phenotype.•NLRP3 inflammasome is essential for the ...tolerogenic function mediated by miR-223-3p.•miR-223-3p-overexpressing DCs ameliorate experimental autoimmune myocarditis in mice.
Autoimmune myocarditis is a cause of dilated cardiomyopathy and heart failure. MicroRNAs regulate many immune processes, but their role in aberrant inflammation during autoimmune myocarditis remains unclear. In this study, we investigated the role of miR-223-3p in experimental autoimmune myocarditis (EAM). We found that miR-223-3p expression was significantly lower in EAM mice than that in normal mice. miR-223-3p inhibited NLRP3 inflammasome expression, promoting the polarization of dendritic cells (DCs) towards a tolerogenic DC phenotype. miR-223-3p effectively induced regulatory T cell (Treg) generation by inhibiting the function of antigen-presenting DCs. Transfer of miR-223-3p-overexpressing DCs protected mice against the development of EAM. Our findings suggest that miR-223-3p is involved in the induction of the tolerogenic DC phenotype and regulates tolerance in autoimmune myocarditis.
The modeling and optimization of copper losses are the basis of magnetic designs. By solving 2-D diffusion and Laplace equations, this paper proposes a 2-D analytical copper loss model for PCB ...inductors and transformers with arbitrary air gaps. The copper loss resistance is decoupled into skin, proximity and fringing resistances. The fringing resistance is caused by the inhomogeneity of magnetic induction expressed as the Fourier series. Based on the proposed model, some conclusions are derived theoretically. For example, fringing resistance of transformers is independent of the arrangements of primary and secondary windings, and fringing resistance increases with winding width, which could be a theoretical reason why matrix transformers should be used in some applications. The proposed model is verified by simulation with a 6.0% average error and by experiment with a 7.7% average error.
Air-cooled, self-humidifying hydrogen fuel cells are often used for backup and portable power sources, with a metal hydride used as the hydrogen storage material. To provide a stable hydrogen flow to ...the fuel cell stack, heat must be provided to the metal hydride. Conventionally, the heat released from the exothermic reaction of hydrogen and oxygen in the fuel cell stack to the exhaust air is used to heat a separate metal hydride container. In this case, the heat is only partially used instead of being more closely coupled because of the heat transfer resistances in the system.
To achieve better heat integration, a novel scheme is proposed whereby hydrogen storage and single fuel cells are more closely coupled. Based on this idea, metal hydride containers in the form of cooling plates were assembled between each pair of cells in the stack so that the heat could be directly transferred to a metal hydride container of much larger surface-to-volume ratio than conventional separate containers. A heat coupled fuel cell portable power source with 10 cells and 11 metal hydride containers was constructed and the experimental results show that this scheme is beneficial for the heat management of fuel cell stack.
•A hydrogen containers and single cells coupling structure for heat coupling is proposed.•A heat coupled novel fuel cell stack and system is developed.•Experimental results prove that the coupling structure works well for heat management.
Characterizing the transition from a crack-free to a cracked state remains a challenging topic in fatigue. Mg-rare earth alloys, containing the long-period stacking ordered (LPSO) phase, exhibit ...superior mechanical properties. Here, microcracks are found to nucleate at the soft α-Mg nano-layers, away from the LPSO lamellae. Notably, severe oxidation is observed along the damage bands. Based on the detailed characterizations, it is suggested that dislocation motions continuously bring the new α-Mg matrix to oxidation transformation, resulting in the thickening MgO layer. However, once the fatigue-induced oxide reaches a certain thickness, it starts acting as a barrier for the further dislocation motions. As a result, dislocation accumulation and cumulative damage occur in the region ahead of the thick oxide, causing microcrack nucleation. This fatigue-induced oxidation, assisting microcrack nucleation, is distinct from the existing fatigue mechanisms.
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