The electrochemical performance of most transition metal oxides based on the conversion mechanism is greatly restricted by inferior cycling stability, rate capability, high overpotential induced by ...the serious irreversible reactions, low electrical conductivity, and poor ion diffusivity. To mitigate these problems, highly porous Mn3O4 micro/nanocuboids with in situ formed carbon matrix (denoted as Mn3O4@C micro/nanocuboids) are designed and synthesized via a one‐pot hydrothermal method, in which glucose plays the roles of a reductive agent and a carbon source simultaneously. The carbon content, particle size, and pore structure in the composite can be facilely controlled, resulting in continuous carbon matrix with abundant pores in the cuboids. The as‐fabricated Mn3O4@C micro/nanocuboids exhibit large reversible specific capacity (879 mAh g−1 at the current density of 100 mA g−1) as well as outstanding cycling stability (86% capacity retention after 500 cycles) and rate capability, making it a potential candidate as anode material for lithium‐ion batteries. Moreover, this facile and effective synthetic strategy can be further explored as a universal approach for the synthesis of other hierarchical transition metal oxides and carbon hybrids with subtle structure engineering.
A facile one‐pot synthetic route is rationally designed and employed for the synthesis of porous Mn3O4 micro/nanocuboids with in situ coated carbon. The smart electrode design realizes efficient transportation of electrons and ions. By tuning the size and porosity of Mn3O4@C micro/nanocuboids, an outstanding cycling stability with a large reversible specific capacity and excellent rate capability are achieved.
In order to improve the quality of urban logistics distribution services and meet customer needs to the greatest extent, improve the utilization rate of service resources and reduce the cost of ...logistics and distribution services, the author proposes an urban logistics distribution scheduling algorithm based on artificial bee colony. Uncertain dynamic customer demands often occur during the execution of logistics distribution services, resulting in the inability to achieve optimal cost by executing the distribution service according to the original plan, in response to such problems with dynamic customer needs, the author conducted a problem analysis, the corresponding mathematical model is established and transformed into a static problem for rescheduling. The result shows: Using the scheduling algorithm to solve the example 100 times, when the vehicle 1 and vehicle 3 can meet their own load, they can serve customers with new needs, which can make the delivery cost the lowest. In the case of a small number of customers, the algorithm can achieve high accuracy, and when the number of customers reaches a certain scale, the stability of the algorithm will decrease slightly.
The algorithm achieves the purpose of promptly responding to changes in customer demand and quickly adjusting distribution services.
Glycerol is one of the most crucial by-products in the production of biodiesel, and owing to its oversaturation in the market, several synthetic strategies have been developed to transform it into ...other higher value-added products such as glycerol carbonate, epichlorohydrin, 1,3-propanediol, etc. Amongst them, glycerol carbonate is considered to be the most valuable product. Considering the facile separation and reusability of catalyst, heterogeneous base catalysts have attracted considerable attention due to the obvious advantages over Brϕnsted acid and homogeneous base catalysts in the transesterification of glycerol. Herein, we will give a short overview on the recent development of the heterogeneous catalysis in the transesterification of glycerol with dialkyl carbonate. Focus will be concentrated on the heterogeneous base catalysts including alkaline-earth metal oxides (MgO, CaO, and mixed oxides), hydrotalcites, zeolites, clinoptilolites, organic bases, etc. Their catalytic mechanisms during the heterogeneous process will be elucidated in detail.
The Tangut character 'j a ¹ (#1718) is usually glossed as Chin. nuò 诺 ‘(to) promise; yes’ in dictionaries. Given the fact that it does occur in rhetorical questions, this article argues that Tangut ...'j a ¹ is instead a constituent question particle and thus not restricted in rhetorical use. The conclusion is based on a detailed philological investigation, employing multilingual parallel texts where applicable. Comparisons with other Qiangic languages reveal several candidates for cognates. Nonetheless, their similarity is more likely to be an areal typological feature, rather than an etymological relation.
The intercalation compounds with various electrochemically active or inactive elements in the layered structure have been the subject of increasing interest due to their high capacities, good ...reversibility, simple structures, and ease of synthesis. However, their reversible intercalation/deintercalation redox chemistries in previous compounds involve a single cationic redox reaction or a cumulative cationic and anionic redox reaction. Here we report an anionic redox chemistry and structural stabilization of layered sodium chromium sulfide. It was discovered that the sulfur in sodium chromium sulfide is electrochemically active, undergoing oxidation/reduction rather than chromium. Significantly, sodium ions can successfully move out and into without changing its lattice parameter c, which is explained in terms of the occurrence of chromium/sodium vacancy antisite during desodiation and sodiation processes. Our present work not only enriches the electrochemistry of layered intercalation compounds, but also extends the scope of investigation on high-capacity electrodes.The rational design of intercalation electrodes is largely confined to the optimization of redox chemistry of transition metals and oxygen. Here, the authors report the single anionic redox process in NaCrS
where it is sulfur rather than chromium that works as the electrochemical active species.
Abstract
Self-assembled architectures of soft matter have fascinated scientists for centuries due to their unique physical properties originated from controllable orientational and/or positional ...orders, and diverse optic and photonic applications. If one could know how to design, fabricate, and manipulate these optical microstructures in soft matter systems, such as liquid crystals (LCs), that would open new opportunities in both scientific research and practical applications, such as the interaction between light and soft matter, the intrinsic assembly of the topological patterns, and the multidimensional control of the light (polarization, phase, spatial distribution, propagation direction). Here, we summarize recent progresses in self-assembled optical architectures in typical thermotropic LCs and bio-based lyotropic LCs. After briefly introducing the basic definitions and properties of the materials, we present the manipulation schemes of various LC microstructures, especially the topological and topographic configurations. This work further illustrates external-stimuli-enabled dynamic controllability of self-assembled optical structures of these soft materials, and demonstrates several emerging applications. Lastly, we discuss the challenges and opportunities of these materials towards soft matter photonics, and envision future perspectives in this field.
Aim: The Himalaya-Hengduan Mountain (HHM) biodiversity hotspot including the 'sky islands' of Southwest China harbour exceptional plant diversity and endemicity at subnival summits (most of them ...exceeding 4300 m a.s.l.). This study is the first using a comparative phylogeographical framework to gain insights into the temporal origin of this highly fragmented subnival flora, and the historical factors shaping its genetic architecture as exemplified by four perennial herbs. Location: Himalaya-Hengduan Mountains, China. Methods: Based on nuclear and/or chloroplast (cp) DNA sequences for each of the four studied species, we performed AMOVA and mismatch distributional analyses to assess molecular structure, diversity and demographic history in relation to current and last glacial distributions using ecological niche modelling (ENM). Time-calibrated phylogenetic reconstructions of cpDNA data were used to infer species-specific stem and crown ages. Results: Our time estimates suggest that these species originated during the Late Pliocene or early-to-mid Pleistocene, whereas their onset of diversification generally falls into the mid-Pleistocene. All four species exhibited island-like population genetic structures, with all of them showing signatures of recent population growth and/or spatial expansion based on cpDNA. By contrast, ENM indicated that species broad-scale distributions remained fairly stable over the last glacial/post-glacial cycle. Main conclusions: The temporal origin of the four subnival HHM species is likely associated with tectonic changes in the region, while their near-simultaneous onset of diversification during the 'Naynayxungla Glaciation' (0.72-0.50 Ma) could reflect initial population divergence through climate-induced habitat fragmentation. Despite a rather stable distributional history, geographical population isolation and localized range expansion/contractions likely resulted in significant genetic structure and differentiation over the last glacial/post-glacial cycle. Overall, the present results are strongly indicative of shared evolutionary histories and phylogeographical structures among subnival plants from the 'sky island system' of the HHM region.
Successive evidence has established that maltol, a flavor‐enhancing agent, could provide resistance to oxidative stress‐induced tissue injury in various animal models though its benefits for ...aging‐induced liver and kidney injuries are still undetermined. In the present work, for demonstrating maltol's ameliorative effect and probable mechanism against aging‐induced liver and kidney injuries, D‐galactose (D‐Gal)‐induced animal in vivo and HEK293 cells in vitro models were established and results demonstrated that long‐term D‐Gal treatment increases the accumulation of advanced glycation end products (AGEs) in liver and kidney tissues, mitigates cell viability, and arrests the cycle. Interestingly, 4‐weeks maltol treatment at 50 and 100 mg/kg activated aging‐associated proteins including p53, p21, and p16 followed by inhibiting malondialdehyde (MDA)'s over‐production and increasing the levels of antioxidant enzymes. Therefore, decreases in cytochrome P450 E1 (CYP2E1) and 4‐hydroxydecene (4‐HNE)'s immunofluorescence expression levels are confirmed. Furthermore, maltol improved oxidative stress injury by activating the phosphatidylinositol‐3‐kinase (PI3K)/protein kinase B (Akt) signaling pathway. In conclusion, the purpose of the present study was to estimate the mechanistic insights into maltol's role as an antioxidant in liver and kidney cell senescence and injury, which will reflect potential of therapeutic strategy for antiaging and aging‐related disease treatment.
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