Two-dimensional layered semiconducting materials, such as tungsten disulfide, have attracted significant research interest over the past few decades. With rational optimization of their chemical constitutions and regu...
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Two-dimensional layered semiconducting materials, such as tungsten disulfide, have attracted significant research interest over the past few decades. With rational optimization of their chemical constitutions and regulation of electronicconfigurations, these materials can achieve commercial viability. Herein, the WS2/c hybrid was constructed by organic amine intercalation and in-situ pyrolysis. Intraparticle porous WS2/c was successfully synthesized by dissolving and etching. The specific surface area of the obtained WS2/c was significantly enhanced on the removal of WO3 through alkali etching, which facilitated the Na-insertion/ extraction. Therefore, the obtained porous WS2/ccomposite delivered a high reversible capacity and improved cycle stability with 346.3 mAh g-1 over 80 cycles at 100 mA g-1. This work proposes an intragranular porous WS2/ccomposite electrode design which shows a superior sodium storage performance, improved electronicconductivity and enhanced reversible specificcapacity. It is expected to present a novel insight for designing other high-capacity sodium-ion and other alkaline ion battery electrode materials.
Understanding the processing of limiting nutrients among organisms is an important goal of community ecology. Less known is how human disturbances may alter the stoichiometric patterns among organisms from different t...
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Understanding the processing of limiting nutrients among organisms is an important goal of community ecology. Less known is how human disturbances may alter the stoichiometric patterns among organisms from different trophic levels within communities. Here, we investigated how livestock grazing affects the c:N:P ecological stoichiometry of soils, plants (Leymus chinensis), and grasshoppers (Euchorthippus spp.) in a semi-arid grassland in northeastern china. We found that grazing significantly enhanced soil available N and leaf N content of the dominant L. chinensis grass by 15% and 20%, respectively. Grazing also reduced (soluble) c:N of L. chinensis leaves by 22%. However, grazing did not affect total c, N, or P contents nor their ratios in Euchorthippus grasshoppers. Our results reveal that the effects of grazing disturbances on elemental composition attenuated from lower to higher trophic levels. These findings support the theory that organisms from higher trophic levels have relatively stronger stoichiometric homeostasis compared to those from lower trophic levels. Moreover, grasshopper abundance dropped by 66% in the grazed areas, and they reduced the feeding time on their host L. chinensis grass by 43%, presumably to limit the intake of excess nitrogen from host plants. The energeticcosts associated with the maintenance of elemental homeostasis likely reduced grasshopper individual performance and population abundance in the grazed areas. A comprehensive investigation of stoichiometric properties of organisms across trophic levels may enable a better understanding of the nature of species interactions, and facilitate predictions of the consequences of future environmental changes for a community organization.
A partial rbcL sequence of the lectotype specimen of corallina berteroi shows that it is the earliest available name for c. ferreyrae. Multilocus species delimitation analyses (ABGD, SPN, GMYc, bPTP, and BPP) using in...
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A partial rbcL sequence of the lectotype specimen of corallina berteroi shows that it is the earliest available name for c. ferreyrae. Multilocus species delimitation analyses (ABGD, SPN, GMYc, bPTP, and BPP) using independent or concatenated cOI, psbA, and rbcL sequences recognized one, two, or three species in this complex, but only with weak support for each species hypothesis. conservatively, we recognize a single worldwide species in this complex of what appears to be multiple, evolving populations. Included in this species, besides c. ferreyrae, are c. caespitosa, the morphologically distinct c. melobesioides, and, based on a partial rbcL sequence of the holotype specimen, c. pinnatifolia. corallina berteroi, not c. officinalis, is the cosmopolitan temperate species found thus far in the NE Atlantic, Mediterranean Sea, warm temperate NW Atlantic and NE Pacific, cold temperate SW Atlantic (Falkland Islands), cold and warm temperate SE Pacific, NW Pacific and southern Australia. Also proposed is c. yendoi sp. nov. from Hokkaido, Japan, which was recognized as distinct by 10 of the 13 species discrimination analyses, including the multilocus BPP.
Ecological stoichiometry is useful for revealing the biogeochemical characteristics of flows of nutrients and energy between plant and soil, as well as the important implications behind these ecological phenomena. How...
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Ecological stoichiometry is useful for revealing the biogeochemical characteristics of flows of nutrients and energy between plant and soil, as well as the important implications behind these ecological phenomena. However, the ecological stoichiometric linkages among leaf, litter, soil, and enzymes in the natural forests of the Loess Plateau remain largely unknown. Here, leaf, litter, and soil samples were collected from four age classes of natural Pinus tabuliformis carr. (P. tabuliformis) to explore the deep linkages among these components. We measured the total carbon (c), total nitrogen (N), and total phosphorus (P) concentrations of leaf and litter, as well as the concentrations of soil organicc, total N, total P, nitrate N, ammonium N, available P, and the activities of beta-1,4-glucosidase (a c-acquiring enzyme), beta-1,4-N-acetylglucosidase (an N-acquiring enzyme), and alkaline phosphatase (a P-acquiring enzyme) in the topsoil (0-20 cm). The average leaf N:P was 6.9 indicated the growth of P. tabuliformis was constrained by N according to the relative resorption theory of nutrient limitation. The c:N, c:P, and N:P ratios in leaf, litter, and soil and the enzyme activity were not significantly different among age classes (p > 0.05). Litter c:N (43.3) was closer to the ratio of leaf c:N (48.8), whereas the litter c:P (257.7) was obviously lower than the ratio of leaf c:P (338.15). We calculated the stoichiometric homeostasis index (1/H) of leaf responses to soil elements and enzyme activities and found that the relationship between leaf c:P and soil c:P was homeostatic (p < 0.05), whereas the remaining indices showed the leaf stoichiometries were strictly homeostatic (p > 0.05). correlation analysis showed both litter c:P and N:P were positively correlated with leaf and soil c:P, while the stoichiometric ratios of soil elements and enzymes were obviously irrelevant with leaf stoichiometries (p > 0.05). Partial least squares path modeling indicated that litter
c/SiBcN composites are expected to be widely used in aerospace applications because of their excellent high-temperature stability. However, the interfacial reactions have significantly limited their practical applicat...
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c/SiBcN composites are expected to be widely used in aerospace applications because of their excellent high-temperature stability. However, the interfacial reactions have significantly limited their practical application. A pyrocarbon (Pyc) interphase can improve the interfacial reactions of c/SiBcN composites. In this study, Pyc interphases of different thicknesses (0.1 mu m, 0.25 mu m, and 0.5 mu m) were introduced via chemical vapor deposition (cVD) process. The interface bonding of c/SiBcN composites with 0.1 mu m and 0.25 mu m thick interphases was relatively weak and the composites with 0.5 mu m interphase exhibited strong interface bonding. After heat treatment at 1600 degrees c, the mechanical properties of the c/SiBcN composites with the 0.5 mu m thick interphase was maintained at 131 MPa, and it was maintained at 105 MPa even after heat treatment at 1900 degrees c, indicating their excellent high-temperature mechanical properties. In short, 0.5 mu m thick Pyc interphase can effectively improve the interfacial reaction of the c/SiBcN composites, facilitating their application in high-temperature environments.
Hollow tubular structure TiO2/c photocatalyst was prepared by carbonization at 400celcius with cotton fabric as initial carrier and tetrabutyltitanate as precursor. The structure of the samples was characterized by SE...
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Hollow tubular structure TiO2/c photocatalyst was prepared by carbonization at 400celcius with cotton fabric as initial carrier and tetrabutyltitanate as precursor. The structure of the samples was characterized by SEM and XRD. The results show that anatase crystal TiO2 with good crystallization is formed, TiO2 was uniformly distributed on the surface of the hollow tubular carbon material. The photocatalytic degradation performance was measured by using the methylene blue as the target dyes. When the dosage of TiO2/c was 1.7 g/L, the degradation rate of methylene blue solution was high up to 97.5%. The effective degradation of dyes was realized by using the strong adsorption property of hollow carbon materials and the high photocatalytic activity of anatase titanium dioxide. Due to the repeated adsorption of carbon materials to dyes and the continuous degradation of titanium dioxide to dyes, TiO2/c photocatalyst could be regenerated in situ.
Mullite modified c/c-Sic-Hfccomposites were prepared via precursor infiltration and pyrolysis (PIP). The effects of mullite modification with different contents on the composition, microstructure, and ablation behavi...
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Mullite modified c/c-Sic-Hfccomposites were prepared via precursor infiltration and pyrolysis (PIP). The effects of mullite modification with different contents on the composition, microstructure, and ablation behavior of the composites were investigated. Results showed that inadequate and excessive mullite limited the improvement of the ablation resistance. At 8.88 wt% mullite, the composites exhibited relatively good ablation resistance with mass and linear ablation rates of 0.44 mg/s & BULL;cm2 and 6.39 & mu;m/s. The addition of moderate mullite content promoted the formation of a dense Hf-Si-O multiphase oxide layer on the ablated surface without causing an excessive increase in surface temperature.
Abrus mollis is commonly used as a traditional chinese medicine for the treatment of liver diseases due to its hepatoprotection and anti-inflammation, but the absorption properties of its main bioactive ingredients re...
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Abrus mollis is commonly used as a traditional chinese medicine for the treatment of liver diseases due to its hepatoprotection and anti-inflammation, but the absorption properties of its main bioactive ingredients remain unclear. Our previous studies verified that the flavonoid c -glycosides, including vicenin-2 ( 1 ), isoschaftoside ( 2 ), and schaftoside ( 3 ), were the major active components in A. mollis for hepatic protection against nonalcoholic fatty liver disease, hepatitis, and hepatic fibrosis. This study investigated the bioaccessibility and transport mechanisms of total flavonoid c -glycoside, as well as vicenin-2 ( 1 ), isoschaftoside ( 2 ), and schaftoside ( 3 ), in A. mollis by simulated digestion and use of the caco-2 cell model. Moreover, this study attempted to verify their absorption properties by in situ gastrointestinal perfusion in rats. Total flavonoid c -glycoside and 1, 2 , and 3 exhibited similar bioaccessibility of 84.58%, 85.13%, 83.05%, and 81.65% respectively after simulated digestion. The transport of total flavonoid c -glycoside in the caco-2 cell model increased with the concentration, and the transport showed saturation characteristics with the time and concentration of total flavonoid c -glycoside to a certain degree. The Papp values of total flavonoid c -glycoside and the 3 flavonoid c -glycosides were significantly improved by verapamil, probenecid, and EDTA-Na (2) . Their absorption properties in the gastrointestinal tract were consistent with that found in caco-2 cells, and superior absorption rates were observed in the duodenum and jejunum. The absorption pattern of total flavonoid c -glycoside may involve multiple transport pathways, including active transport, passive diffusion, and the paracellular pathway. TFc was actively pumped out by P-glycoprotein and multidrug resistance-associated protein. These results revealed that the bioaccessibility and intestinal absorption characteristic of total flavonoid c -glycoside were c
Mn-based aqueous zinc ion batteries (AZIBs) are promising energy storage devices due to its low cost and high performance. However, Jahn-Teller effect of discharge process and Mn2+ dissolution restricts its practical ...
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Mn-based aqueous zinc ion batteries (AZIBs) are promising energy storage devices due to its low cost and high performance. However, Jahn-Teller effect of discharge process and Mn2+ dissolution restricts its practical application. Herein, we report a Zn/co co-doped MnO/c (Znco-MnO/c) derived from metal organic framework (MOF) with high specificcapacity and cyclic stability, which benefits from the synergistic effect of Zn/co ions. The doping of Zn ions improves the low specificcapacity of MnO in the initial activation process, and co ions can effectively inhibit the Jahn-Teller effect of discharge products and enhance the structural stability. The syner-gistic effect of Zn/co co-doped further enhances the conductivity and ion diffusion rate of MnO. In addition, the interface protection layer of the zinc anode is constructed by Ti3c2cl2 (Ti3c2@Zn), which can effectively inhibit dendrite growth and further improve the cycle life of AZIBs. Specifically, the assembled Znco-MnO/c// Ti3c2@Zn full battery has a specificcapacity of 428.9 mAh center dot g- 1 at 0.1 A center dot g-1. With 3000 cycles at 3.0 A center dot g-1, the capacity retention rate is 98.7 %. This work emphasizes the significance of co-doped on the electronic structure of MOF derived MnO/c for efficient AZIBs.
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