Photocatalytic hydrogen evolution from water splitting is a promising strategy to solve the energy demand of human beings. Here, we first designed a c-Mn0.5cd0.5S/cu3P ternary heterojunction catalyst for photocatalyti...
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Photocatalytic hydrogen evolution from water splitting is a promising strategy to solve the energy demand of human beings. Here, we first designed a c-Mn0.5cd0.5S/cu3P ternary heterojunction catalyst for photocatalytic hydrogen production. The results show that the combination of c and cu3P can effectively improve the photocatalytic activity of Mn0.5cd0.5S. c-Mn0.5cd0.5S loading with 5 wt% cu3P exhibits the highest hydrogen evolution rate (44.1 mmol g(-1) h(-1)), which is 3.2 and 2.8 times higher than that of pure Mn0.5cd0.5S (13.7 mmol g(-1) h(-1)) and Mn0.5cd0.5S/3 wt%Pt (15.6 mmol g(-1) h(-1)), respectively. In addition, it shows a high hydrogen evolution rate (19.6 mmol g(-1) h(-1)) under visible light (>= 420 nm) irritation and the apparent quantum efficiency (AQE) is detected to be 3.2% at 420 nm. The enhanced photocatalytic activity can be attributed to the good conductivity of c and the formation of p-n heterojunction, which is beneficial for light harvesting and the separation and transportation of charge carriers. Besides, a possible mechanism is proposed. This work provides an effective way to improve the photocatalytic activity of Mn0.5cd0.5S by using non noble metal co-catalysts. (c) 2021 Hydrogen Energy Publications LLc. Published by Elsevier Ltd. All rights reserved.
Author Summary "Synthetic lethality" in cell biology is an extreme example of the effects of higher order genetic interactions: The simultaneous knockout of two or more individually nonessential genes leads ...
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Author Summary "Synthetic lethality" in cell biology is an extreme example of the effects of higher order genetic interactions: The simultaneous knockout of two or more individually nonessential genes leads to cell death. We define a neural analog to this concept in relation to the locomotor response to gentle touch in c. elegans. Two or more neurons are synthetic essential if individually they are not required for this behavior, yet their combination is. We employ a network control approach to systematically assess all pairs and triplets of neurons by their effect on body wall muscle controllability, and find that only surprisingly small sets of neurons are synthetic essential. They are highly localized in the nervous system and predicted to affect control over specific sets of muscles. Synthetic lethality, the finding that the simultaneous knockout of two or more individually nonessential genes leads to cell or organism death, has offered a systematic framework to explore cellular function, and also offered therapeutic applications. Yet the concept lacks its parallel in neuroscience-a systematic knowledge base on the role of double or higher order ablations in the functioning of a neural system. Here, we use the framework of network control to systematically predict the effects of ablating neuron pairs and triplets on the gentle touch response. We find that surprisingly small sets of 58 pairs and 46 triplets can reduce muscle controllability in this context, and that these sets are localized in the nervous system in distinct groups. Further, they lead to highly specific experimentally testable predictions about mechanisms of loss of control, and which muscle cells are expected to experience this loss.
The aboveground primary production is a major source of carbon(c) and nitrogen(N) pool and plays an important role in regulating the response of ecosystem and nutrient cycling to natural and anthropogenic disturbances...
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The aboveground primary production is a major source of carbon(c) and nitrogen(N) pool and plays an important role in regulating the response of ecosystem and nutrient cycling to natural and anthropogenic disturbances. To explore the mechanisms underlying the effect of spring fire and topography on the aboveground biomass(AGB) and the soil c and N pool, we conducted a field experiment between April 2014 and August 2016 in a semi-arid grassland of northern china to examine the effects of slope and spring fire, and their potential interactions on the AGB and organicc and total N contents in different plant functional groups(c_3 grasses, c_4 grasses, forbs, Artemisia frigida plants, total grasses and total plants).The dynamics of AGB and the contents of organicc and N in the plants were examined in the burned and unburned plots on different slope positions(upper and lower). There were differences in the total AGB of all plants between the two slope positions. The AGB of grasses was higher on the lower slope than on the upper slope in July. On the lower slope, spring fire marginally or significantly increased the AGB of c_3 grasses, forbs, total grasses and total plants in June and August, but decreased the AGB of c_4 grasses and *** plants from June to August. On the upper slope, however, spring fire significantly increased the AGB of forbs in June, the AGB of c_3 grasses and total grasses in July, and the AGB of forbs and c_4 grasses in August. Spring fire exhibited no significant effect on the total AGB of all plants on the lower and upper slopes in 2014 and 2015. In 2016, the total AGB in the burned plots showed a decreasing trend after fire burning compared with the unburned plots. The different plant functional groups had different responses to slope positions in terms of organicc and N contents in the plants. The lower and upper slopes differed with respect to the organicc and N contents of c_3 grasses, c_4 grasses, total grasses, forbs, A. frigida plan
Through a stepwise synthesis, intercalation followed by chemical vapor deposition (cVD) method, WP nanorods have been grown on the surface of WS2/ccomposite. compared to WS2/c, WP nanorods@WS2/c demonstrate better hy...
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Through a stepwise synthesis, intercalation followed by chemical vapor deposition (cVD) method, WP nanorods have been grown on the surface of WS2/ccomposite. compared to WS2/c, WP nanorods@WS2/c demonstrate better hydrogen evolution reaction (HER) activity and long-term chronopotentiometric stability as well as suitability in both acid electrolyte and alkaline electrolyte. In order to uncover the enhanced HER property reason, systematiccharacterizations were applied to assist analyzing. The characterizations used include X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), electrochemical active surface area (EcSA), Raman, and BET. Based on the analysis, it points that improved EcSA, synergy between WS(2)and WP nanorods, and enhanced degree of graphitization as well, leads to better HER activities of WP nanorods@WS2/c over WS2/c. This work highlights significant role of WP nanorods in WP/WS2/c three-phase composite in electrocatalytic hydrogen evolution and may evoke new interest in related nanostructure study.
In order to study the solid-solution process between amorphous BcN and metal Ta, Ta(B, c, N), (Ta, Nb)(B, c, N), and (Ta, W)(B, c, N) ceramics were prepared by high-energy ball milling, and their phase composition, mi...
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In order to study the solid-solution process between amorphous BcN and metal Ta, Ta(B, c, N), (Ta, Nb)(B, c, N), and (Ta, W)(B, c, N) ceramics were prepared by high-energy ball milling, and their phase composition, microstructures, and binding bonds have been analyzed. The results show that all the three ceramics are hard agglomeration state, formed by stacking of nanoparticles. The mechanical alloying process is accompanied by the formation of chemical bonds, such as B-Ta, N-Ta, c-Ta, and O-Ta for Ta(B, c, N) ceramic, and the order of solid solution is c > N > B. When heated at 1500 degrees c, a second diboride phase precipitates from (Ta, Nb)(B, c, N) ceramic, whereas the second phase of Wc gradually dissolved from (Ta, W)(B, c, N) ceramic. This work provides theoretical and data supporting to analyze the solid-solution process of Ta(B, c, N) ceramic.
carbon fibre-reinforced silicon carbide composites (c/Sic) are a type of high-temperature structural ceramics that can be widely applied in aerospace, hypersonic aircraft, and military fields. However, the practical a...
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carbon fibre-reinforced silicon carbide composites (c/Sic) are a type of high-temperature structural ceramics that can be widely applied in aerospace, hypersonic aircraft, and military fields. However, the practical application of such materials in some complex high-temperature environments is still limited owing to drawbacks such as the bulging problem. In this study, the bulging of a c/Siccoating in a high-temperature wind tunnel is investigated. The surface data of specimens in the high-temperature arc wind tunnel were obtained using optical visualisation equipment, and the entire process of the formation of coating bulges, and their evolution and fusion is illustrated. Then, a fully coupled thermal fluid-solid simulation model is established, and the influence of defects on the internal heat transfer of materials is analysed. Further, the thermal fluid-solid coupling simulation technology is also used to analyse the bulging process of the coating to understand the mechanism of chemical reactions in defects between the coating and substrate. This work can serve as a guide for the screening and improvement of the material coating process.
The main objective of the present study was to understand the influences of different atomic ratios of Ti/Mo and (Ti + Mo)/c on the precipitation behaviors in Ti-Mo HSLA steels. It was found that the steel with a high...
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The main objective of the present study was to understand the influences of different atomic ratios of Ti/Mo and (Ti + Mo)/c on the precipitation behaviors in Ti-Mo HSLA steels. It was found that the steel with a higher Ti/Mo atomic ratio possessed a large theoretical volume fraction of precipitated carbides, but the ferrite matrix did not achieve a corresponding higher microhardness. On the other hand, the experimental results also indicated that it was not suitable to assess the precipitation strengthening effect of the ferrite matrix based on only one of the atomic factors, i.e., (Ti + Mo)/c or Ti/Mo. In addition, from the present study, similarity of the (Ti + Mo)/c atomic ratios is a prerequisite for comparing the precipitation hardening effects in steels having different Ti/Mo atomic ratios. Besides experimental data, the main deduction is also supported by related patent information, which further corroborates the reliability of the present study. Furthermore, of the two steels with different M/c atomic ratios, the ferrite matrix of the H-(M/c) steel showed a rising trend in Vickers hardness when the isothermal holding time was increased from 5 min to 60 min at 650-700 degrees c. This higher strengthening ability, which occurs within ferrite grains after holding at longer times, can be ascribed to the higher austenite decomposition rate occurring in the H-(M/c) atomic ratio steel. Therefore, the hardening mechanisms in both kinds of steel are also discussed in the present study.
A series of 1D and 2D 1H NMR studies are presented, which aim at assigning the hyperfine shifted resonances of the heme and the spin systems of more than 20 amino acid side chains, and characterizing the heme and liga...
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A series of 1D and 2D 1H NMR studies are presented, which aim at assigning the hyperfine shifted resonances of the heme and the spin systems of more than 20 amino acid side chains, and characterizing the heme and ligand environment of the low spin imidazole complex of cytochrome c. Some details of the structure in the heme pocket of the cytochrome c-imidazole complex are shownqualitatively to have changed relatively to the native oxidized protein. The orientation of the coordinated imidazole is also determined based on the interpretation of a number of NOEs.
In this study, Ti-Fe-Si composites were prepared by one step ball-milling method as anode materials for Li-ion batteries. The effects of ball-milling speed and time were studied by X-ray diffraction, electron microsco...
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In this study, Ti-Fe-Si composites were prepared by one step ball-milling method as anode materials for Li-ion batteries. The effects of ball-milling speed and time were studied by X-ray diffraction, electron microscopy, and Fe-57 Mossbauer spectroscopy. changes in the composition and microstructure of the composites were observed and related to the electrochemical performance. Increasing ball-milling speed led to the formation of FeSix alloys that reduced the specificcapacity while increasing the ball-milling time improved the particle size morphology and homogeneity. Discharge/charge profiles for the first two cycles were carried out at 0.05ccurrent rate (1c = 1260 mAh.g(-1)for Li3.75Si). The first discharge for Ti-Fe-Si showed a LixSi reaction plateau of 1100 mAh.g(-1), which were reversible and yielded columbic efficiency (cE) 77% and 90% in the first and second cycles, respectively. This capacity plateau indicated the insertion of about 3.25 Li into silicon. For the composite containing an additional 10% carbon SP, the theoretical capacity was about 1130 mAh.g(-1), the discharge curve showed that the first discharge plateau reaches 1030 mAh.g(-1) corresponding to 3.5 Li with the first cE was about 85%, and 98% for the second cycle. The addition of carbon to Ti-Fe-Si-c played a key role in capacity retention. The best results were obtained for the composite Fe/Ti/Si (1:1:2) with 10 wt% of carbon, ball-milled at 500 rpm for 48 hours. The specificcapacities were about 900 mAh.g(-1) at c/5 and 700 mAh.g(-1) at 1c (c = 1200 mAg(-1)) with a capacity retention of about 90% for 100 cycles.
Sicceramiccoating, for prevention of c/ccomposites against oxidation, was prepared by pressure-less reactive sintering to investigate the oxidation behaviour in an oxidising environment containing water vapour at 1...
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Sicceramiccoating, for prevention of c/ccomposites against oxidation, was prepared by pressure-less reactive sintering to investigate the oxidation behaviour in an oxidising environment containing water vapour at 1773 K. The experimental results demonstrated that the oxidation behaviour of porous Sicceramics could be divided into two stages, following the parabolic model, which was attributed to the variation in the contact area involved in the oxidation reactions. During the entire oxidation process, water vapour could accelerate the oxidation of the Sicceramics, according to the weight change. By first-principle calculations, the accelerated oxidation rate of the Sicceramics was attributed to weakened Si?O and Al?O bonds in the formed glassy scale, which were caused by hydroxide radicals from the water. Atomic thermal motions at high temperature could lead to the breakage of the network structure, promoting the diffusion and solution of oxidising gases. When the as-prepared Sicceramics were applied as anti-oxidative coatings for the c/ccomposites, the Sicceramiccoating and c/c matrix could be sealed and protected faster per unit time, because water vapour was beneficial to the formation of a glassy layer. The weight loss of the c/c matrix could be attributed to unsealed microcracks inside the Siccoating in the initial stage.
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