Improving hydrogen storage thermodynamics and kinetics of Ce-Mg-Ni-based alloy by mechanical milling with TiF_(3)

Mg-based hydrides are too stable and the kinetics of hydrogen absorption and desorption is not satisfactory.An efficient way to improve these shortcomings is to employ reactive ball milling to synthesize the nanocomposite materials of Mg and additives.In this experiment,TiF_(3)was selected as an additive,and the mechanical milling method was employed to prepare the experimental alloys.The alloys used in this experiment were the as-cast Ce_(5)Mg_(85)Ni_(10),as-milled Ce_(5)Mg_(85)Ni_(10)and Ce_(5)Mg_(85)Ni_(10)+3 wt.%TiF3.The phase transformation,structural evolution,isothermal and non-isothermal hydrogenation and dehydrogenation performances of the alloys were inspected by XRD,SEM,TEM,Sievert apparatus,DSC and TGA.It revealed that nanocrystalline appeared in the as-milled samples.Compared with the as-cast alloy,ball milling made the particle dimension and grain size decrease dramatically and the defect density increase significantly.The addition of TiF_(3)made the surface of ball milling alloy particles markedly coarser and more irregular.Ball milling and adding TiF_(3)distinctly improved the activation and kinetics of the alloys.Moreover,ball milling along with TiF_(3)can decrease the onset dehydrogenation temperature of Mg-based hydrides and slightly ameliorate their thermodynamics.

Identification of niclosamide as a novel antiviral agent against porcine epidemic diarrhea virus infection by targeting viral internalization

Porcine epidemic diarrhea virus(PEDV),an enteropathogenic coronavirus,has catastrophic impacts on the global pig industry.However,there remain no effective drugs against PEDV infection.In this study,we utilized a recombinant PEDV expressing renilla luciferase(PEDV-Rluc)to screen potential anti-PEDV agents from an FDAapproved drug library in Vero cells.Four compounds were identified that significantly decreased luciferase activity of PEDV-Rluc.Among them,niclosamide was further characterized because it exhibited the most potent antiviral activity with the highest selectivity index.It can efficiently inhibit viral RNA synthesis,protein expression and viral progeny production of classical and variant PEDV strains in a dose-dependent manner.Time of addition assay showed that niclosamide exhibited potent anti-PEDV activity when added simultaneously with or after virus infection.Furthermore,niclosamide significantly inhibited the entry stage of PEDV infection by affecting viral internalization rather than viral attachment to cells.In addition,a combination with other small molecule inhibitors of endosomal acidification enhanced the anti-PEDV effect of niclosamide in vitro.Taken together,these findings suggested that niclosamide is a novel antiviral agent that might provide a basis for the development of novel drug therapies against PEDV and other related pathogenic coronavirus infections.

Highly stableβ‑ketoenamine‑based covalent organic frameworks(COFs):synthesis and optoelectrical applications

Covalent organic frameworks(COFs)are one class of porous materials with permanent porosity and regular channels,and have a covalent bond structure.Due to their interesting characteristics,COFs have exhibited diverse potential applications in many felds.However,some applications require the frameworks to possess high structural stability,excellent crystallinity,and suitable pore size.COFs based onβ-ketoenamine and imines are prepared through the irreversible enol-to-keto tautomerization.These materials have high crystallinity and exhibit high stability in boiling water,with strong resistance to acids and bases,resulting in various possible applications.In this review,we frst summarize the preparation methods for COFs based onβ-ketoenamine,in the form of powders,flms and foams.Then,the efects of diferent synthetic methods on the crystallinity and pore structure of COFs based onβ-ketoenamine are analyzed and compared.The relationship between structures and diferent applications including fuorescence sensors,energy storage,photocatalysis,electrocatalysis,batteries and proton conduction are carefully summarized.Finally,the potential applications,large-scale industrial preparation and challenges in the future are presented.

Structures and electrochemical performances of as-spun RE-Mg-Ni-Co-Al alloys applied to Ni-MH battery

The La-Mg-Ni-Co-Al-based AB2-type La0.8-xCe0.2YxMgNi3.4Co0.4Al0.1 （x = 0, 0.05, 0.1, 0.15, 0.2） alloys were prepared by melt spinning. The effects of Y content on the structures and electrochemical hydrogen storage characters were thoroughly studied. The structures of the experimental samples were analyzed by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. It is shown that there are a main phase LaMgNi4 and a second phase LaNi5 in the experimental samples. The variation of Y content incurs obvious changes of the phase abundance without changing phase composition. Namely, with the increase of Y content, the LaMgNi4 phase increases and LaNi5 phase decreases. Furthermore, melt spinning and the replacement of Y for La also lead to the grains refinement of the alloy. The electrochemical tests display that the as-spun alloys possess excellent activation properties, and obtain the maximums of discharge capacity at the first cycling. The replacement of Y for La can visibly facilitate the discharge potential characteristics, however,diminish the discharge capacity. The electrochemical kinetics, involving in the high rate discharge ability （HRD）, hydrogen diffusion coefficient （D）, limiting current density （IL） and charge transfer rate, increases firstly and then decreases with the increase of Y content. The cyclic stability is greatly improved by melt spinning and the replacement of Y for La, which is derived from the improvement of the anti-corrosion, oxidation-resistance and the anti-pulverization abilities.

Gaseous hydrogen storage properties of Mg-Y-Ni-Cu alloys prepared by melt spinning

For purpose of promoting the hydrogen absorption and desorption thermodynamics and kinetics properties of Mg-Ni-based alloys, partially substituting Y and Cu for Mg and Ni respectively and melt spinning technique were applied for getting Mg25-xYxNi9 Cu(χ = 0-7) alloys. Their microstructures and phases were characterized with the help of X-ray diffraction and transmission electron microscopy. Their hydrogen absorbing and desorbing properties were tested by a Sievert apparatus, DSC, and TGA, which were connected with a H2 detector. In order to estimate the dehydrogenation activation energy of alloy hydride, both Arrhenius and Kissinger methods were applied for calculation. It is found that their hydriding kinetics notably declines, however, their hydrogen desorption kinetics conspicuously improves, with spinning rate and Y content increasing. Their hydrogen desorption activation energy markedly decreases under the same constraint, and it is found that melt spinning and Y substituting Mg improve the real driving force for dehydrogenation. As for the tendency of hydrogen absorption capacity,it presents an elevation firstly and soon after a decline with the rising of spinning rate, however, it always lowers with Y content growing. With Y content and spinning rate increasing, their thermodynamic parameters(△H and △S absolute values) visibly decrease, and the starting hydrogen desorption temperatures of alloy hydrides obviously lower.

Use of natural trophic resources by Eastern oysters and Pacific oysters of different ploidy

Ploidy manipulation,such as triploidy,in farmed oysters has been used as a tool to enhance oyster quality throughout all seasons because triploid oysters allocate less energy to gametogenesis,and therefore are deemed better performers than fertile diploids.Nevertheless,scientific reports describing no differences between ploidies and,in certain conditions,disadvantages of triploids are not uncommon.As the use of triploid oyster seed increases culture cost for growers,consistency in performance of triploids is considered to be an important goal.Thus,research to assess how ploidy affects physiological processes underlying oyster performance is fundamental for the aquaculture industry.This work was undertaken to assess if ploidy-based differences in performance in the two most commonly cultivated commercial species of oyster in the United States,Crassostrea virginica and Crassostrea gigas,are associated with filtration,feeding,and metabolism.To test this hypothesis,biodeposition measurements were made with oysters exposed to ambient water conditions at locations and seasons providing a variety of environmental conditions.Oysters did not show differences in filtration and feeding associated with ploidy,but physiological feeding variables fluctuated with environmental characteristics associated with spatial and seasonal differences.A preliminarily test of the hypothesis that differences in energy metabolism may account for differences in performance among ploidy levels indicates that basal metabolic rates of diploid,triploid,and tetraploid Eastern oysters are not different.