Improved Corrosion Behavior of Biodegradable Mg-4Zn-1Mn Alloy Modified by Sr/F co-doped CaP Micro-arc Oxidation Coatings

The Sr/F co-doped CaP(Sr/F-CaP)coatings were prepared by micro-arc oxidation(MAO)under different voltages to modify the microstructure and corrosion behavior of Mg-4Zn-1Mn alloy.The surface and interface characteristics investigated using scanning electron microscopy(SEM)and energy dispersive X-ray spectrometer(EDS)showed that the MAO coatings displayed uneven crater-like holes and tiny cracks under lower voltage,while they exhibited relatively homogeneous crater-like holes without cracks under higher voltage.The thickness of MAO coatings increased with increasing voltage.The corrosion behavior of Mg-4Zn-1Mn alloy was improved by the MAO coatings.The MAO coatings prepared under 450 V and 500 V voltages possessed the best corrosion resistance with regard to the electrochemical corrosion tests and immersion corrosion tests,respectively.The MAO coatings fabricated under 450-500 V could provide a better corrosion protection effect for the substrate.

混合学习空间的特征、形态与构建策略

《2022年EDUCAUSE地平线报告(教与学版)》指出混合学习空间是未来教育中教与学采纳的六项关键技术之一,也是未来教与学场景转型的趋势。目前,数字化正在不断赋能高等教育变革,教育数字化转型也是推动我国教育高质量发展的重要途径。文章基于教育数字化转型背景,结合混合学习空间相关的应用案例,对混合学习空间的内涵与特征进行了深入探究,提出混合学习空间的构建策略:即构建以数据驱动为核心的混合学习空间、基于学习分析技术的混合学习空间、基于虚拟仿真技术的沉浸式教学场景等。

Low-dose IL-2 therapy compensates for metabolic shifts and reverses anxiety-like behavior in PD-1 deficiency-induced autoimmunity

In patients with autoimmune diseases,psychological comorbidities,including anxiety,depression and cognitive dysfunction,often occur.1 Anxiety and depression in these patients not only cause a significant disease burden1 but also might prevent effective treatment through the neuro-immune axis.2 The latter issue results in disease aggravation and,in turn,adversely impacts psychological and social wellbeing.Therefore,effective treatment is required to break the vicious feedforward cycle of physical–psychological interactions.

Global model of plasma-activated water over long time scale:Pulsed discharge and afterglow

Plasma-activated water(PAW)has been utilised in various application fields,and a deep understanding on the plasma chemistry is the foundation of application-orientated optimisation.In this paper,a global model is built to study the chemical properties of PAW produced by a dielectric barrier discharge that is powered by nanosecond voltage pulses.The applied voltage is firstly repeated with 10 kHz frequency for 100 s,and then shut down for 200 s afterglow,providing a long-term evolution regarding the production and consumption of some typical reactive oxygen/nitrogen species(RONS)in PAW.The calculated results agree principally with experimental measurements from literature.During the pulsed discharge,the water gradually acidises,and the long-lived species accumulate;while in the afterglow,most of the aqueous RONS decay rapidly,except for O_(3aq),NO_(3aq)^(−),H_(2)O_(2aq)and N_(2)O_(aq),which might be the main sources to sustain long-term effects.Furthermore,the effects of applied voltage and gap distance on RONS are investigated.Correlation analyses from Pearson correlation coefficient indicate that gaseous RONS are more sensitive to the gap distance,while the aqueous ones are more sensitive to the voltage amplitude,suggesting the possibility to independently regulating the gaseous and aqueous chemistry.

Hydrous cerium oxides coated glass fiber for efficient and long-lasting arsenic removal from drinking water

A novel arsenic adsorbent with hydrous cerium oxides coated on glass fiber cloth(HCO/GFC)was synthesized.The HCO/GFC adsorbents were rolled into a cartridge for arsenic removal test.Due to the large pores between the glass fibers,the arsenic polluted water can flow through easily.The arsenic removal performance was evaluated by testing the equilibrium adsorption isotherm,adsorption kinetics,and packed-bed operation.The pH effects on arsenic removal were conducted.The test results show that HCO/GFC filter has high As(Ⅴ)and As(Ⅲ)removal capacity even at low equilibrium concentration.The more toxic As(Ⅲ)in water can be easily removed within a wide range of solution p H without pre-treatment.Arsenic contaminated ground-water from Yangzong Lake(China)was used in the column test.At typical breakthrough conditions(the empty bed contact time,EBCT=2 min),arsenic researched breakthrough at over 24,000 bed volumes(World Health Organization(WHO)suggested that the maximum contaminant level(MCL)for arsenic in drinking water is 10 mg/L).The Ce content in the treated water was lower than 5 ppb during the column test,which showed that cerium did not leach from the HCO/GFC material into the treated water.The relationship between dosage of adsorbents and the adsorption kinetic model was also clarified,which suggested that the pseudo second order model could fit the kinetic experimental data better when the adsorbent loading was relatively low,and the pseudo first order model could fit the kinetic experimental data better when the adsorbent loading amount was relatively high.

Ionic Potential:A General Material Criterion for the Selection of Highly Efficient Arsenic Adsorbents

Arsenic is a highly toxic element and its contamination in water bodies is a worldwide problem. Arsenic adsorption with metal oxides/hydroxides-based adsorbents is an effective approach to remove arsenic species from water for the health of both human beings and the environment. However, no material criterion had been proposed for the selection of potential candidates. Equally puzzling is the fact that no clear explanation was available on the poor arsenic adsorption performance of some commonly used adsorbents, such as active carbon or silica. Furthermore, in-depth examination was also not available for the dramatically different competing adsorption effects of various anions on the arsenic adsorption. Through the arsenic adsorption mechanism study on these highly efficient arsenic adsorbents, we found that ionic potential could be used as a general material criterion for the selection of highly efficient arsenic adsorbents and such a criterion could help us to understand the above questions on arsenic adsorbents. This material criterion could be further applied to the selection of highly efficient adsorbents based on ligand exchange between their surface hydroxyl groups and adsorbates in general, which may be used for the prediction of novel adsorbents for the removal of various contaminations in water.

Real Time,in situ Observation of the Photocatalytic Destruction of Saccharomyces cerevisiae Cells by Palladium-modified Nitrogen-doped Titanium Oxide Thin Film

Palladium-modified nitrogen-doped titanium oxide(TiON/PdO) thin film was synthesized by the ion-beamassisted deposition technique,which enabled a heavy nitrogen doping and the subsequent light absorption extension to700 nm for a better usage of the solar spectrum.Based on TiON/PdO thin film and a phase contrast microscope,a micro-reaction chamber was developed,which allowed the simultaneous optical excitation of the photocatalytic thin film and the phase contrast image observation of cells in it.The real time,in situ observation of the photocatalytic destruction of Saccharomyces cerevisiae(S.cerevisiae),an essential eukaryotic unicellular model of living cells,was conducted with this new observation technique,which demonstrated clearly that the photocatalytic destruction effect was much stronger than the photodamage effect caused by the visible light irradiation alone in the disinfection process.