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China was the first country to undergo large-scale lockdowns in response to the pandemic in early 2020 and a progressive return to normalization after April 2020. Spaceborne observations of atmospheric nitrogen dioxide (NO2) and oxygenated volatile organic compounds (OVOCs), including formaldehyde (HCHO), glyoxal (CHOCHO), and peroxyacetyl nitrate (PAN), reveal important changes over China in 2020, relative to 2019, in response to the pandemic-induced shutdown and the subsequent drop in pollutant emissions. In February, at the peak of the shutdown, the observed declines in OVOC levels were generally weaker (less than 20%) compared to the observed NO2 reductions (-40%). In May 2020, the observations reveal moderate decreases in NO2 (-15%) and PAN (-21%), small changes in CHOCHO (-3%) and HCHO (6%). Model simulations using the regional model MAGRITTEv1.1 with anthropogenic emissions accounting for the reductions due to the pandemic explain to a large extent the observed changes in lockdown-affected regions. The model results suggest that meteorological variability accounts for a minor but non-negligible part (~-5%) of the observed changes for NO2, whereas it is negligible for CHOCHO but plays a more substantial role for HCHO and PAN, especially in May. The interannual variability of biogenic and biomass burning emissions also contribute to the observed variations, explaining e.g. the important column increases of NO2 and OVOCs in February 2020, relative to 2019. These changes are well captured by the model simulations., SCOPUS: ar.j, info:eu-repo/semantics/published

Solvent-based absorption using aqueous monoethanolamine (MEA) is the most mature and commercially available carbon dioxide capture technique. However, high capital cost and large energy consumption...

Blends of amines with alkoxyethanols have been potentially used as alternative absorbents to conventional aqueous amines for energy-efficient CO2 capture, due to the lower specific heat capacity an...

High energy consumption for CO2 capture using aqueous amines is still a major drawback limiting its deployment on a global scale. In this work, the absorption-desorption performance of CO2 into several blends of monoethanolamine (MEA) or diethanolamine (DEA) with glycol ethers (2-methoxyethanol (2ME) and 2-ethoxyethanol (2EE)) as nonaqueous solvents has been investigated at ambient pressure. Reaction mechanisms and the relative heat duty for these nonaqueous systems were also explored and compared with those of the aqueous MEA. Results showed that the nonaqueous absorbents with 5.0 M MEA had comparable absorption capacity with aqueous 5.0 M MEA and higher desorption efficiency resulting in a larger cyclic capacity (1.45 mol kg−1). Higher partial pressure ratio of CO2 to solvent vapor under the desorption conditions was also observed for these nonaqueous systems. 13C NMR, FTIR spectra and online conductivity analysis provided evidences that CO2 can react with MEA in nonaqueous solvents forming the ionic couples (i.e. protonated MEA and carbamate) as well as carbamic acid at high CO2 loading. The mixture of MEA and 2ME or 2EE could significantly reduce the energy consumption by about 55% as compared to the benchmark aqueous 5.0 M MEA system.

Using the CAM-chem Model, we simulate the response of chemical species in the free troposphere to scenarios of primary pollutant emission reductions during the COVID-19 pandemic. Zonally averaged ozone in the free troposphere during Northern Hemisphere spring and summer is found to be 5%–15% lower than 19-yr climatological values, in good agreement with observations. About one third of this anomaly is attributed to the reduction scenario of air traffic during the pandemic, another third to the reduction scenario of surface emissions, the remainder to 2020 meteorological conditions, including the exceptional springtime Arctic stratospheric ozone depletion. For the combined emission reductions, the overall COVID-19 reduction in northern hemisphere tropospheric ozone in June is less than 5ppb below 400hPa, but reaches 8ppb at 250hPa. In the Southern Hemisphere, COVID-19 related ozone reductions by 4%–6% were masked by comparable ozone increases due to other changes in 2020.

We use the global Community Earth System Model to investigate the response of secondary pollutants (ozone O3, secondary organic aerosols SOA) in different parts of the world in response to modified emissions of primary pollutants during the COVID‐19 pandemic. We quantify the respective effects of the reductions in NOx and in volatile organic carbon (VOC) emissions, which, in most cases, affect oxidants in opposite ways. Using model simulations, we show that the level of NOx has been reduced by typically 40% in China during February 2020 and by similar amounts in many areas of Europe and North America in mid‐March to mid‐April 2020, in good agreement with space and surface observations. We show that, relative to a situation in which the emission reductions are ignored and despite the calculated increase in hydroxyl and peroxy radicals, the ozone concentration increased only in a few NOx‐saturated regions (northern China, northern Europe, and the US) during the winter months of the pandemic when the titration of this molecule by NOx was reduced. In other regions, where ozone is NOx‐controlled, the concentration of ozone decreased. SOA concentrations decrease in response to the concurrent reduction in the NOx and VOC emissions. The model also shows that atmospheric meteorological anomalies produced substantial variations in the concentrations of chemical species during the pandemic. In Europe, for example, a large fraction of the ozone increase in February 2020 was associated with meteorological anomalies, while in the North China Plain, enhanced ozone concentrations resulted primarily from reduced emissions of primary pollutants., Plain Language Summary: With the reduction in economic activities following the COVID‐19 pandemic outbreak in early 2020, most emissions of air pollutants (i.e., nitrogen oxides [NOx], carbon monoxide [CO], sulfur dioxide [SO2], volatile organic carbon [VOC], black carbon [BC], organic carbon [OC]) have decreased substantially during several months in different regions of the world. This unintended global experiment offered a glimpse into a potential future in which air quality would be improved. Here, a global atmospheric model is used to assess the changes in the chemical composition of the atmosphere during the pandemic period and in the related chemical processes that lead to the formation of ozone (O3) and secondary organic aerosols (SOA). The study illustrates the nonlinearity of the air quality response to reduced NOx and VOC emissions, which depends on the chemical environment including the background level of nitrogen oxides. Meteorological variability can lead to anomalies in the concentration of chemical species with magnitudes that are as large or even larger than the perturbations due to COVID‐induced changes in the emissions., Key Points: During the COVID‐19 lockdown, the atmospheric concentration of primary pollutants (NOx, VOCs, CO, SO2) was considerably reduced The concentration of secondary pollutants increased in NOx‐saturated areas and decreased in NOx‐limited areas The response of the chemical system depends on the relative changes in NOx and VOC emissions, and is affected by weather variability, AQ‐WATCH European project, HORIZON 2020 Research and Innovation Action, Hong Kong Research Grants Council

During the COVID‐19 outbreak that took place in early 2020, the economic activities in China were drastically reduced and accompanied by a strong reduction in the emission of primary air pollutants. On the basis of measurements made at the monitoring stations operated by the China National Environmental Monitoring Center, we quantify the reduction in surface PM2.5, NO2, CO and SO2 concentrations in northern China during the lockdown, which started on 23 January 2020. We find that, on the average, the levels of surface PM2.5 and NO2 have decreased by approximately 35 and 60 percent, respectively, between the period 1‐22 January 2020 and the period 23 January‐29 February 2020. At the same time, the mean ozone concentration has increased by a factor 1.5–2. In urban area of Wuhan, where drastic measures were adopted to limit the spread of the coronavirus, similar changes in the concentrations of PM2.5, NO2 and ozone are found., Key Points The levels of PM2.5 and NO2 in northern China have decreased by 35 and 60 percent following the coronavirus outbreak of early 2020.Simultaneously, the ozone concentration, a secondary pollutant responsible for severe health problems, has increased by a factor 1.5‐2.The same type of behavior was observed specifically in the city of Wuhan, where the virus outbreak originated.

Nonaqueous blends of alkanolamines with 2-alkoxyethanols have recently attracted much attention for an energy-efficient CO2 capture process. In this work, densities and viscosities of partially CO2-loaded mixtures of 2- (methylamino)ethanol (MAE) with 2-methoxyethanol (EGME), 2-ethoxyethanol (EGEE) and 2-butoxyethanol (EGBE) were measured at atmospheric pressure over the temperature range of (293.15 to 353.15) K with amine mass fractions of (0.10, 0.30 0.40 and 0.50) containing various CO2 loading. It was observed that both densities and viscosities of the carbonated solutions showed noticeable changes as increasing CO2 loading, amine concentration and temperature. Dimensionless parameters from the CO2-free and CO2-loaded property data were fitted by proposed correlations. The calculated values of density and viscosity from the correlation models matched well with the experimental results of MAE + CO2 + 2-alkoxyethanols, with AARDs within 0.28% and 2.20% for density and viscosity respectively. These results are useful to evaluate the mass transfer and hydrodynamic performance in a CO2 capture process using these nonaqueous absorbents.

Traditional thiazolidinediones (TZDs), such as rosiglitazone, are peroxisome proliferator-activated receptor γ (PPARγ) potent agonists that can be used to treat type 2 diabetes but carry unwanted effects, including increased risk for fracture. The present work aimed to compare the insulin-sensitizing efficacies and bone-loss side effects of CMHX008, a novel TZDs-like PPARγ partial agonist, with those of rosiglitazone. A TR-FRET PPARγ competitive binding assay was used to compare the binding affinity between CMHX008 and rosiglitazone. Mice were administered vehicle, CMHX008 or rosiglitazone for 16 weeks. Mesenchymal stem cells (MSCs) were used to examine differences in differentiation into osteoblasts after compounds treatment. TR-FRET showed lower affinity to PPARγ by CMHX008 compared with rosiglitazone. Mice treated with CMHX008 showed insulin sensitization similar to that of mice treated with rosiglitazone, which was related to the significant inhibition of PPARγ Ser273 phosphorylation and improved insulin sensitivity by facilitating the phosphorylation of insulin receptor and Akt in adipose tissues. Micro-CT and histomorphometric analyses demonstrated that the degree of trabecular bone loss after treatment with CMHX008 was weaker than that observed with rosiglitazone, as evidenced by consistent changes in BV/TV, Tb.N, Tb.Th, Tb.Sp, and the mineral apposition rate. MSCs treated with CMHX008 showed higher ALP activity and mRNA levels of bone formation markers than did cells treated with rosiglitazone in the osteoblast differentiation test. Thus, CMHX008 showed insulin-sensitizing effects similar to those of rosiglitazone with a lower risk of bone loss, suggesting that PPARγ sparing eliminates the skeletal side effects of TZDs while maintaining their insulin-sensitizing properties. Keywords: Osteoblasts, Peroxisome proliferator-activated receptor γ, Thiazolidinediones, TR-FRET, Type 2 diabetes mellitus

Nonaqueous secondary alkanolamine-based systems, replacing conventional water with 2-alkoxyethanols as cosolvents, have recently attracted much attention for an energy-efficient CO2 capture process. In this work, physical solubility of N2O and CO2 in 2-(methylamino)ethanol (MAE), 2-methoxyethanol (2-ME) and their blends was measured and correlated at temperatures ranging from (283.2 to 333.2) K. Vapor-liquid equilibrium (VLE) data for the CO2 + MAE + 2-ME system at 7.8, 19.4 and 39.1 mass% MAE were also measured in a stirred equilibrium cell at temperatures of (313.2–393.2) K and CO2 partial pressures up to 270 kPa. VLE data were represented by a modified Kent-Eisenberg model with an AARD of 12.6%. The apparent equilibrium constants considering the liquid nonideality were well correlated as a function of temperature, concentration of carbamate product and CO2 loading.

The interactions of the lignin model, the lignin oligomer with degree of polymerization n = 2, with 1-butyl-3-methylimidazolium chloride ionic liquid were investigated through DFT calculations in detail. Computational results revealed that lignin dissolution in ionic liquids should be a result of the joint interactions of lignin with anion and cation of ionic liquid, and the formation of ion pair weakens the interactions between lignin and ionic liquid components. Unlike the dominant H-bonds within the lignin–anion interactions, the lignin–cation interactions involve a combination of hydrogen bond and π-stacking. These results would provide mechanistic insights and suggestions for lignocellulosic dissolution in ionic liquids.

Geometries and properties of the complex are investigated theoretically through HF and DFT methods. Computational results reveal that the most accurate structural parameters can be predicted at the B2PLYP/SDD level of theory. AIM and NBO analyses are performed to investigate the nature of the Mo–W and the metal-carbonyl interaction in . It is confirmed that there is a Mo–W bond and a semi-bridging carbonyl group in the complex. The formation of the Mo–W bond accompanies the dominant charge transfer interactions: BD(1)Mo1–W2 → BD*(1)Mo1–W2 and BD(2)Mo1–W2 → BD*(2)Mo1–W2. The real interaction between W and the CO ligand coordinated to molybdenum explains the observed IR ν(CO) band at 1876 cm–1 at room temperature and δ(13CO) at 218.69 ppm at 210 K.

Amorphous zinc oxide (a-ZnO) based resistive random access memory (RRAM) Ag/a-ZnO/Pt devices were fabricated and their resistive switching characteristics investigated. The Ag/a-ZnO/Pt RRAMs exhibit typical bipolar resistive switching features with the resistance ratio of high to low resistance states (HRS/LRS) more than 107. Detailed current–voltage I–V characteristic analysis suggests that the conduction mechanism in the low resistance state is due to the formation of metallic filaments. Schottky emission is proven to be the dominant conduction mechanism in the high resistance state which results from the Schottky contacts between the metal electrodes and ZnO. The Ag/a-ZnO/Pt devices also show excellent retention performance. These results suggest promising application potentials for Ag/a-ZnO/Pt RRAMs.

As Moore's law is approaching its physical limit, two-dimensional (2D) materials have been expected to be favorable silicon alternatives. Here, the electronic properties and the ballistic quantum transport performances of monolayer InOBr are studied through the density functional theory coupled with nonequilibrium Green function formalism. Monolayer InOBr is a dynamic and thermodynamic stable system and has an indirect bandgap of 3.37 eV at HSE06 level. Interestingly, the ballistic transport simulations show that the monolayer InOBr can effectively suppress the short channel effect at sub-5nm nodes. For high-performance applications, the on-currents of a- and b-directed monolayer InOBr field-effect-transistors (FETs) with 5-nm channel length exceed 3200 μA μm−1 and the sub-threshold swings of about 70 mV/dec. Besides, the 5-nm a-directed FETs can also satisfy the low-power applications with the on/off ratio of more than 107. Thus, monolayer InOBr will be an attractive channel material to extend Moore's law to sub-5 nm.

Nonaqueous amine-based blends have great potential for energy-efficient CO2 absorbent. In this work, densities and viscosities were measured for liquid binary mixtures of 2-(ethylamino)ethanol (EAE) and 2-(butylamino)ethanol (BAE) with 2-butoxyethanol (EGBE) at temperatures of (293.15–353.15)K over the entire concentration range and atmospheric pressure. Intermolecular interactions between EGBE and two secondary amines with different carbon chain length were discussed. The excess molar volume (VE), viscosity deviations (∆η) and excess Gibbs free energy (∆G⁎E) were calculated from the experimental data and also correlated with the Redlich-Kister equation to estimate the binary interaction parameters. The experimental data and the calculated from the proposed correlations for the studied binary mixtures matched well each other, with AADs within 0.01% and 1.45% for density and viscosity respectively. The variation of excess properties was also discussed in terms of intermolecular interactions. Weak interactions on mixing these binary mixtures with different mass fractions were observed from the FTIR spectra analysis.

The increasing power demand for flexible electronics stimulates the development of flexible batteries with high performance, light weight, and low cost. However, the fabrication of flexible cathodes for sodium-ion batteries is still a great challenge. In this work, freestanding three-dimensional P2/P3 heterostructured Na0.7CoO2 nanosheet arrays are grown on carbon cloth via a “solvothermal sodiation” reaction followed by calcination in argon atmosphere. The P2 and P3 phases have coherent interface perpendicular to the [00l] direction in the P2/P3–Na0.7CoO2 nanosheets, which effectively suppresses the interlayer variation during charge/discharge, resulting in smaller volume change and improved structure stability with repeated Na+ intercalation/deintercalation. The self-standing P2/P3–Na0.7CoO2 nanosheet array electrode exhibits high specific capacity (126.2 mAh g−1 at 0.1 C and 85.5 mAh g−1 at 10 C) and superior cycle performance (92.4% after 300 cycles at 1 C). By coupling with hard carbon (HC) coated carbon cloth as anode, a P2/P3–Na0.7CoO2//HC flexible sodium-ion battery device is successfully constructed, delivering large reversible capacity of 120.5 mAh g−1 at 0.1 C (based on the weight of cathode material). The present fabrication of the three-dimensional flexible P2/P3–Na0.7CoO2 cathode provides new opportunity for the construction of advanced flexible sodium-ion batteries.

Covalent organic frameworks are unique for their highly open architecture and attractive for use as promising gas adsorption and storage carriers. In this work, density functional theory calculations have been performed to investigate the properties of metal-doped covalent organic frameworks and their interactions with the SO2 gas molecule. It is found that a single metal atom (including Li, Na, K, and Sc) doped at the top of phenyls within the tetra(4-dihydroxyborylphenyl) silane (TBPS) building block of covalent organic frameworks can easily lose its valence electrons and can be positively charged. The SO2 gas molecule could be stably absorbed onto the metal-doped covalent organic frameworks. The absorbed SO2 molecule interacts with Li, Na, K, and Sc metal-doped covalent organic frameworks by the dominant donor-acceptor delocalization between 1-center lone pair of an oxygen atom within SO2 and 1-center non-Lewis lone pairs of the doped metal atom.

The co-encapsulation of two different medium guests inside the cavity of the cylindrical capsular host molecule was investigated with DFT calculations in detail. This study addresses the question how the host and two medium co-guest molecules match each other to form the stable weak interaction systems. Computational analyses revealed that the co-encapsulation of two medium guests is more favorable for the formation and stability of the host-guest complex than encapsulating the single guest inside the cavity of the capsular host molecule. The proper filling of the guest molecules accommodated inside the cavity of the capsular host does not only depend on the polarity of the different parts of the capsule, but also depends on the guest’s polarity, congesting degree inside the capsule, and whether there are hydrogen bonds between the host and guest molecules.

Polyvinylidene fluoride (PVDF), a piezoelectric polymer material, is well known as one of the best smart materials to be used for tactile sensors in robots for its good performance. It has been used in many applications including sensors, actuators and surface acoustic wave (SAW) devices. This paper presents an experimental setup and experimental procedures for studying the electromechanical characterization of piezoelectric polymer films, by which the electromechanical characterization of the PVDF films under quasi-static loads and dynamic loads in a wide range of frequency can be researched. Through quasi-static tests, the stress–strain relationships of PVDF films in different directions were obtained. Furthermore, the viscoelastic and piezoelectric properties of PVDF films were analyzed based on the measurement results of dynamic tests under low frequency from 5 Hz to 200 Hz, and some suggestions of the applications of PVDF piezoelectric films in robot tactile sensor are presented.

According to the method of turbidity titration and 63 cloud point data minimum volume closure ellipsoid fitting, the solubility parameter of polyester resin DM-700 was determined to be 22.84(MPa)1/2, and the three-dimensional solubility parameter was (δd=17.15 (MPa)1/2; δp=9.97(MPa)1/2; δH=11.32(MPa)1/2). This value is close to the result calculated by the group contribution method (22.68(MPa)1/2), which further proves that the method is accurate and reliable.

Graphical abstract: - Highlights: • Carbon-coated Fe{sub 3}O{sub 4} nanoflakes have been synthesized by hydrothermal method. • The nanocomposite electrode shows a large reversible capacity up to 740 mAh g{sup −1}. • The nanocomposite electrode shows promising cycling stability and rate capability. - Abstract: The carbon-coated Fe{sub 3}O{sub 4} nanoflakes were synthesized by partial reduction of monodispersed hematite (Fe{sub 2}O{sub 3}) nanoflakes with carbon coating. The carbon-coated Fe{sub 3}O{sub 4} nanoflakes were characterized by X-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and galvanostatic charge/discharge measurements. It has been demonstrated that Fe{sub 2}O{sub 3} can be completely converted to Fe{sub 3}O{sub 4} during the reduction process and carbon can be successfully coated on the surface of Fe{sub 3}O{sub 4} nanoflakes, forming a conductive matrix. As anode material for lithium-ion batteries, the carbon-coated Fe{sub 3}O{sub 4} nanoflakes exhibit a large reversible capacity up to 740 mAh g{sup −1} with significantly improved cycling stability and rate capability compared to the bare Fe{sub 2}O{sub 3} nanoflakes. The superior electrochemical performance of the carbon-coated Fe{sub 3}O{sub 4} nanoflakes can be attributed to the synthetic effects between small particle size and highly conductive carbon matrix.

Nanostructured lipid carriers (NLC) exhibit high skin targeting efficiency and good safety. They are promising vehicles for topical drug delivery. This study aims to increase the skin distribution of podophyllotoxin (POD) by incorporating it into NLCs. Two kinds of POD-loaded NLCs (POD-NLCs)—POD-NLCformulation 1 and POD-NLCformulation 2—were prepared and characterized. Their skin targeting efficiencies were compared by conducting in vitro and in vivo experiments. Obviously smaller mean particle size was observed for POD-NLCformulation 1 (106 nm) than POD-NLCformulation 2 (219 nm), whereas relatively low POD loadings (less than 0.5%) were observed for both POD-NLCformulation 1 (0.33%) and POD-NLCformulation 2 (0.49%). Significantly higher in vitro and in vivo rat skin deposit amounts of POD (p ˂ 0.01) were detected after the topical application of POD-NLCformulation 1 compared to POD-NLCformulation 2. To visualize the skin distribution behavior of hydrophobic active pharmaceutical ingredients (APIs) when NLCs were used as carriers, POD was replaced with Nile red (NR—a hydrophobic fluorescent probe), and the distribution behavior of NR-NLCformulation 1 and NR-NLCformulation 2 in rat skin in vivo was observed using confocal laser scanning microscopy (CLSM). Higher fluorescent intensity was observed in rat skin after the topical application of NR-NLCformulation 1 than NR-NLCformulation 2, suggesting that higher skin targeting efficiency might be obtained when NLCs with smaller mean particle size were used as carriers for hydrophobic APIs. This result was in accordance with those of skin distribution evaluation experiments of POD-NLCs. Skin irritation property of POD-NLCformulation 1 was investigated and no irritation was observed in intact or damaged rabbit skin, suggesting it is safe for topical use. Our results validated the safety of NLCs when applied topically. More importantly, mean particle size might be an important parameter for formulation optimization when NLCs are used as carriers for hydrophobic APIs for topical application, considering that their loading is relatively low.

Nanodiamond (ND) supported metal oxide or metal catalysts exhibit excellent catalytic activity. ND/Cu nanocomposites and Cu nanoparticles were prepared by reducing Cu(NO{sub 3}){sub 2} in reverses micelle solution. Products were analyzed by X-ray diffraction (XRD), electron paramagnetic resonance (EPR) spectra, UV-vis optical characteristic and transmission electron microscopy (TEM). From the point of nucleation and grow of crystal, ND contributed to heterogeneous nucleation of Cu nanocrystal. The reactive mechanism was explored based on theory of free energy. The formation of resultant self-assembled structures was explained through diffusion-limited aggregation model and Marangoni effect. Both Cu and ND/Cu nanoparticles were strong catalysts on decomposition of NH{sub 4}ClO{sub 4} (AP), and ND/Cu is more effective.

Self-assembed microspheres formed from single-crystal α-MnO2 nanotubes have been successfully synthesized by a facile hydrothermal treatment of KMnO4 in the hydrochloric acid solution. The effect of the reaction time on the microstructure and morphology of the sample is investigated systemically. Meanwhile, the forming mechanism of nano-structured α-MnO2 is carefully studied by X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy. The MnO2 nanotube microspheres exhibit large reversible capacity up to 807 mA h g(-1) as well as good cycling stability and rate capability, making them promising as anode material for lithium-ion batteries.

The effect of season on phosphorylation of myofibrillar proteins and meat quality of pork longissimus muscles was investigated. Muscle samples were obtained from 40 pork carcasses (10 for each season) at 45 min and 3 and 9 h post-mortem. Myofibrillar proteins were extracted, separated by SDS-PAGE, quantified by phosphor-specific staining, and finally identified by LC-MS/MS. Muscle pH, glycogen, and ATP were measured, and pale, soft, and exudative (PSE) meat was identified by pH value at 45 min post-mortem. A total of 23 bands were detected on SDS-PAGE gels. The phosphorylation levels of bands did not differ between PSE and normal meat. However, the phosphorylation levels of 22 bands were significantly changed by season. Nine of them showed different changes from 45 min to 9 h post-mortem, which were identified to be involved in energy metabolism and sarcomere contraction. Correlation analysis indicated the regulatory progress of these proteins during rigor mortis. These observations contribute to a better understanding of the biochemical processes for the conversion of muscle to meat varying with season.

Pomegranate peel, a waste generated from fruit processing industry, which contains maximum amounts of bioactive compounds than the juice, is a potential source of active ingredient such as flavonoids that are known for their antioxidant properties. Microwave-assisted extraction (MAE) of flavonoids from pomegranate peel and its antioxidant activity were investigated. Three independent and main variables, including ethanol concentration(%), solvent/solid ratio(mL/g) and MAE time(min), which were of significance for the yields of flavonoids were studied. The optimal conditions were determined by the orthogonal design. The maximum extraction yield of 4.260% was achieved at ethanol concentration of 60%, ratio of solvent to material of 40:1 and MAE time of 3min. In vitro antioxidant assays showed that the extract exhibited a strong DPPH radical-scavenging ability with IC50 value of 0.187 mg/mL. Results indicated that MAE was a suitable approach for the extraction of flavonoids from pomegranate peel.

Well-dispersed mesoporousγ-alumina microfibers with high surface were prepared by thermal decomposition of the ammonium aluminum carbonate hydroxide (AACH) precursors. The as-synthesized alumina retained the morphology of its precursor and exhibited memory effect. The structural, morphological, porous, and adsorptive properties of the samples were investigated by XRD, FTIR, TGA-DSC, SEM, TEM, and UV-vis spectroscopy. The preparedγ-alumina microfibers exhibited excellent ability to remove organic pollutants from waste water because of their mesoporous structures. Theγ-alumina in situ converted from AACH synthesized without surfactant exhibited adsorption ability for Congo red as good as that synthesized with PEG2000 and better than PEG20000 that provided a facile method without surfactant to synthesizeγ-alumina with excellent adsorption performance.

We carry out a comparative study on resistive switching in CuO/ZnO bilayer films; both samples grown Pt and Ag electrodes show bipolar switching behaviors. The two kinds of current-voltage curves reveal the different resistive switching behaviors in Pt/CuO/ZnO/Pt and Ag/CuO/ZnO/Pt, respectively. We conjecture that the formation and rupture of conducting filaments are responsible for the switching effect. Filaments induced by migration of oxygen ions are responsible for resistive switching with the Pt electrode. In contrast, resistive switching with the Ag electrode is attributed to the migration of metal cations and the corresponding electrochemical metallization. It is also inferred that the characteristic nature of the conducting filaments influences many aspects of switching characteristics, including the switching voltages and cycling variations at room temperature.