The dust originating from the extinct lake of the Aral Sea poses a considerable threat to the surrounding communities and ecosystems. The accurate location of these wind erosion areas is an essential ...prerequisite for controlling sand and dust activity. However, few relevant indicators reported in this current study can accurately describe and measure wind erosion intensity. A novel wind erosion intensity (WEI) of a pixel resolution unit was defined in this paper based on deformation due to the wind erosion in this pixel resolution unit. We also derived the relationship between WEI and soil InSAR temporal decorrelation (ITD). ITD is usually caused by the surface change over time, which is very suitable for describing wind erosion. However, within a pixel resolution unit, the ITD signal usually includes soil and vegetation contributions, and extant studies concerning this issue are considerably limited. Therefore, we proposed an ITD decomposition model (ITDDM) to decompose the ITD signal of a pixel resolution unit. The least-square method (LSM) based on singular value decomposition (SVD) is used to estimate the ITD of soil (SITD) within a pixel resolution unit. We verified the results qualitatively by the landscape photos, which can reflect the actual conditions of the soil. At last, the WEI of the Aral Sea from 23 June 2020, to 5 July 2020 was mapped. The results confirmed that (1) based on the ITDDM model, the SITD can be accurately estimated by the LSM; (2) the Aral Sea is experiencing severe wind erosion; and (3) the middle, northeast, and southeast bare areas of the South Aral Sea are where salt dust storms may occur.
The effects of hydrogen (H2) addition on the freely-propagating acetylene-oxygen (C2H2–O2) flames in a doubly-infinite domain are investigated, considering separate and coupled chemical and transport ...phenomena. Results show that increasing proportions of H2 enhance the laminar flame speeds of C2H2–O2 mixtures. Moreover, H2 promotes the C2H2–O2 flame to contain both light (H, H2) and heavy (C2H2) species. Compared with the Soret diffusion and radiation effect, the unity Lewis number assumption can induce substantial inaccuracies. Sensitivity analysis indicates that the key elementary reaction H + O2O + OH exerts stronger influences on the laminar flame speed. Additionally, due to the effective enthalpy of C2H2 being greater than H2, adding H2 decreases both adiabatic flame temperature and enthalpy of C2H2–O2 flames. Notably, reactions C2H2 + OH + HCCO and C2H + H2H + C2H2 in the C2H2 sub-mechanism are identified as important exothermic- and endothermic-reactions respectively. Furthermore, it is demonstrated that dilution effects from CO2 have a larger impact compared to those from H2O and Ar. Finally, the effects of initial pressure and temperature on the laminar flame speeds are also discussed. The results of the present work provide guidance for the effective use of binary fuel and risk control as well as fire suppression.
•The effects of hydrogen additions on acetylene-oxygen flames are numerically studied.•Different flame diffusion models are characterized.•Chemical and thermal structures are revealed separately.•The effects of different dilution gases and initial conditions are considered.
Phase evolution of CoCrFeNiMo0.3 high entropy alloy (HEA) under different annealing temperatures was investigated by means of ultra-small-angle neutron scattering (USANS), X-ray diffraction (XRD), ...and scanning electron microscopy (SEM). For the as-cast CoCrFeNiMo0.3 alloy, a dendritic structure consisting of mainly face-centered cubic (FCC) solid solution matrix and small amount of micro-sized σ precipitates was observed. Upon isothermal annealing, secondary phase precipitation occurred and precipitates with two size ranges (i.e., microscale and nanoscale) generated in the alloy. These precipitates were identified as newly formed μ and σ phases. Specifically, the size distribution of the nanoscale μ precipitates was determined by USANS measurements. It was found that the size of the nanoscale precipitates increased with the annealing temperature, jumping from 72 nm at 750 °C to 258 nm at 800 °C, which contributed to the sharp drop in hardness of the alloy. The present alloy maintained high hardness within a wide temperature range of 550–750 °C, which makes it a promising material for structural applications at intermediate temperatures.
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The separation of electron–hole pairs has a significant influence on the photocatalytic process on semiconductors. In this work, BiOCl nanosheets with oxygen vacancies (BiOCl-OVs) have been prepared ...by reconstructing small hydrophobic BiOCl nanosheets. The transient photoresponse and the electron spin resonance (ESR) results prove that the separation of the charge carriers can be promoted by the oxygen vacancies via trapping the photoexcited electrons. Because of the improved charge separation and wide absorption of the solar spectrum, more photogenerated charge carriers are produced, as confirmed by the photocurrent response and the ESR measurements of the reactive oxygen species •O2 – and •OH. Consequently, BiOCl-OVs present enhanced photocatalytic properties toward NO removal. Our study illustrates the importance of the construction of vacancies for improving photocatalytic performance.
Phase transformation is an effective means to increase the ductility of a material. However, even for a commonly observed face-centered-cubic to hexagonal-close-packed (fcc-to-hcp) phase ...transformation, the underlying mechanisms are far from being settled. In fact, different transformation pathways have been proposed, especially with regard to nucleation of the hcp phase at the nanoscale. In CrCoNi, a so-called medium-entropy alloy, an fcc-to-hcp phase transformation has long been anticipated. Here, we report an in situ loading study with neutron diffraction, which revealed a bulk fcc-to-hcp phase transformation in CrCoNi at 15 K under tensile loading. By correlating deformation characteristics of the fcc phase with the development of the hcp phase, it is shown that the nucleation of the hcp phase was triggered by intrinsic stacking faults. The confirmation of a bulk phase transformation adds to the myriads of deformation mechanisms available in CrCoNi, which together underpin the unusually large ductility at low temperatures.
Non-small cell lung cancer (NSCLC) causes considerable mortality in the world. Owing to molecular biological progress, treatments in adenocarcinoma have evolved revolutionarily while those in ...squamous lung cancer remain unsatisfied. Recent studies revealed high-frequency alteration of Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-like factor 2 (Keap1/Nrf2) pathway within squamous lung cancer, attracting researchers to focus on this particular pathway. In NSCLC patients, deregulated Nrf2 signal is recognized as a common feature at both DNA and protein level. Emerging associations between Nrf2 and other pathways have been elucidated. MicroRNA was also implicated in the regulation of Nrf2. Agents activating or antagonizing Nrf2 showed an effect in preclinical researches, reflecting different effects of Nrf2 during tumor initiation and progression. Prognostic evaluation demonstrated a negative impact of Nrf2 signal on NSCLC patients' survival. Considering the importance of Nrf2 signal in NSCLC, further studies are required in the future.
Supramolecular organogel coatings that can disinfect the deposited microbial pathogens are emerging as an effective vehicle to prevent pathogen transmission. However, the development of anti-pathogen ...supramolecular adhesives with mechanical robustness and controlled oil inclusion is technically challenging. Here, we report supramolecular adhesives with mechanical integrity and robust interfacial adhesion over a wide range of biogenic antimicrobial oil. Bifunctional monomers are synthesized and assembled into linear polymers with semicrystalline stackings through hierarchical hydrogen bonds, where incorporated bioactive oil could regulate the semicrystalline stackings into nanosized crystalline domains through intermolecular hydrogen bonds. The abundant bonding motifs provided by the supramolecular cross-linked networks could accommodate oil molecules with high inclusion capability and provide more interfacial binding sites with high adhesion strength, and the nanosized crystalline domains could stabilize the organogel network and compensate for the interactions with oil molecules to enhance structural and mechanical stability. In addition, rapid healing, robust adhesion, and antimicrobial and antiviral properties of the resultant organogel coatings are demonstrated. This study paves the way for the development of high-performance antimicrobial supramolecular adhesives with controlled oil inclusion, showing potential applications in soft robotics, tissue engineering, and biomedical devices.
The efficient detection of illicit drugs such as cocaine continues to be important for the fight against drug trafficking. Herein, we report a one-step method for rapid and specific cocaine ...detection. The method is based on our finding that small-molecule Thioflavin T (ThT) can act as a fluorescence indicator, which can be bonded with the anti-cocaine aptamer (MNS-4.1) to generate an enhanced fluorescence signal. More interestingly, upon cocaine binding, the intercalated ThT can be replaced, causing a drastic fluorescence reduction. We further optimized the sequence of MNS-4.1 and a new anti-cocaine aptamer (coc.ap2-GC) was obtained. This aptamer showed a higher affinity to both ligands, which increased the ThT binding fluorescence intensity and showed the highest quenching efficiency. Based on the fluorescence change induced by competitive binding, cocaine detection could be accomplished by a "mix-and-detect" strategy within seconds. Such a label-free method exhibits high sensitivity to cocaine with a low detection limit of 250 nM. Moreover, the practical sample analysis (2.5% human urine and saliva) also exhibits good precision and high sensitivity.
The efficient detection of illicit drugs such as cocaine continues to be important for the fight against drug trafficking.
•Noble gases dissolved in shallow aquifers as geochemical tool to unveil subsurface geothermal state.•Subsurface boiling temperature estimation in the Wudalianchi volcanic field.•Geochemical ...constraints for identifying potential geothermal anomalies above where only no surface geothermal expression.
The study on whether there is a magma chamber under Wudalianchi is a hot topic recently, as it holds great significances for the theory of plate tectonics, early warning of volcano eruption and geothermal exploration. There is no near surface geothermal abnormality reported in Weishan, the widely used and well-studied tool, geochemistry of geothermal fluids and geothermal gases, cannot be applied to this area. To reveal the thermal conditions under Weishan, we conducted a study about the abundances and isotope ratios of dissolved noble gases in shallow groundwater and springs of Weishan. The concentrations of noble gases display obvious Ne excesses and mass-dependent differentiation, the isotopic ratios indicate that Ne, Ar, Kr, and Xe are atmosphere-derived noble gases (ANGs). We apply the closed-system equilibrium (CE) model to process the data of noble gases, and indicate that the excess ANGs are not caused by the increased hydrostatic pressure or diffusive influx. Neither meltwater mixing nor oxygen consumption alone could generate sufficient noble gas excesses in our samples. Based on the reconstructed abundances of noble gases in vapor phases produced at different boiling temperatures, which are calculated according to the boiling model established on Henry's law, we conclude that the abundances of noble gases in these samples were influenced by vapor–liquid partition caused by underground boiling. The diagrams of 84Kr/36Ar, 20Ne/36Ar and 130Xe/36Ar confine the temperature range where the boiling events occur in ∼100 °C–300 °C. We argued that the excess ANGs in shallow groundwater are geochemical evidence of boiling events, which seems to be continuously happening during the time range confined by the young groundwater in basalt aquifer and old groundwater in sandstone aquifer. Our findings also corroborate the recent results of geophysical survey works that a potential magma chamber exists under Weishan area. We suggest that noble gases dissolved in shallow aquifers represent a reliable geochemical tool to unveil subsurface geothermal state, where no near-surface thermal anomaly occurs.
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