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Interference Induced Enhancement of Magneto-Optical Effect in Pt/TbCo Hetero-Structured Films
摘要： Magnetic ?lms with a heavy metal layer show strong interfacial interaction of spin-orbit. Spin-orbit interaction is one of the key technologies for spintronics. In this paper, we measured magneto-optical Kerr spectra of Pt/TbCo hetero-structure ?lms on a thermally oxidized silicon substrate (0.3 mm); A: Pt (3 nm)/TbCo (6 nm)/Pt (3 nm), B: Si3N4 (10 nm)/TbCo (6 nm)/Pt (3 nm), and C: Pt (3 nm)/TbCo (6 nm)/Si3N4 (10 nm). Magneto-optical Kerr spectra of each sample were measured with a wavelength range of 300–700 nm, and were compared to the simulated spectra using the effective refractive index method. In the sample A, which has a symmetric structure, the simulated spectra are consistent with the measured ones. On the other hand, in the samples B and C, with an asymmetric structure, there are some differences between the simulated spectra and the measured ones in a lower photon energy region. This may be caused by interfacial effects of the spin-orbit interaction.
关键词： spin-orbit interaction,heavy metal,hetero structure,magnetooptical,TbCo
更新于2025-09-10 09:29:36
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Synthesis of Novel Organic-Inorganic Hybrid Fluorescent Microspheres and Their Applications as Fe(III), Hg(II) and Biothiols Probes
摘要： Organic-inorganic hybrid fluorescent microspheres (OI-FMs) without typical fluorophores were prepared. Fluorescence quantum yield of OI-FMs is up to 0.7 after being heated in an oven at 120°C (named as OIFMs-120). Interestingly, OI-FMs-120 shows different detection performances in different solvents. It can be used for qualitative and quantitative detection of Fe3+ with a detection limit of 37.8 nM in absolute ethanol. While in aqueous solution, it can be applied as an ONOFF-ON fluorescent probe. Fluorescence of the probe is quenched by Hg2+and later recovered by biothiols. The detection limit are as low as 34.9 nM for Hg2+, 91.0 nM for Cys, 0.12 μM for Hcy and 0.13 μM for GSH in aqueous medium, respectively.
关键词： Biothiols,Heavy metal ions,Atypical fluorophores,Fluorescence sensor
更新于2025-09-09 09:28:46
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Microalgae biochar-derived carbon dots and their application in heavy metal sensing in aqueous systems
摘要： This research seeks a coupled solution for managing the large amounts of biochar produced by microalgae biofuel production, and the necessity for novel, economic and accurate heavy metal sensing methods. Therefore, this study evaluated the transformation of microalgae biochar (MAB) into carbon dots (Cdots) and their subsequent application as heavy metal ion sensors in aqueous systems. The experimental phase included the transformation of MAB into microalgae biochar-derived carbon dots (MAB–Cdots), MAB–Cdot characterisation and the evaluation of the MAB–Cdots as transducers for the detection of four heavy metal ions (Pb2+, Cu2+, Cd2+, and Ni2+). MAB–Cdot fluorescence was stable over a wide range of pH and resistant to photo-bleaching, making them suitable as fluorescence probes. The MAB–Cdot fluorescence was quenched by all of the metal ions and displayed different quenching levels. Depending upon the ions involved, MAB–Cdots were used to detect the presence of heavy metal ions from concentrations of 0.012 μM up to 2 mM by measuring the reduction in fluorescence intensity. Neutral and slightly alkaline pHs were optimal for Cu2+ Ni2+ and Pb2+ heavy metal quenching. To quantify the concentration of the heavy metal ions, linear and logarithmic functions were used to model the MAB–Cdot fluorescence quenching. The sensing mechanism was determined to be reversible and purely collisional with some fluorophores less accessible than the others. This work demonstrated the ability to produce Cdots from microalgae biochar, examined their application as a transducer for detecting heavy metal ions in aqueous systems and paves the way for novel sensing systems using MAB-Cdots.
关键词： Heavy metal ion,Carbon dots,Renewable nanomaterials,Quenching,Biochar,Microalgae,Fluorescence sensors
更新于2025-09-09 09:28:46
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[IEEE 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Greifswald, Germany (2018.9.23-2018.9.28)] 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Advanced Vacuum Arc Plasma Source: Principles and Perspective Applications
摘要： A combined system including a MEVVA plasma source with a cylindrical electrostatic plasma-optical lens is considered for the first time. This combined system is of fundamental interest and could be attractive for a number of practical applications. The system can be used for effective repetitively pulsed, high current, moderate energy plasma sources of heavy metal ions and electrons. The hardware is interesting for high productivity technological equipment using dense pure plasma flow for the synthesis of fine coatings and thin films. We have studied the plasma-dynamic characteristics of high density plasma flow propagating through the plasma lens, the optical emission spectra and the charge state distribution, as a function of different experimental conditions. Application of the plasma lens to the transport of low energy high-current ion beams can improve the delivery of plasma to a substrate, as well as providing micro-droplet evaporation and elimination due to the presence of fast electrons within the lens region.
关键词： plasma-optical lens,vacuum arc,heavy metal ion source,plasmadynamics
更新于2025-09-09 09:28:46
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Nanohybrid and Nanoporous Materials for Aquatic Pollution Control || Nanohybrid Photocatalysts for Heavy Metal Pollutant Control
摘要： In this decade, the environmental problem, especially for the wastewater treatment issue, has become a widespread concern. In the meantime, heavy metal pollutants have also caused great attention owing to their recalcitrance persistence and the large discharge scale into the environment. Heavy metal is defined as the element with the atomic weights between 63.5 and 200.6. In our environment, some hazardous heavy metals such as chromium (Cr), mercury (Hg), arsenic (As), lead (Pb), copper (Cu), nickel (Ni), etc. exist in the surface fresh water. Heavy metals tend to accumulate in the organism via the food chain and caused serious harm to the organism. Therefore, it is urgent for the worldwide researchers to find effective treatment strategies to remove heavy metal from wastewater.
关键词： Environmental Remediation,Photocatalysis,Wastewater Treatment,Nanohybrid Photocatalysts,Heavy Metal Pollutant Control
更新于2025-09-04 15:30:14
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The structure, spectra and properties of Dy2O3 modified diamagentic lead-bismuth-germanium glasses
摘要： Dy2O3 is potential and attractive as scintillator, mid infrared laser and Faraday rotation materials in high energy physics, general radiation and magneto optical sensing systems. In this study, Dy3+ doped diamagnetic glasses with compositions of 10GeO2 – 30PbO – 50Bi2O3 – (10-x)B2O3 –xDy2O3 (x = 0, 0.5, 1, 2, 3, 5 M %) were fabricated by a melt quenching technique. The modification of Dy3+on glass forming, structure, UV–Vis, FT-IR, Raman and photoluminescence spectra and properties were investigated through XRD, Raman spectra, DSC, Vicker's hardness and Verdet constant measurements etc. Melt with Dy2O3 content beyond 5% prefer to crystallize, not to form glassy matrix. The UV visible absorption spectra showed three intense bands at 483 nm, 575 nm and 661 nm due to 4F9/2 → 6H15/2 (blue), 4F9/2 → 6H13/2 (yellow) and 4F9/2 → 6H11/2 (red) transitions, respectively. Judd-Ofelt paramaters have been calculated to verify network connectivity of Dy2O3 doped glasses. FT-IR and Raman spectrum depicted the presence of PbO4, BiO3, GeO6, BO3 frame groups and DyeO bonds from cubit Dy2O3. Glass doped with 1%Dy2O3 exhibited promising thermal stability (97 °C), microhardness (480 HV) and magneto-optical activity (0.1864 min/G.cm@532 nm) due to the high optical dispersion, high ion polarizability of Dy3+ ions
关键词： Heavy metal oxide glass,Faraday rotation,Dy2O3,Diamagnetic glass
更新于2025-09-04 15:30:14
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Hyperspectral inversion of heavy metal content in reclaimed soil from a mining wasteland based on different spectral transformation and modeling methods
摘要： Conventional methods for investigating heavy metal contamination in soil are time consuming and expensive. We explored reflectance spectroscopy as an alternative method for assessing heavy metals. Four spectral transformation methods, first-order differential (FDR), second-order differential (SDR), continuum removal (CR) and continuous wavelet transform (CWT), are used for the original spectral data. Spectral preprocessing effectively eliminated the noise and baseline drifting and also highlighted the locations of the spectral feature bands. Partial least squares regression (PLSR) and radial basis function neural network (RBF) were used to study the hyperspectral inversion of four heavy metals (Cr, As, Ni, Cd). The inversion models of four heavy metals were established in the bands with the highest correlation coefficient. The inversion effects were evaluated by the coefficient of determination (R2), root mean square error (RMSE) and residual predictive deviation (RPD) indexes. The R values of the correlation coefficient were significantly improved after smoothing and spectral transformation compared to the original waveband. The method combining continuous wavelet transform (CWT) with radial basis function neural network (RBF) had the best inversion effect on the four heavy metals. When compared to partial least squares regression (PLSR), the RMSE values were reduced by approximately 2. The CWT-RBF method can be used as a means of inversion of heavy metals in mining wasteland reclaimed land.
关键词： Continuous Wavelet Transform,Heavy metal,Spectral analysis,Radial Basis Function Neural Network,Reclamation soil
更新于2025-09-04 15:30:14
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Classification of Rice Heavy Metal Stress Levels Based on Phenological Characteristics Using Remote Sensing Time-Series Images and Data Mining Algorithms
摘要： Heavy metal pollution in crops leads to phenological changes, which can be monitored by remote sensing technology. The present study aims to develop a method for accurately evaluating heavy metal stress in rice based on remote sensing phenology. First, the enhanced spatial and temporal adaptive reflectance fusion model (ESTARFM) was applied to blend Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat to generate a time series of fusion images at 30 m resolution, and then the vegetation indices (VIs) related to greenness and moisture content of the rice canopy were calculated to create the time-series of VIs. Second, phenological metrics were extracted from the time-series data of VIs, and a feature selection scheme was designed to acquire an optimal phenological metric subset. Finally, an ensemble model with optimal phenological metrics as classification features was built using random forest (RF) and gradient boosting (GB) classifiers, and the classification of stress levels was implemented. The results demonstrated that the overall accuracy of discrimination for different stress levels is greater than 98%. This study suggests that fusion images can be utilized to detect heavy metal stress in rice, and the proposed method may be applicable to classify stress levels.
关键词： ensemble model,feature selection,time-series,MODIS and Landsat,remote sensing phenology,heavy metal stress
更新于2025-09-04 15:30:14