Source Of Ions Research Articles

Lebt of the Heavy Ion Linear Accelerator

At the NRC “Kurchatov Institute” (Kurchatov Complex for Theoretical and Experimental Physics), the pulsed linear resonant heavy ion accelerator is being developed. The Low Energy Beam Transport (LEBT) channel transports the beam from a laser-plasma source of multi-charged ions with an A/Z ratio from 4 to 8 (up to Bi27+) to the RFQ. This paper shares the results of the beam dynamics simulation of the LEBT, which ensures the separation of the working fraction of the ion beam and its matching with the RFQ.

Control System for a Heavy Ion Laser Source at Synchrotron Complex ICCR

The article describes the control system for a laser source of heavy ions. The control system has a hierarchical multilevel architecture, determined by the hierarchical structure of the laser ion source, and is a part of the control systems of the linear heavy ion injector and the entire synchrotron complex. The article describes the basic requirements for the control system and the general principles of its construction, and the circuitry and software solutions selected in accordance with these requirements and principles, such as: organization of data exchange between individual nodes in the automated control system; determination of algorithms for working with individual devices and subsystems of the ion source, and with the ion source as a unified system; selection of types and structural schemes of controllers of individual subsystems. The hierarchical structure of the automated control system and control subsystems for all the main devices of the laser source are also described.

Beam Dynamics in the Heavy Ion Injector LU2 for the Synchrotron Research Complex (SRC)

The project of the complex for studying ionizing radiation exposure from outer space based on the synchrotron accelerator of protons and various types of ions up to 209Bi is being developed at the Russian Federal Nuclear Center - All-Russian Research Institute ofExperimental Physics (FSUE RFNC - VNIIEF). The accelerator includes two injection complexes (one of which is the source of protons and light ions, the second - heavy ions), the booster accelerator and the main synchrotron. The pulsed type heavy ions linac is being developed at the NRC “Kurchatov Institute” - KCTEF (Kurchatov Complex for Theoretical and Experimental Physics). The ions with mass-to-charge ratio 4÷8 with current of 10 mA will be accelerated up to 4 MeV/u. The linac is proposed, including the RFQ and two DTL sections operating at multiple frequencies. Each DTL section is modular and consists of individually phased H-type resonators (IH-DTLs). Quadrupole lenses located between the resonators for the beam focusing. This DTL structure ensures the accelerator compactness and allows section-by-section configuration and sequential commissioning. 6D beam matching between all sections of the linac is carried out. The results ofbeam dynamics simulation in linear accelerator are presented.

Sources, Performance and Mechanisms of Metal Ions in the Flotation Process of Copper, Lead, and Zinc Ores: A Review

In mineral processing operations, besides target minerals, slurries often contain various metal ions, including common ones with different valence states such as Pb2+, Cu2+, Fe2+, and Fe3+. These metal ions originate from multiple sources during the flotation process, including the dissolution of co-occurring metal minerals during crushing and grinding, the addition of flotation reagents, and the flotation water. Investigators have long recognized that metal ions significantly affect mineral flotation behavior. Due to physical and chemical interactions, some ions in the slurry will interact with target mineral. If these ions form hydrophobic substances on the mineral surface or increase the active sites between the mineral and collectors or sulfide agent, they will have a positive impact on the flotation process. Conversely, if they produce hydrophilic substances or deplete added collectors and sulfides, they negatively impact mineral enrichment. Meanwhile, metal ions can regulate the electrostatic repulsion between reagents and mineral surfaces in the slurry system, which has a certain impact on the flotation results. This study provides a comprehensive overview of the sources of metal ions in flotation, explores their adsorption characteristics on mineral surfaces, and examines their impact on the flotation process. It provides a theoretical basis for improving mineral flotation processes in the presence of metal ions.

A SIMPLE SOURCE OF METAL AND GAS IONS FOR ION BEAM TECHNOLOGICAL INSTALLATIONS

At the stand of the Institute of Applied Physics of the National Academy of Sciences of Ukraine, a small-sized spattering source of metal and gas ions was developed, manufactured and tested. Ionization of sputtered atoms occurs by fast oscillating electrons in a longitudinal magnetic field. A beam containing ions of plasma-forming gas and metal is output through an emission hole in the anticathode. The source has high ion current stability, is easy to maintain, and can generate ions from any conductive solid. Modeling and manufacturing of an ion-optical system for this source, which is part of the injector of the implanter of the Institute of Applied Physics of the National Academy of Sciences of Ukraine, was carried out.

Carbon-based Nanocomposite Materials for Electrochemical Monitoring of Cadmium Ions

In the present era of science and technology, cadmium poisoning in humans is reported from several parts of the world and now it is a global health problem. Accumulation of cadmium in human organs and tissues, such as the liver, kidney, etc., leads to carcinogenic effects and toxicity to the organ system. Therefore, several efforts are being made to develop a monitoring system for cadmium metal ions in the environment. This review aimed to summarise the different carbon-composite materials-based electrochemical sensors reported to date for cadmium ions detection. The first section of this review provides a brief discussion on the source and harmful effects of cadmium ions, and the rest part includes different carbon (graphite, graphene, graphene oxide, carbon nanotubes, etc.)-based composite nanomaterials reported to date for the electrochemical detection of cadmium ions in different analytes. Carbon-based nanocomposite materials have been found to be very suitable for the detection of Cd(II) ions due to their boosted electron transportation and high surface, leading towards high sensitivity and high selectivity.

Effect of succinonitrile on the structural, ion conductivity, and dielectric properties of PVDF‐HFP based solid polymer electrolytes

AbstractA detailed account of the poly(vinylidene difluoride‐co‐hexafluoropropylene) (PVDF‐HFP)/succinonitrile (SN)/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) based solid polymer electrolytes (SPEs) of various compositions is reported. SN is incorporated as plasticizer, while LiTFSI is employed as the source of lithium ions. Fourier transfer infrared (FTIR) spectroscopy reveals the formation of polar and electroactive γ crystal phase by PVDF in pristine PVDF‐HFP and the prepared SPE films. FTIR further confirms the interaction between the host polymer and the salt and between the salt and the plasticizer. The interaction between the salt and plasticizer suggests that SN not only offers the plasticization effect but also facilitates salt dissociation. The ion conductivity increases with increasing salt content up to 20 wt% but beyond that concentration a decline in ion conductivity is observed, which could be attributed to the ion pair association or cluster formation due to the excess salt concentration that reduces the availability of free ions and ultimately leads to the reduction in ion conductivity. After including SN in the SPE formulation, electrochemical impedance spectroscopy reveals a substantial increase in room temperature ion conductivity of the SPE from ~1.08 × 10−5 S cm−1 for pristine SPE with 20 wt% salt to ~2.7 × 10−4 S cm−1 for plasticized SPE with 40 wt% SN and 20 wt% salt. This is attributed to the plasticizing effect of SN that enhances ion mobility through the matrix and to the increased charge carrier concentration (SN facilities salt dissociation). The fabricated SPEs exhibit a significant enhancement in ion conductivity with increasing temperature and the maximum ion conductivity of 1.1 × 10−3 S cm−1 is attained at 393 K by plasticized SPE with 40 wt% SN content. The ion conductivity of all the prepared SPEs follows the temperature dependent Arrhenius behavior, suggesting the thermally activated ion hopping mechanism of ionic conduction. Further, the plasticized SPEs display near unity ion transference number indicating the predominance of the ionic mode of conduction. The dielectric and electric modulus analysis reveal a faster relaxation phenomenon and hence higher ion conductivity of the prepared SPEs with increasing salt and plasticizer content.

A 2‐Billion‐Year History of Water‐Alteration in Terra Sirenum, Mars: Volcanism's Influence on Aluminum Clay Formation and Chemically Distinct Waters Forming Sulfates and Chlorides Into the Amazonian

AbstractTerra Sirenum, a region of Noachian highlands southwest of the Tharsis volcanic complex, is unique in the number, proximity, and diversity of orbital detections of secondary minerals, as the sole region found to date hosting large‐scale deposits of all of Mars' major salts (chlorides, sulfates, carbonates) as well as diverse hydrated silicates. We combine mineralogical information, high‐resolution imagery, and elevation models to investigate the geologic context of these secondary minerals to understand the sources of water and ions for each type of deposit and their spatial/temporal relationships. Carbonates, where present, are part of Noachian basement rocks exposed through cratering and do not appear associated with evaporative sequences. Numerous small detections of the acid sulfate minerals alunite and jarosite mirror the dominant clay cation in the localities they are found—Al phyllosilicates and Fe phyllosilicates, respectively—suggesting in situ formation. We interpret a previously discovered kaolinite‐rich unit overlying Fe/Mg clays across northeast Terra Sirenum as remnants of a widespread ash unit rather than a pedogenic weathering sequence. Sulfate and chloride detections are decoupled, with sulfates in topographic lows likely precipitated from volcanism‐associated groundwaters, while chloride detections are consistent with surface water runoff, in some instances clearly post‐dating volcanic units capping sulfate detections. Volcanic resurfacing of craters in the region is progressively younger from west to east, and crater statistics‐based ages indicate localized sulfate‐ and chloride‐forming processes continue to occur from ∼3.5 to ∼1.4 Ga. We hypothesize that their decoupling points to disconnected, episodic surface and groundwater reservoirs, perhaps separated by a permafrost layer.

Ensuring the normalization of the aero-ionic regime in production areas by means of ultrasonic air ionization

The results of studies on the normalization of the aeroionic regime in rooms under ultrasonic ionization of humidified air are presented. The increase in the concentration of negative aeroions under these conditions by the combined effect of the balloelectric effect and ultrasonic cavitation is substantiated. It has been established that when distilled water is used as a source of air ions under the action of a 10 W ultrasonic generator at a distance of 0.5 m, the concentration of negative air ions increases almost sixfold. At the same time, due to the joint effect of ultrasonic cavitation in the surface layer of water and the balloelectric effect, no generation of ozone and nitrogen oxides is caused. It is proved that with a decrease in the degree of water mineralization, the concentrations of negative and positive aeroions increase due to changes in the physicochemical properties of water and the resulting mechanochemical phenomena. The mechanism of formation of air ions in the air of industrial premises under the combined action of the balloelectric effect and ultrasound is proposed. It is substantiated that the quality of the air ionic composition of industrial premises air improves at a temperature of demineralized water of 20-25 °C and a directed air flow of 6 m/s towards the working area with the combined effect of ultrasound and balloelectric effect, which contributes to the improvement of sanitary and hygienic working conditions. The structure of an automated system for controlling the aeroionic regime of the working area of industrial premises with artificial ionization of humidified air using an aeroion generator and a ventilation system is proposed. This will allow monitoring and processing of information on technological, electrical and microclimatic parameters, adjusting, coordinating and jointly controlling the ventilation system devices and the ultrasonic generator of air ions.

Acid-catalyzed Transformation of Nitrite to Nitric Oxide on Copper(II)-Cobalt(II) Centers in a Bimetallic Complex.

Nitrite (NO2 -) serves as a pool of nitric oxide (NO) in biological systems under hypoxic conditions, and it is transformed to NO by nitrite reductase (NiR) enzyme in the presence of acid (H+ ions). However, NO synthases (NOSs) generate NO via L-arginine oxidation in normoxic conditions. Previously, acid-induced NO2 - reduction chemistry was modeled on mono-metallic 3d-metals, generating metal-nitrosyls or NO(g) with H2O or H2O2 products. Herein, to understand the relative potency of a bimetallic system, we report the acid-induced reductive conversion of η2-bound NO2 - to NO on CuII-CoII centers of a hetero-bimetallic CuII-nitrito-CoII complex, [(LN8H)CuII-NO2 --CoII]3+ (CuII-NO2 --CoII, 2) bearing an octadentate N8-cryptand ligand (LN8H). The CuII-NO2 --CoII generates [CuII(LN8H)CoII]4+ (1) upon reaction with one equiv. acid (HClO4, H+ ions source) with NO(g) via a presumed transient nitrousacid (ONOH) intermediate species. Likewise, this NO2 - reduction was found to form H2O, which is believed to be from the decomposition of H2O2, an intermediate species. In addition, complex 2, in the presence of more than one equiv. H+ ions also showed the formation of NO(g) with H2O. Mechanistic investigations, using 15N-labeled-15NO2 -, 18O-labeled-18O14N16O- and 2H-labeled-DClO4 (D+ source), revealed that the N-atom and O-atom in the 14/15NO and 14N18O gases are derived from NO2 - ligand and H-atom in H2O derived from H+-source, respectively.

Halogen and Chalcogen Activation by Nucleophilic Catalysis.

The high utility of halogenated organic compounds has prompted the development of numerous transformations that install the carbon-halogen motif. Halogen functionalities, deemed as "functional and functionalizable" molecules due to their capacity to modulate diverse internal properties, constitute a pivotal strategy in drug discovery and development. Traditional routes to these building blocks have commonly involved multiple steps, harsh reaction conditions, and the use of stoichiometric and/or toxic reagents. With the emergence of solid halogen carriers such as N-halosuccinimides, and halohydantoins as popular sources of halonium ions, the past decade has witnessed enormous growth in the development of new catalytic strategies for halofunctionalization. This review aims to provide a nuanced perspective on nucleophilic activators and their roles in halogen activation. It will highlight critical discoveries in effecting racemic and asymmetric variants of these reactions, driven by the development of new catalysts, activation modes, and improved understanding of chemical reactivity and reaction kinetics.

The difference in hydrochemical characteristics of geothermal water between the eastern and western parts of the Wugongshan area and its genetic mechanism

The hydrogeochemical signature of the discharged water can reveal significant information on the circulation and evolution of geothermal water, which can further guide the exploration and utilization of geothermal water resources. In this study, the source of major ions, reservoir temperature, and cycle time of geothermal fluids were clarified by the Ion relationship analysis, integrated multicomponent solute geothermometry method, and 14C isotope analysis, respectively, in the Wugongshan area of South China. Results show that the eastern and western parts of the Wugongshan area have distinct types of geothermal fluids, i.e. HCO3-Na and SO4HCO3-Na, respectively. The major source of HCO3− and Na+ is the hydrolysis of silicate minerals, partially accompanied by cation exchange. While gypsum hydrolysis and sulfide oxidation are the primary producers of SO42−. Moreover, higher TDS, PH, and degree of cation exchange of geothermal fluids were found in the western part than that in the eastern part. The reservoir temperatures in the eastern and western portions are comparable (115–150 °C). However, the cycle time of the geothermal fluids in the western part (15,743 years on average) is much greater than in the eastern part (2160 years on average), which is considered to be the main reason for the difference in hydrogeochemical characteristics. This study can provide theoretical support for the rational development and usage of geothermal water resources.

Groundwater quality in high-sulfur coal mining region of India: Spatial distribution, source control, and health risk assessment

The groundwater quality in the vicinity of the Makum coalfield, renowned for its high-sulfur coal deposits, was investigated. The oxidation of sulfur in the coal generates acid mine drainage (AMD), a global environmental challenge that contaminates natural resources. The region's high sulfur coal content intensifies AMD formation, necessitating a comprehensive assessment of its impact on human health and the environment. This study analyzes the water quality parameters such as pH, EC, TDS, Na+, Ca+2, Mg+2, K+, HCO3‐, SO4−2, F−, Cl -, and NO3− in groundwater, findings concerning low pH levels (5.8) and fluoride concentration (0.15 mg/L) compared to standards. Groundwater chemistry was analyzed to identify the sources controlling water composition through Gibbs diagrams, Piper diagrams, and saturation indices. The Gibbs diagram shows that rock weathering is the crucial factor controlling groundwater chemistry, while the Piper diagram indicates Ca-Cl as the Principal water type. Additionally, an in-depth analysis of groundwater chemistry reveals that carbonate dissolution primarily occurs due to minerals like calcite, dolomite, and gypsum, findings supported by saturation indices. The present study yielded an average water quality index of 40.19, indicating excellent to good water quality in 51 out of 52 samples analyzed. The average hazard index values for adults and children were 0.60 and 0.58, respectively, indicating that 49 of 52 samples pose negative non-carcinogenic risks associated with nitrate and fluoride contamination. The irrigation indices, graphical representations such as the Wilcox and Doneen classification, and the USSL diagram elucidate the suitability for irrigation purposes. Moreover, the Principal Component Analysis identified the sources of ions as originating from geogenic processes and mining activities. The study stresses environmental assessments, health risk management, and sustainable practices for groundwater in high-sulfur coal mining areas.

Energy and spectroscopic parameters of neutral and cations isomers of the CnH2 (n = 2-6) families using high-level ab-initio approaches.

Cationic species, previously detected from ion-induced desorption of solid methane by plasma desorption mass spectrometry (PDMS), and neutral species, are investigated using high-level ab-initio approaches. From a set of 25 cationic and 26 neutral structures belonging to CnH2 (n = 2-6) families, it was obtained the energy, rotational constants, harmonic vibrational frequency, charge distribution and excitation energies. The ZPVE-corrected energies, at CCSD(T)-F12; CCSD(T)-F12/RI/(cc-pVTZ-F12, cc-pVTZ-F12-CABS, cc-pVQZ/C) (n = 2-5) and CCSD(T)/cc-pVTZ (n = 6) levels, reveal that the topology of the most stable isomer vary with n and the charge. Out of 674 harmonic frequencies, those with maximum intensity are generally in the 3000-3500 cm-1 range. Analysis of 169 vertical transition energies calculated with the EOM-CCSD approach, suggest three C6H2 species as potential carriers of the diffuse interstellar bands (DIB). Systematic comparison of properties between neutral and cationic species can assist in the structural description of complex matrices.

Modelling of ICRH slow wave propagation and absorption in Wendelstein 7-X stellarator

Abstract The propagation and absorption of the slow waves in the three-ion plasma of the Wendelstein 7-X stellarator have been investigated by ray tracing. The aim of the study is to obtain a qualitative notion of the penetration into the plasma and absorption of the wave excited by the potential difference between the antenna conductors and the antenna box. It has been discovered that the rays propagate along the magnetic field lines over a significant distance, up to 6 m, from the antenna. They weakly, to a depth of 0.1 m, penetrate into the plasma. Absorption of the slow waves by electrons does not lead to the generation of the currents capable of affecting the plasma equilibrium. Most of the slow waves are absorbed beyond the region of ion-ion hybrid resonance in the zone of cyclotron resonance of He3 ions at the periphery of the plasma. The ICRH of the three-ion W 7-X plasma will be used to heat He3 ions to high energies and simulate the confinement of alpha particles in an optimized stellarator configuration. The presence of a source of hot He3 ions, which are poorly confined, at the periphery of the plasma can affect the experimental results.

Zinc-doped phosphate coatings for enhanced corrosion resistance, antibacterial properties, and biocompatibility of AZ91D Mg alloy

Magnesium and its alloys have been foreseen as promising bone-implant owing to good biocompatibility, high strength, mechanical properties, and biodegradability to replace the conventional bio-metals (Titanium, stainless-steel, Co-Cr alloys) in orthopedic applications. However, high corrosion rate and high degradation rates adversely effects like abrupt evolution of H2 gas and localized alkalization in a physiological environment limit its medical applications. To overcome these issues, phosphate-based surface coating is developed on Mg-alloy to resist the high biodegradation and corrosion rate utilizing magnesium substrate as source of magnesium ion through a single-step hydrothermal process. Controlling the fast corrosion rate and localized alkalization would reduce the antibacterial character of magnesium-based implants therefore, the simple phosphate-based coatings has been induced by doping it with zinc ions due to its physiological tolerance and excellent antibacterial efficacy. The doping of zinc ions may provide a sustained drug-free antibacterial characteristic for potential application in orthopedics. The synthesized phosphate-based coating was characterized using advanced techniques like Scanning Electron Microscopy, X-ray Diffraction, and wettability test, followed by comprehensive electrochemical testing to assess its corrosion behavior. The in vitro immersion test in simulated body fluid (SBF) indicates that deposition of phosphate and zinc doped phosphate coatings reduces the degradation rate consequently minimized the fast dissolution of Mg2+ ions and OH- in physiological environment. Additionally, cytotoxicity and biocompatibility were evaluated using Alamar Blue and live/dead assays on the MC3T3-E1 mouse osteoblast cell line. These assays demonstrated good cell viability, indicating the coatings possess favorable cytocompatibility and support cellular metabolic activity.

Study on main sources of aerosol pH and new methods for additional reduction of PM2.5 during winter severe pollution: Based on the PMF-GAS model

In recent years, the air quality in urban areas of China has been a significant improvement. However, further advancements in air quality remain challenging, particularly in addressing the persistent problem of severe particulate matter (PM) pollution in winter. In-depth research on the aerosol acidity (pH) is beneficial for analyzing the pollution characteristics of PM and providing support for the continuous improvement of PM pollution. In this study, the sources of water-soluble inorganic ions (WSIIs) of PM2.5 in Zhengzhou were analyzed based on the PMF-GAS method, and the contribution of different sources to aerosol acidity was further investigated in conjunction with the ISORROPIA-II thermodynamic model. The research results indicate that secondary aerosols are the main source, and controlling the emissions of secondary aerosols and gaseous precursors is a crucial measure for reducing PM2.5 concentrations. Furthermore, the study revealed that targeted reductions of major pollution sources across varying pH ranges could significantly lower PM2.5 concentrations. In the range of pH < 4, when the contribution of secondary aerosol source is 23.9%, PM2.5 concentrations can be reduced by 40.6%, resulting in an additional emission reduction of 5.9 μg m−3. In the range of 4 < pH < 6, PM2.5 can be reduced by 36.9% at a contribution of 16.5% from secondary aerosol source, achieving an additional emission reduction of 7.0 μg m−3. This research provides important theoretical support for gaining a deeper understanding of the sources and control of atmospheric pollution, offering strategies to expedite the achievement of PM2.5 standards and further mitigating its impacts on human health and the environment.

Enhancing the Performance of Electrochemical RAM (ECRAM) through Modeling Guided Device Engineering

Traditionally, the only ions allowed or welcomed by the microelectronic industry are those that act as fixed dopants. The issue of mobile ions became welcome primarily due to the memristor technology however, thin film transistor technologies benefit from them too. The electrochemical (transistor) random access memory (ECRAM) is emerging as a promising building block for multi-level neuromorphic computing. Using FAB-compatible materials we construct the ECRAM using CuOx as the gate and ions source (Cu+). The morphology of the HfOx gate insulator layer is tuned to render it ion transporting such that it can act as a uniform electrolyte layer. Lastly, the channel material is WOx with tungsten metal as the source/drain contact.While there are several reports of ECRAM devices, the operation mechanisms are not fully known/understood thus withholding progress of this field. Using the Sentaurus device simulator by Synopsis, including the hydrogen diffusion module, we simulate the mixed ionic electronic operation of the device. We have recently reported that by fitting the simulation to the device performance, we could identify the potentiation mechanism (i.e., insulator charging) and the occurrence of copper plating that takes place under high Cu+ ion flux (as in fast charging of Li batteries).[1]In the first part of the talk, we will expand on the chemical-physics details of the ECRAM device mentioned above. Next, we will present a new device architecture where we remove the WOx layer and study the ionic-electronic conduction of a modified HfOx layer. By fine-tuning the stoichiometry of the HfOx layer, it assumes both roles of ionic electrolyte and electronic conducting channel. Following detailed modelling of the measured properties, we introduce AlO2 as an ionic barrier layer at the WOx/HfOx interface to enhance the ionic retention of the HfOx layer. Using the above three device architectures in conjunction with the mixed ionic-electronic device simulation we reveal the role of the two memory mechanisms: a) Electric field-activated ion transport and b) Structure-induced trapping by ion-barrier layers.Reference[1] Nir Tessler, Nayeon Kim, Heebum Kang, Jiyong Woo; Switching mechanisms of CMOS-compatible ECRAM transistors—Electrolyte charging and ion plating. J. Appl. Phys. 21 August 2023; 134 (7): 074501. https://doi.org/10.1063/5.0154153 Figure 1

Advanced approach combines integrated weight water quality index and potential toxic elements for environmental and health risk assessment supported by simulation technique in Oued Souf, Algeria

The current research study evaluated the health and environmental risks issues associated with potentially toxic elements (PTEs) in the complex terminal aquifer located in the Algerian desert. The methods used included principal component and cluster (dendrogram) analysis to estimate source of ions and contamination. Various indices such as the Heavy Metal Pollution Index (HPI), Metal Index, hazard quotient, hazard index (HI), and cancer risk (CR) were applied to assess both environmental and human health risks. Furthermore, the Monte Carlo method was applied for probabilistic assessment of carcinogenic and non-carcinogenic risks through oral and dermal exposure routes in both adults and children. The results revealed that approximately 16% of the samples fell within the low pollution category (HPI < 100), indicating relatively lower levels of heavy metal contamination. However, the remaining 84% of the samples exhibited high pollution levels, indicating a significant presence of heavy metal pollutants in the northeastern part of the investigated area. The calculated average risk index (RI) for the collected samples was 18.99, with a range from 0.03 to 103.21. This indicates that a large portion, 82% of the samples, could cause low ecological risk (RI < 30), whereas the remaining 18% indicate a significant environmental pollution risk. The HI for oral ingestion showed that adults had HI values ranging from 0.231 to 1.54, while children exhibited higher values, ranging from 0.884 to 5.9 (Fig. 5a). For dermal exposure, HI values in adults ranged from 2.71E−07 to 8.74E−06 and in children, from 2.18E−06 to 7.03E−05. These findings highlight the potential non-carcinogenic risks associated with oral exposure to PTEs and underscore the increased vulnerability of children to metals such as Fe, Mn, Pb, and Cr. Most samples showed CR exceeding 1 × 10−4 for chromium (Cr) and lead (Pb), indicating a significant vulnerability to carcinogenic effects in both children and adults.

Enhanced corrosion resistance of LaBC film for bipolar plate coatings in proton exchange membrane fuel cells

LaB6 have been using as hot electron emission materials to serve as hollow cathode ions source, which can help to enhance forming densen films. Besides, La can easy oxide to form La2O3 which can hinder penetration of water to improve the anti-corrosion properties. Thus, we embed LaB6 in carbon which can be employed as sputtering target, expecting to hot the plasma to get more sp2 carbon involved in growth a-C films. As a result, the LaBC film show higher ID/IG values, which improves the graphitization of the carbon matrix, thus partially solving the contradiction between electrical conductivity and corrosion resistance of the LaBC film. The corrosion current density of the LaBC film coated SS316L reduced by one and two orders of magnitude compared to the a-C film coated and uncoated SS316L, respectively, which can be attributed to the formation of boron oxide and lanthanum oxide on the surface of the film. Boron oxide is a waxy substance, and under the dual obstruction of boron oxide and lanthanide oxide, the corrosive solution is difficult to penetrate into the surface and reach the substrate, which greatly delays the oxidation and corrosion of the substrate. Therefore, the LaBC film are expected to be effective bipolar plate coatings for proton exchange membrane fuel cells.