Inductively Coupled Plasma Research Articles

Are nano-colloids controlling rare earth elements mobility or is it the opposite? Insight from A4F-UV-QQQ-ICP-MS

Rare earth element (REE) mobility in the environment is expected to be controlled by colloids. Recent research has detailed the structure of iron-organic colloids (Fe-OM colloids), which include both large colloids and smaller nano-colloids. To assess how these nano-colloids affect REE mobility, their interactions with REE and calcium (Ca) were investigated at pH 4 and 6. Using Asymmetric Flow Field Flow Fractionation (A4F) combined with UV and Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry (QQQ-ICP-MS), Fe-OM nano-colloids were separated from bulk Fe-OM colloids and their REE and Ca content were analyzed. Without REE and Ca, nano-colloids had an average diameter of approximately 25 nm. Their structure is pH-dependent, with aggregation increasing as pH decreases. At high REE loadings (REE/Fe ≥ 0.05), REE induced a size increase of nano-colloids, regardless of pH. Heavy REE (HREE), with their high affinity for organic matter, formed strong complexes with Fe-OM colloids, resulting in large aggregates. In contrast, light REE (LREE), which bind less strongly to organic molecules, were associated with the smallest nano-colloids. Low REE loading did not cause noticeable fractionation. Calcium further enhanced the aggregation process at both pH levels by neutralizing the charges on nano-colloids. These findings indicate that REE can act as aggregating agent controlling their own mobility, and regulating colloid transfer.

Assessment of leachate potential contamination of municipal landfill using leachate pollution index and multivariate statistical analysis based on seasonal variations

Sanitary landfills offer a convenient and cost-effective way to dispose of MSW waste. The breakdown of waste in landfills generates highly poisonous leachate. This liquid can disperse and percolate through the soil, potentially polluting the surrounding water bodies; minimizing the environmental damage caused by leachate lies in thoroughly understanding its unique characteristics at each landfill site. The present study evaluates the leachate's physio-chemical characteristics from municipal landfills and adjacent groundwater sources. To evaluate the impact of temporal seasonal fluctuation, leachate and water samples were collected in three distinct seasons such as pre-monsoon (Pre-M), monsoon (In-M), and post-monsoon (Post-M). The analysis revealed a seasonal variation in pollution levels in the leachate sample, as evidenced by the high Leachate Pollution Index (LPI) spanning 27.121–17.396. Water samples collected across three seasons yielded Water Quality Index (WQI) values ranging from 55.59 to 279.64, with the Pre-M season exhibiting the highest level of water quality. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis were employed to understand the elemental composition further. The presence of heavy metals Zn, Cr, Cu, Ni, Fe, Si, and Hg was determined combined through the Inductive Coupled Plasma Atomic Emission Spectroscopy technique and EDX. The correlation matrix heat map helped to reveal the interconnection between different leachate parameters, and dendrogram clusters revealed the relation between the six sampling points. At the same time, Principal component analysis was performed to simplify the complex data set and determine the predominance of pollutants over the sample points. As explored in this study, understanding the contamination potential of landfill leachate is crucial for developing strategies before its disposal to mitigate its impact.

Efficient Mercury Ion Detection in Water: CdTe/CdS/ZnS Quantum Dots as a Simple, Sensitive, and Rapid Fluorescence Sensor.

Mercury (Hg), a notorious heavy metal with detrimental impacts on human health and the environment, necessitates the development of precise measurement methods. This study introduces an expeditious and straightforward photochemical approach to synthesize thioglycolic acid (TGA)-stabilized CdTe/CdS/ZnS core/multi-shell quantum dots (QDs). The synthesized CdTe/CdS/ZnS QDs were comprehensively characterized using fluorescence spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), Field Emission Scanning Electron Microscopy (FESEM), and X-Ray diffraction (XRD). XRD and EDS results confirmed the successful formation of CdTe/CdS/ZnS structure. Also, FESEM and TEM results showed that CdTe/CdS/ZnS QDs were spherical. Results showed that synthesized Exhibiting vibrant green fluorescence and notable quenching in the presence of Hg2+ ions, these QDs emerge as promising candidates for fabricating a fluorescent sensor. The proposed sensor demonstrates notable sensitivity to Hg2+, featuring a detection limit of 16.32 nM and a linear range from 20 nM to 70 nM. The sensor's selectivity was confirmed by analyzing various anions and cations. Moreover, when tested with tap water, river water, and agricultural samples, the sensor exhibited reliable performance, validated by Inductively Coupled Plasma (ICP) analysis. Additionally, CdTe/CdS/ZnS QDs immobilized on micro pads proved effective for on-site water sample analysis, presenting a versatile solution for environmental monitoring.

Enhanced oil recovery and mitigating challenges in sandstone oil reservoirs employing EDTA chelating agent/ seawater flooding

While low salinity water (LSW) holds promise for improving oil recovery, its implementation is comparatively costly due to the substantial volumes of fresh water required to dilute seawater (SW). Additionally, concerns arise regarding potential issues related to LSW, including fines migration in sandstone reservoirs and scale formation in carbonate reservoirs. Chelating agents can be introduced into undiluted SW to bind with metal ions, thereby lowering its salinity. This approach mimics the behavior of LSW injection while overcoming associated challenges. This study involves measuring oil/injected solution interfacial tension (IFT), evaluating sandstone surface wettability alteration, along with conducting different sand pack flooding scenarios using Ethylenediaminetetraacetic acid (EDTA) chelating agent. The aim was to comprehend the EDTA oil recovery mechanisms and determine the optimal concentration of EDTA that minimizes chemical consumption while maximizing oil recovery. The findings indicated that incorporating 5 wt% EDTA into SW significantly reduced IFT from 29.52 mN/m to 4.75 mN/m, making the oil nearly miscible in the solution. Moreover, wettability tests confirmed that a minimum EDTA concentration of 5 wt% is required to shift wettability from oil-wet to strongly water-wet conditions. Sand pack flooding experiments, on the other hand, further demonstrated that this optimized fluid system can potentially recover an additional 16.1 % of oil following SW flooding. Finally, inductively coupled plasma (ICP) analysis revealed a notable increase in metal ion concentration during EDTA flooding, indicating enhanced leaching of metals from the sandstone surface and improved wettability characteristics.

Novel and Low-Cost Techniques for Extending the Etch Capabilities of an Inductively Coupled Plasma Etch Tool That Has Clamp Fingers for Clamping 4-Inch Diameter Wafers

Widening the processing capabilities of an inductively coupled plasma (ICP) etch tool by “preventing wafer breakage” during processing of wafers, or by gaining the capability to do “through-wafer silicon etch” are important challenges that may need to be resolved with very limited resources. Resolving the undesired wafer breakage issues caused during processing of wafers is important to reduce the manufacturing costs, and increase production yield. Furthermore, considering the high prices of the state-of-the-art wafer processing tools, it is also important to prevent wafer breakage by using low-cost approaches especially if the resources for purchasing state-of-the-art processing equipment are not available. Two novel methods (method #1, and method #2) are developed to prevent wafer breakage and allow through-wafer silicon etching. With method #1, an aluminium alloy ring (AAR) and an o-ring are employed to obtain uniform load distribution (instead of point loads) on the required outer region on the surface of a wafer, and to minimize or completely remove the bending moment that may be formed on the possible cross-sections of the entire wafer, during clamping of the wafer. With method #2, through-wafer silicon etching is made possible by simultaneous application of method #1 and addition of a helium cooling gas (HCG) leakage blocking dicing tape at the back side of the wafer that is under processing for through-wafer etching. By using the explained methods, wafer breakage during ICP etch processing is eliminated, and through-wafer silicon etching is made possible. From the other side, the effective wafer area that can be used for processing is reduced by 48%. Novel and capability enabling 2 different techniques that are extremely low-cost compared to purchasing a state-of-the-art ICP etch tool are presented to extend the processing capabilities of an ICP etch tool for deep silicon etching (method #1), and through-wafer silicon etching (method #2).

Palladium fabricated on Fe3O4 as an organic-inorganic hybrid nanocatalyst for the Suzuki and Stille coupling reactions

The Fe3O4@L-Threonine-Pd complex, comprising palladium supported on modified Fe3O4 magnetic nanoparticles (MNPs), has been documented for its use in Stille and Suzuki coupling reactions. The catalyst's environmental friendliness was assessed through a range of techniques including vibrating sample magnetometry (VSM), Fourier-transform infrared spectroscopy (FTIR), inductively coupled plasma (ICP), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), energy dispersive X-ray photoelectron spectroscopy (XPS), and X-ray spectroscopy (EDS). Using an external magnet, it is easy to separate nanoparticles from the mixture. The nanocatalyst underwent Metal leaching and heterogeneity testing using the ICP-OES technique, demonstrating its ability to be recovered and reused multiple times without a significant loss of catalytic efficiency or palladium leaching.

Modeling and Experimental Validation on a Bipolar Membrane Electrodialysis Stack for Lithium Sulfate Separation

Recycling lithium-ion battery materials is a crucial step to achieving a circular economy. Among a few methods for recycling spent battery materials, a novel hydrometallurgical recycling process with leaching by acids and precipitation by bases was proposed [1]. Lithium sulfate (Li2SO4) leachate solution is generated at the end of the closed-loop recycling process. Such Li2SO4 solution can be separated by electrodialysis (ED) to form H2SO4 and LiOH solutions, which are reused for leaching and precipitation of the recycling process. The present study attempts to model this ED process and validate the model with experimental data.An ED stack based on bipolar membranes (EDBM); see Fig. 1a, was built with repetitive unit cells, each consisting of a bipolar membrane, anion exchange membrane (AEM), and cation exchange membrane (CEM). Li2SO4 enters the dilute channel and splits into SO4 2- and Li+, which travel through the AEM and CEM, respectively. Water electrolysis occurs within the bipolar membrane to produce H+ and OH-, which react with SO4 2- and Li+ to form H2SO4 and LiOH, respectively; see Fig. 1b. A two-dimensional (2D) multiphysics model is developed to elucidate the coupled transport processes within the unit cell. Conservation equations for mass, momentum, and species are solved. The transport of ions is described by the Nernst-Planck equation. Electroneutrality equations are satisfied in these membranes and channels. Electro-osmotic water transport across the membranes is considered.The effective cross-sectional area of the stack was 121.8 cm2 (70mm×174mm). The flow channel between consecutive membranes was 0.8 mm, with a mesh inserted to facilitate mixing. Experiments were carried out with the EDBM stack over different conditions such as current density, number of cell pairs, and flow rates. All experiments were operated at constant current mode [2]. The feed, acid, and base solutions were recirculated through their tanks at initial concentrations of 1.1, 0.1, and 0.1 mol/L. The ion concentrations of the solutions were measured periodically with inductively coupled plasma (ICP) mass spectrometry. The weight and the pH value of the solution tanks were also recorded.The concentration of H2SO4 is found to increase with time linearly, whereas that of LiOH levels off due to a significant electro-osmosis that drags water through the CEM into the concentrate channel. This drag reduces the performance of EDBM due to the dilution of water into the concentrate compartment. However, electro-osmotic water transport also leads to a velocity increase in the concentrate channel, which is consistent with the simulation results in our previous ED model [3]. It is found that the voltage loss across the bipolar membrane ca. 1V accounts for a significant part of the unit cell of about 1.27V.The migration of ions in electrodialysis mainly relies on diffusion and electric drive. The streamlines and the concentration distribution of Li+ under different voltages indicate that increasing voltage accelerates ion migration, see Fig. 1(c). Furthermore, the effect of the potential and concentration variations on EDBM performance is also investigated. The effects of applied current density and inlet velocity are studied on species concentrations and fluxes. Increasing the stack current density accelerates the separation process, see Fig. 1(d). It is found that increasing the solution flow rate can increase LiOH solution concentration, ion recovery rate, and current efficiency. However, the impact of the flow rate is low.This work demonstrates that EDBM can be a simple and energy-saving alternative to the current chemical precipitation method to produce LiOH from Li2SO4. The present study provides new insights into optimal operation and design for Li2SO4 EDBM. The findings are helpful in determining how the stack can be scaled up for practical application.[1] A review of recycling spent lithium-ion battery cathode materials using hydrometallurgical treatments, JCY Jung, PC Sui, J Zhang, J. Energy Storage 35, 102217, 2021.[2] Electrodialysis of a Lithium Sulphate Solution: An Experimental Investigation. B Kang, D Kang, JCY Jung, A Asadi, PC Sui, J. Electrochem. Soc. 169 (6), 063515, 2022.[3] A Comprehensive Computational Fluid Dynamics Modeling of Lithium Sulphate Electrodialysis, A Asadi, HB Harandi, JCY Jung, PC Sui, J. Electrochem. Soc. 170(9), 093502, 2023. Figure 1

Degradation and Protection Mechanisms of Platinum-Based Catalysts in Hydrogen-Bromine Flow Batteries

Cost-effective and large-scale electrical energy storage is pivotal in facilitating the assimilation of renewable energy sources like wind and solar, as well as enhancing the resilience of the future electricity grid. Hydrogen-Bromine flow battery (HBFB) technology is a candidate for a low cost and flexible system. Bromine is abundantly available on Earth. In addition, the reaction between bromine and bromide is characterized by rapid kinetic properties, thus no platinum group metals (PGMs) are required on the bromine side of the cell as a catalyst to sustain a high current density of >500 mA/cm2. Moreover, hydrogen-based flow batteries can be coupled with hydrogen pipelines & electrolyzers to boost the integration of new energy systems.However, the selection of bromine brings technical challenges that can limit the commercial deployment of such HBFB systems. We have proven a lifetime of more than 8,000 hours of continuous cycling at the lab scale. During this proof-of-concept validation, we found that bromine species (liquid) crosses through a dense proton exchange membrane to the hydrogen side of the cell. On this side, a Platinum-based catalyst layer is present to promote hydrogen oxidation-evolution reactions (HOR/HER). The crossover liquid interacts first with the catalyst layer before it crosses through the gas diffusion layer and exits the membrane electrode assembly (MEA). Chemical interactions between the crossover liquid and the catalyst can lead to catalyst migration, Ostwald ripening, or even permanent catalyst dissolution. This is a concern and must be addressed. The root of this concern is that the Platinum-based catalyst is highly reactive (high surface-active area respective to the loading, m2/g), and also the crossover bromine species are likely corrosive (highly acidic, pH <0, and contain polybromides). Therefore, chemical interaction cannot be fully avoided. Nevertheless, the cathodic protection reduces this interaction, which prolongs the lifetime of the electrochemical system. The cathodic protection consists of an applied positive potential and the presence of hydrogen gas on the catalyst nanoparticles. The catalyst degradation together with cathodic protection needs to be better understood and quantified to gain the confidence that the HBFB system fundamentally can last for more than 10 years of continuous operation. This confidence is essential to deliver a minimum viable product (MVP) of HBFB, e.g. on a 100 kW – 1 MW scale, to the market.To address the aforementioned scientific challenges, this work studies the liquid crossover phenomena and the interaction between the crossover liquid and platinum-based catalyst in depth. Liquid crossover rate, concentration, and bromine speciation from working electrochemical cells are quantified at different states of charge (SoCs) and different modes (charge or discharge). This information is used to set up further ex-situ experiments to understand and determine the chemical interaction between crossover liquid and catalyst. Electrochemical ex-situ tests for Pt dissolution measurement such as determination of the electrochemically active surface area (ECSA), are performed before and after soaking hydrogen electrodes in different concentrations of hydrogen bromide solutions that mimic the crossover liquid. These results are then combined with in-situ tests, where the catalyst dissolution rate is quantified in actual crossover liquid and electrolyte by the inductively coupled plasma (ICP) method. Finally, post-mortem analyses on the catalyst layer based on scanning electron microscopy (SEM), transmission electron microscopy (TEM), etc. will give quantitative and qualitative insights into the impact of cycling and liquid crossover on the catalyst performance, morphology, crystal structure, and chemical state of the catalyst.The goal of this work is to quantify the extrapolated lifetime of HBFB systems within a high confidence level. Then conclude if this technology is fundamentally sound and can be scaled up to an MVP to be deployed to the market. As a low cost energy storage solution, the HBFB’s lifetime should be at least 5 years and preferably more than 10 years to attract commercial attention. Moreover, the collective knowledge gained in this work about the catalyst degradation mechanisms will spark further ideas and guide the next generation of the system and its operating conditions to reduce the degradation rate. These presented ideas may also shine a light on catalyst degradation and protection mechanisms in other electrochemical applications that operate in corrosive conditions.Figure 1 Membrane electrode assembly architecture, incl. electrochemical reactions and species transport phenomena in the charge and discharge modes. Figure 1

(Invited) Scalable 2-Step Fabrication of Core-Shell GaN Micropillars

Group III-Nitride three-dimensional structures have gained substantial interest for application in optoelectronic, energy, and sensor devices with non-planar geometries [1-4]. The benefits of 3D structures, such as GaN-based nano-/micro-rods, compared to planar films include large surface area, high structural quality, non-polar-surface utilization, small footprint, mechanical flexibility, and enhanced light absorption/extraction efficiency. To advance the technology of non-planar III-Nitride semiconductors, it is necessary to optimize and scale up the fabrication of such structures with controlled geometries and desired electronic and optical properties. Here, we report the fabrication of wafer-scale periodic arrays of vertically aligned GaN core-shell micropillars using a combination of top-down etch and epitaxial overgrowth.The two-step process consists of inductively coupled plasma (ICP) etching of lithographically patterned GaN-on-Si substrate to produce an array of micropillars followed by selective growth of GaN shells over these pillars using Hydride Vapor Phase Epitaxy (HVPE). The most significant aspect of the study is the demonstration of the sidewall facet control in the shells, ranging from truncated hexagonal pyramids with the (1-101) semi-polar sidewalls to hexagonal prisms with the (1-100) non-polar sidewalls, by employing a post-ICP wet chemical etch and by tuning the HVPE growth temperature. Optimization of both ICP etching and epitaxial overgrowth reduced dislocation density in the GaN shells, thus enhancing the transport and optical characteristics of these device platforms. Photo- and cathodoluminescence showed a substantial reduction of parasitic yellow luminescence as well as strain-relaxation in the core-shell structures, supported by Raman scattering, electron-backscatter-diffraction (EBSD), and X-ray-diffraction measurements. Transmission electron microscopy revealed improved crystal quality with reduced dislocation density in the epitaxially grown shells. This work demonstrates the feasibility of selective epitaxy on micro/nano-engineered 3D templates for realizing high-quality GaN-on-Si devices such as LEDs and p-i-n photodetectors.

Ion Conductive High Li+ Transference Number Polymer Composites for Solid-State Batteries

Solid-state electrolytes are a promising field of study to improve the safety and energy density of lithium-based batteries. Composite solid electrolytes seek to leverage both the desirable mechanical properties of polymers and the high conductivity of active ceramic fillers; however, Li+ transport through the composite, and especially the extent of Li+ through the ceramic phase, remains an open question.1, 2 Simulations suggest that decreasing interfacial resistance between polymer and ceramic would promote transport through ceramic particles.1 Our work seeks to improve Li+ transport in the ceramic phase by engineering both polymer and ceramic materials that minimize the interfacial resistance between the two.Traditional polymer electrolytes have a low transference number (~0.15) compared to ceramics (~1), and when combined in composites this mismatch has been suggested as a major contributor to interfacial impedance.3 We explore the effect of the transference number mismatch by using a single-ion conducting polymer poly((trifluoromethane)sulfonamide lithium methacrylate) (PMTFSILi). The Li+ transport in a composite electrolyte with high transference number PMTFSILi is compared with that of a system utilizing a lithium salt.Contaminants on ceramic surface can also contribute to interfacial resistance. We consider how lithium carbonate (Li2CO3) content on the surface of LLZTO (Li6.4La3Zr2Ta0.6O12) affects Li+ transport. Accompanying this study is a detailed description of washing procedures used to clean the LLZTO surface. Titration Mass Spectrometry (TiMS) is used to quantify Li2CO3 content in our ceramic particles and assess the effectiveness of our cleaning procedures. Inductively-coupled plasma mass spectrometry (ICP-MS) data also assists in measuring the impact (Li+ exchange and transition metal dissolution) of various washing procedures (basic, acidic) on the LLZTO particles.Solid-state NMR has proven to be a useful tool in deconvoluting Li+ transport in different phases of composite electrolytes2 and is the primary technique we use to quantify transport in our system. These findings will provide a deeper understanding into the relationship between interfacial resistance and Li+ transport in composite electrolyte systems and shed light on how material choices can better utilize the highly conductive ceramic phase for Li+ transport. Kim, HK., Barai, P., Chavan, K. et al.Transport and mechanical behavior in PEO-LLZO composite electrolytes. J Solid State Electrochem 26, 2059–2075 (2022). https://doi.org/10.1007/s10008-022-05231-wZheng J., Hu, Y. New Insights into the Compositional Dependence of Li-Ion transport in polymer-ceramic composite electrolytes. ACS Appl. Mater. Interfaces, 10, 4, 4113–4120 (2018). https://doi.org/10.1021/acsami.7b17301Mehrotra A. et al. Quantifying Polarization Losses in an Organic Liquid Electrolyte/Single Ion Conductor Interface. Electrochem. Soc. 161 A1681 (2014). https://doi.org /10.1149/2.0721410jes

Parametric study of a vortex-enhanced supersonic inductive plasma torch

The feed gas injection configuration in radio-frequency (RF) inductively coupled plasma (ICP) torches plays a critical role in discharge stability, gas heating, and device thermal management: particularly if a supersonic nozzle is used to subsequently accelerate the hot gas. A novel injection configuration is the bidirectional vortex, which segments the internal ICP flow field into two counter-propagating vortices that can significantly enhance gas heating and reduce heat losses. The diameter of the interface between the vortices (known as the mantle) is expected to be an important dimensional parameter affecting torch operation, especially relative to the nozzle size. In this work, we investigate the effect of nozzle throat diameter on the behaviour and performance of a vortex-enhanced supersonic ICP torch. The system is operated at RF powers and argon mass flow rates between 200–1000 W and 0–400 mg s−1 respectively, and different nozzle diameters ranging from 1.5 to 4 mm are explored. Because of the high-temperature environment, and to prevent disruption of the vortex flow fields, non-invasive diagnostics are used to measure the gas temperature and plasma density, and to infer the torch thermal efficiency and achievable gas specific enthalpy change. The maximum temperature is between 8500–9500 K with the 1.5 mm nozzle giving the highest temperature for a given power and mass flow rate, while plasma densities vary between 1020–1021 m−3 depending on the operating conditions. The thermal efficiency increases from 29% for the 1.5 mm nozzle to just above 70% for the 4 mm nozzle with a similar maximum specific enthalpy of around 1.5 MJ kg−1. These results demonstrate the important coupling between torch properties, and how system optimization can lead to tailored performance of potential interest to several ground and space-based applications.

High-power 940 nm DFB laser diode with large optical cavity.

High-power laser diodes with a stable wavelength and narrow linewidth are crucial for many applications. In this study, we introduce a first-order distributed feedback (DFB) grating into an asymmetric large-cavity laser diode operating around 940 nm. This design maintains high output power and offers a wide temperature locking range. The nearly sinusoidal shape first-order grating is fabricated by ultraviolet (UV) nanoimprint lithography, inductively coupled plasma (ICP) dry etching, and wet polishing. At a heat sink temperature of 25°C, the DFB laser diode, with a 200 µm stripe width and 4 mm cavity length, achieves a maximum output power of 24.8 W and a full width at half maximum (FWHM) of 0.4 nm under continuous-wave (CW) conditions. The maximum slope efficiency is calculated to be 1.04 W/A. At an output power of 10.7 W, the device reaches a peak wall-plug efficiency of 56%. Under quasi-continuous operation at 20 A, the laser output spectrum remains locked to the DFB grating over a temperature range from -10°C to 110°C, with a temperature coefficient of 0.062 nm/°C.

Development and Evaluation of Ferrite Core Inductively Coupled Plasma Radio Frequency Ion Source for High-Current Ion Implanters in Semiconductor Applications.

This study presents the development of a ferrite core inductively coupled plasma (ICP) radio frequency (RF) ion source designed to improve the lifetime of ion sources in commercial ion implanters. Unlike existing DC methods, this novel approach aims to enhance the performance and lifetime of the ion source. We constructed a high-vacuum evaluation chamber to thoroughly examine RF ion source characteristics using a Langmuir probe. Comparative experiments assessed the extraction current of two upgraded ferrite core RF ion sources in a commercial ion implanter setting. Additionally, we tested the plasma lifetime of the ICP source and took temperature measurements of various components to verify the operational stability and efficiency of the innovative design. This study confirmed that the ICP RF ion source operated effectively under a high vacuum of 10-5 torr and in a high-voltage environment of 30 kV. We observed that the extraction current increased linearly with RF power. We also confirmed that BF3 gas, which presents challenging conditions, was stably ionized in the ICP RF ion sources.

MCM-41 supported 2-aminothiophenol/Cu complex as a sustainable nanocatalyst for Suzuki coupling reaction

We have developed an innovative mesoporous nanocatalyst by carefully attaching a 2-aminothiophenol-Cu complex onto functionalized MCM-41. This straightforward synthesis process has yielded a versatile nanocatalyst known for its outstanding efficiency, recyclability, and enhanced stability. The structural integrity of the nanocatalyst was comprehensively analyzed using an array of techniques, including BET (Brunauer–Emmett–Teller) for surface area measurement, ICP (Inductively Coupled Plasma) for metal content determination, EDS (Energy-Dispersive X-ray Spectroscopy) for elemental mapping, XRD (X-ray Diffraction) for crystalline structure elucidation, SEM (Scanning Electron Microscopy), EMA (Elemental Mapping Analysis), TEM (Transmission Electron Microscopy), TGA (Thermogravimetric Analysis), FT-IR (Fourier Transform Infrared Spectroscopy), AFM (Atomic Force Microscopy), and CV (cyclic voltammetry). Subsequently, the catalytic properties of the newly developed MCM-41-CPTEO-2-aminothiophenol-Cu catalyst was evaluated in the synthesis of biphenyls, demonstrating outstanding yields through a Suzuki coupling reaction between phenylboronic acid and aryl halides. Importantly, this reaction was conducted in an environmentally friendly medium. Note the remarkable recyclability of the catalyst, proving its sustainability over six cycles with minimal loss in activity additionally hot filtration test was prepared to examine the stability of this nanocatalyst. This outstanding feature emphasizes the catalyst's potential for long-term, environmentally conscious catalytic applications.

Effects of contactless photoelectrochemical reaction on repair of etching damage in GaN SBD

This research investigates the reparative impact of photoelectrochemical (PEC) reactions on damage induced by inductively coupled plasma (ICP) etching in process of the Schottky barrier diodes (SBDs). After the PEC reaction repair, the reverse leakage current of the devices exhibited a significant reduction, typically ranging from 1 to 3 orders of magnitude. The ideality factor decreased from approximately 5 to 2, accompanied by a simultaneous decrease in series resistance. SBDs subjected to PEC processing displayed a notable decline in frequency dispersion. Quantitative analysis from capacitance-frequency measurements indicated that the PEC process effectively rectified the damage caused by dry etching on the GaN surface. The results of X-ray Photoelectron Spectroscopy (XPS) showed that the gallium oxide formed on a GaN surface by PEC treatment and the ratio of N/(Al + Ga) becomes larger, which indicates that fewer nitrogen vacancies (NV) after PEC repair process. The mechanism of the repair effects of PEC for the SBDs were discussed and analyzed. The observed improvements underscore the efficacy of PEC reactions in mitigating the adverse effects of etching, providing some inspirations for the enhancement of SBD performance in GaN-based devices.

Preparation of a novel Cu‐Ni mixed nanoparticles immobilized on clay: An Eco-friendly Nanocatalyst for mild synthesis of Benzimidazoles and pyrimidines

In the present work, Cu‐Ni mixed nanoparticles immobilized in magnetic clay (MMT-BAC@Fe3O4@CuNi) nanocatalyst were successfully synthesized using a simple method for the first time. In the design of this catalyst, nickel and copper ions were reduced and deposited on clay layers using a benzalkonium chloride directing group. The proposed method offers a safe, sustainable, and selective approach for the synthesis of 2-substituted benzimidazole and 3,4-dihydropyrimidin-2(1H)-ones using an environmentally friendly nanocatalyst. The solid catalyst was distinguished using a diversity of methods, including EDX (Energy Dispersive X-Ray), XRD (X-ray Diffraction), ICP (Inductively Coupled Plasma), VSM (Vibrating Sample Magnetometer), FT-IR (Fourier Transform Infrared Spectroscopy), TEM (Transmission Electron Microscopy) and FE-SEM (Field Emission Scanning Electron Microscopy). The significant features of this new protocol include good to excellent efficiency, oxidant-free conditions, low catalyst loading, inexpensive and non-toxic catalyst, simple procedure, moderate conditions, straightforward work-up, short reaction times, and easy reuse of the nanocatalyst.

Improving plasma uniformity in the inductively coupled plasma by external magnetic field

To enhance etching efficiency and uniformity in process production, in this work, a two-dimensional fluid model was used to study the modulation effect of an external magnetic field on the argon–oxygen inductively coupled plasma (ICP). The study found that as the magnetic coil current increases, the electron density changes from center-high to uniform to edge-high distribution. The best plasma uniformity degree is 94%, obtained at a magnetic coil current of 10 A, which represents a 39% improvement over the unmagnetized ICP. The electric field reversal occurs during the transition from weak magnetization to strong magnetization. The electron temperature shows a single-peak to dual-peak to single-peak distribution during this period. In addition, we also found that gas pressure and oxygen ratio also impact magnetized plasma, where the effect of gas pressure on magnetized plasma is more significant than that of oxygen ratio. The results show that introducing an external magnetic field can significantly improve the plasma density and radial uniformity. This finding has contributed to enhancing plasma etching uniformity and optimizing etching processes.

Piezoresistive performance of self-sensing bitumen emulsion-cement mortar with multi-walled carbon nanotubes

In this study, multi-walled carbon nanotubes (MWCNTs) were incorporated as functional fillers into bitumen emulsion, along with self-sensing cementitious sensors, to investigate their internal curing and ion conduction. The mechanical properties, piezoresistivity, moisture content, and internal curing of cementitious sensors were analysed under different MWCNTs and water contents. Isothermal Calorimetry (IC), Nuclear Magnetic Resonance (NMR), Thermogravimetric Analysis (TGA), and Inductively Coupled Plasma (ICP) methods were employed to supplement the findings and unveil the mechanism. The compressive strength of bitumen-cement mortars was found to be comparable to that of the counterpart cement mortars. The results confirmed that bitumen emulsion improved the piezoresistivity due to the increased water content in the mortars and the influence of micro-holes. Additionally, the bitumen emulsion limited the moisture loss, leading to improved internal curing. The piezoresistivity was observed to be affected by ion conduction, which in return was influenced by water content. Moreover, as water content of self-sensing mortar decreased, the piezoresistivity initially increased and then decreased, flowing the moisture loss rate. These outcomes can offer insights into the performance of self-sensing bitumen cementitious sensors and their potential application in traffic condition detection and road health monitoring.

Exploring the biodegradability of candidate metallic intravascular stent materials using X-ray microfocus computed tomography: An in vitro study.

In vitro testing for evaluating degradation mode and rate of candidate biodegradable metals to be used as intravascular stents is crucial before going to in vivo animal models. In this study, we show that X-ray microfocus computed tomography (microCT) presents a key added value to visualize degradation mode and to evaluate degradation rate and material surface properties in 3D and at high resolution of large regions of interest. The in vitro degradation behavior of three candidate biodegradable stent materials was evaluated: pure iron (Fe), pure zinc (Zn), and a quinary Zn alloy (ZnAgCuMnZr). These metals were compared to a reference biostable cobaltchromium (CoCr) alloy. To compare the degradation mode and degradation rate evaluated with microCT, scanning electron microscopy (SEM) and inductively-coupled plasma (ICP) were included. We confirmed that Fe degrades very slowly but with desirable uniform surface corrosion. Zn degrades faster but exhibits localized deep pitting corrosion. The Zn alloy degrades at a similar rate as the pure Zn, but more homogeneously. However, the formation of deep internal dendrites was observed. Our study provides a detailed microCT-based comparison of essential surface and corrosion properties, with a structural characterization of the corrosion behavior, of different candidate stent materials in 3D in a non-destructive way.

Mineral Nutrition In The Leaves of Cocculus hirsutus (L) Under Pathogenesis

The present research paper deals with mineral content in the leaves of Cocculus hirsutus(L) affected by powdery mildew fungus Oidium Sp. (Imperfect stage). The healthy and infected leaves were digested by tri-acid, prescribed by Toth et al., (1948) method. The digested sample was further subjected to Inductive Coupled Plasma Optical Emission spectroscopy. ICP-OES (Agilent 5800ICP-OES FEQ’S), MY 1523001 software version: 7.3.0.8799. Firm ware version: 3354 for analysis of mineral element. The infected leaf shows enhanced content in potassium, iron, manganese, copper, nickel, chromium, and aluminium element. On the Contrary, elements such as magnesium, sodium, calcium, lead, zinc, boron, strontium and thallium were reduced in their contents reflect a high metabolic activity during pathogenesis.