Commercial Metal Research Articles

Facile construction of self-supported Fe-doped Ni3S2 nanoparticle arrays for the ultralow-overpotential oxygen evolution reaction.

Constructing high-performance and cost-effective electrocatalysts for water oxidation, particularly for overall water splitting, is extremely needed, whereas still challenging. Herein, based on an economical and facile one-step surface sulfurization strategy, a three-dimensional nanostructure with uniform Fe-doped Ni3S2 nanoparticle arrays tightly implanted on nickel foam (Fe-doped Ni3S2-NF) has been fabricated for the extremely efficient electrochemical oxygen evolution reaction (OER). Owing to the unique electronic structure modulation between Ni and Fe sites, and high interfacial charge communication during the electrocatalytic process, the optimal Fe-doped Ni3S2-NF electrode shows an excellent OER activity with ultralow overpotentials of 166 and 235 mV at 10 and 100 mA cm-2 in alkaline solution, respectively, remarkably outcompeting the benchmark RuO2/NF and the overwhelming majority of the reported electrocatalysts. Furthermore, for overall water splitting, the Fe-doped Ni3S2-NF electrode as a bifunctional electrocatalyst assembled in a two-electrode device requires merely 1.56 V to gain a current density of 10 mA cm-2. This study presents a universal surface engineering strategy to conveniently and economically remould commercial metal materials into efficient electrocatalysts for various electrochemical reactions.

Trimetallic NiFeCr-LDH/MoS2composites as novel electrocatalyst for OER

The development of efficient and stable oxygen evolution reaction (OER) catalysts is an ongoing challenge. In order to solve the problem of low oxygen evolution efficiency of the current OER catalysts, a novel material was synthesized by the incorporation of NiFeCr-LDH and MoS2, and its structural and electrochemical properties were also investigated. The introduction of MoS2 improves the electrochemical performance of NiFeCr-LDH. The polarization curve shows that the potential of composite material is only 1.50 V at a current density of 10 mA cm−2, which is far superior to commercial precious metal catalysts. In addition, the stability experiment shows that the composite material has excellent stability, and the current density has little change after 500 cycles. Furthermore, we found that some metal ions, such as Ni, Cr and Mo, exist in the form of high valence on the surface of NiFeCr-LDH@MoS2, which is also conducive to the occurrence of oxygen evolution reaction.

A CMOS-integrated compute-in-memory macro based on resistive random-access memory for AI edge devices

The development of small, energy-efficient artificial intelligence edge devices is limited in conventional computing architectures by the need to transfer data between the processor and memory. Non-volatile compute-in-memory (nvCIM) architectures have the potential to overcome such issues, but the development of high-bit-precision configurations required for dot-product operations remains challenging. In particular, input–output parallelism and cell-area limitations, as well as signal margin degradation, computing latency in multibit analogue readout operations and manufacturing challenges, still need to be addressed. Here we report a 2 Mb nvCIM macro (which combines memory cells and related peripheral circuitry) that is based on single-level cell resistive random-access memory devices and is fabricated in a 22 nm complementary metal–oxide–semiconductor foundry process. Compared with previous nvCIM schemes, our macro can perform multibit dot-product operations with increased input–output parallelism, reduced cell-array area, improved accuracy, and reduced computing latency and energy consumption. The macro can, in particular, achieve latencies between 9.2 and 18.3 ns, and energy efficiencies between 146.21 and 36.61 tera-operations per second per watt, for binary and multibit input–weight–output configurations, respectively. Commercial complementary metal–oxide–semiconductor and resistive random-access memory technologies can be used to create multibit compute-in-memory circuits capable of fast and energy-efficient inference for use in small artificial intelligence edge devices.

Dosimetric impact of commercial CT metal artifact reduction algorithms and a novel in-house algorithm for proton therapy of head and neck cancer.

To compare the dosimetric impact of all major commercial vendors' metal artifact reduction (MAR) algorithms to one another, as well as to a novel in-house technique (AMPP) using an anthropomorphic head phantom. The phantom was an Alderson phantom, modified to allow for artifact-filled and baseline (no artifacts) computed tomography (CT) scans using teeth capsules made with metal amalgams or bone-equivalent materials. It also included a cylindrical insert that was accessible from the bottom of the neck and designed to introduce soft tissue features into the phantom that were used in the analysis. The phantom was scanned with the metal teeth in place using each respective vendor's MAR algorithm: OMAR (Philips), iMAR (Siemens), SEMAR (Canon), and SmartMAR (GE); the AMPP algorithm was designed in-house. Uncorrected and baseline (bone-equivalent teeth) image sets were also acquired using a Siemens scanner. Proton spot scanning treatment plans were designed on the baseline image set for five targets in the phantom. Once optimized, the proton beams were copied onto the different artifact-corrected image sets, with no reoptimization of the beams' parameters, to evaluate dose distribution differences in the different MAR-corrected and -uncorrected image sets. Dose distribution differences were evaluated by comparing dose-volume histogram (DVH) metrics, including planning target volume D95 and clinical target volume D99 coverages, V100, D0.03cc, and heterogeneity indexes, along with a qualitative and water equivalent thickness (WET) analysis. Uncorrected CT metal artifacts and commercial MAR algorithms negatively impacted the proton dose distributions of all five target shapes and locations in an inconsistent manner, sometimes overdosing by as much as 11.1% (D0.03) or underdosing by as much as 11.7% (V100) the planning target volumes. The AMPP-corrected images, however, provided dose distributions that consistently agreed with the baseline dose distribution. The dosimetry results also suggest that the commercial MAR algorithms' performances varied more with target location and less with target shape. Once relocated further from the metal, the target showed dose distributions that agreed more with the baseline for all commercial solutions, improving the overdosing by as much as 6%, implying inadequate HU correction from commercial MAR algorithms. In comparison to the baseline, HU profile shapes were considerably altered by commercial algorithms and reference values showed differences that represent stopping power percentage differences of 2.7-10%. The AMPP algorithm plans showed the smallest WET differences with the baseline (0.06cm on average), while the commercial image sets created differences that ranged from 0.11 to 0.54cm. Computed tomography metal artifacts negatively impacted proton dose distributions on all five targets analyzed. The commercial MAR solutions performed inconsistently throughout all targets compared to the metal-free baseline. A lack of CTV coverage and an increased number of hotspots were observed throughout all commercial solutions. Dose distribution errors were related to the proximity to the artifacts, demonstrating the inability of commercial techniques to adequately correct severe artifacts. In contrast, AMPP consistently showed dose distributions that best matched the baseline, likely because it makes use of accurate HU information, as opposed to interpolated data like commercial algorithms.

(Invited) Development of High-performance Si Anodes and O3-type Metal Oxide Cathodes for Next Generation Li-ion Batteries and Beyond

Silicon is the most promising anode material for next generation high energy Li-ion batteries. While Na-ion battery is one of the closest beyond Li-ion technologies to commercial production and O3-type metal oxide cathodes are expected to deliver high performance in terms of specific capacity and energy density. In this talk, we will discuss the progress of our recent development on porous structured Si materials and localized high concentration electrolyte towards practical applications. For the development of O3-type layered cathode for Na-ion batteries, we will report the synthesis of O3-NaNi0.68Mn0.22Co0.10O2 cathode, which delivers a specific capacity of ~196 mAh/g and a specific energy of ~612 Wh/kg (based on the cathode). By controlling the surface phase transition and chemical reactivity with localized high concentration electrolyte, the Ni-rich NMC cathode demonstrated >83% capacity retention over 100 cycles between 2-4.2V (vs. Na/Na+). The cathode has a specific capacity of ~151 mAh/g between 2-4V and ~80% capacity retention over 1000 cycles. NaNi0.68Mn0.22Co0.10O2-hard carbon full-cells with practical loading (>2.5 mAh/cm2) and lean electrolyte (~40 µL) also were demonstrated. The capacity retention is ~82% after 450 cycles.

CORNERSTONE’s Silicon Photonics Rapid Prototyping Platforms: Current Status and Future Outlook

The field of silicon photonics has experienced widespread adoption in the datacoms industry over the past decade, with a plethora of other applications emerging more recently such as light detection and ranging (LIDAR), sensing, quantum photonics, programmable photonics and artificial intelligence. As a result of this, many commercial complementary metal oxide semiconductor (CMOS) foundries have developed open access silicon photonics process lines, enabling the mass production of silicon photonics systems. On the other side of the spectrum, several research labs, typically within universities, have opened up their facilities for small scale prototyping, commonly exploiting e-beam lithography for wafer patterning. Within this ecosystem, there remains a challenge for early stage researchers to progress their novel and innovate designs from the research lab to the commercial foundries because of the lack of compatibility of the processing technologies (e-beam lithography is not an industry tool). The CORNERSTONE rapid-prototyping capability bridges this gap between research and industry by providing a rapid prototyping fabrication line based on deep-UV lithography to enable seamless scaling up of production volumes, whilst also retaining the ability for device level innovation, crucial for researchers, by offering flexibility in its process flows. This review article presents a summary of the current CORNERSTONE capabilities and an outlook for the future.

In-situ monitoring of a laser metal deposition (LMD) process: comparison of MWIR, SWIR and high-speed NIR thermography

ABSTRACT Additive manufacturing offers a range of novel applications. However, the manufacturing process is complex and the production of almost defect-free parts with high reliability and durability is still a challenge. Thermography is a valuable tool for process surveillance, especially in metal additive manufacturing processes. The high process temperatures allow one to use cameras usually operating in the visible spectral range. Here, we compare the results of measurements during the manufacturing process of a commercial laser metal deposition setup using a mid wavelength infrared camera with those from a short wavelength infrared camera and those from a visual spectrum high-speed camera with band pass filter in the near infrared range.

A room temperature alloying strategy to enable commercial metal foil for efficient Li/Na storage and deposition

Metal substrate has significant functions in regulating Li/Na deposit behaviors to inhibit dendrite growth, but most alloyable metal foils such as Al, Sn, Zn suffer from severe low energy efficiency upon charge/discharge. Herein, it is demonstrated a novel room-temperature alloying strategy to enable commercial Sn foil as hybrid anode/current collector in Li and Na metal batteries. By introducing tiny Hg into Sn foil, the spontaneous alloying reaction afford uniform distribution of Hg into the entire Sn foil, forming a hexagonal Sn0.9Hg0.1 amalgam phase. Compared to pristine metallic β-Sn, this binary alloy electrode allows highly reversible Li/Na diffusion within the foil, and thus considerably promotes the efficiency of Li/Na utilization as well as the inhibition of dendric morphologies. Prototype cell configurations composed of both LiFePO4|Sn-Hg and NaxFe[Fe(CN)6]|Sn-Hg demonstrate stable lifespan over 1000 cycles with high Coulombic efficiency. In addition, this facile room-temperature alloying process has been successfully extended to Zn foil, indicating it can be a universal strategy to design versatile polynary alloy electrodes for alkali metal batteries.

Antibodies fragments as enablers of cardiac troponin (cTn) detection with extended gate metal-oxide-semiconductor field effect transistors (EGFET)

Abstract Background Cardiac troponin is the gold standard biomarker used to rule in or out acute myocardial infarction (AMI) in patients. Highly sensitive and reliable detection mechanisms for this important biomarker are required for advancing the field of early detection in medical applications. Field effect transistor (FET) sensors, specifically functionalised with troponin antibodies, can perform specific detection of cardiac troponin I or T, with high sensitivity and low limit of detection (LoD), in fully scalable and low power operated intelligent sensing systems. Purpose To design and realize a new wearable blood or sweat on-chip sensor, able to perform a real-time reliable detection of the cardiac troponin level in a patient suffering of AMI symptoms or during the post-operative phase. The sensor exploits the voltammetric detection of biomarkers, and offers the potential for miniaturization and reduced hospitalization costs. Methods Electrical current modulation in field effect transistor-based sensors is used as transducing principle, as a result of the surface potential change following exposure to biological fluids containing different concentrations of antigens. The use of antibodies fragments, properly attached to the sensor surface, enhances the sensitivity. Proof of concept tests involve the detection of fluorescein. Results The specific antigen detection by means of an electrical measurement has been proved, with a detection limit of <1 nM (24ng/mL), linear range over one decade and a sensitivity around 70mV/decade. Fluorescein antibodies fragments, commercially purchased, were attached to the gate of an EGFET device; the binding events between fluorescein molecules and the correspondent antibodies modify the electrical conduction properties of the transducer, creating a current shift whose amplitude is univocally related to the antigen concentration. The exploitation of the antibodies fragments allows the antigens to bind closer to the sensing surface, creating a more noticeable electrical perturbation. The device is made of a commercial Metal Oxide Semiconductor FET (MOSFET), whose gate is extended by a platinum electrode for sensing. The metal is then functionalised by attaching covalently antibodies fragments that act as probes for the antigens in the tested biofluids. Laboratory samples were prepared in house, using fluorescein as antigen. Concentrations between 45pM and 1uM have been tested, and the absence of non-specific binding has been successfully proved with bovine serum albumin (BSA), for which any noticeable response has been recorded. Conclusion We report an important step towards a real-time and reliable detection of cardiac troponin by means of nano-ISFETs, demonstrating the fluorescein antigens-antibodies specific binding. Further steps consists in correctly achieve a surface functionalisation with cardiac troponin I antibodies, and further enhance the sensor LoD. Antigens detection with EGFET Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Swiss National Science Foundation: ERA-NET, FLAG-ERA CONVERGENCE

High-Density Mo–W–Cu Pseudoalloys Based on Homogenous Mo–25% W Powder Alloy Produced by Reducing Oxide Powders in Moving Layers

The article aimed to obtain a structural material with increased plasticity and density of 98.5–99.5% based on (Mo–25% W)–20 vol.% Cu pseudoalloys with a homogeneous refractory skeleton obtained by a single-time pressing and sintering of the dispersed mixture at temperatures 1400–1500°C. The production of a dispersed granulated Mo–25% W alloy with a powder particle size of 0.1–0.3 μm through the decomposition of complex ammonium paramolybdate and paratungstate salts into oxide compounds xWO3 · yMoO3 with their subsequent reduction by hydrogen in a rotary chamber was studied. Considering the temperature and decomposition time of complex salts in the moving layers, the physical and technological properties (such as phase composition, oxygen content, specific surface, bulk density, and tap density) of complex oxide powders xWO3 · yMoO3 and metal Mo– 25% W powders after reduction by hydrogen were compared with the corresponding properties of powders obtained in a stationary tube furnace in fixed layers. Temperature dependencies of porosity in (Mo–25% W)–20 vol.% Cu pseudoalloys after sintering at the temperature between 900 and 1500°C has been examined. It has been established that compaction of dispersed powder mixtures of (Mo–25% W)–20 vol.% Cu and homogenization of Mo–25% W alloy after sintering begin at the temperature 300°C lower than when sintering mechanical mixtures of commercial metal powders. It has been shown that (Mo–25% W)–20 vol.% Cu pseudoalloys obtained by liquid-phase sintering at 1500°C for 1 hour have the following characteristics: at 20°C, the ultimate tensile strength σt == 490 MPa, relative elongation δ = 1.1, Brinell hardness HB = 3.3 GPa, and at 500°C— σt == 370 MPa, δ = 4.4, and HB = 2.7 GPa.

Ultralight and fire-extinguishing current collectors for high-energy and high-safety lithium-ion batteries

Inactive components and safety hazards are two critical challenges in realizing high-energy lithium-ion batteries. Metal foil current collectors with high density are typically an integrated part of lithium-ion batteries yet deliver no capacity. Meanwhile, high-energy batteries can entail increased fire safety issues. Here we report a composite current collector design that simultaneously minimizes the ‘dead weight’ within the cell and improves fire safety. An ultralight polyimide-based current collector (9 μm thick, specific mass 1.54 mg cm−2) is prepared by sandwiching a polyimide embedded with triphenyl phosphate flame retardant between two superthin Cu layers (~500 nm). Compared to lithium-ion batteries assembled with the thinnest commercial metal foil current collectors (~6 µm), batteries equipped with our composite current collectors can realize a 16–26% improvement in specific energy and rapidly self-extinguish fires under extreme conditions such as short circuits and thermal runaway.

Using in situ polymerisation to enhance adhesion of dissimilar materials

Dissimilar material bonding is a challenge constantly being considered within engineering. This paper presents a method for tailoring metal surfaces by covalently grafting polymers that are directly complimentary to their respective dissimilar material. Acrylic acid was grafted onto the surface of aluminium which was subsequently bonded to poly-lactic acid (PLA), nylon-6, and a nylon-6/carbon fiber hybrid via hot pressing. Improvements over 500% and 100% in lap shear strength were observed when bonded to Nylon-6 and Nylon-6/carbon fiber joints, respectively, while no improvements were observed for PLA. Poly (acrylic acid) grafted to the surface of A36 Steel and adhered to a commercial metal joining epoxy adhesive showed an improvement of 49% in lap shear strength. This paper shows that electro-grafting can be used to both supplement existing adhesive bonding techniques but also act as an avenue for tailoring of dissimilar material interfaces and create novel, adhesive free bonding opportunities with thermoplastics.

ZIF-67-derived Co nanoparticles anchored in N doped hollow carbon nanofibers as bifunctional oxygen electrocatalysts

Developing highly active and robust bifunctional non-precious oxygen electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is of paramount importance for enhancing the efficiency of zinc-air battery. Herein, Co nanoparticles anchored in N doped hollow and porous carbon nanofibers (CoN-HPCNF) are obtained via an in-situ growth-pyrolysis approach with the hybrid of ZIF-67 and carbon nanofibers as the precursor. Originating from its high surface area, firm and hierarchical porous structure, effective doping of N as well as synergistic effect from Co nanoparticles and HPCNF, the optimized CoN-HPCNF shows prominent bifunctional catalytic activity and long-term stability toward OER and ORR. Importantly, the assembled aqueous zinc-air battery with the prepared catalyst as the air cathode delivers a peak power density of 126.6 mW cm−2 and narrow charge-discharge voltage gap together with excellent operation durability (more than 280 h at the current density of 5 mA cm−2), outdoing the commercial precious metal catalysts (Pt/C + IrO2).

Synthesis of α–MnO2–like rod catalyst using YMn2O5 A–site sacrificial strategy for efficient benzene oxidation

The elimination of benzene, a typical volatile organic pollutant, is one of the most challenging topics for environmental scientists. Catalytic oxidation technology is considered the most efficient approach for its elimination. Herein, we report the successful preparation of a novel α–MnO2–like rod catalyst via an acid etching route and propose YMn2O5 mullite as a novel precursor. The optimized α–MnO2–like rod catalyst showed significantly improved benzene oxidation activity compared to the raw YMn2O5 and commercial MnO2 catalysts, resulting in 100 % benzene conversion at 200 °C at a GHSV of 60,000 mL g–1 h–1. Notably, the α–MnO2–like rod catalyst performance at lower temperatures (100–175 ℃) exceeded that of a commercial Pt/Al2O3 catalyst. The excellent catalytic performance of the α–MnO2–like rod catalyst is associated with its low–temperature reducibility and abundant surface–active oxygen species. During the acid etching process, more Mn3+ is oxidized to Mn4+, and more surface oxygen vacancies are generated on the α–MnO2–like rod catalyst, which provides more adsorption sites for oxygen molecules to promote the benzene oxidation reaction. The α–MnO2–like rod catalyst should be a great alternative to commercial noble metal catalysts for the elimination of volatile organic pollutants, especially at lower temperatures.

Characterization of Commercial Metal Oxide Nanomaterials: Crystalline Phase, Particle Size and Specific Surface Area.

Physical chemical characterization of nanomaterials is critical to assessing quality control during production, evaluating the impact of material properties on human health and the environment, and developing regulatory frameworks for their use. We have investigated a set of 29 nanomaterials from four metal oxide families (aluminum, copper, titanium and zinc) with a focus on the measurands that are important for the basic characterization of dry nanomaterials and the determination of the dose metrics for nanotoxicology. These include crystalline phase and crystallite size, measured by powder X-ray diffraction, particle shape and size distributions from transmission electron microscopy, and specific surface area, measured by gas adsorption. The results are compared to the nominal data provided by the manufacturer, where available. While the crystalline phase data are generally reliable, data on minor components that may impact toxicity is often lacking. The crystal and particle size data highlight the issues in obtaining size measurements of materials with broad size distributions and significant levels of aggregation, and indicate that reliance on nominal values provided by the manufacturer is frequently inadequate for toxicological studies aimed at identifying differences between nanoforms. The data will be used for the development of models and strategies for grouping and read-across to support regulatory human health and environmental assessments of metal oxide nanomaterials.

Assessing Cobalt Metal Nanoparticles Uptake by Cancer Cells Using Live Raman Spectroscopy.

PurposeNanotechnology applied to cancer treatment is a growing area of research in nanomedicine with magnetic nanoparticle-mediated anti-cancer drug delivery systems offering least possible side effects. To that end, both structural and chemical properties of commercial cobalt metal nanoparticles were studied using label-free confocal Raman spectroscopy.Materials and MethodsCrystal structure and morphology of cobalt nanoparticles were studied by XRD and TEM. Magnetic properties were studied with SQUID and PPMS. Confocal Raman microscopy has high spatial resolution and compositional sensitivity. It, therefore, serves as a label-free tool to trace nanoparticles within cells and investigate the interaction between coating-free cobalt metal nanoparticles and cancer cells. The toxicity of cobalt nanoparticles against human cells was assessed by MTT assay.ResultsSuperparamagnetic Co metal nanoparticle uptake by MCF7 and HCT116 cancer cells and DPSC mesenchymal stem cells was investigated by confocal Raman microscopy. The Raman nanoparticle signature also allowed accurate detection of the nanoparticle within the cell without labelling. A rapid uptake of the cobalt nanoparticles followed by rapid apoptosis was observed. Their low cytotoxicity, assessed by means of MTT assay against human embryonic kidney (HEK) cells, makes them promising candidates for the development of targeted therapies. Moreover, under a laser irradiation of 20mW with a wavelength of 532nm, it is possible to bring about local heating leading to combustion of the cobalt metal nanoparticles within cells, whereupon opening new routes for cancer phototherapy.ConclusionLabel-free confocal Raman spectroscopy enables accurately localizing the Co metal nanoparticles in cellular environments. The interaction between the surfactant-free cobalt metal nanoparticles and cancer cells was investigated. The facile endocytosis in cancer cells shows that these nanoparticles have potential in engendering their apoptosis. This preliminary study demonstrates the feasibility and relevance of cobalt nanomaterials for applications in nanomedicine such as phototherapy, hyperthermia or stem cell delivery.

Polydopamine nanoparticles modified nanofiber supported thin film composite membrane with enhanced adhesion strength for forward osmosis

To minimize the internal polarization concentration (ICP) in FO process and improve the structural stability of thin film composite (TFC) forward osmosis (FO) membrane, a reactable hydrophilic nanofiber substrate was prepared by vacuum filtrating an interlayer composed of polydopamine nanoparticles (PDA NPs) onto an electrospun polyacrylonitrile nanofiber substrate. Then a TFC FO membrane with dense selective layer, low structure parameter, high water permeability and low salt permeability was prepared by the interfacial polymerization thereon. According to the T-peel test, the resulting TFC FO membrane showed greatly improved adhesion strength between selective layer and substrate due to the chemical bonding and entanglement between polyamides and the PDA NPs, and the strong adhesion between PDA NPs and the nanofibers. The ICP in FO process for the resulting membranes were minimized due to the application of the nanofiber substrates with low structure parameter (in the range of 290 ± 36 μm–354 ± 20 μm). These FO membranes performed well in the heavy metal ions contained water treatment, showed 1–2 times higher water flux (29.2 ± 0.3 L/m2h) compared with commercial TFC membrane (HTI-TFC) and high heavy metal ions rejection (99.5% ± 0.4%, 99.1% ± 0.5%, 98.1% ± 0.7% for Cr3+, Cu2+ and Ni2+, respectively) when using 2.0 M NaCl as draw solution. The findings provide the pathway for the design of nanofiber based FO membrane with improved structure stability and high performance by interfacial polymerization.

Magnetic Micro Sensors with Two Magnetic Field Effect Transistors Fabricated Using the Commercial Complementary Metal Oxide Semiconductor Process.

The fabrication and characterization of a magnetic micro sensor (MMS) with two magnetic field effect transistors (MAGFETs) based on the commercial complementary metal oxide semiconductor (CMOS) process are investigated. The magnetic micro sensor is a three-axis sensing type. The structure of the magnetic microsensor is composed of an x/y-MAGFET and a z-MAGFET. The x/y-MAGFET is employed to sense the magnetic field (MF) in the x- and y-axis, and the z-MAGFET is used to detect the MF in the z-axis. To increase the sensitivity of the magnetic microsensor, gates are introduced into the two MAGFETs. The sensing current of the MAGFET enhances when a bias voltage is applied to the gates. The finite element method software Sentaurus TCAD was used to analyze the MMS’s performance. Experiments show that the MMS has a sensitivity of 182 mV/T in the x-axis MF and a sensitivity of 180 mV/T in the y-axis MF. The sensitivity of the MMS is 27.8 mV/T in the z-axis MF.

A Study of the Performance of an N-Channel MOSFET Under Gamma Radiation as a Dosimeter

This paper is devoted to the effect of gamma radiation on commercial IRFP250 N-channel metal oxide semiconductor field effect transistors (MOSFETs) in a dose range from 0.5 Gy up to 50 Gy. The device under investigation can be utilized for radiation therapy and dose detection and measurement. The different MOSFETs parameters such as drain current ID, threshold voltage Vth, sensitivity S, transconductance G, and annealing are studied. The main goal of this work is to accurately determine the previous parameters before and after ionizing radiation. From the obtained results, one can estimate the dosage by measuring the mentioned device parameters. The study will be of benefit not only for MOSFET applications as a dosimeter, but also for selecting the type which can tolerate this kind of radiation, especially for space and satellite applications. Finally, the annealing process is done at different temperatures and time. This will aid in determining the ability of the device under test (DUT) to recover. Therefore, the fading of the DUT is studied. From our results, the MOSFET device has excellent properties as a dosimeter. Moreover, in our case, the transconductance and sensitivity were enhanced after irradiation.

The non-precious metal ORR catalysts for the anion exchange membrane fuel cells application: A numerical simulation and experimental study

Alkaline anion exchange membrane fuel cells (AEMFCs) are attracting more and more attention due to the advantages of using non-platinum-group (NPG) metal catalysts and less expensive metal hardware at the high pH conditions. However, the studies of electrodes with the non-precious metal are still less and the performance of the AEMFC operated with the NPG metal catalysts need to improve. In this work, based on AEMFCs operated with the commercial non-precious metal ORR catalysts (Acta 4020), a two dimensional, two-phase flow and steady-state agglomerates model is developed, and the effects of operational conditions of the relative humidity and the structure of the catalyst layer on fuel cell performance are numerically studied and analyzed. The results demonstrate that the relative humidity directly impacts the water distribution and transport in the MEA, and the low relative humidity in the cathode can increase the water back diffusion from the anode to the cathode and improve the fuel cell performance. An increase in the catalyst loading has been found to have a positive effects on the fuel cell performance, but the improvement is limited when the catalyst loading increases to a certain value. In addition, the increase in the mass ratio of catalyst to ionomer results in a decrease in the thickness of the ionomer film, but the excessive mass ratio of the catalyst to the ionomer also leads to a decrease in ionic conductivity, thereby deteriorating the performance of fuel cell. At last, operating with the optimized conditions from the model, the AEMFC realized a good fuel cell performance, and the peak power density reached 566 mW cm−2 and 326 mW cm−2 for H2/O2 and H2/Air (CO2-free) at 60 °C, respectively, and the results are higher than those reported in references.