The quality of coatings deposited by magnetron sputtering is known to depend on, among others, the magnetic field strength (Φ) and the magnetic field configuration. Furthermore, high power impulse ...magnetron sputtering (HiPIMS) is known to result in low defect - high density coatings, and is therefore used to deposit barrier coatings against wear and corrosion. The influence of varying the Φ, on deposition rate (R), structure and hardness of titanium nitride coatings prepared by HiPIMS and dc magnetron sputtering (dcMS) was investigated. At 22mT, the ratio between HiPIMS deposition rate and dcMS deposition rate (RHiPIMS/RdcMS) was almost equal to 1. As Φ was increased from 22mT to 35mT, R decreased by 28% for HiPIMS and increased by 15.6% for dcMS, and RHiPIMS/RdcMS was reduced from 1 to 0.63. From 35mT to 44mT, the decrease in R slowed to 6% for HiPIMS and to 12.5% for dcMS. The (111) orientation was dominant over (200) orientation for both HiPIMS and dcMS, and become less dominant with the Φ in the case of dcMS. The residual stresses and surface roughness were determined and their evolution with Φ is highlighted. Mechanical characterization of the deposited coatings was performed, where the hardness tests showed that on average the HiPIMS coatings (29-34GPa) were some 5 GPa harder than dcMS coatings (25-27GPa).
•TiN films were deposited using HiPIMS and dcMS technologies.•The effect of magnetic field strength on structure, hardness and deposition rate of TiN coatings was studied.•TiN coatings obtained using HIPIMS have shown a higher hardness than those obtained using dcMS..•The hardness did not show a noticeable change with the magnetic field strength in the range studied 22-44mT.
•For measuring the magnetic field strength of the micro-coil in the WP-μMS (structure: transmitting coil-micro-coil).•The calculation of the magnetic field strength is obtained through the mutual ...inductance coefficient.•Increase the mutual inductance measurement to nH-scale by using magnetically coupled resonance.•The magnetic field of the micro-coil is measured by eliminating magnetic field interference from the transmitting coil.
In recent years, the wireless passive micro-magnetic stimulator (WP-μMS) has emerged as a focal for implantable neuromagnetism modulation research. However, accurately measuring the magnetic field strength of the micro-coil presents a significant challenge due to its small size and low mutual inductance (M). Firstly, this paper establishes a theoretical model of magnetic coupling with a three-stage structure of transmitting coil-micro-coil-detecting coil. The calculation method of detecting the coil to measure the magnetic field is determined by calculating the M between each pair of coils. Secondly, the magnetic coupling resonance method enhances the measured value M to the nH-scale. This approach also eliminates the influence of the M between the transmitting coil-detecting coil on the measurement of the transmitting coil-micro-coil M, thereby achieving accurate measurement of the mT-scale magnetic field strength of the WP-μMS micro-coil. Finally, the effectiveness of the measured mT-scale magnitude magnetic stimulation is validated biologically.
Highlights • Objective IQ for T2WI was at 1.5T under optimized parameters comparable to 3T. • SNR and CNR of DWI were significantly higher at 3T. • Subjective IQ on was significantly better at 3T. • ...PI-RADS v2 scores were similar at 3T and 1.5T.
Capacitive deionization is an environment friendly electro-sorption desalination technology that has broad application prospects in high-efficiency seawater desalination and brackish water ...purification. However, the insufficient ion separation performance and desalination capacity restrict the large-scale application of capacitive deionization with flow-by structure. Since the separation of cations and anions is intensified via the synergetic manipulation of the electric field force and Lorentz force, a magnetic-assisted strategy was proposed to enhance the performance of capacitive deionization. The effects of magnetic field strength and layout on the desalination performance of capacitive deionization were experimentally investigated. The results confirmed the feasibility of performance enhancement via the effect of the magnetic field. The performance of capacitive deionization under a vertical magnet layout was increased by 25.2 % at a magnetic field strength of 0.33 T, compared to that without a magnetic field. However, the deionization performance decreased when the magnetic field strength was further increased to 0.45 T, which indicates the existence of a critical magnetic field strength. Benefitting from the superposition of magnetic fields, the horizontal layout of magnets can provide a stronger average magnetic field than the vertical layout. This study provides insights into a new design of flow-by capacitive deionization.
•A magnetic-assisted strategy was proposed to enhance capacitive deionization.•The feasibility of performance enhancement via magnetic field was confirmed.•Deionization performance was increased by 25.2 % at 0.33 T.•A critical magnetic field strength for the performance enhancement existed.•Horizontal layout provides a stronger magnetic field than the vertical layout.
Self-assembly is a process in which interacting bodies are autonomously driven into ordered structures. Static structures such as crystals often form through simple energy minimization, whereas ...dynamic ones require continuous energy input to grow and sustain. Dynamic systems are ubiquitous in nature and biology but have proven challenging to understand and engineer. Here, we bridge the gap from static to dynamic self-assembly by introducing a model system based on ferrofluid droplets on superhydrophobic surfaces. The droplets self-assemble under a static external magnetic field into simple patterns that can be switched to complicated dynamic dissipative structures by applying a time-varying magnetic field. The transition between the static and dynamic patterns involves kinetic trapping and shows complexity that can be directly visualized.
Heating of nanoparticles (NPs) using an AC magnetic field depends on several factors, and optimization of these parameters can improve the efficiency of heat generation for effective cancer therapy ...while administering a low NP treatment dose. This study investigated magnetic field strength and frequency, NP size, NP concentration, and solution viscosity as important parameters that impact the heating efficiency of iron oxide NPs with magnetite (Fe3O4) and maghemite (γ-Fe2O3) crystal structures. Heating efficiencies were determined for each experimental setting, with specific absorption rates (SARs) ranging from 3.7 to 325.9W/g Fe. Magnetic heating was conducted on iron oxide NPs synthesized in our laboratories (with average core sizes of 8, 11, 13, and 18nm), as well as commercially-available iron oxides (with average core sizes of 8, 9, and 16nm). The experimental magnetic coil system made it possible to isolate the effect of magnetic field parameters and independently study the effect on heat generation. The highest SAR values were found for the 18nm synthesized particles and the maghemite nanopowder. Magnetic field strengths were applied in the range of 15.1–47.7kA/m, with field frequencies ranging from 123 to 430kHz. The best heating was observed for the highest field strengths and frequencies tested, with results following trends predicted by the Rosensweig equation. An increase in solution viscosity led to lower heating rates in nanoparticle solutions, which can have significant implications for the application of magnetic fluid hyperthermia in vivo.
•Heating was tested in seven iron oxide nanoparticles for different magnetic fields.•Confirms an optimal nanoparticle size for heating that agrees with the literature.•Verifies Rosenweig's equation to predict the effect of field frequency on heating.•Reports reduced heating in high viscosity environments.
Frequency-dependent leakage inductance is often observed. The high-frequency eddy current effects cause a reduction in leakage inductance. The proximity effect between adjacent layers is responsible ...for the reduction of leakage inductance. This paper gives a detailed analysis of high-frequency leakage inductance and proposes an accurate prediction methodology. High-frequency leakage inductances in several interleaved winding configurations are also discussed. Interleaved winding configurations actually give a smaller degree of reduction of leakage induction at high frequency. Finite-element analysis simulation and measurement validate the models.
•This paper presents the design, simulation, fabrication and basic testing of non-spiral based fluxgate sensor.•This fluxgate sensor simulated using Ansys Maxwell software.•Fabricated using the PCB ...technology.•Tested the sensor using the measurement setup by using the Function generator, Oscilloscope and BPF filter.•Observed that sensor detects the strength of Earth’s magnetic field and plotted the frequency response of the sensor.
This paper presents performance characteristics of non-spiral planar excitation and pick-up micro-coils implemented for a fluxgate sensor with a NiFe magnetic rod core.Using Ansys Maxwell's software, the sensor performance is simulated. Magnetic fluxϕ, magnetic flux density B, magnetic field intensity H, coupling coefficient, inductance L and magnetic energy E of the coils are simulated for a set of excitation currents. A simple, cost-effective and less complex fabrication method is implemented to fabricate the sensor using Printed Circuit Board (PCB) technology. Non-spiral 5-turn fluxgate sensor of dimensions 50mmx 20mmx 0.5 mm length × breadth × width is fabricated and analysed at an excitation current with a fundamental frequency of 500 kHz. Two excitation coils and one pick-up coil are deposited on a horizontal PCB plane and NiFe rod type material is placed on it, which acts as the core. Synthetic glue is spread on the coils; it acts a insulator between the coils and the core. Copper is used for deposition of the both the excitation and pick-up coils. On applying different excitation current, the frequency response of the non-spiral fluxgate sensor is plotted. The sensor demonstrated earth magnetic field strength detection (∼25 μT).
Galaxy clusters form through a sequence of mergers of smaller galaxy clusters and groups. Models of diffusive shock acceleration suggest that in shocks that occur during cluster mergers, particles ...are accelerated to relativistic energies, similar to conditions within supernova remnants. In the presence of magnetic fields, these particles emit synchrotron radiation and may form so-called radio relics. We detected a radio relic that displays highly aligned magnetic fields, a strong spectral index gradient, and a narrow relic width, giving a measure of the magnetic field in an unexplored site of the universe. Our observations show that diffusive shock acceleration also operates on scales much larger than in supernova remnants and that shocks in galaxy clusters are capable of producing extremely energetic cosmic rays.
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