Field Intensity Research Articles

Sodium dodecyl sulfate assisted electric field treatment for deproteinization of chitosan

Chitosan with a low protein residue is required as it is widely used in the field of biomedicine. Herein, we proposed a novel method for deproteinizing industrial grade chitosan via electric field treatment in a medium containing sodium dodecyl sulfate (SDS). The effects of electric field intensity, SDS concentration, and electrophoresis time on the protein removal efficiency were optimized by orthogonal experimental design and model building. Chitosan with an ultra-low protein residue (0.151 wt%) can be obtained at the voltage of 300 V, the SDS concentration of 1 wt%, and the electrophoresis time of 2 h. The strong binding between SDS and residue protein renders the conjugate with negative charges, which can migrate under the electric field. In addition, the electric field deproteinization process reduces the heavy metal content of chitosan slightly, while keeping the chemical structure of chitosan unchanged. The methodology provided in this work suggests the great potential of electric field treatment in removing residue protein in chitosan.

A Study on the Motion Behavior of Metallic Contaminant Particles in Transformer Insulation Oil under Multiphysical Fields.

When using transformer insulation oil as a liquid dielectric, the oil is easily polluted by the solid particles generated in the operation of the transformer, and these metallic impurity particles have a significant impact on the insulation performance inside the power transformer. The force of the metal particles suspended in the flow insulation oil is multidimensional, which will lead to a change in the movement characteristics of the metal particles. Based on this, this study explored the motion rules of suspended metallic impurity particles in mobile insulating oil in different electric field environments and the influencing factors. A multiphysical field model of the solid-liquid two-phase flow of single-particle metallic impurity particles in mobile insulating oil was constructed using the dynamic analysis method, and the particles' motion characteristics in the oil in different electric field environments were simulated. The motion characteristics of metallic impurity particles under conditions of different particle sizes, oil flow velocities, and insulation oil qualities and influencing factors were analyzed to provide theoretical support for the detection of impurity particles in transformer insulation oil and enable accurate estimations of the location of equipment faults. Our results show that there are obvious differences in the trajectory of metallic impurity particles under different electric field distributions. The particles will move towards the region of high field intensity under an electric field, and the metallic impurity particles will not collide with the electrode under an AC field. When the electric field intensity and particle size increase, the trajectory of the metallic impurity particles between electrodes becomes denser, and the number of collisions between particles and electrodes and the motion speed both increase. Under the condition of a higher oil flow velocity, the number of collisions between metal particles and electrodes is reduced, which reduces the possibility of particle agglomeration. When the temperature of the insulation oil changes and the quality deteriorates, its dynamic viscosity changes. With a decrease in the dynamic viscosity of the insulation oil, the movement of the metallic impurity particles between the electrodes becomes denser, the collision times between the particles and electrodes increase, and the maximum motion speed of the particles increases.

Theoretical study of tip-enhanced photoluminescence of single molecule in nanocavity formed by apex protrusion and substrate

Tip-enhanced photoluminescence techniques, characterized by ultra-high detection sensitivity and spatial resolution, have exhibited unprecedented capabilities in exploring optoelectronic phenomena and unraveling intrinsic physical mechanism at the single-molecule level. To suppress the quenching of molecular luminescence and achieve high-resolution optical imaging, a rational design of the tip-substrate configuration is required. In this paper, we systematically investigate the tip-enhanced photoluminescence characteristics of single molecules located within the plasmonic nanocavity formed by the tip protrusion and the substrate from a theoretical perspective. The impacts of electron tunneling and electron-hole pair creation on localized electric field and quantum yield are discussed using the quantum correction model and nonlocal dielectric theory, respectively. The crucial roles of atomic-scale protrusion at the tip apex and the decoupling layer on the substrate in enhancing vertical and horizontal electric fields as well as quantum yields have been emphasized. The results indicate that in smaller sub-nanometer cavities, electron tunneling and nonlocal dielectric effects greatly weaken the electric field intensity and fluorescence quantum yield. Meanwhile, due to the sharp lightning rod effect, the presence of atomic-level protrusion at the tip apex can provide a strong and highly localized plasmonic field. We find that the added NaCl layer not only blocks charge transfer between molecules and the substrate but also effectively prevents fluorescence quenching. The maximum fluorescence and Raman enhancement factors near the tip apex approach up to 5 and 12 orders of magnitude, respectively, achieving sub-nanometer spatial resolution. Finally, compared to vertical electric field and dipole, sharp protrusion can excite a stronger horizontal electric field and couple with horizontal dipoles to yield a higher quantum yield, resulting in a three orders of magnitude higher in the fluorescence enhancement of horizontal dipole compared to the tip without protrusion. Our theoretical research not only confirms the experimental results of spectral enhancement with the proximity of the tip to the molecule in tip-enhanced photoluminescence, but also provides effective guidance for a deeper understanding of the mechanism of tip-enhanced fluorescence and Raman spectroscopy, as well as optimizing the experimental system.

Adhesive strength improvement by providing steps in joints and differentiating initial and final debonding stresses

Step adhesive joints have a special characteristic quite different from other joints. When initial delamination occurs in other joints such as butt, lap and scarf joints, final failure always occurs. In these cases, the external stress causing initial delamination σcInitial is equal to the final failure stress as σcFinal = σcInitial. However, in step joints, the final failure stress σcFinal can be greater than the initial delamination stress σcInitial < σcFinal. To clarify the adhesive improvement mechanism, first, this paper discusses the ISSF (Intensity of Singular Stress Fields) for fully bonded step joint by varying the number of steps NS. Second, the singular stress field causing 2nd debonding is discussed by analyzing partially delaminated step joint. The results show that 2nd debonding requires larger external load than the initial debonding as σcInitial < σcFinal. This is because under the same external load the singular stress causing the 2nd deboning is smaller than the one causing the initial debonding. When NS≥6 and suitable overlap length, the final bond strength σcFinal can be more than 3.6 ∼ 4.4 times larger than the initial delamination stress σcInitial≪σcFinal resulting in much larger bond strength.

Effect of applying a magnetic field on the biofiltration of hexane over long-term operation period.

The present study reports on the effect of magnetic field (MF) intensity on the biofiltration of hexane vapors. MF ranging from 0 to 30 mT (millitesla) was used to evaluate the biofiltration of hexane for 191days under a fixed inlet load of 40gm-3h-1. A homogeneous MF generated by Helmholtz coils was used. The performance of the reactors was evaluated in terms of removal efficiency (RE), elimination capacity (EC), biomass content, and exopolysaccharide (EPS) production. Maximal removal efficiencies of 25%, 36%, and 40% were found for the control (H0), 10 mT (H10), and 30 mT (H30) reactors, corresponding to ECs of 14.2, 15, and 18gm-3h-1, respectively. In the last period (days 94 to 162), H10 and H30 showed 40% of RE improvement compared with Ho. Also, the removal occurred all along the bioreactor height for biofilters exposed to MF. Reactors achieved a total biomass content of 152, 180, and 147mg VS (volatile solids) g-1 dry perlite for H0, H10, and H30, correspondingly, associated with EPS production of 30, 30, and 40mg EPS g-1 VS. The main components of EPS affected by the MF were carbohydrates and glucuronic acid; proteins were slightly affected. Experiments with MF pulses of 4 and 2h confirmed that MF exposure improved the removal efficiency of hexane, and after the pulse, removal enhancement was maintained for 5days. Thus, the MF application by pulses could be an economically and friendly technology to improve the RE of volatile organic compounds (VOCs).

Regulating molecules/ions sieving channels of MXene-based membranes by edge-capping strategy

Regulating molecules/ions transport within two-dimensional (2D) sub-nanometer channels to achieve a higher separation efficiency is of considerable interest for MXene membranes in sustainable water treatment. Herein, sodium tripolyphosphate (STPP) was introduced into Ti3C2Tx nanosheets to construct a series of modified STPP-MXene membranes based on the edge-capping strategy. The critical role of edge-capping in modulating selective molecules/ions separation within 2D sub-nanometer channels was highlighted. The edge-capping method was demonstrated to moderately narrow the shoulder spacing between adjacent Ti3C2Tx nanosheets and impaired their positive electric field intensity. In addition, the DFT results showed that the cations exhibited a much lower relative energy with STPP-Ti3C2Tx (-0.0024 eV) compared to Ti3C2Tx nanosheets (-0.2092 eV), causing cations to permeate more readily through the STPP-MXene membrane. As a result, the appropriately designed and prepared STPP-MXene membrane demonstrated an excellent molecules/ions selectivity (CR/NaCl selectivity = 52.6, CR/Na2SO4 selectivity = 30.3), much higher than that of the pristine MXene membrane. Moreover, by protecting the Ti at the edges of Ti3C2Tx nanosheets, the STPP-MXene membrane retained its original two-dimensional structure to maintain a stable separation performance, even when exposed to a water environment for up to 60 days. In contrast, the pristine MXene membrane was completely oxidized due to its weak stability. This study provides a theoretical basis for the feasibility of edge-capping strategy as a broad modification alternative to design high-efficiency molecular/ionic sieving MXene membranes.

Enhanced transmission and group delay in optomechanics with an optical parametric amplifier

In this paper, we investigate the phenomenon of optomechanically induced transparency (OMIT) in a cavity that has a moving end mirror and is subjected to an external force. Furthermore, we place an optical parametric amplifier (OPA) inside the cavity. We show that the transmission intensity of the probe field and the group delay is enhanced by the parametric gain and phase of the OPA. We also show that this enhancement is influenced by external forces. We believe that these findings could be valuable in the area of quantum information processing.

Reliability of the palaeomagnetic signal recorded in a lava flow erupted on 4 December 2021 in La Palma (Canary Islands, Spain)

SUMMARY A basaltic lava flow erupted from the Tajogaite volcano on 4 December 2021, in La Palma (Canary Islands, Spain) was sampled to find out to what extent reliable and correct information on both intensity and direction of the Earth's magnetic field can be obtained from the palaeomagnetic signal recorded in a lava flow which erupted under known conditions. Samples were taken every few centimetres across a flow up to a total of 27 oriented cores. Palaeomagnetic experiments showed a strong viscous overprint in many samples. Nevertheless, the mean palaeomagnetic direction obtained agrees well with the actual value from IGRF-13. Rock magnetic experiments were performed to obtain additional information about the quality and reliability of the results and the reasons for unsuccessful determinations. Analysis of mostly irreversible thermomagnetic curves showed that the carriers of remanence were magnetite and titanomagnetite of low and/or intermediate Curie-temperature. Hysteresis parameter ratios showed a pronounced variability across the flow. Analyses of frequency dependent susceptibility, IRM acquisition coercivity spectra and FORCs showed a noticeably presence of very low coercivity grains (multidomain and superparamagnetic-single domain boundary). Multimethod palaeointensity experiments were performed with the Thellier-Coe, multispecimen and Tsunakawa-Shaw methods. Only three of 25 cores from the flow yielded successful Thellier-Coe determinations, in agreement with the expected field value of 38.7 μT (IGRF-13). However, palaeointensities of 60 per cent of the specimens agree with the expected value performing an informal analysis without considering criteria thresholds. Four of six Tsunakawa-Shaw determinations performed on samples from the flow yielded correct results, but three multispecimen determinations providing apparently successful determinations largely underestimate the expected field intensity. Combination of three Thellier-Coe and four Tsunakawa-Shaw successful determinations yields a multimethod palaeointensity result B = (36.9 ± 2.0) μT in good agreement with the expected field intensity.

Deciphering the role of three-color synthesized laser pulse parameters in N2 ionization and attosecond pulse shaping

Photoionization of atoms or molecules is a fundamental process in strong-field physics, essential for generating high-order harmonics and producing attosecond pulses. Here, we investigate how a three-color laser field, consisting of wavelengths at 800 nm and its second and third harmonics, photoionizes N2 molecules and evaluates its effect on the properties of attosecond pulses. It has been discovered that by altering the relative phase, these harmonics periodically influence molecular ionization, increasing the discreteness and strength of the attosecond pulse trains. Three-color field driving dramatically raises the pulse peak while decreasing the width of the strongest peak pulse, whereas two-color field driving just slightly enhances the pulse intensity and duration. Furthermore, the effectiveness of harmonic production is significantly increased by varying the laser intensity ratios. Even though the efficiency and pulse intensity of the three-color field are limited by conversion efficiency, attosecond pulses with higher intensities can be produced with proper parameter tuning at lower ionization rates. These findings offer a significant foundation for precisely controlling attosecond pulse generation. Ocis codes320.7110; 320.7120.

Spatial Identification of Mott-Schottky Effect at Electrocatalytic Pd/Metal Oxide Interfaces for the Oxygen Reduction Reaction.

To elucidate the microstructure and charge transfer behavior at the interface of Pd/metal oxide semiconductor (MOS) catalysts and systematically explore the crucial role of the Mott-Schottky effect in the oxygen reduction reaction (ORR) electrocatalysis process, this study established a testing system for spatially identifying Mott-Schottky effects and electronic properties at Pd/MOS interfaces, leveraging highly sensitive Kelvin probe force microscopy (KPFM). This system enabled visualization and quantification of the surface potential difference and Mott-Schottky barrier height (ΦSBH) at the Pd/MOS heterojunction interfaces. Furthermore, a series of Pd/MOS Mott-Schottky catalysts were constructed based on differences in work functions between Pd and n-type MOS. The abundant oxygen vacancies in these catalysts facilitated the adsorption and activation of oxygen molecules. Notably, the intensity of the built-in electric field in the Pd/MOS Mott-Schottky catalysts was calculated through surface potential and zeta potential analysis, systematically correlating the Mott-Schottky effect at the heterojunction interface of Pd/MOS with ORR activity and kinetics. By comprehensively exploring the correlation between the Mott-Schottky effect and ORR performance in Pd/MOS catalysts using the KPFM testing system, this study provides necessary tools and approaches for a deep understanding of heterogeneous interface charge transfer mechanisms, as well as for optimizing catalyst design and enhancing ORR performance.

Influence of La3+ ions on the structural, elastic, optical, and radiation shielding properties of Cr2O3-Doped heavy metal glasses

This study investigates the effect of La³⁺ rare earth ions on the structural, elastic, optical, and radiation shielding features of heavy metal borate glass (B₂O₃-PbO) doped with Cr₂O₃. Density measurements and FT-IR spectra analysis revealed the role of La3+ ions as a network modifier, where successive additions of La2O3 content led to a gradual increase in the density and an increase in the non-bridging oxygen content resulting from the structural transformation between the BO4 and BO3 units. The significant improvement in the elastic modulus and microhardness factor moduli was confirmed by calculating the change in ultrasonic velocities through the glassy system. The structural modifications induced by La³⁺ ions narrowed the band gap and increased the Urbach energy, indicating higher disorder within the glass network. The linear refractive indices increased due to increased optical basicity and electronic polarization. Optical absorption results showed that Cr⁶⁺/Cr³⁺ ions occupy octahedral/tetrahedral sites, with the tendency for Cr³⁺ cations to occupy more octahedral sites with increasing La₂O₃ content. The produced samples showed a greenish-yellow color caused by the absorption band centered at ∼415 nm associated with the electronic transition ⁴A₂g(F)→2Eg(G). The ligand field effect highlighted the significance of La³⁺ cations in increasing the crystalline field intensity surrounding Cr³⁺ cations and reducing the nephelauxetic ratio, signifying enhanced covalent character between Cr³⁺ cations and neighboring ions. Moreover, the radiation shielding capabilities of the glassy system were analyzed and compared with standard shielding materials, confirming superior shielding performance in samples with the highest La₂O₃ content.

Soil microbial community composition and nitrogen enrichment responses to the operation of electric power substation.

The surge in global energy demand mandates a significant expansion of electric power substations. Nevertheless, the ecological consequences of electric power substation operation, particularly concerning the electromagnetic field, on soil microbial communities and nitrogen enrichment remain unexplored. In this study, we collected soil samples from six distinct sites at varying distances from an electric power substation in Xintang village, southeastern China, and investigated the impacts of electromagnetic field on the microbial diversity and community structures employing metagenomic sequencing technique. Our results showed discernible dissimilarities in the fungal community across the six distinct sites, each characterized by unique magnetic and electric intensities, whereas comparable variations were not evident within bacterial communities. Correlation analysis revealed a diminished nitrogen fixation capacity at the site nearest to the substation, characterized by low moisture content, elevated pH, and robust magnetic induction intensity and electric field intensity. Conversely, heightened nitrification processes were observed at this location compared to others. These findings were substantiated by the relative abundance of key genes associated with ammonium nitrogen and nitrate nitrogen production. This study provides insights into the relationships between soil microbial communities and the enduring operation of electric power substations, thereby contributing fundamental information essential for the rigorous environmental impact assessments of these facilities.

Nonlocal dynamic response of FGP sandwich microbeam with 2D PSH network incorporating adatoms-surface interactions energy under magnetic field

The present work models and studies the resonance frequency change due to adsorption phenomena in a simply-supported adatom-microbeam system under an axial magnetic environment. The microbeam structure is a functionally graded (FG) sandwich that includes a rectangular configuration and a ceramic perforated core with periodic square holes network and FG porous material faces. To evaluate the adsorption-induced energies produced by van der Waals interaction (vdW), the Morse and Lennard-Jones (6–12) potentials are included in conjunction with nonlocal material elasticity to adopt the small-scale impact. Moreover, the explicit formulas for the inertia moments and shear force are developed by the Timoshenko beam equations, considering the residual stress influence as an additional axial load. The Navier-type solution and the differential quadratic method (DQM) are implemented to compute the solution of the governing equations. It is established that the resonance frequency change for the O/Si (100) and H/Si (100) is dependent on the geometrical, perforation, and porosity parameters, adsorption density, mode number, and the magnetic field intensity as well. Therefore, these numerical results have been discussed in detail to properly examine dynamic vibration behavior and a suitable mass detection design of M/NEMS structures.

Modeling methods in overlapping electroporation treatments: Pulse number effects on tissue conductivity and ablation area

Irreversible electroporation (IRE) is a non-thermal tissue ablation technique that utilizes high-voltage pulses between electrode pairs to destroy tissue. Numerical models are essential for predicting treatment outcomes and aiding in treatment planning. This paper studies a nonlinear conductivity model (NC) and a multiparametric nonlinear conductivity model (MPNC) to investigate overlapping electroporation treatments using a three-needle electrode configuration. The NC model accounts for the effects of the electric field and temperature on tissue conductivity during multiple pulsed electric field applications. The MPNC model incorporates the influence of pulse number, alongside electric field and temperature, on tissue conductivity. Results indicate that in the MPNC model, tissue conductivity is significantly higher in regions where the electric field intensity is below the threshold for irreversible electroporation, with the maximum difference reaching 0.4S/m. In contrast, tissue conductivity is slightly lower in regions where the electric field intensity exceeds the IRE threshold. Additionally, the MPNC model predicts a smaller area of irreversible electroporation and a larger area of reversible electroporation, with these differences becoming more pronounced as the distance between electrode needles increases. These findings underscore the importance of considering pulse number effects in numerical models to enhance the accuracy of treatment planning for irreversible electroporation-based therapies.

Influence of beam polarization on underwater femtosecond laser machining of silicon wafer

This paper investigates the effect of polarization directions on underwater femtosecond laser machining of silicon wafer. Firstly, laser ablation in liquids produces laser-induced periodic surface structures (LIPSS) on both edges of the groove. The direction of LIPSS has direct correlation with the polarization of the laser beam. Secondly, the electric field intensity distribution within the groove is analyzed by numerical simulation employing the finite-difference-time-domain (FDTD) method. The simulation and experimental results reveal that the distribution of the inter electric field intensity within the grooves varies with polarization direction. As the angle between the polarization and scanning directions decreases, the peak electric field strength and groove depth gradually increase. Finally, changing the direction of polarization of the beam affects the symmetry of the groove profile. The groove profile produced by ablation is symmetrical when the beam polarization direction is parallel to the scanning direction. By modulating and optimizing the direction of polarization, grooves with large depth and symmetrical shape can be obtained.

Numerical investigation of free convection inside square wavy enclosure using response surface methodology

AbstractFree convection is commonly applied in various engineering fields such as solar energy, electronic devices, nuclear energy, and heat exchangers. A computational simulation was used to analyze the natural heat transfer through convection in a wavy cavity with squared shape that was filled with tap water and saturated metal foam to assess the influence of hump configuration (square, triangle, circular, down semicircular, and up semicircular) and magnetic fields (magnetohydrodynamics) on heat transfer rate. The bottom wavy wall of the enclosure exhibits a high temperature (Th), whereas the top and side walls maintain a low temperature (Tc). The present paper will examine how the bottom wall hump number (N), aspect ratio (L), geometry inclination angle (θ), Hartman number (Ha), magnetic field intensity inclination angle (ɤ) affects the heat transfer rate at various Rayleigh numbers. When the circular hump design is used with specific parameters, including ɛ = 0.85, L = 1.25, N = 4, Tc = 0°C, θ = 0°, Ha = 600 and ɤ = 45°, for different Ra values, it leads to increased heat transfer and notable improvements in heat transfer enhancement (ɸ) and energy enhancement (e). The enhancements were measured at 2.5 times for heat transfer enhancement and 8.9 times for energy enhancement. Moreover, the ideal case of the current study had Ha = 600, L = 1.25, Ra = 30 × 103, and θ = 0° compared to the baseline case. Simulations were accomplished using CFD. The results demonstrate that the primary goal of the research was achieved by optimizing the design, leading to a significant improvement in hydrothermal performance for both ɸ = 2.5 and e = 8.9.

Magnetic-field-assisted extraction of phycocyanin from Spirulina platensis

Phycocyanin is the major natural pigment of phycobiliproteins produced by Spirulina platensis. Extraction and release of this pigment from cells depend on the disruption of the cell membrane. Extraction of bioactive compounds in magnetic field is a novel extraction method with unique characteristics and cost-effectiveness with high precision. Aim of the present study was to develop an efficient protocol for the extraction of phycocyanin from Spirulina platensis using magnetic-field-assisted extraction. Extraction process of phycocyanin via magnetic-field-assisted method was optimized using response surface methodology of three-level, three-variable central composite design. Results included optimum extraction conditions of solid-to-liquid ratio of 17.11 %, magnetic field intensity of 27.13 mT and extraction time of 49.87 min. Under the highlighted conditions, phycocyanin concentration, yield and purity included 5.44 mg/ml, 26.34 mg/g and 24.32, respectively. The experimental yield under optimal conditions was similar to the predictive yield. Magnetic-field-assisted extraction increased concentration, yield and purity of phycocyanin up to 97.7, 91.5 and 28.32 %, compared to conventional methods.

Features of distribution of electric field strength and current density in the reactor during treatment of liquid media with high-voltage pulse discharges

Purpose. Development and use of a mathematical model of the stages of formation of high-voltage pulse discharges in gas bubbles in the discharge gap «rod-plane» to identify the features of the electric field intensity distribution in the reactor and determine the current density in the load during disinfection and purification of liquid media by high-voltage pulse discharges and find the most rational treatment. Methodology. To achieve this goal, we used computer modeling using the finite element method as a method of numerical analysis. An experimental reactor model was created that takes into account the dynamics of discharges in gas bubbles in water. The equations describing the system include the generalized Ampere equation, the Poisson equation and the electric displacement equation, taking into account the corresponding initial and boundary conditions, as well as the properties of materials. The dependence of the potential of a high-voltage electrode on time has the form of a damped sinusoid, and the specific electrical conductivity in a gas bubble is a function of time. Processes occurring at the front of the voltage pulse from 0 to 20 ns are considered. Results. It is shown that with an increase in conductivity and high-voltage potential to amplitude values in a gas bubble, the electric field strength in the water layer in the reactor reaches 70 kV/cm, and it is in the water layer that there is a strong electric field. The calculations show that already by 19th ns the density of conduction currents in water prevails over that of displacement currents. At the same time, additional inclusions in the water significantly affect the distribution of electric field strength and current density, creating a significant difference in their values at the boundaries of the interface between the bubble, conductive element and water. Originality. A simulation of the dynamics of transient discharge processes in a gas bubble and a layer of water with impurities was carried out, including an analysis of the distribution of the electric field strength and current density in a system with rod-plane electrodes in the phase transition section of a gas bubble-water. This approach allows us to reveal the features of processes in reactors and to investigate the influence of phase transitions on the distribution of electrophysical quantities. Practical value. Computer simulations confirm the prospect of using nanosecond discharges generated in gas bubbles within a volume of water for widespread industrial use and are of great interest for further experimental and theoretical research. References 25, figures 9.

Two-photon polymerization-based fabrication of millimeter-sized precision Fresnel optics

Two-photon polymerization (2PP) is known to be the most precise and highest resolution additive manufacturing process for printing optics, but its applicability is restricted to a few applications due to the limited size of printable objects and low throughput. The presented work is intended to demonstrate the performance of printing millimeter-scale optics by implementing appropriate stitching methods into a setup that combines a Galvo scanner and translational axes. In this work, specifically, Fresnel axicons with a diameter of 3.5 mm are manufactured by 2PP to substantiate the applicability of the process. Manufacturing Fresnel optics instead of volumetric optics allows for attaining acceptable process times with durations of tens of hours highlighting the appeal of 2PP for rapid prototyping in optics. The suitability of the Fresnel axicons for beam shaping is confirmed through illumination with a laser beam. The resulting ring-shaped intensity distribution in the far field behind the Fresnel axicon is captured using a beam profiler. Furthermore, the influence of different stitching parameters on the resulting intensity distribution is investigated. The experimental results are validated by simulations, where the intensity distribution in the far field behind an axicon was calculated by Fourier transformation. Simulations were carried out to discuss the effect of manufacturing errors on the far field intensity distribution.

Personalized optimization strategy for electrode array layout in TTFields of glioblastoma.

Tumor treating fields (TTFields) is a novel therapeutic approach for the treatment of glioblastoma. The electric field intensity is a critical factor in the therapeutic efficacy of TTFields, as stronger electric field can more effectively impede the proliferation and survival of tumor cells. In this study, we aimed to improve the therapeutic effectiveness of TTFields by optimizing the position of electrode arrays, resulting in an increased electric field intensity at the tumor. Three representative head models of real glioblastoma patients were used as the research subjects in this study. The improved subtraction-average-based optimization (ISABO) algorithm based on circle chaos mapping, opposition-based learning and golden sine strategy, was employed to optimize the positions of the four sets of electrode arrays on the scalp. The electrode positions are dynamically adjusted through iterative search to maximize the electric field intensity at the tumor. The experimental results indicate that, in comparison to the conventional layout, the positions of the electrode arrays obtained by the ISABO algorithm can achieve average electric field intensity of 1.7887, 2.0058, and 1.3497 V/cm at the tumor of three glioblastoma patients, which are 23.6%, 29.4%, and 8.5% higher than the conventional layout, respectively. This study demonstrates that optimizing the location of the TTFields electrode array using the ISABO algorithm can effectively enhance the electric field intensity and treatment coverage in the tumor area, offering a more effective approach for personalized TTFields treatment.