AIP Advances

Atmospheric pressure cold plasma technology has demonstrated promising anticancer effects in cancer therapy, but the small effective treatment area limits its ability to meet the need for larger treatment zones in practical applications. In this study, a hollow needle-ring electrode structure was used to achieve a laterally broadened discharge at low gas flow rates through a slit dielectric tube nozzle. At an argon gas flow rate of 3 standard liters per minute (SLM), the nozzle was fully filled with visible plasma filaments, so there was no need to increase the gas flow rate, which reduced the cost investment. By maintaining the argon gas flow rate at 3 SLM, the effect of different voltages on discharge characteristics was studied. It was found that increasing the voltage improved the uniformity of the lateral discharge and the intensity of reactive species. At 12 kV, the discharge area reached 25 (laterally) × 7 mm² (vertically), achieving a uniform and effective widening of the plasma treatment area. In addition, the measured values for human-safe current and gas temperature met the requirements for safety, making the plasma suitable for biomedical applications. With the increase in plasma treatment time, the concentrations of H2O2, NO2⁻,and ONOO⁻/O2⁻ also increased. 57% of A549 cells cultured in vitro can be inactivated within 4 min by apoptosis, demonstrating the device’s effective anticancer potential.

The applications of plasma-activated water have drawn a lot of attention in plasma agriculture in recent years. Plasma-activated water provides the reactive oxide and nitrogen species in water, and the rest of the nutrients are supplied by the chemical fertilizer or organic fertilizer in previous studies. We report the procedures to produce the phosphate-rich water and potassium-rich water by atmospheric pressure plasma jet to fill in the blanks of major nutrients in plasma agriculture. The production rate of phosphoric acid is found greatly enhanced by using an air plasma jet compared with an N2 and CO2 plasma jet. We show the concentration of potassium-rich water is affected by the oxide layer on the potassium chunk. Potassium-rich water is more effectively produced in air and CO2 plasma jets than in N2 and Ar plasma jets, which is evidenced by the plasma emission spectrum intensity and current profile. Taking the growth of Arabidopsis thaliana as an example, we demonstrate that the plasma fertilized waters, including the nitrate-rich water, phosphate-rich water, and potassium-rich water, can help the growth of plants in plasma agriculture.

Single-molecule magnets (SMMs) are pivotal in molecular spintronics, showing unique quantum behaviors that can advance spin-based technologies. By incorporating SMMs into magnetic tunnel junctions (MTJs), new possibilities emerge for low-power, energy-efficient data storage, memory devices and quantum computing. This study explores how SMMs influence spin-dependent transport in antiferromagnet-based MTJ molecular spintronic devices (MTJMSDs). We fabricated cross-junction MTJ devices with an antiferromagnetic Ta/FeMn bottom electrode and ferromagnetic NiFe/Ta top electrode, with a ∼2 nm AlOx layer, designed so that the AlOx barrier thickness at the junction intersection matched the SMM length, allowing them to act as spin channels bridging the two electrodes. Following SMM treatment, the MTJMSDs exhibited significant current enhancement, reaching a peak of 40 μA at 400 mV at room temperature. In contrast, bare MTJ junctions experienced a sharp current reduction, falling to the pA range at 0°C and remaining stable at lower temperatures—a suppression notably greater than in SMM-treated samples (Ref: Sankhi et al., Journal of Magnetism and Magnetic Materials, p. 172608, 2024). Additional vibration sample magnetometry on pillar shaped devices of same material stacks indicated a slight decrease in magnetic moment after incorporating SMMs, suggesting an effect on magnetic coupling of molecule with electrodes. Overall, this work highlights the promise of antiferromagnetic materials in optimizing MTJMSD devices and advancing molecular spintronics.

Ag3Sn plays a connecting role in the bonding between a Sn-based solder and an Ag substrate due to its excellent connectivity performance. Therefore, it is particularly important to explore the Ag3Sn/Ag interface. The binding energies, interfacial energies, wetting behaviors, electronic structures, and interfacial bonding properties of fourteen Ag(2̄2̄4)/Ag3Sn(002̄) interfaces were investigated by using the first-principles calculation. The layer spacing convergence results show that an eight-layered Ag(2̄2̄4) surface and a nine-layered Ag3Sn(002̄) surface are enough thick to be chosen for the interface models. The calculated results showed that the surface energies are 0.91 , 0.91–0.96, and 0.70–0.75 J/m² for the Ag(2̄2̄4) surface, Ag3Sn(002̄) surface I, and Ag3Sn(002̄) surface II, respectively. It is shown that the interface I (A-Sb) configuration is the most stable structure with the largest adhesion work and the smallest interface energy. The calculation results for the contact angle indicated that the interface I (A-Sb) configuration exhibits good wettability. The density of states and electron difference density were calculated for the four most representative interfacial configurations. In addition, the results showed that the main bonding characteristic of the interface I (A-Sb) configuration is composed of Ag–Sn and Ag–Ag covalent bonds.

We aim to find the ideal parameters that will yield the best sensitivity for surface plasmon resonance measurements using attenuated total reflection. Several geometries and parameters are explored. Prism and metal choices are explored over a range of relative permittivities. In addition, the effect of frequency on sensitivity and, finally, the addition of layers of nanomaterials are explored as an aid to sensitivity. The results presented are appropriate for a sensing medium (water) with a refractive index of 1.33 and small changes due to an added analyte. The maximum sensitivity of the proposed structure is found to be 580 (degree/refractive index unit) for a wavelength of 633 nm. This is substantially larger than the typical value found in current applications.

Gas disasters pose a significant constraint on the safe development of coal mines. Focusing on the problem of gas over-limits in the upper corner of a hard roof, this study takes the I010206 working face of Kuangou Coal Mine as a case study and proposes a high-level borehole gas extraction method. Initially, FLAC3D was employed to analyze the development pattern of the “three zones” in the overlying strata of the working face. The results revealed that the height of the fractured zone in the I010206 working face is approximately in the range of 30–90 m. Subsequently, COMSOL was utilized to elaborate on the effective extraction radius of boreholes. The influence laws of factors such as extraction time and borehole arrangement on the extraction effect were analyzed, and an optimized borehole-layout plan for high-level borehole gas extraction was put forward. Furthermore, based on the above-mentioned analysis, FLUENT was used to establish a borehole gas extraction model to study the gas extraction effect of high-position boreholes arranged in the fractured zone. The research demonstrated that the triangular-pyramid-type borehole layout is reasonable and effective. In addition, the optimal vertical height for high-level drilling was found to be 28–32 m from the roof, and the optimal horizontal distance is 10–15 m from the model boundary. These findings are expected to offer technical references and guidance for gas control in the upper corners of hard roofs.

With the increasing demand for high-strength thin-gauge plates, the challenge of straightening these materials remains critical. This study investigates the elastic–plastic deformation behavior of plates and strips under significant deformation conditions during the positive and negative bending processes. It focuses on the influence of the stress inheritance effect on the curvature–bending moment (M–K) relationship and establishes an analytical model for the continuous straightening process based on the curvature integral method while incorporating the stress inheritance effect. The proposed model is validated through experiments and finite element simulations, achieving a residual stress error within 10%, confirming its accuracy. In addition, this study examines the effects of the plasticity rate and the number of rollers in the straightening machine. The findings indicated that as the plasticity rate increases, the plate exhibits a significant stress–strain hysteresis effect during multiple positive and negative bending cycles, causing the M–K relationship to enter the nonlinear range prematurely. This phenomenon significantly affects the central deformation of the plate and the final residual stress distribution. In addition, increasing the number of straightening rollers and elastic–plastic deformation cycles results in more residual stress inflection points across the plate section. This leads to a more uniform residual stress distribution, ultimately enhancing plate quality and advancing intelligent straightening technology.

The etching process was used to create MXenes (Nb2C, Ti2C, Ti3C2, Cr2C, and V2C) utilizing their respective predecessors, MAX phases Nb2AlC, Ti2AlC, Ti3AlC2, Cr2AlC, and V2AlC. The surface morphology and structural characteristics of the material were examined using x-ray diffraction and a scanning electron microscope (SEM), respectively. The SEM pictures are used to corroborate the layer architectures of the MXenes. The estimated bandgaps range from 1.76 to 1.81 eV, aligning with published values and suitable for light interaction and photodegradation processes. The Fourier transform infrared analysis further validates the functional group of the synthesized MXenes. Higher degradation efficiencies of 96%, 94%, and 75% within 120, 160, and 160 min are demonstrated by Nb2C, Ti2C, and Ti3C2, respectively. The etching of Al from the Nb2AlC, Ti2AlC, and Ti3AlC2 MAX phases leads to an enhanced surface area, which improves the photodegradation performance. The findings align with the SEM pictures, which unequivocally demonstrate the strong gaps formed by etching the middle layer of their predecessor MAX phases. As a result, Nb2C, Ti2C, and Ti3C2 MXenes can be suggested as a very efficient and rapid catalyst to address significant environmental pollution issues.

Three shunted Nb/Al–AlOx/Nb Josephson junctions (JJs) were fabricated, and the current–voltage (I–V) curve of JJs was measured at 4.2 K. The complex dynamical behaviors of the Josephson junctions (JJs) with parallel and series connection were investigated based on the resistive–capacitive–inductive shunted junction (RCLSJ) model with normalized characteristics parameters βC = 1.4 and βL1 = 2.5393. Numerical simulations revealed that specific features in the experimental I–V characteristic of these devices are a DC phenomenon of complex AC dynamic behavior. The influence of varied critical currents on the I–V characteristics of JJs and the details of intrinsic junction resonances were simulated based on the RCLSJ model. For the parallel-connected JJs with βC = 1.7 and βL1 = 1.9, the grouped critical currents iC1 = iC3 = 1 and iC2 = 1.1 would excite the controllable resonant state position of the paralleled JJs. For the JJs in series with βC = 1.7 and βL1 = 1.9, the unified Shapiro step can be constructed when the normalized critical current difference is within 3%, which reveals intrinsic junctions generally hard to generate unified Shapiro step. The normalized critical boundaries of the chaos state and the periodic dynamic state are proposed, with the chaos state occurring at normalized inductance values above three. The model of five JJs in series with and without irradiation was also simulated. The JJs have two groups of critical currents; therefore, two voltage jumps could be observed in the I–V curves with fixed inductance and capacitance. Under irradiation, two first-order Shapiro steps appeared in the I–V curves at voltages of 2 and 3. In addition, as critical current of each JJ increases, the current steps also increased in an ordered manner.

Tin oxide (SnO2) is a promising semiconducting material for use in dye-sensitized solar cells (DSSCs) as a potential alternative to titanium dioxide. Its advantageous properties, such as a wide energy bandgap, excellent photostability, and high charge carrier mobility, make it a suitable candidate for photovoltaic applications. In this study, we report the synthesis of SnO2 nanoparticles with sizes ranging from 5 to 20 nm using the co-precipitation method. The synthesized nanoparticles were thoroughly characterized using various analytical techniques to evaluate their structural, crystallographic, and electronic properties. X-ray diffraction was employed to assess crystallinity, while scanning electron microscopy and Raman spectroscopy were used to investigate morphological and structural features. UV-visible spectroscopy was utilized to determine the bandgap of the material. In addition, transmission electron microscopy and x-ray photoemission spectroscopy were conducted to gain deeper insights into the nanoparticle morphology and surface chemistry. For the fabrication of photoelectrodes, a simple yet effective doctor blade method was employed. The photoelectrodes were sensitized with Rhodamine B (Rh-B) dye and subsequently characterized for their performance in DSSCs. Under one-sun illumination conditions, the SnO2-based photoanode sensitized with Rhodamine B (Rh-B) dye demonstrated a solar conversion efficiency of ∼0.78%. These findings highlight the potential of SnO2 nanoparticles as a viable material for DSSC applications and provide a foundation for further optimization of their photovoltaic performance.

In this study, we investigate the soliton dynamics and stability properties of the time-fractional Hamiltonian amplitude (FHA) equation using the improved F-expansion method. The FHA equation, a fractional extension of the nonlinear Schrödinger equation, governs a wide range of nonlinear physical phenomena, including plasma physics, fluid dynamics, and optical communications. We exploit the beta fractional derivative approach to explore soliton solutions, chaotic behavior, bifurcations, and sensitivity analysis of the model parameters. The attained results reveal a variety of soliton structures, such as quasiperiodic, anti-peakon, and multi-periodic solitons, which are graphically represented to highlight their physical significance. Stability analysis using the linear stability method confirms the robustness of these solutions under certain perturbations. Moreover, bifurcation analysis via phase plane diagrams exposes key insights into the qualitative changes in the dynamical system, including the presence of quasiperiodic and chaotic behavior under external perturbations. These findings contribute to a deeper understanding of complex nonlinear systems and have potential applications in signal processing, optical fiber communications, and materials science.

Here, we present results of a computational study of electronic, magnetic, and structural properties of FeVTaAl and FeCrZrAl, quaternary Heusler alloys that have been recently reported to exhibit spin-gapless semiconducting behavior. Our calculations indicate that these materials may crystallize in regular Heusler cubic structure, which has a significantly lower energy than the inverted Heusler cubic phase. Both FeVTaAl and FeCrZrAl exhibit ferromagnetic alignment, with an integer magnetic moment per unit cell at equilibrium lattice constant. Band structure analysis reveals that while both FeVTaAl and FeCrZrAl indeed exhibit nearly spin-gapless semiconducting electronic structure at their optimal lattice parameters, FeVTaAl is a 100% spin-polarized semimetal, while FeCrZrAl is a magnetic semiconductor. Our calculations indicate that expansion of the unit cell volume retains 100% spin-polarization of both compounds. In particular, both FeVTaAl and FeCrZrAl are 100% spin-polarized magnetic semiconductors at the largest considered lattice constant. At the same time, at smaller lattice parameters, both compounds exhibit a more complex electronic structure, somewhat resembling half-metallic properties. Thus, both of these alloys may be potentially useful for practical applications in spin-based electronics, but their electronic structure is very sensitive to the external pressure. We hope that these results will stimulate experimental efforts to synthesize these materials.

The behavior of second-grade nanofluid is investigated in this work using entropy formation, thermal radiation, and changing thermal conductivity. The objective of this study is to provide deeper insights into how these variables influence fluid flow characteristics and heat transfer in nanofluid. To assess their impact on fluid dynamics and thermal behavior, the Tomson–Troian velocity slip condition and temperature slip boundary conditions are incorporated to examine mass and heat transport. The governing partial differential equations are simplified and effectively analyzed by transforming them into a collection of ordinary differential equations employing stream functions and similarity transformations. The shooting approach is used to produce numerical solutions for the physical phenomena, with the addition of the Newton–Raphson and Keller-box scheme for improved accuracy and convergence. This method also assesses the impact of physical parameters on temperature, velocity, and mass transfer sketches graphically for a clear understanding of their behavior. These parameters include heat production, variable thermal conductivity, the second-grade fluid parameter, the Eckert number, the Brownian motion, the Prandtl number, thermophoresis, and the Lewis number. This study found that the raising parameter for variable thermal conductivity enhances both temperature and velocity profiles. For the maximum second-grade fluid parameter, the temperature profile diminishes, while the velocity profile exhibits an upward trend. The Eckert number enhances the concentration and temperature profiles. The velocity profile of second-grade nanofluid decreases with increasing Prandtl numbers. Higher temperature-dependent density results in the greatest fluid temperature and concentration values. Greater Brownian motion results in improved mass and heat transmission magnitudes. The Sherwood number, Nusselt number, and skin friction coefficient decrease as the Prandtl number rises, but increase when the Lewis number rises.

The single harmonic oscillator and double-well potentials are important systems in quantum mechanics. The single harmonic oscillator is the paradigm in physics and is taught in nearly all beginner undergraduate classes, while the double-well potential illustrates the two important principles of quantum tunneling and linear superposition. While exact analytical solutions of the Schrödinger equation exist for both of these potentials, they are also employed to benchmark the use of approximate techniques, which may be the only recourse for more complicated potentials. In this paper, we review the Wentzel–Kramers–Brillouin (WKB) approximation for both these potentials. While this approximation is known for its accurate energies, we will instead emphasize how poor the WKB wave functions are. The inaccuracy of the WKB wave functions will then motivate us to adopt the lesser-known Modified Airy Function (MAF) approximation, which alleviates the deficiencies of the WKB wave functions. We will review the MAF solution to the simple harmonic oscillator potential and then apply the MAF to the double-well potential. We find accurate eigenvalues and, more importantly, very accurate wave functions. We conclude with the suggestion that an introduction to the MAF should be included in undergraduate courses to complement the WKB.

In this study, first-principles calculations were performed by different functionals to investigate the structural, electronic, and optical properties of Cs2NaSbBr6 double perovskite using density functional theory. The computed lattice constants a = 8.220 Å, Generalized Gradient Approximation-Perdew–Burke–Ernzerhof (GGA-PBE), unit cell volume, V = 392.789 ų, and formation enthalpy, ΔEf = −1431.59 eV/atom, confirm the structural stability and thermodynamic feasibility of the material. The tolerance factor τ = 0.810 further supports its structural robustness. The electronic structure analysis reveals a bandgap of 2.820 eV (GGA-PBE), indicating its potential for optoelectronic applications. The band structure and density of states (DOS) calculations provide insights into its electronic properties. Partial DOS was also used to discuss the bonding nature and strength among the different states. The optical properties of these phases have also been computed and analyzed to reveal possible relevance in diverse fields. Optical properties, including strong absorption in the visible spectrum, suggest its suitability for photovoltaic and energy-harvesting applications. The findings of this study highlight Cs2NaSbBr6 as a promising candidate for future experimental and technological advancements in renewable energy applications.

The China Fusion Engineering Test Reactor (CFETR) is a magnetic confinement tokamak experimental device currently under development in China, which is used to bridge the scientific and technical gaps between the International Thermonuclear Experimental Reactor (ITER) and Demonstration (DEMO). The common reaction in fusion reactors is the D-T reaction, which produces neutrons with energies of up to 14 MeV. This has a significant effect on the surrounding components and may cause issues such as irradiation damage, activation of structural materials, etc. Therefore, in order to provide a reliable reference for subsequent structural design and safety, the study of neutronics performance under different neutron source models is essential. Using a 3D neutronics model containing the water-cooled ceramic blanket (WCCB) blanket, the impact of different neutron source models on the neutronics performance for the CFETR at 1.5 GW is studied. The nuclear analyses are carried out by the Monte Carlo N-particle transport code, including the tritium breeding ratio (TBR), neutron wall loading (NWL), fast neutron flux, and nuclear heating deposition. The results indicate that different descriptions of neutron source models have a relatively small impact on the TBR, fast neutron flux, and nuclear heat, but a more significant impact on NWL.

The residual force vector method is commonly used for damage identification in truss structures but faces challenges when applied to planar plate elements due to their numerous characteristic parameters. To overcome this limitation, an improved method based on multi-characteristic parameter decomposition is proposed for damage identification in complex structural components. The method involves the following key steps: (1) decomposing the matrix element into eigenvalues to simplify the analysis, (2) calculating the stiffness connection matrix using the coordinate relationships of the structure, and (3) determining the damage location and severity by utilizing the damage location matrix and the element eigenvalues. The application of this improved method to a practical example demonstrates its effectiveness in accurately identifying damage, highlighting its potential for real-world structural health monitoring.

To address the “S” characteristic issue of pump–turbines under small opening conditions, this study investigates the impact of pre-guide vanes on the bladeless region dynamics, a critical yet underexplored area. This study investigates the changes in the bladeless region caused by the addition of pre-guide vanes in detail, providing insights for future theoretical research and engineering applications. Using a prototype from a Chinese pumped storage plant, three-dimensional unsteady flow simulations with the shear stress transport k–ω turbulence model were validated against experimental data. The results show that adding pre-guide vanes improves the “S” characteristic under small opening conditions and significantly influences the bladeless region. The arrangement and opening of the pre-guide vanes increase the opening of the synchronous guide vanes, which in turn raises the velocity within the bladeless region. Turbulent kinetic energy is concentrated in the bladeless region, where pre-guide vanes at positions 1#, 6#, 11#, and 16# disrupt the flow, generating strong turbulence. The maximum velocity is typically located at 0.005 m relative to the length of A–B, with velocity first increasing and then decreasing. High-frequency pressure pulsations dominate the bladeless region, with amplitude generally decreasing as the synchronous guide vane opening increases. Overall, the addition of pre-guide vanes significantly alters the flow structure and turbulence characteristics in the bladeless region, as well as the high-frequency pressure pulsations.

In the design of intelligent antennas, the integrated dynamic control of radiation and scattering characteristics is a core technology to improve antenna performance and broaden application scenarios. In this paper, such an electrically small antenna is designed by integrating an inner plasma layer for communication enhancement and an outer array composed of discrete cylindrical subwavelength plasma units for cloaking to radar detection. Numerical simulations are carried out with results indicating that the designed structure has synergistic modulation capability for improving radiation characteristics and controlling scattering properties simultaneously. It is shown that the inner subwavelength plasma ring provides a radiation gain of over 10 dB for the communication in the L-band, while the outer design of discrete surrounding units dominates omnidirectional suppression of radar cross section by ∼−15 dBsm. Meanwhile, both globally and locally fine-tuning parameters of the outer plasma units can achieve a transformation in forward- and backward-dominated scattering modes. Furthermore, the design of outer plasma units with heterogeneous plasma parameters enables possibilities of implementing targeted and more flexible scattering patterns. Our results offer practical solutions for designing various plasma-based tunable, reconfigurable, and multifunctional electromagnetic devices.

In this study, a four-grid retarding potential analyzer (RPA) with drilled grid holes is investigated, focusing on correlations between grid orientations and resulting characteristics. The individual grids have a hexagonal hole pattern and can be mounted rotated relative to each other in multiples of 90°. An ion beam with a small divergence and a narrow energy distribution directed perpendicularly to the RPA grid system is used. We find that for certain grid configurations, particularly when grids are aligned, the characteristics deviate from the expectation of strictly monotonic behavior in plots of the collector current against the discriminator voltage. Specifically, aligning two of the inner grids leads to a positive slope and a distinct hump at voltages below the falling edge. When all three inner grids are aligned, the hump becomes significantly more pronounced, with the signal intensity nearly doubling. Several models are presented to reproduce and understand these observations. We find that grid holes can act as scattering centers, and a finite grid thickness mitigates the potential reduction that occurs inside the grid holes. Suggestions for the design of RPAs are derived based on the findings.

Generally, a parallel connection of generators is required to meet the power need to supply the load demand. As a preferable replacement for typical generation units, a topology based on three-phase voltage source converters has been proposed. This paper proposes an approach based on virtual synchronous generator-based synchronverters for parallel operation of alternators. This approach automatically exchanges active and reactive power between parallel operated inverters of the same kind. Furthermore, to serve the purpose of synchronization, a Phase Locked Loop (PLL) is used. To avoid the tuning complexities and stability margin issue, a common PLL is used for both the converters. The PLL detects the grid voltage angle and helps with initial synchronization of the synchronverter in an easier way. The simulation studies are carried out to validate the performance and control of the proposed system. In addition, stability analysis has been performed using a state space approach to prove the efficacy of the system.

As the development of offshore oil and gas resources extends into deep sea, the reel-lay method was invented. During the entire process of reeling and unreeling in the reel-lay method, the pipeline undergoes several bends and experiences significant plastic deformation, which may lead to potential failure of the pipeline. To ensure the safety of subsea pipelines laid by the reel-lay method, this paper analyzes failure modes during reel laying and examines the limit states under combined loads. A model is developed using elasto-plastic theory to assess the pipeline’s ultimate bearing and strain capacities during the reeling and unreeling processes. Based on this model, a reel-lay system for 6-in. steel pipes was designed and tested in the Bohai Sea. The results, with average ellipticity at 1.215% and straightness at 0.0014 m, confirm the design’s validity and the accuracy of the proposed analysis method. This study proposes a criterion for ensuring the safety of pipelines during the reel-laying process, which can better guide the design of reel-laying equipment and operational safety.

The problem of water coning into the sandstone gas reservoirs has become one of the major concerns in terms of productivity and increased operating costs. However, the microscopic and macroscopic mechanism of water coning in the phenomenon remains unclear. To evaluate the microscopic water locks and macroscopic water seals in low-permeability sandstone gas reservoirs, the evaluation models of microscopic water locks and macroscopic water seals in low-permeability sandstone gas reservoirs were established based on the critical pressure gradient and water phase relative permeability of the water locking in the reservoir. The impact of production displacement pressure difference and stress sensitivity on the degree of water lock damage was analyzed in this study. The feasibilities of the models were verified through the water lock damage experiments in the sandstone, and the results showed that the model results were in good agreement with the experimental results. The water locking effect is the result of the reduction in gas phase relative permeability and absolute permeability caused by stress sensitivity, and the increasing back-pressure differential can reduce the water saturation in the sealed area. The stress sensitivity of the rocks can enhance the microscopic water locking effect in gas reservoirs, which leads to the increasing damage rate of the water locking permeability. Moreover, the macroscopic water sealing evaluation illustrates that natural gas needs to overcome adsorption force, capillary pressure, water phase gravity, static friction force, and frictional resistance along the flow path to generate flow when it is sealed. As the length of the flow path increases, the critical pressure differential for sealing increases in a positive correlation, while the critical pressure differential for sealing increases in a quadratic relationship when the flow velocity increases.

The discovery of photo-enhanced outputs in the fabricated memdiodes based on metal halide-embedded polymeric hybrid composites has meaningful and practical implications. The two-terminal devices exhibit typical rectifying characteristics, similar to a standard pn junction diode, with unusual photo-enhanced charge transportation and hysteresis behaviors. The MDs consist of an active layer of blended organic–inorganic hybrid material [a mixture of CuCl2 and polyethylene glycol (PEG)] deposited on a layer of pure polymer (polymethyl methacrylate) and, in turn, on a rigid substrate (ITO glass or Si wafer). It is found that the photoinduced current increases hundreds of times in magnitude on the ITO glass-substrate sample, much higher than that of the Si-substrate sample. The substrate-dependent photocurrent can be attributed to charge carrier generation by optical absorption correlated with transport paths at different interfaces and variations of working areas by different substrates. The energy bandgaps extrapolated from the UV–Vis absorption spectroscopy are at 1.50 and 3.1 eV, consistent with two applied voltages at which the currents jump abruptly under light-on and light-off statuses, respectively. The study of time-dependent resistances displays an exponential decay, a memristive feature, and a long relaxation time between high-resistance and low-resistance. The memdiodes are stable with repeatable working values in a bio-applicable range, assuring that the hybrid materials are excellent candidates for potential applications in biomedical electronic circuits, artificial neuromorphic synapses, and brain-inspired quantum computing.

Environmental perception is a crucial issue for underwater vehicles. This study investigates the use of the ensemble Kalman filter to reconstruct unsteady currents ahead of these vehicles by sampling the surrounding flow fields at scattered locations, which leads to an inverse problem. To mitigate the high computational cost associated with Monte Carlo methods, an axisymmetric simulation is employed for data assimilation. Therefore, it is important to discuss the influence of factors such as observation noise, sample size, and covariance inflation parameters on the final performance, especially when compared to the full three-dimensional model. The results suggest that while most of the error stems from model discrepancies, careful parameter selection can effectively control the error within acceptable limits.