Search Results (18,221)

Reliable high-fidelity video transmission over noisy quantum channels remains challenging, especially due to temporal dependencies introduced by modern video compression standards. These codecs, such as versatile video coding (VVC), employ inter-frame prediction and group-of-pictures (GOP) structures, which are highly sensitive to channel noise and can lead to error propagation across frames. Conventional quantum encoding schemes, such as Hadamard-based superposition encoding, use fixed real-valued basis transformations that provide limited phase diversity and underutilize the multi-qubit state-space, reducing robustness under noisy quantum channels. To overcome these limitations, this study proposes a multi-qubit complex-valued orthogonal unitary superposition (COUS) encoding framework for quantum video transmission. In the proposed system, VVC-compressed video bitstreams are first protected using classical channel encoding, then segmented and mapped onto multi-qubit COUS quantum states, enabling joint amplitude and phase representation with improved resilience to quantum noise. At the receiver, transmitted quantum states undergo sequential COUS decoding, channel decoding, and VVC bitstream reconstruction to recover the original video frames. The simulation results show that COUS-based multi-qubit system outperforms the Hadamard encoding-based multi-qubit system, achieving peak signal-to-noise ratio (PSNR) up to 47.22 dB, structural similarity index measure (SSIM) up to 0.9905, and video multi-method assessment fusion (VMAF) up to 96.49. Even single-qubit COUS encoding achieves 3–4 dB channel SNR gain, while higher-qubit configurations further enhance robustness and reconstructed video quality. These results confirm that the proposed framework is scalable, noise-resilient, and provides high-fidelity quantum video transmission over noisy channels. Full article

Background/Objectives: Copper (Cu²⁺) is an essential trace element that participates as a cofactor in key metabolic enzymes such as cytochrome c oxidase and superoxide dismutase. However, excessive copper exposure can be toxic and disturbances in copper homeostasis have been associated with neurodegenerative diseases including Alzheimer’s and Parkinson’s disease. Despite growing evidence linking copper to neuronal dysfunction, the cellular mechanisms by which Cu²⁺ affects neuronal excitability and neurotransmission remain poorly understood. The aim of this study was to investigate the effects of acute Cu²⁺ exposure on ionic currents involved in cellular excitability and neurotransmitter release in bovine chromaffin cells. Methods: Primary cultures of bovine chromaffin cells were used as a neuroendocrine model to study cellular excitability. Voltage-dependent ionic currents were recorded using the whole-cell patch-clamp technique in voltage-clamp configuration. Catecholamine secretion was monitored by amperometry, and cytosolic Ca²⁺ dynamics were measured in fluo-4-loaded cells during depolarization induced by high K⁺ stimulation. Results: Acute Cu²⁺ exposure produced a concentration-dependent enhancement of depolarization-evoked catecholamine release. In parallel, Cu²⁺ inhibited voltage-dependent calcium (ICa), sodium (INa), potassium (IKv), and calcium/voltage-dependent potassium (IKCa-v) currents in a concentration-dependent and partially reversible manner. In addition, Cu²⁺ increased basal cytosolic Ca²⁺ levels while reducing the amplitude of depolarization-evoked Ca²⁺ transients. Conclusions: Acute Cu²⁺ exposure exerts a dual effect in bovine chromaffin cells, inhibiting the ionic currents that support cellular excitability while potentiating catecholamine secretion. This apparent paradox is consistent with a disruption of intracellular Ca²⁺ homeostasis, in which elevated basal cytosolic Ca²⁺ may facilitate exocytosis despite reduced depolarization-evoked Ca²⁺ entry. These findings provide new insight into the mechanisms by which copper may alter neuronal signaling and contribute to neurotoxicity. Full article

We present a method to control broadband terahertz generation rapidly during the interaction of a strong laser field with a gas. To achieve it, we utilize a few-cycle double-pulse, which is a combination of two identically colored femtosecond fields with a time delay, as a driving laser field. By varying the laser delay, the magnitude of the amplitude of generated terahertz field changes drastically, making it suitable for use as a terahertz optical ultrafast switch, with an optical period of only a few femtoseconds from ON-OFF-ON and an enhancement ratio of 100. Furthermore, a change in time delay can alter the terahertz field waveform, easily generating terahertz electric fields with positive and negative polarity or any phase in the range of [0, 1.0$\pi$]. The strength of such terahertz source can be boosted by raising the laser wavelength. Our study will provide an effective approach for ultrafast terahertz modulation. Full article

High-voltage direct current (HVDC) transmission systems are increasingly used for long-distance power transmission and the integration of renewable energy sources. In such systems, outdoor insulators are exposed to combined electrical stresses, including steady DC voltage, transient overvoltages, and environmental contamination, which can significantly influence leakage current behaviour and insulation performance. This work presents an experimental and numerical investigation of leakage currents on artificially contaminated polymer insulators under two application-relevant HVDC operating scenarios. The first scenario considers superimposed HVDC voltage with switching impulses and very slow front overvoltages, which may occur during fault conditions in converter-based HVDC systems. The second scenario investigates electromagnetic coupling effects in a hybrid HVDC/HVAC transmission line configuration, where AC and DC conductors are installed on the same tower. Artificial contamination layers with different morphologies and conductivities are applied to the insulator surface to reproduce realistic pollution conditions. Leakage currents are measured using a high-resolution acquisition system, and the results are supported with numerical simulations based on finite-element modelling. The results show that transient overvoltages significantly increase leakage current amplitude and duration, leading to increased electrical stress on contaminated insulators. In the hybrid transmission configuration, electromagnetic coupling between AC and DC paths induces additional current components in the DC leakage current. The presented results contribute to a better understanding of leakage current behaviour under realistic HVDC operating conditions and provide useful information for insulation assessment and condition monitoring of outdoor insulators in modern HVDC transmission systems. Full article

Background: Corylin (3-(2,2-dimethylchromen-6-yl)-7-hydroxychromen-4-one), a bioactive flavonoid, has been reported to exercise anti-inflammatory, antineoplastic, and antioxidant effects, and may also possess lifespan-extending properties. Objectives: Any modifications of transmembrane ionic currents produced by corylin remain largely unknown. Methods: The patch-clamp technique and docking prediction were used in this study. Results: In pituitary GH₃ somatolactotrophs, corylin concentration-dependently increased the magnitude of the M-type K⁺ current (I_K(M)), with an EC₅₀ of 3.8 μM. Concurrently, the activation time constant of I_K(M) was shortened. The addition of linopirdine (10 μM), an I_K(M) inhibitor, suppressed the current amplitude. Corylin also induced a leftward shift in the steady-state activation curve and enhanced I_K(M) during pulse-train stimulation. Moreover, corylin increases the hysteretic strength of I_K(M) evoked by a long-lasting triangular ramp pulse; this effect was attenuated by linopirdine. The stimulatory effect of corylin on I_K(M) was not altered by carvedilol or iberiotoxin but was reduced by dapagliflozin. In contrast, depolarization-activated I_K(M) was not affected by 17β-estradiol alone. In cell-attached recordings, corylin increased M-type K⁺ (K_M)-channel activity with minimal change in single-channel amplitude, while prolonging the mean open time. This stimulatory effect was reversed by linopirdine or dapagliflozin. Additionally, corylin slightly inhibited the erg-mediated current. Docking analysis further suggested that corylin potentially interacts with residues in KCNQ2 or KCNH2 channels via hydrogen bonding and hydrophobic interactions. Conclusions: These findings suggest that corylin modulates ionic currents, primarily through K_M (KCNQ/K_V7) channels, which may underlie its in vivo actions and those of related flavonoids. These effects may contribute to the regulation of functional activities of neuronal, neuroendocrine, and endocrine cells. Full article

Background/Objectives: Sensory experiences and emotional information contribute to conceptual knowledge. Compared to exteroceptive modality (e.g., visual, auditory), interoceptive modality predominates in the representation of emotional concepts. However, few studies have examined the interoceptive modality-specific effects on emotional word processing. Additionally, questions remain about when emotional valence interacts with sensory experiences during the processing of emotional words, and to what extent these words are grounded in different sensory experiences. Methods: To address these gaps, the present ERP study investigated how sensory information (interoception and vision) influences emotional word processing in a lexical decision task. Results: Behavioral results showed significant differences between interoceptive and visual words, as well as between positive and negative valence. A trend toward an interaction between sensory modality and emotional valence was also observed. ERP results indicated that negative words elicited a more positive-going P2 than positive words. Significantly smaller N400 amplitudes were observed for interoceptive words than visual words in the positive condition. Negative visual words evoked enhanced LPC amplitudes compared with both negative interoceptive words and positive visual words. Conclusions: The present findings suggest a dynamic pattern of valence effects in emotional word processing, characterized by a negativity bias and a positivity bias at different stages. Furthermore, our findings highlight that interoception promotes the semantic retrieval and integration of emotional words. This study provides empirical support for the modality-specific hypothesis within the framework of interoceptive embodied cognition and offers novel implications for future research on emotional word processing. Full article

This paper presents a new type of ultrasonic gyroscopic sensor based on a solid-state standing-wave vibrator, which is promising for shock-resistant applications. A theoretical model of the proposed design, which is a layered structure, and the numerical simulation of its frequency response using the developed software are presented. A test sample of the novel sensing element was made and experimental studies of its frequency response were conducted. The results showed a high correlation between the resonant frequencies both for the real sample research and numerical modeling; thus, the validity of the theoretical model was confirmed. The laboratory investigation of the developed sensing element on a test bench under rotating conditions was carried out and a shift in the standing-wave amplitude proportional to the angular velocity of rotation was revealed; thus, an informative signal for this type of gyroscopic sensor was found. It is shown that the amplitude of the output signal of the new sensor on standing waves compares favorably with the signal levels reported for similar traveling-wave solutions in previous studies. The optimization strategies for the new sensor’s design and operating mode to increase signal to noise ratio are also identified. Thus, the potential of using the developed solid-state standing-wave vibrator as a shock-resistant ultrasonic gyroscopic sensor is supported. Full article

This study investigates ultrasonic vibration-assisted (UV) CNC milling of hardened 90CrSi steel cylindrical surfaces, with emphasis on ultrasonic horn design, experimental analysis, and multi-objective optimization of machining parameters, addressing the need for an integrated framework combining system design, experimental validation, and multi-objective optimization. A quarter-wavelength ultrasonic horn was designed and experimentally validated to operate at a frequency of 20 kHz. By adjusting the horn–workpiece system, stable vibration amplitudes were achieved to enable effective ultrasonic-assisted milling of cylindrical surfaces. Milling experiments based on a Box–Behnken design were conducted to examine the effects of vibration amplitude, cutting speed, feed rate, and radial depth of cut on material removal rate (MRR) and surface roughness (Ra). Surrogate models using response surface methodology (RSM) and Gaussian process regression (GPR) were developed to predict machining performance. A GPR-assisted NSGA-II algorithm was then applied to simultaneously maximize MRR and minimize Ra, resulting in a well-defined Pareto front that reveals the trade-off between machining productivity and surface quality. Furthermore, an AHP-based decision-making approach was employed to select preferred machining conditions from the Pareto-optimal solutions. The GPR models demonstrated high predictive accuracy (R² > 0.98), and validation experiments confirmed the reliability of the predicted optimal results, with deviations below 5%. In addition, a comparative analysis between ultrasonic-assisted and conventional milling showed that MRR increased by 10.81–40.17%, Ra decreased by 27.11–44.44%, and cutting force was reduced by 14.2–42.65%, providing direct experimental evidence of improved machinability. The results demonstrate that the proposed integrated framework provides an effective strategy for optimizing ultrasonic vibration-assisted milling processes and improving the machinability of hardened 90CrSi cylindrical surfaces. Overall, the proposed framework provides a practical and cost-effective strategy for enhancing machining performance and offers a robust approach for multi-objective optimization of ultrasonic vibration-assisted milling processes. Full article

The purpose of this research is to determine which factors contribute to extending the read range of transponders equipped with different coupling-circuit topologies operating within selected RFID frequency bands. The analysis covered transponders that varied in both the configuration of their coupling circuits and their geometric dimensions. To accomplish this, transponder models were created using the EMCoS Studio electromagnetic simulation environment. Each model was subjected to simulations that yielded the mutual inductance and the voltage induced at the chip terminals. This study examines how the impedance of the embroidered antenna, the impedance of the chip’s coupling circuit, and the magnetic flux density affect the resulting chip voltage. In several of the investigated configurations, the peak chip voltage appeared outside the frequency range normally associated with RFID systems. The frequency at which this maximum occurred was dependent on the mutual inductance value. Understanding how individual parameters influence mutual inductance makes it possible to shift the voltage peak into a target operating band. Numerical simulation results, combined with the transponder’s mathematical model, enabled the calculation of the mutual inductance and the terminal voltage—quantities that directly determine the achievable read range. This study focuses on factors such as the resonant frequencies of the antenna and coupling circuit, their impedances, and the characteristics of the magnetic field. The findings show that tuning these parameters can affect not only the location of the voltage maximum, but also its amplitude. This effect introduces additional complexity in designing and selecting suitable transponder configurations. Full article

Typhoon passages typically induce significant upper-ocean responses, especially on the right side of the typhoon track. However, how mesoscale eddies modulate this left–right asymmetry remains insufficiently understood. Using high-resolution remote sensing data and reanalysis datasets, this study examines the impacts of a mesoscale eddy dipole influenced by Typhoon Ma-on (2011). The study finds that: (1) The eddy responses exhibit significant asymmetry: during Typhoon Ma-on (2011), the amplitude, circulation speed, and radius of the left side cyclonic eddy (CE) showed anomaly increases of 8.6 cm, 4.3 cm/s, and 54.3 km, respectively, whereas those of the right-side anticyclonic eddy (AE) showed anomaly decreases of 2.9 cm, 4.8 cm/s, and 13.9 km. (2) Mesoscale eddies modulate sea surface cooling with significant left–right asymmetry, differing from the conventional pattern of stronger right-side cooling. The left side CE enhanced surface cooling by up to 2.38 °C, while the right-side AE exerted a suppressing effect, with a cooling magnitude of 0.96 °C. (3) Within the CE, a significant negative temperature anomaly develops below about 20 m. Despite a relatively high Richardson number ($Ri$) and weak vertical shear that suppress excessive turbulent mixing, negative $W_s$-driven upwelling dominates, allowing cold water to be efficiently uplifted and maintaining or intensifying surface cooling. In contrast, the AE exhibits surface cooling but persistent positive anomalies below about 40 m, reflecting the partial retention of its subsurface warm water. In this case, reduced $Ri$ and enhanced shear instability promote stronger vertical mixing, enabling subsurface heat to be transported upward, thereby offsetting and weakening the surface cooling signal. Full article

Polarity-tunable photocurrents provide an intrinsic decision variable that enables in-sensor computing within a single device, moving beyond simple intensity detection toward next-generation intelligent vision, yet traditional photodetectors are limited by static doping profiles and fixed junction polarities. To overcome this bottleneck, we propose a Te_0.61Se_0.39 nanowire device with polarity-tunable photoresponse for broadband optoelectronic logic operation via photocarrier diffusion under localized light illumination. By simultaneously harnessing temporal (pulse width), spatial (light positions), amplitude (light intensity), and bias, our polarity-tunable devices deterministically realize the four fundamental Boolean logic gates (AND, NAND, XNOR, XOR), with a responsivity of 1.39 A/W and a specific detectivity of 1.75 × 10¹⁰ Jones across the visible to mid-wave infrared spectrum. We further showcased its scalability by constructing a two-layer composite Boolean circuit through the integration of optoelectronic AND and NAND gates. Practical applications in optical encoding/decoding transmission and differential perception highlight its broad functional adaptability. This work establishes a paradigm for broadband polarity devices in low-dimensional nanowires, providing a versatile platform for optoelectronic logic and differential imaging applications. Full article

Residual stress induced by shot peening (SP) is inherently unstable. Stress relaxation has attracted widespread attention, and related research has been carried out. This study aims to study the residual stress relaxation phenomenon in a shot-peened TC4 titanium alloy due to cyclic load. Numerical simulations and experiments were performed to investigate the effects of the applied load amplitude, the number of cycles, the depth and the load ratios. The study may make contributions to the literature on understanding the residual stress relaxation induced by shot peening. The numerical and experimental results showed that the relaxation rate of the residual stress is correlated to the applied stress amplitude. Most of the relaxation of the residual stress was observed in the first cycle, which is up to 47.2% and 62.3% after 1000 cycles for the two different shot peening intensities. After the high relaxation at the first cycle, the residual stresses gradually decreased at a lower rate, remaining almost stable for up to 1000 cycles. The experimental residual stress in the specimens at a load of 550 MPa decreased more than that for a load of 450 Mpa; the decrease was more than 29.6% for the 550 MPa load with 1000 cycles, and the relaxation was stable after 10,000 cycles. Also, the relaxations in the surface and depth were studied. The maximum residual stress was more prone to relaxation. The presented model of residual stress relaxation, validated with experimental data, showed good agreement for the residual stress relaxation. Full article

Phase-resolved wave estimation during operation of floating structures based on motion measurements provides an efficient, low-cost approach to enhancing operations. Prolate spheroidal wave functions (PSWFs) enable the reconstruction of wave profiles in short time windows with the help of a wave-to-motion response amplitude operator (RAO). Although fully linear hydrodynamic modeling can efficiently derive the RAO of floating structures, its applicability is highly limited to rather linear operation conditions. This study extends the PSWF methodology for wave estimation by combining it with the statistical linearization approach, which allows nonlinearities to be incorporated into the RAO based on the measured motion. The combined methodology is verified with motions for a floating cylinder and sphere, whose motions were calculated using a time domain simulation based on Cummins equation. Viscous drag and nonlinear hydrostatic forces were investigated. The results showed that the combined methodology increased the accuracy of the resulting wave profiles, measured in terms of correlation and spectral differences. Combining PSWFs and statistical linearization reproduced wave profiles with correlation values above 0.9 in waves with periods greater than 9 s. Combining both nonlinear effects for the sphere slightly increased the method’s accuracy due to the reduced motion amplitudes. Full article

The influence of conducted electromagnetic disturbances on the energy measurement error of electricity meters remains insufficiently explored in electromagnetic compatibility (EMC) studies, particularly in the frequency range above the classical harmonic domain. The aim of this study was to investigate the susceptibility of electricity meters with different input configurations to conducted disturbances in the frequency range 1 kHz–150 kHz, including the 2 kHz–150 kHz band covered by IEC 61000-4-19. The novelty of this work lies in the comparative analysis of meters employing a shunt resistor, current transformer, Rogowski coil, Hall-effect sensor, and a digital system based on a Merging Unit and Sampled Values. The tests were performed as a preliminary screening stage of the study, using a test procedure based on IEC 61000-4-19, in which the energy measurement error was determined from the difference between the energy measured by the meter under test and that measured by a reference meter while disturbances were injected into the current circuit. The results showed that, for most of the tested electronic meters, the influence of the disturbances at the applied 1 A level was limited. For the tested Class B meters, the observed maximum error deviations remained below 1%, while the largest deviation under continuous-wave disturbance was observed for the Merging Unit + SV system. The highest immunity to amplitude-modulated disturbances was found for the shunt-based meter and the Rogowski coil-based meter. In none of the investigated cases were large error deviations on the order of several percent or several tens of percent observed. The obtained results indicate that, under the applied test conditions, conducted disturbances in the investigated frequency range did not cause significant deterioration of the metrological performance of most of the analyzed electronic meters. However, the results should be interpreted as a comparative assessment under modified IEC-based test conditions, rather than as a full compliance evaluation at the normative disturbance levels for directly connected meters. Full article

This paper presents a theoretical analysis of frequency shifts in broadband acoustic field interference structures caused by an internal soliton wave in shallow water. It analyzes the spectral signature of interference-maxima frequency shifts within a coupled-mode framework that describes the scattering of acoustic normal modes under soliton-induced perturbations. Using the weak coupling approximation, analytical expressions are obtained for modal phase variations and the spectral peak frequency associated with the temporal evolution of frequency shifts induced by internal soliton waves. The analytical estimates obtained in the weak coupling approximation are extensively validated using numerical simulations under realistic ocean conditions without invoking it. This paper’s theoretical analysis demonstrates that internal soliton wave-induced mode coupling produces frequency shift spectrum signatures that strongly depend on soliton parameters. These results suggest that it is potentially feasible to estimate key soliton parameters, such as propagation direction, velocity, and effective amplitude, from measured frequency shifts. Numerical simulations demonstrate the feasibility of solving this inverse problem. These findings highlight the potential of frequency shift analysis as a practical, robust tool for remote sensing of internal wave dynamics in ocean acoustics. Full article