Search Results (1,170)

As the process node is scaled down, the spin-transfer-torque magnetic random-access memory (STT-MRAM) exhibits higher memory density than the static random-access memory (SRAM), making it one of the more promising successors of the low-level on-chip cache memory. However, the low read margin (RM) of the magnetic tunnel junction (MTJ) in STT-MRAM can limit the achievable read accuracy. We implemented 2-bit channel quantization for error-correcting code (ECC) schemes and explored the trade-offs between improved read accuracy and factors such as circuit area, power consumption, and latency. The proposed quantization scheme consists of a sensing amplifier-based 2-bit quantizer and MTJ resistor-based soft-decision thresholds. Compared to 1-bit channel quantization using the Bose–Chaudhuri–Hocquenghem (BCH) code, the proposed 2-bit quantization architecture achieves a fourfold reduction in frame error rate (FER) from $8.0\times {10}^{-4}$ to $2.0\times {10}^{-4}$ when paired with polar codes and successive cancellation (SC) decoding. Additionally, this approach results in decoding complexity that is only 1/13th of that required for BCH at a 0.7 code rate. Full article

Coaxial cable plays a vital role in the wide application of telecommunications, network, and television broadcasting and other fields, with its transmission performance directly affecting signal quality and transmission efficiency. In practical applications, the length of the cable and the terminal load state of the connection often affect the stability of the signal. In order to solve this problem, we used STMicroelectronics STM32F407VET6 (STMicroelectronics, Geneva, Switzerland) as the master controller in this system, and deduced the length of the cable by analyzing the functional relationship between the length of the cable and the open circuit frequency. An open cable is regarded as a capacitor, and any two core wires are regarded as two plates of a flat capacitor. The linear relationship between open frequency and length is used to detect the length of the coaxial cable. The system then determines whether the terminal load is capacitance or resistance based on the detected frequency. If no frequency is detected, then the load is considered resistance. The system detects the resistance value of the resistor through series voltage division. If a frequency is detected, this indicates that the load is capacitance. At this time, the system uses an RC oscillation circuit composed of HGSEMI ICL8038 (Huagao Semiconductor Co., Ltd., Wuxi, China) for testing, and provides the phase shift required by the corresponding signal through the RC network, so as to detect the capacitance value. Finally, we successfully designed a coaxial cable length and terminal load detection system based on STM32F407VET6. Through this system, the user can accurately understand the length of the coaxial cable and the load of the connection terminal, which provides a reliable guarantee for the stability of signal transmission. Full article

Frequency-selective attenuation is widely needed in integrated analog front-ends, yet conventional on-chip RC low-pass filters occupy unfeasibly large silicon areas for low-frequency cutoffs and inherently introduce cumulative phase lag. Motivated by the nonlinear, frequency-dependent state evolution of memristive devices, this work experimentally demonstrates a highly compact, capacitor-free memristor–resistor network that functions as a variable-cutoff, zero-phase-lag resistive attenuator. An Au/HfO₂/Au memristor (15 µm × 15 µm) is connected in series with a load resistor and characterized over a wide frequency range. By leveraging the finite time constant of internal ionic drift, the attenuation bandwidth is strictly programmable via the device’s initial resistance. Cutoff frequencies of approximately 10 Hz, 1 kHz, and 10 kHz are achieved for initial resistances of 400 k$\Omega \pm$30 k$\Omega$, 300 k$\Omega \pm$30 k$\Omega$, and 200 k$\Omega \pm$30 k$\Omega$, respectively. Remarkably, the nonlinear state-switching mechanism enables a steep post-cutoff attenuation rate approaching −60 dB/dec—equivalent to a cascaded third-order RC network—using only a single nanoscale device. Rather than functioning as a strictly linear time-invariant (LTI) filter, the proposed circuit operates as a state-adaptive edge-processor. Its inherent amplitude-dependent dynamics and total absence of reactive poles make it exceptionally suited for highly specialized, area-constrained applications, including zero-phase closed-loop noise suppression, frequency-to-amplitude conversion, and amplitude-aware event-driven sensory preprocessing. Full article

Insulated-gate bipolar transistor (IGBT) power modules suffer efficiency degradation at elevated operating junction temperatures. The thermal sensitivity of the collector–emitter saturation voltage (V_CEsat) induces thermal stress imbalance, constraining system efficiency and reliability. A multi-resistor cascade network model for carrier-storage trench-gate IGBTs (CS-IGBTs) is established. The simulation results agree with the measurements within 10% error. The model decomposes the temperature coefficient contributions of individual structural regions. Analysis reveals that the drift region resistance dominates the V_CEsat temperature coefficient. Based on this finding, a co-doping strategy is proposed through simultaneously increasing the doping concentration in the carrier-storage layer and P⁺ collector. This approach reduces the temperature sensitivity of carrier mobility in the drift region, thereby optimizing V_CEsat’s temperature sensitivity. For the fabricated 1200 V/40 A CS-IGBT, the V_CEsat temperature coefficient decreases from 2.38 mV/K to 1.76 mV/K over 300 K to 450 K, which represents a 25.4% reduction. The total switching loss at 450 K decreases from 9.32 mJ to 8.70 mJ, achieving a 6.7% improvement. This device-level optimization suppresses V_CEsat’s temperature sensitivity and switching losses, enhancing efficiency in high-temperature power module applications. Full article

We say a finite simple connected undirected graph is equiresistant if all its edges have the same effective resistance when the graph is considered as an electric circuit where the edges are unit resistors. Using simple properties of electric circuits, we identify some new families of graphs that are equiresistant and then apply this knowledge to find upper bounds for some molecular indices that improve; in the case of equiresistant graphs, similar upper bounds are found in the literature. Full article

Continuous plantar-pressure monitoring is important for objective gait analysis and early detection of abnormal loading; however, many existing solutions remain laboratory-bound (force plates and instrumented walkways) or rely on costly in-shoe multilayer sensor arrays. Here, we developed and optimized a fully screen-printed pressure-sensing insole based on carbon–polymer nanocomposite layers, with an emphasis on manufacturability and process control to bridge the gap between proof-of-concept force-sensitive resistor (FSR)-based insoles and scalable printed-electronics manufacturing workflows. Composite pastes containing carbon fillers (graphene nanoplatelets, carbon black, and graphite) were formulated to improve sensor repeatability and sensitivity. Sensors were characterized under compression loads from 100 N to 1300 N, showing a sensitivity of 10.5 ± 2.8 Ω per 100 N and a sheet-to-sheet coefficient of variation of 22.1% in resistance response. The effects of paste composition, screen mesh density, electrode layout, and lamination on sensitivity and repeatability were systematically evaluated. In addition, correlation analysis of resistance values from integrated quality-control meanders proved useful for monitoring screen-printing process stability. The final insole integrates printed carbon sensing pads and contacts, a dielectric spacer, and an adhesive layer in a thin, flexible format suitable for integration with wearable electronics. In practical static-load tests, repeated manual placement of weights yielded coefficients of variation as low as 4% at 500 g and a detection limit of ~0.1 N, comparable to a very light finger touch. These results demonstrate that low-cost screen-printed electronics can provide robust pressure sensing for wearable plantar-pressure monitoring. Full article

This study proposes a three-dimensional forward modeling framework for geoelectric current distribution under high-voltage direct current (HVDC) monopolar operation. The proposed approach is based on a multi-resolution resistor network (MR-RN) discretization, in which gradient fusion interpolation is employed to suppress flux discontinuities at coarse–fine interfaces, and exterior equivalent boundary resistors are introduced to approximate open boundaries, enabling efficient and stable large-scale three-dimensional forward modeling. Compared with the traditional structured grid and finite element method (FEM), the proposed MR-RN achieves comparable accuracy while reducing computation time by up to 96% and the number of degrees of freedom by two orders of magnitude. Case studies on layered Earth, boundary extension, and substation–field coupling demonstrate that the MR-RN model maintains errors within 1–3%, confirming its suitability for large-scale HVDC ground return simulations and geoelectric safety assessment. Full article

This paper presents a compact floating memtranstor (MT) emulator, a memory element characterized by a direct φ–q relationship, realized without analog multipliers or complex circuitry. The proposed design employs only two active blocks—a voltage differential transconductance amplifier (VDTA) and a voltage differential current conveyor (VDCC)—along with three grounded capacitors and a single grounded electronically tunable resistor. The emulator accurately reproduces the fundamental φ–q dynamics, exhibiting origin-crossing pinched hysteresis loops under sinusoidal excitation, and operates at a low supply voltage of ±0.9 V. Electronic tunability is achieved via bias-controlled transconductance modulation, enabling flexible adaptation across excitation frequencies and operating conditions. Validation is performed through analytical modeling, Monte Carlo simulations, temperature sensitivity analysis, and full LTspice post-layout simulations using a 180 nm CMOS process. The full-custom layout occupies 2529.49 μm², with robust performance confirmed under parasitic and process variations. Adaptive learning simulations demonstrate the emulator’s artificial synaptic plasticity, highlighting its suitability for neuromorphic computing, chaos-based circuits, and nonlinear dynamical systems. The compact, low-power, and multiplier-free architecture establishes the proposed MT emulator as a practical platform for emerging analog memory-centric applications. To validate the feasibility of the proposed solution, experimental tests are performed using commercially available components. Full article

Pulse thyristors are extensively utilized in pulsed plasma discharge applications. In this study, a pulse switch prototype is built using two parallel valve groups, each consisting of seven series-connected thyristors. Each thyristor is equipped with an anti-parallel protection diode, a static voltage-sharing resistor, and an RCD (resistor-capacitor-diode) dynamic voltage-sharing circuit. The prototype withstands 24 kV, delivers 150 kA peak current, operates at 10 Hz, and can run continuously for 1 s. Thermal analysis is essential under narrow-pulse high-current conditions to avoid failure from localized overheating. By investigating the expansion process of the conduction zone during thyristor turn-on, a single-thyristor turn-on model and a finite-element model of the multi-layer series thyristor module are established to analyze transient temperature distributions. Results show a non-uniform temperature profile across the silicon wafer, with the hottest zone near the gate ring. During repetitive pulses, the silicon temperature fluctuates rapidly, while the copper base heats up gradually. At a spreading speed of 30 m/s, the gate terminal temperature rises about 38 °C—within safe limits for now, but projected to exceed them under future operating conditions. Thus, improved thermal management will be critical in further development. Full article

Background: Arterial stenosis produces nonlinear changes in vascular impedance that are challenging to investigate in real time using either benchtop flow phantoms or high-fidelity computational fluid dynamics (CFD) models. Objective: This study aimed to develop and evaluate a low-cost printed circuit board (PCB) analog capable of reproducing the hemodynamic effects of progressive arterial stenosis through an R–L–C mapping of vascular mechanics. Methods: A lumped-parameter (0D) electrical network was constructed in which voltage represented pressure, current represented flow, resistance modeled viscous losses, capacitance corresponded to vessel compliance, and inductance represented fluid inertance. A variable resistor simulated focal stenosis and was adjusted incrementally to represent progressive narrowing. Input U_in, output U_out, peak-to-peak V_pp, and mean V_avg voltages were recorded at a driving frequency of 50 Hz. Physiological correspondence was established using the canonical relationships. $R={\displaystyle \frac{8\mu l}{\pi r^4}}$, $L={\displaystyle \frac{pl}{\pi r^2}}$, $C={\displaystyle \frac{3\pi r^3}{2Eh}}$, where μ is blood viscosity, ρ is density, E is Young’s modulus, and h is wall thickness. A calibration constant was applied to convert measured voltage differences into pressure differences. Results: As simulated stenosis increased, the circuit exhibited a monotonic rise in U_out and V_pp, with a precise inflection beyond mid-range narrowing—consistent with the nonlinear growth in pressure loss predicted by fluid dynamic theory. Replicate measurements yielded stable, repeatable traces with no outliers under nominal test conditions. Qualitative trends matched those of surrogate 0D and CFD analyses, showing minimal changes for mild narrowing (≤25%) and a sharp increase in pressure loss for moderate to severe stenoses (≥50%). The PCB analog uses a simplified, lumped-parameter representation driven by a fixed-frequency sinusoidal excitation and therefore does not reproduce fully characterized physiological systolic–diastolic waveforms or heart–arterial coupling. In addition, the present configuration is intended for relatively straight peripheral arterial segments and is not designed to capture the complex geometry and branching of specialized vascular beds (e.g., intracranial circulation) or strongly curved elastic vessels (e.g., the thoracic aorta). Conclusions: The PCB analog successfully reproduces the characteristic hemodynamic signatures of arterial stenosis in real time and at low cost. The model provides a valuable tool for educational and research applications, offering rapid and intuitive visualization of vascular behavior. Current accuracy reflects assumptions of Newtonian, laminar, and lumped flow; future work will refine calibration, quantify uncertainty, and benchmark results against physiological measurements and full CFD simulations. Full article

Alumina-spinel refractory bricks, composed of 82 wt.% alumina and 18 wt.% MgAl₂O₄ spinel phases, are used in steel ladles due to their ability to resist chemical attack and thermal shock. Thermal shock resistance is determined, in part, by the thermal conductivity of the material. Thermal conductivity measurements for alumina-spinel refractory, three model alumina ceramics, and single crystal sapphire were made with the laser-flash technique from 20 °C to 1000 °C. At room temperature, these gave 6.5 W m⁻¹ K⁻¹ for the refractory, 5.8 to 22 W m⁻¹ K⁻¹ for the alumina ceramics, and 36 W m⁻¹ K⁻¹ for sapphire, despite all materials containing >81 vol.% of alumina. The differences are explained by the roles of porosity, grain boundary thermal resistance, and the spinel phase (refractory). In order to estimate the thermal conductivity of alumina grains in each material, these microstructural effects are modelled with Landauer’s relation for porosity and thermal resistors in series for grains combined with grain boundaries. For two alumina ceramics, the grains yielded similar behaviour to the single crystal. By taking the spinel phase into account with a two-phase mixture relation, the alumina grains in the refractory were estimated with a value of 31 ± 2 W m⁻¹ K⁻¹, close to sapphire. Full article

In this paper, we propose the generalized approach for a dual absorption frequency selective absorber (FSA) with controllable center frequency and passband bandwidth. The designed dual absorption FSA consists of a lossy layer and a frequency selective surface (FSS) layer. Furthermore, the lossy layer is composed of a square ring loaded with four resistors, four circular patches, and four interconnected patches, while the lossless layer is composed of four circular grooves. As for the operating mechanism, the center frequency of the transmission characteristics is mainly determined by the radius of the circular patch (‘a’), while the bandwidth of the transmission characteristics is mainly influenced by the angle of interconnected patch (‘θ’). Then, the generalized approach for dual absorption FSA with controllable center frequency and passband bandwidth was proposed, which could provide effective guidance for the design of dual absorption FSA. To verify the presented concept and design method, the dual absorption FSA was fabricated and measured. Experimental measurements demonstrate a −3 dB transmission fractional bandwidth of approximately 10.74%. Moreover, the proposed structure achieves an absorption rate of over 80% across the 2.95–7.00 GHz band and more than 72% absorption over the 7.80–10.20 GHz band. Full article

Immune response evasion is one of the hallmark features of cancer, which is not only the basis for cancer progression and metastasis but also affects the clinical management of cancer. Tumor immune evasion is mainly attributed to the dynamic and immunosuppressive tumor microenvironment (TME), which is regulated by a complex system including immunosuppressive cells and cytokines. Interleukin-18 (IL-18) is an important cytokine that plays a multifaceted role in immune system regulation, and its function is strictly regulated by the natural antagonist IL-18 binding protein (IL-18BP). IL-18 exhibits context-dependent immunoregulatory characteristics (acting as a “context resistor”) during tumor occurrence and progression, which is closely related to cancer type, stage, and the signaling network of the tumor microenvironment. The multifaceted functions of IL-18 have been utilized in cancer treatment to reduce the phenomenon of immune escape of tumors. With the latest advancements in cancer research related to IL-18, it is necessary to integrate the latest research findings to deepen the understanding of the mechanism of tumor immune escape and promote the improvement of cancer treatment levels. This review will systematically elaborate on the action mode, core regulatory mechanism and key signaling pathways of IL-18 in tumor immune evasion, analyze the heterogeneity patterns associated with its context-dependent effects, comprehensively sort out the core obstacles in clinical translation, and at the same time, envision new precision treatment strategies based on IL-18 regulation. Full article

This study presents the results of electrochemical impedance spectroscopy (EIS) conducted on a commercial 38120S cylindrical LiFePO₄ cell with a nominal capacity of 10 Ah. Measurements were performed at various states of charge, and the parameters of an equivalent circuit model were subsequently identified. The model consists of an inductance, ohmic resistance, two resistor–constant phase element (R-CPE) pairs, and a CPE representing diffusion effects. To ensure high measurement repeatability and minimize data dispersion, a surrogate model was used for equipment calibration, and a custom fixture was designed to maintain consistent cell positioning. Each measurement session was preceded by an open-circuit voltage reading and a relaxation period of approximately 24 h to ensure steady-state conditions. Furthermore, impedance spectra were analyzed over a range of frequencies by simulating model responses using various CPE constants. These simulations were visualized in LTspice and discussed, providing practical insights into the initialization of equivalent circuit model identification algorithms. Full article

This work addresses the low pyroelectric coefficient that limits the practical application of lithium niobate (LN) crystals. A defect modulation process based on reduction annealing treatment is proposed. This reduction annealing treatment increased the pyroelectric coefficient of LN crystals maximally to 3.362 × 10⁻⁴ C/m²K. At room temperature, the voltage responsivity figure of merit (F_V) and detectivity figure of merit (F_D) were both improved more than three-fold. All material properties exceeded those of commercial lead zirconate titanate (PZT) ceramic. This process achieves the simultaneous modulation of high pyroelectric coefficients and low impedance in LN crystals. Based on the LN crystals with optimized properties, pyroelectric infrared detectors (center wavelength 9.4 μm) without external matching resistors were prepared. The response voltage of the detector reached 2.8 times that of commercial PZT detectors while exhibiting lower noise, and has achieved practical applicability. This work provides a simple and efficient method for developing environmentally friendly, low-cost, high-sensitivity pyroelectric infrared detectors. It also establishes the foundations for the application of LN crystals in emerging pyroelectric detection fields. Full article