Search Results (613)

Achieving stable local focus-height measurement across different material surfaces is important for I-line-lithography-related inspection, where sub-micrometer height deviations can affect imaging quality, exposure uniformity, and subsequent autofocus performance. This study evaluates the local focus-height repeatability of a linear charge-coupled device (LCCD)-based focus metrology system under several I-line-lithography-related material-surface conditions. The prototype integrates fiber-coupled LED illumination, telecentric projection and imaging optics, reference marks, and a two-step localization procedure based on template matching and centroid estimation; the dual-wavelength source is treated as part of the fixed optical configuration. Tests were performed on silicon wafers, GaAs bright substrates, sapphire, infrared transmissive material, and SiC, covering different reflectivity levels and surface structures. The measured peak-to-valley repeatability was 35–37 nm for highly reflective samples and 40–54 nm for intermediate- or low-reflectivity and microstructured samples, all below the selected 70 nm conservative engineering criterion derived from the depth-of-focus estimate. These results indicate that the integrated LCCD measurement chain maintained stable local repeatability within the tested material-surface range, providing experimental support for further development of local focus metrology and precision optical inspection. Full article

Processing-in-memory and in-memory computing (PIM/IMC) are increasingly explored to mitigate the von Neumann data-movement bottleneck that limits deep neural network (DNN) performance and energy efficiency. Progress, however, remains fragmented across device substrates, architectural prototypes, mapping and scheduling methods, compiler toolchains, and benchmarking practices, making results hard to compare and slowing deployment. This survey synthesizes developments from 2019–2025 along four coupled axes: (i) memory substrates and architectural design, (ii) mapping, partitioning, and scheduling, including learning- and graph-based strategies, (iii) compilers and end-to-end deployment flows, and (iv) benchmarking datasets, metrics, and reporting norms. Drawing on over twenty representative platforms spanning static random-access memory (SRAM) and dynamic random-access memory (DRAM), emerging non-volatile, capacitive, and photonic substrates, we clarify the trade-offs separating analog/charge-domain IMC from digital SRAM/DRAM-centric PIM, including reported peaks up to 600 TOPS/W and 1.5 TOPS/mm². We organize mapping frameworks into a unified reference taxonomy, identify recurrent evaluation pitfalls that undermine reproducibility, and highlight persistent gaps in training support, robustness under non-idealities, and coverage of large-scale GNN workloads. Finally, we outline a five-phase roadmap from benchmark standardization to industrial validation toward compiler-integrated, GNN-informed PIM/IMC systems validated on production-scale workloads. Full article

This study investigates the modulation of coercivity and magnetodielectric coupling in heat-treated, nickel-substituted lanthanum ferrite. LaFe_0.7Ni_0.3O₃ samples were synthesized by high-energy ball milling and sintered at temperatures between 1073 and 1473 K. Chemical composition, crystalline structural evolution, surface morphology, magnetic, dielectric, and electrical properties, as well as magnetodielectric coupling, were analyzed. The XPS spectra revealed the presence of adsorbed oxygen, associated with the high oxygen affinity of the material. This behavior is interpreted as a charge-compensation mechanism, related both to the formation of oxygen vacancies and to the partial oxidation of Fe³⁺ to Fe⁴⁺. XRD and Rietveld refinement confirmed a single-phase orthorhombic Pnma structure, and structural simulations revealed progressive octahedral distortions with increasing temperature, affecting the octahedral tilting and electronic bandwidth. Magnetic characterization revealed that thermal processing modifies the magnetic behavior, inducing weak ferromagnetism and a significant increase in coercivity, correlating with progressive densification, greater domain stability, and reduced microstrain. Impedance measurements revealed magnetodielectric coupling, the Maxwell–Wagner interfacial polarization mechanism, and reduced dielectric losses. These findings demonstrate that the coercivity and magnetodielectric response in cationic nickel-substituted lanthanum ferrite can be tuned through thermal processing. A semi-empirical magnetocrystalline anisotropy model is proposed to explain the coercivity evolution and associated multiferroic behaviors, thus contributing to the study of functional ferrites as sustainable alternatives to rare-earth magnetic materials with potential in sensors and memory devices. Full article

The laser irradiation effect on Charge-Coupled Devices (CCDs) has attracted wide attention in photoelectric countermeasures and imaging system hardening. This review provides a systematic analysis of the phenomena and mechanisms of laser-induced dazzling and damage effects on CCD sensors. It summarizes experimental and theoretical research progress with continuous-wave (CW), pulsed, and composite lasers, revealing distinct interaction mechanisms such as thermal effects, dielectric breakdown, and plasma ablation. The review also covers quantitative evaluation methods for assessing laser irradiation effects. This work provides a comprehensive reference for future studies. Full article

This work presents the realization of a compact and embedded impedance-based sensor system for the characterization of lithium-ion batteries by means of electrical impedance spectroscopy (EIS). The analog magnitude-ratio and phase-difference detection (MRPDD) method is implemented and extended through a generalized formulation that models the shunt element as a frequency-dependent impedance and compensates the parasitic contributions of the printed circuit board. This reformulation corrects magnitude and phase errors introduced by the measurement hardware without increasing the overall complexity. The prototype comprises two main functional blocks: current-mode excitation and voltage-mode measurement. The excitation stage uses an operational transconductance amplifier and a power MOSFET to generate a voltage-controlled current source, whereas the sinusoidal voltage signal is generated by means of a direct digital synthesizer. The measurement chain relies on differential acquisition using instrumentation amplifiers and analog magnitude/phase detection based on the AD8302 vector detector under microcontroller control. The proposed method has been first validated by simulations using both a linear RC equivalent model and an extended Randles-type battery-equivalent model, and then experimentally characterized using a linear RC equivalent model of the device under test. Measurements show that the generalized formulation recovers the ideal impedance response in the presence of parasitic effects, both in the shunt device and in the printed circuit board. In the experimental validation with the RC model, a magnitude error of 1.65% is obtained at 1 kHz, which is adopted as the upper frequency limit for battery characterization, even though operation up to 10 kHz is possible. Phase measurements revealed that the input capacitive coupling of the vector detector, conceived for operation in the RF range, requires an adaptation for appropriate operation in the intended frequency range. The prototype has been also applied to the characterization of a commercial lithium-ion 18650 cell, enabling the measurement of battery impedance and the analysis of its dependence on the state-of-charge and on the discharge current. Full article

We study the planar dynamics of a charged particle subjected to a radially repulsive inverted harmonic potential and a perpendicular uniform magnetic field, a configuration that is relevant to nanoscale-charged transport and confinement in low-dimensional systems. The competition between the destabilizing central repulsion and magnetic field-induced rotational motion gives rise to rich trajectory behavior, including spiraling, unbounded escape, and parameter-dependent quasi-confined motion. The governing coupled differential equations of motion are solved analytically. The resulting trajectories are classified as functions of system parameters. The proposed framework provides insight into charge carrier dynamics in nanostructured environments such as quantum wells, 2D materials, and plasma-like nanosystems, where effective repulsive potentials may arise from external gating or collective interactions. In addition, the model offers a classical analogue for interpreting features associated with magnetic confinement in non-equilibrium or unstable regimes. These results contribute to the theoretical foundation for designing and controlling charged particle motion in emerging nanomaterials and devices. Full article

Electrochemical sensors have emerged as promising tools for rapid pesticide screening in food and environmental samples because they combine simple instrumentation, fast response, portability, and compatibility with disposable electrodes. This review organizes recent progress through a cross-system framework linking pesticide class, interfacial electrochemical process, and material design. Carbon materials, metal–organic frameworks and their derivatives, metal nanoparticles, metal compounds, conducting polymers, MXene-based composites, and selected emerging materials are compared in terms of enrichment capability, charge-transfer regulation, catalytic amplification, recognition-layer integration, and suitability for real-sample analysis. Emphasis is placed on issues that are often under-discussed in performance-centered surveys, including matrix interference, electrode fouling, batch-to-batch reproducibility, storage stability, scalability, and cost-effectiveness. Representative examples show that the most useful advances arise not simply from lowering the limit of detection but from improving structure–function understanding and translating interfacial design into robust analytical performance. Future work should prioritize standardized fabrication and benchmarking protocols, in situ and operando identification of active sites and interface evolution, matrix-specific antifouling validation, multiresidue and metabolite analysis, and hybrid portable devices coupled with intelligent readout. Full article

Miniature vapor compression refrigeration systems are gaining increasing relevance in cutting-edge applications such as drone docking station cooling, electric vehicle battery thermal management, portable medical and diagnostic devices, compact beverage dispensers, field-mounted telecom cabinet cooling, as well as the already established fields of electronics and personal cooling. These systems offer a promising pathway to localized and mobile cooling solutions. When coupled with the implementation of alternative low-GWP refrigerants that match or even enhance system performance, the result is a more efficient, environmentally responsible, and potentially sustainable refrigeration technology. Therefore, this study experimentally evaluates the performance of R515B as a low-GWP drop-in replacement for R134a in a miniature vapor compression refrigeration system. Key parameters were analyzed to determine the most suitable operating conditions, resulting in a capillary length of 1.25 m, refrigerant charge of 110 g, compressor speed of 4500 rpm, and high condenser fan speed, under which R515B achieved a COP of 5.16 and a cooling capacity of 252.20 W, representing improvements of 38% and 6.5%, respectively, compared to R134a. These results confirm the viability of R515B as an efficient, environmentally friendly alternative for miniature small-scale vapor compression systems. Full article

The increasing penetration of single-phase photovoltaic (PV) generation and electric vehicle (EV) charging has aggravated phase current asymmetry in low-voltage distribution networks. In contrast to voltage-oriented control strategies, this work focuses directly on mitigating current imbalance at the point of common coupling (PCC). A coordinated control framework based on multi-agent deep deterministic policy gradient (MADDPG) is developed to regulate distributed battery energy storage systems (BESS). The control objective is formulated in terms of the Current Unbalance Factor (IUF), derived from symmetrical component theory. A linearized DistFlow model is embedded in the learning environment to preserve physical consistency while maintaining computational tractability. Device-level constraints, including state-of-charge limits and ramp-rate bounds, are enforced through action projection, whereas network security limits are incorporated via reward penalties. Case studies on a modified residential feeder indicate that coordinated BESS control reduces the peak IUF from 2.75% to 2.50% under the studied operating condition. The maximum dominant-phase current decreases from 125 A to 110 A. The performance is close to that of centralized convex optimization while enabling decentralized real-time execution after offline training. These results suggest that multi-agent reinforcement learning can serve as a feasible alternative for phase imbalance mitigation in distribution networks with high renewable penetration. Full article

Current-source DC links and their associated power converters require continuous conduction mode (CCM), necessitating specialized switching device configurations. These topologies have gained significant attention due to the increasing adoption of current-mode power distribution systems. The operation of a current-source DC-DC converter relies on temporary magnetic energy storage, typically regulated using established switch-mode power conversion techniques. For a stable current step up or step down the use of the tapped inductor concept can provide an ultimate stable solution for current adjustment and the proposed concept is now developed on a step-down current source DC-DC power converter for the first time to reveal in the power electronics field. The use of tapping concept is similar to a coupled inductor and this allows flexible current modification. In this article, this concept is extended to a family of Tapped inductor current-based DC-DC together with soft-switching to reduce the loss of the switching devices. The key advantage is that it can offer a wide range of current conversions with high efficiency. The theoretical and experimental analysis of the proposed converter family is presented. An experimental prototype of the converter was built and tested, operating with a switching frequency of 100 kHz and accommodating input currents ranging from 1 A to 10 A. The converter achieved current conversion ratios of 0.8, 0.67 and 0.57 times the input current, with an output power range of 1 W to 314 W. The maximum efficiency of 88% was achieved at an output power of 314 W. The high efficiency and wide current conversion range of this current-based converter make it suitable for a variety of applications such as current driving LED systems, photovoltaic (PV) system current source control, and constant current fast charging systems for electric vehicles (EVs). Full article

Sodium-ion batteries (SIBs) are emerging as attractive electrochemical energy-storage systems owing to the natural abundance and low cost of sodium resources. However, their structural integrity and electrochemical stability under mechanical abuse remain insufficiently understood, particularly from the perspective of coupled morphological and transport responses in porous electrode assemblies. In this work, the material deformation behavior and electrochemical evolution of SIBs under compressional loading are systematically investigated, with particular attention to the roles of state of charge (SOC), electrode microstructure, and separator integrity. Electrochemical impedance analysis reveals that the ohmic response is mainly dominated by the extent of compressional deformation, whereas interfacial and diffusion-related resistances are jointly regulated by deformation and SOC. In particular, elevated SOC significantly intensifies the increase in diffusion impedance during compression, indicating a strong coupling between sodium-storage state and mass-transport deterioration. Moreover, cells at higher SOCs exhibit accelerated open-circuit voltage decay during extrusion, suggesting enhanced internal stress accumulation and aggravated instability of the electrode/electrolyte interface. Post-mortem morphological characterization demonstrates substantial particle fracture, pore collapse, and crack propagation in both cathode and anode materials, accompanied by severe shrinkage and partial destruction of the separator microporous network. These results establish a direct correlation between compressional deformation, microstructural damage, and electrochemical degradation in SIBs, and provide useful insights for the design of mechanically resilient electrode architectures, separator materials, and safety-oriented diagnostic strategies for next-generation sodium-ion energy-storage devices. Full article

The aim of this work is to develop high-precision time-of-flight (TOF) devices based on high-refractive-index solid Cherenkov radiators read out by silicon photomultipliers (SiPMs). Cherenkov light is prompt and, therefore, ideal for reaching the intrinsic timing limits of TOF systems. By utilizing a thin, high-refractive-index radiator, a nearly instantaneous signal is generated by particles exceeding the Cherenkov threshold. In order to achieve the ultimate time resolution, we carried out a rigorous optimization of the radiator material and geometry, alongside the efficiency of the optical coupling to the SiPM sensors. The key factors limiting the time resolution were characterized by comprehensive Monte Carlo simulations, subsequently validated against experimental beam test data. We assembled small-scale prototypes instrumented with various Hamamatsu SiPM array sensors with active areas ranging from 1.3 to 3 mm, coupled with various window materials, such as fused silica and MgF₂, featuring various thickness values. The prototypes were successfully tested in beam test campaigns at the CERN-PS T10 beamline. The data were collected with a complete chain of front-end and readout electronics based on either the Petiroc 2A or the Radioroc 2 interfaced to a picoTDC to measure charges and times. By comparing the time measurements from two SiPM arrays, we were able to measure a time resolution better than 33.2 ps at the full system level, with a charged-particle detection efficiency of 100%. Our results demonstrate the expected performance benchmarks for the charged-particle detection efficiency and time resolution, and they highlight the potential of the developed Cherenkov-based TOF detectors for next-generation particle identification systems. Full article

Thin-film interference in photoresist stacks can become a significant source of uncertainty in lithographic focus metrology, particularly when high measurement stability is required. To evaluate this effect, a Fresnel-based multilayer reflection model is used to analyze the optical response of the resist stack and to guide the selection of dual-wavelength illumination. On this basis, a dual-wavelength optical triangulation system is developed for focus metrology in 350 nm lithography, with signal acquisition performed by a linear charge-coupled device (LCCD). Rather than improving precision by reducing detector pitch, the system employs a two-stage sub-pixel localization strategy in which template matching provides coarse spot localization and weighted centroid interpolation refines the final position within localized calculation windows, keeping the computational cost manageable. A covariance-based uncertainty analysis predicts a total root-mean-square uncertainty of 27.23 nm. Prototype experiments were performed on a bare silicon wafer to establish the intrinsic performance of the instrument before introducing process-dependent optical effects. Under these conditions, the system achieved a vertical resolution of 10 nm, a repeatability of 35 nm, and a stability of 13.16 nm. The additional uncertainty expected under resist-coated-wafer conditions was assessed separately through the thin-film model. These results verify the baseline capability of the proposed system and support the feasibility of the dual-wavelength strategy for focus metrology in 350 nm lithography. Full article

The twist angle serves as a geometric tuning parameter in two-dimensional layered materials, enabling modulation of interlayer coupling and band structures without altering the chemical composition. In this work, six commensurate twisted bilayer WSe₂ configurations with rotation angles of 0°, 9.4°, 13.14°, 21.9°, 27.8°, and 60° were systematically investigated using first-principles density functional theory. Structural optimization, together with calculations of electronic structures, density of states, charge redistribution, effective masses, and optical properties, was performed. The results show that AA (0°) and 2H (60°) stackings exhibit the largest and smallest interlayer separations, respectively, whereas intermediate twist angles yield similar average spacings but distinct local stacking registries. All configurations remain indirect-gap semiconductors, with the valence band maximum located at K and the conduction band minimum near the Q point along the K–Γ path. The band gap increases from 1.450 eV at 0° to 1.579 eV at 27.8°, before decreasing to 1.333 eV at 60°, indicating strong twist-angle modulation of interlayer coupling. Density-of-states analysis shows that the valence-band edge mainly originates from Se-p and W-d hybridized states, whereas the conduction-band edge is dominated by W-d states, with intermediate angles exhibiting enhanced band folding and localization features. Charge-density analyses further reveal notable interfacial charge redistribution, which is most pronounced at 9.4°. Optical responses in the in-plane directions are nearly identical and significantly stronger than those along the out-of-plane direction. Optical absorption mainly occurs in the ultraviolet region, with band-edge features appearing in the near-infrared range. Intermediate twist angles exhibit broader dielectric responses in the visible region and extended long-wavelength tails, indicating enhanced interband transition channels. These results demonstrate that twist-angle engineering enables effective tuning of electronic and optical properties in bilayer WSe₂, providing theoretical guidance for the design of tunable optoelectronic devices. Full article

The commercialization of perovskite solar cells (PSCs) hinges on replacing toxic lead-based absorbers with environmentally benign alternatives while maintaining competitive power conversion efficiencies (PCE). However, the enormous parameter space governing lead-free device architectures—spanning absorber thickness, defect density, doping concentration, and charge transport layer (CTL) selection—renders traditional trial-and-error optimization impractical. This paper introduces PerovskiteOpt-AI, a machine learning (ML)-driven multi-parameter optimization framework that integrates SCAPS-1D device simulation with Gaussian process (GP) surrogate modeling and Bayesian optimization (BO) to systematically identify high-efficiency lead-free PSC configurations. A synthetic dataset of 12,000 device-level simulations generated for the FTO/WS₂/CsSnI₃/CuSCN/Au architecture by varying eight critical parameters. An ensemble of ML models—random forest (RF), XGBoost, and GP regression (GPR)—is trained and benchmarked, with XGBoost achieving an ${\mathrm{R}}^2$ of 0.9987 and RMSE of 0.041% for PCE prediction. The GP surrogate is then coupled with a BO loop employing expected improvement (EI) acquisition to navigate the design space, converging on an optimized PCE of 27.83% ± 0.21% within 150 iterations—a 38.6% relative improvement over the baseline. Shapley additive explanations (SHAP) analysis reveals that absorber defect density and perovskite thickness are the dominant efficiency drivers, while conduction band offset at the ETL/absorber interface governs open-circuit voltage. The proposed framework reduces the computational cost of full-factorial parametric sweeps by over 95%, establishing a scalable paradigm for accelerated, interpretable design of next-generation lead-free consumer-grade photovoltaic devices. Full article