Toshiba (Japan)

The properties of superconducting joints for REBa<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>Cu<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>O<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">_y</i> (REBCO, RE = rare earth) superconducting tapes fabricated using a slurry process were investigated. Microstructural observation revealed that a joining layer fabricated using a slurry was well-connected to the REBCO layer of the joined tape. The resistance and critical current of closed-loop samples containing slurry-processed superconducting joint were evaluated using current decay measurements. The joint resistance was found to be lower than 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−12</sup> and 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−11</sup> Ω at 4 and 77 K, respectively, in the self-field. It is inferred that a persistent current can flow through a slurry-processed superconducting joint. Conversely, in-field critical current was low and exhibited hysteresis due to weak links in the joining layer.

Abstract The effect of Mg doping on photon-enhanced thermionic emission (PETE) of InGaN emitters was investigated to reduce the high operating temperatures of thermionic energy converters (TECs). Mg-doped In 0.15 Ga 0.85 N enabled TEC operation at 100 °C and enhanced power generation at lower temperatures (100 °C–400 °C). In contrast, In 0.15 Ga 0.85 N without Mg doping required temperatures above 300 °C. Notably, the output power of TEC using Mg-doped In 0.15 Ga 0.85 N was approximately 8.6 times higher at 400 °C than that of InGaN emitter without Mg doping. This enhancement is attributed to Mg doping, which reduces the energy barrier for electron emission and increase the quasi-Fermi level under light irradiation. However, the performance of Mg-doped InGaN decreased at temperatures exceeding 400 °C, due to the limited availability of thermally excited electrons in p-type semiconductors and the increased work function resulting from Cs desorption. Overall, Mg-doped InGaN demonstrates strong potential as a PETE emitter for low-temperature operation and visible-light-driven applications.

This study presents SALMON VR, a visualization program designed to visualize the time evolution of electronic density changes and vector potentials in virtual reality (VR) space. The time-series electronic density data computed by SALMON are stored in CUBE format. SALMON VR processes these data to construct isosurfaces of electronic density variations and two-dimensional representations of vector potentials. Equipped with a user-friendly interface using VR technology, the program is available in two versions: one for the Meta Quest 3 head-mount display (Meta Platforms Inc., California) and one for PCs. Atoms are displayed as spheres of different sizes and colors according to their elemental properties. This visual representation facilitates a deeper understanding of the complex interactions between light and electrons. Users can easily manipulate the isosurface values, speed of animation, and color map of the vector potential. SALMON VR will enable researchers and educators to enhance their understanding of physical phenomena and improve engagement in learning environments.

Abstract Dynamic interactions between magnetizations enable complex operations in spintronic devices, such as coupled oscillation in spin-torque oscillators (STOs). Here, we report the experimental determination of coupling states in an STO using an analysis method based on injection locking. The STO is developed for assisted magnetic recording in hard disk drives and exhibits coupled oscillation of two magnetic layers and oscillation of a single magnetic layer depending on bias current polarities, with the former operation improving recording performance. While conventional spectrum measurements yield similar peaks for both oscillations, our method clearly distinguishes between the coupled and single oscillation modes through resistance measurements because of the insensitivity of the coupled oscillation to injection locking, as supported by simulations. Our results demonstrate that the injection locking method provides a sensitive probe for examining coupled oscillation states and is widely applicable to the development of spintronic devices functionalized through dynamic coupling.

The rapid expansion of Internet of Things (IoT) devices has heightened the need for effective intrusion detection systems (IDS) that operate under strict resource constraints. Conventional IDS implementations require substantial computational resources, making them unsuitable for low-power microcontroller-based devices. This paper proposes a novel collaborative IDS architecture that separates centralised model training from distributed edge inference. The system employs an autoencoder-based labelling mechanism trained on regular traffic to identify anomalies. Each ESP32 device performs local inference and exchanges predictions via UDP multicast, whilst MD5 hashing ensures model consistency across the network. Collaborative verification enables devices to identify and isolate compromised nodes without central coordination. Experimental evaluation demonstrates 98.5% F-score with 3ms average inference latency and 12.7KB memory footprint, consuming only 2.4% of available SRAM. Our approach achieves superior detection accuracy compared to existing cloud-edge systems whilst operating on severely resource-constrained hardware, making it a practical solution for large-scale IoT security deployments.

Good health encompasses not only physical well-being but also mental wellness. Achieving and maintaining good health often necessitates a financial investment in essential health services. For economically disadvantaged segments of society, health-related expenditures can deplete savings and potentially thrust individuals into poverty. Health insurance offers financial protection when accessing healthcare services. This study aims to analyse health insurance coverage in India over the past two decades using secondary data from NFHS 3, NFHS 4 and NFHS 5. The findings indicate a significant increase in enrollment in health insurance; however, it is noteworthy that the majority of those covered are beneficiaries of the Employees' State Insurance Scheme (ESIS) or government-funded health insurance programs. Higher enrollment rates are observed in rural areas, primarily due to these government-sponsored health insurance initiatives. Most states exhibited an increase in beneficiaries, with Rajasthan, Andhra Pradesh, and Chhattisgarh emerging as the top-performing states. However, there is considerable variation among states; many states, such as Bihar and Uttar Pradesh, have among the lowest coverage rates. Chhattisgarh stands out for having one of the highest coverage levels, largely attributed to the government-funded health insurance schemes (RSBY and the State Health Insurance Scheme), which have led to increased coverage in rural areas.

The MOSFET is one of the most widely used power devices in mid-voltage applications, offering advantages such as fast switching, high power density, and miniaturized power electronics converters. However, rapid switching transients also introduce high-frequency oscillations, which pose a significant challenge and require mitigation with minimal system modifications. T his p aper p resents a n ovel t ransfer function-based methodology for analytically modeling MOSFET switching behavior, enabling precise prediction of drain current and voltage transitions under controlled gate current. The transfer function-based analysis reveals that the drain current oscillation is dependent on the change of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">di_D</i>/<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dt</i> at its peak magnitude, regardless of other time intervals during the switching transient. A quadratic equation is obtained to comprehensively describe the behavior of increasing drain current, and a linear function for the drain-source voltage. The proposed gate current profile is implemented via a fully integrated digital active gate driver IC that reduces oscillations by 32 % without additional switching losses. Unlike previous works that primarily rely on empirical gate driver design, the fundamental transfer function-based analytical model introduced in this paper directly links the gate current profile to MOSFET oscillation behavior. Based on this model, a three-step gate current profile is systematically constructed, which is straightforward to implement and adapt using a fully digital, programmable AGD IC. This enables oscillation suppression and loss minimization to be achieved with a practical, integrated solution beyond conventional analog-based approaches.