Operation Range Research Articles

46-nA High-PSR CMOS Buffered Voltage Reference With 1.2–5 V and −40 ◦C to 125 ◦C Operating Range

46-nA High-PSR CMOS Buffered Voltage Reference With 1.2–5 V and −40 ^◦C to 125 ^◦C Operating Range

Design and Stability Study of a Distortion-Tolerant Axial Compressor Based on an Alternating Stator Layout

To effectively suppress flow separation in the corner regions of a compressor, improve aerodynamic performance, and enhance distortion tolerance, this study focuses on a single-stage high-load transonic axial flow compressor and introduces a novel and effective unconventional stator design known as an alternating stator (AS) vane layout. This study examines the relationship between the AS layout and the flow separation in the corner regions from a fluid dynamics perspective and investigates the enhancement effects of different AS designs on the compressor's aerodynamic performance and stability margin (SM). Numerical investigations indicate that the alternating layout scheme, which is developed by locally adjusting the inlet geometric angle of the stator vanes, can effectively improve the aerodynamic performance and stability of the compressor. Compared to the original compressor design, the scheme with a 12° adjustment in the blade tip's geometric angle significantly increases both the total pressure ratio and efficiency. This scheme also enhances the SM by 34.69%. With this alternating layout, the novel stator arrangement induces differentiation in the flow field structure among adjacent passages. Internally, an alternating separation forms at the top and root corner regions of the adjacent stator passages, effectively preventing extensive flow separation from occurring at the top or root corner regions of the compressor and thereby delaying a compressor stall. When this design is applied to the compressor stage with inlet distortion conditions, the AS scheme with a 12° adjustment in the blade tip's geometric angle effectively improves the compressor's aerodynamic performance and distortion tolerance and holds significant potential for expanding the stable operating range of the compressor with inlet distortion conditions. Relative to the original design, the SM of the AS compressor can be increased by 83.09%.

Configuration of Timepix3 read-out parameters for spectral measurements in proton therapy applications.

With the increasing use of proton therapy, there is a growing emphasis on including radiation quality, often quantified by linear energy transfer, as a treatment plan optimization factor. The Timepix detectors offer energy-sensitive particle tracking useful for the characterization of proton linear energy transfer. To improve the detector's performance in mixed radiation fields produced in proton therapy, we customized the detector settings and performed the per-pixel energy calibration. The detection threshold and per-pixel signal shaping time (IKrum current) were customized, and energy calibration was performed for MiniPIX Timepix3. The detector calibration was verified using α source and clinical proton beams, as well as Monte Carlo simulations. The effects on the detector's performance, in terms of spectral saturation and pixel occupancy, were evaluated. Measurements with proton beams showed a good agreement with simulations. With the customized settings, the measurable energy range in the detector data-driven mode was extended, and the signal duration time was reduced by 80%, while the yield of pixel time occupancy reduction depends on the number of occupied pixels. For performed measurements with proton beams, the number of occupied pixels was further reduced up to 40% due to the increased threshold. Customized detector configuration of the Timepix3 detector allowed for reduced pixel occupancy and mitigation of signal saturation in a data-driven mode without significantly interfering with the energy deposition measurement. The presented approach enables the extension of the operational range, including higher intensities and mixed-radiation fields in particle radiotherapy environments.

IoT-Based Metal Detector Robot with Wireless Surveillance

Abstract: This project presents the design and development of an IoT-based metal detector robot equipped with wireless surveillance capabilities. The robot is designed to autonomously navigate its environment while detecting metallic objects underground, with real-time monitoring provided through a wireless camera system. The core components of the system include a metal detector sensor, an ESP8266 NodeMCU for wireless communication, an L298 motor driver for controlling the robot’s movement, and a surveillance camera for live video streaming. The system is powered by 3.7V battery cells, ensuring mobility and operational autonomy.The metal detector sensor scans for metallic objects, and upon detection, an alert is generated. Simultaneously, a wireless camera transmits real-time footage, allowing remote monitoring and control via a web interface or mobile device. The robot's movement is controlled through a second ESP8266 module, enabling wireless command inputs for navigation.This robot is envisioned for use in security applications, such as detecting landmines or hazardous metallic objects in sensitive areas, as well as for archaeological and construction projects. The integration of IoT technology enhances the robot’s operational range and effectiveness, providing a scalable solution for remote metal detection and surveillance.The integration of IoT technology significantly enhances the system's operational efficiency and range, enabling seamless remote control and monitoring. This innovation not only improves safety in hazardous conditions but also increases the effectiveness of metal detection and surveillance tasks in diverse environments

Constraints to the drag-based reverse modeling

One of the most widely used space weather forecast models to simulate the propagation of coronal mass ejections (CMEs) is the analytical drag-based model (DBM). It predicts the CME arrival time and speed at Earth or at a specific target (planets, spacecraft) in the Solar System. The corresponding drag-based ensemble model (DBEM) additionally takes into account the uncertainty of the input parameters by making n ensembles and provides the most probable arrival time and speed as well as their uncertainty intervals. An important input parameter for DBM and DBEM is the drag parameter γ, which depends on the CME cross-section and mass, as well as the solar-wind density. The reverse-modeling technique applied to the DBM allows us to derive γ values that minimize transit time (TT) and arrival-speed (v_tar) errors. The present study highlights the limitations and constraints of such a procedure. We searched for optimal γ values that would yield the perfect TT within one hour of the actual observed CME transit time as well as perfect v_tar within ±75 km,s^-1. This optimal window for v_tar was found by increasing v_tar from ±10 to ±100 km,s^-1, where the ±75 km,s^-1 window gave the perfect TT and v_tar in the case of 87% of CMEs compared to the ±10 km,s^-1 window, which was used in some previous reverse-modeling studies and gave optimal results for only 45% of the events from our CME list. For our analysis, a 31 CME-ICME pair sample is used from the period spanning 1997 to 2018. The reverse-modeling method is applied using the DBEMv3 tool for different γ ranges from 0.01 to 10 times km^-1. We tested whether and how the obtained optimal γ depends on the chosen γ range. By increasing the γ range, we find that the optimal γ converges to a certain value for two thirds of the analyzed events. The highly constrained γ ranges resulted in shifted and skewed γ distributions. By using the largest γ range (0.01--10 times 10^ km^-1), the medians of the optimal γ distributions are obtained for two thirds of the events in the common operational DBEMv3 range of 0.01--0.5 times 10^ km^-1. We also found that the important quantity in determining the range of γ distribution and ability to find an optimal γ is the difference between the CME launch speed and the solar-wind speed (v_0-w), which together with γ define the drag acceleration in the DBM. For small v_0-w differences (e.g., < 200 km,s^-1), the reverse modeling may not be the appropriate method to find the optimal γ due to large divergence of γ values found, which may additionally be caused by larger input uncertainties and physical model limitations in turn leading to inappropriate γ values.

Tunable polarization entangled photon-pair source in rhombohedral boron nitride.

Entangled photon-pair sources are pivotal in various quantum applications. Miniaturizing the quantum devices to meet the requirement in limited space applications drives the search for ultracompact entangled photon-pair sources. The rise of two-dimensional (2D) semiconductors has been demonstrated as ultracompact entangled photon-pair sources. However, the photon-pair generation rate and purity are relatively low, and the strong photoluminescence in 2D semiconductors also makes the operational wavelength range limited. Here, we use the spontaneous parametric down conversion (SPDC) of rhombohedral boron nitride (rBN) as a polarization entangled photon-pair source. We have achieved a generation rate of more than 120 hertz (a record-high SPDC coincidence rate with 2D materials) and a high-purity photon-pair generation with a coincidence-to-accidental ratio of above 200. Tunable Bell state generation is also demonstrated by simply rotating the pump polarization, with a fidelity up to 0.93. Our results suggest rBN as an ideal candidate for on-chip integrated quantum devices.

Design of IPMSM Considering Shaft Voltage and AC Copper Loss for EV Propulsion with Wide Operating Range

Abstract This study investigates the interrelationship between shaft voltage (SV) and AC copper loss (ACCL) based on design variables that influence both characteristics. In previous works, issues with SV and ACCL have been reported in electric vehicle propulsion motors operating at high speeds. While methods to individually reduce these characteristics are well established, the correlation between them with respect to design variables has not yet been explored. To analyze this correlation, an analysis of the equations related to parasitic capacitances and ACCL is conducted to identify the key design variables affecting both SV and ACCL. These variables include the distance between the winding and the rotor, slot opening width, and winding width. Based on these design variables, a correlation analysis is conducted to confirm how these characteristics change simultaneously, and the results are verified through finite element analysis. Finally, an optimization process is implemented to minimize SV and ACCL while achieving the target average torque. The results are validated experimentally.

Probing (2D) thin-film temperature sensors: materials and fabrication perspective

Purpose This study aims to provide a comprehensive overview of thin-film temperature sensors (TTS), focusing on the interplay between material properties and fabrication techniques. It evaluates the current state of the art, addressing both low- and high-temperature sensors, and explores the potential applications across various fields. The study also identifies challenges and highlights emerging trends that may shape the future of this technology. Design/methodology/approach This study systematically examines existing literature on TTS, categorizing the materials and fabrication methods used. The study compares the performance metrics of different materials, addresses the challenges encountered in thin-film sensors and reviews the case studies to identify successful applications. Emerging trends and future directions are also analyzed. Findings This study finds that TTS are integral to various advanced technologies, particularly in high-performance and specialized applications. However, their development is constrained by challenges such as limited operational range, material degradation, fabrication complexities and long-term stability. The integration of nanostructured materials and the advancement of wireless, self-powered and multifunctional sensors are poised to drive significant advancements in this field. Originality/value This study offers a unique perspective by bridging the gap between material science and application engineering in TTS. By critically analyzing both established and emerging technologies, the study provides valuable insights into the current state of the field and proposes pathways for future innovation in terms of interdisciplinary approaches. The focus on emerging trends and multifunctional applications sets this review apart from existing literature.

The Impact of Air Pressure on Performance, Combustion Behavior, and Emissions of An Air-assisted Port Fuel Injection HCCI Engine

Low-temperature combustion is achieved through homogeneous charge compression ignition (HCCI), which lowers the emission of nitrogen oxides (NOx) associated with diesel engines. HCCI combustion faces various obstacles, including combustion phasing, high hydrocarbon (HC) emissions, a limited operation range, and homogeneous mixture preparation. This research aims to compare the influence of air pressure in an air-assisted injector on performance, combustion behavior, and emissions. The experiment was conducted at an intake temperature of 50oC, speed of 2100 RPM and air pressures of 3,4 and 5 bar. Intake air was heated in an intake pipe heater, and an air regulator regulated the air pressure. An air assist pressure of 5 bar resulted in the highest brake thermal efficiency, ranging from 20.5% to 23.3%. For brake-specific fuel consumption, an air pressure 3 bar produced higher values ranging from 410.8 g/kWh to 500.8 g/kWh. The in-cylinder pressure for 3,4 and 5 bar pressure exceeds 80 bar at 25% load. Air pressure of 4 bar recorded the lowest HC, ranging from 50 to 75 ppm. For NOx emission, 3 bar air pressure showed the lowest levels, ranging from 8 to 12 ppm across the tested loads. The highest carbon monoxide (CO) percentage was recorded at 5 bar air pressure at 20% load with a CO value of 0.53%. At 20% and 25% load, the combustion profile displayed a three-stage ignition process, indicating the occurrence of diffusive combustion.

Temperature-compensated ultra-stable optical cavity with re-entrant design

Ultra-stable optical cavities with adjustable zero-crossing temperatures feature low thermal expansion and low-temperature control power consumption. We develop a re-entrant cavity featuring flexible and nondestructive zero-crossing temperature tuning capabilities, with a tunable range of 49°C. Using the same ultra-low expansion glass (ULE) batch with a zero-crossing temperature of 16.0(4)°C, we experimentally demonstrate a re-entrant cavity with a higher zero-crossing temperature tuning to 24.7(4)°C, significantly increasing the operational range compared to traditional sandwich cavities. The ultra-stable laser system developed on this re-entrant cavity shows a thermal noise limited performance of 1.05(1) × 10−15 at 0.2 s and a good long-term performance, making it suitable for portable applications such as space-borne laser sources.

NLO SMEFT electroweak corrections to Higgs boson decays to four leptons in the narrow width approximation

Some of the most precise measurements of Higgs boson couplings are from the Higgs decays to 4 leptons, where deviations from the Standard Model predictions can be quantified in the framework of the Standard Model effective field theory (SMEFT). In this work, we present a complete next-to-leading order (NLO) SMEFT electroweak calculation of the rate for H→ℓ+ℓ−Z which we combine with the NLO SMEFT result for Z→ℓ+ℓ− to obtain the NLO rate for the H→4 lepton process in the narrow width approximation. The NLO calculation provides sensitivity to a wide range of SMEFT operators that do not contribute to the rate at lowest order and demonstrates the importance of including correlations between the effects of different operators when extracting limits on SMEFT parameters. We show that the extraction of the Higgs trilinear coupling from the decay H→ℓ+ℓ−Z,Z→ℓ+ℓ− in the narrow width approximation strongly depends on the contributions of other operators that first occur at NLO. Published by the American Physical Society 2025

Multifunctional Conductive Hydrogel for Sensing Underwater Applications and Wearable Electroencephalogram Recording.

Flexible electronics have been rapidly advancing and have garnered significant interest in monitoring physiological activities and health conditions. However, flexible electronics are prone to detachment in humid environments, so developing human-friendly flexible electronic devices that can effectively monitor human movement under various aquatic conditions and function as flexible electrodes remains a significant challenge. Here, we report a strongly adherent, self-healing, and swelling-resistant conductive hydrogel formed by combining the dual synergistic effects of hydrogen bonding and dipole-dipole interactions. The hydrogel has a commendable linear operating range (∼200% strain, GF = 1.44), stability of electrical signals for 200 cycles, excellent conductivity (2.18 S m-1), self-healing properties (∼30 min), and durable underwater adhesion stability. The conductive hydrogel can be developed into a flexible electronic sensor for detecting motion signals, such as joint flexion and swallowing, as well as for real-time underwater communication using Morse code. Additionally, the integration of this polymer with a low contact impedance facilitates real-time, high-fidelity detection of electroencephalogram (EEG) signals, serving as a flexible electrode. It is believed that our hydrogel will have good prospects in future wearable electronics.

Passive highly dispersive matching network enabling broadband electromagnetic absorption

In numerous applications from radio to optical frequencies including stealth and energy harvesting, there is a need to design electrically thin layers capable of perfectly absorbing electromagnetic waves over a wide bandwidth. However, a theoretical upper bound exists on the bandwidth-to-thickness ratio of metal-backed, passive, linear, and time-invariant absorbing layers. Absorbers developed to date, irrespective of their operational frequency range or material thickness, significantly underperform when compared to this upper bound, failing to exploit the full potential that passive, linear, and time-invariant systems can provide. Here, we introduce a new concept for designing ultra-thin absorbers that enables absorbing layers with a record-high bandwidth-to-thickness ratio, potentially several times greater than that of absorbers designed using conventional approaches. Absorbers designed based on this concept can achieve a bandwidth-to-thickness ratio arbitrarily close to the ultimate bound. Utilizing this concept, we design and experimentally verify an absorber yielding a very high bandwidth-to-thickness ratio.

Analisa Sinyal Remote Control Untuk Aplikasi Pengendali Jarak Jauh

Indonesia's aerospace sector plays a crucial role in maintaining national sovereignty. However, the country's airspace is often infiltrated by irresponsible parties, necessitating an effective monitoring system. Unmanned radio-controlled helicopters are a potential solution, although they are limited in range. This study aims to design a long-range control system for radio-controlled helicopters using satellite phone communication, which offers wide coverage and can reach remote areas. The system comprises a remote control, a radio converter circuit, an audio mixer, and a satellite phone. The radio converter functions to transform the radio control signal frequency into its original frequency without a carrier frequency, which is then re-converted to be compatible with satellite phone input for signal transmission. Test results indicate that the system can transmit control signals with adequate frequency stability within the expected range. Despite minor oscillator instability at certain stages, the system overall operates as designed. In conclusion, this satellite phone-based control system effectively extends the operational range of radio-controlled helicopters and serves as a strategic solution for monitoring Indonesia's airspace.

Cavity Wavelength on Erbium-Doped Fiber Ring Laser Depending on Fabry–Pérot Etalon Steering Angle

This study presents the liquid crystal Fabry–Pérot etalon (LC-FP) as the preferred laser wavelength tuning solution within a erbium-doped fiber ring laser architecture. The laser cavity wavelength can be adjusted by applying varying voltages to the LC-FP. Furthermore, tuning the laser wavelength can be facilitated by modifying the incident light through changes in the steering angle of the LC-FP, which is attributed to the angular dispersion characteristics of the device. The operational range for the steering angle of the LC-FP is ± 4 to 18 degrees. This architectural framework is adept at facilitating the generation of single-wavelength and dual-wavelength lasers within the C band. The tunable range for a single wavelength is approximately 13 nm, while the tunable range for dual wavelengths is around 14 nm, with a wavelength spacing of approximately 17.5 nm. These capabilities are primarily influenced by the operational wavelength of the erbium-doped fiber amplifier (EDFA), the operating wavelength of the collimator that directs the fiber optic beam into the LC-FP, and the fixed thickness of the LC-FP.

Revealing the Potential-Dependent Rate-Determining Step of Oxygen Reduction Reaction on Single-Atom Catalysts.

Single-atom catalysts (SACs) have attracted widespread attention due to their potential to replace platinum-based catalysts in achieving efficient oxygen reduction reaction (ORR), yet the rational optimization of SACs remains challenging due to their elusive reaction mechanisms. Herein, by employing ab initio molecular dynamics simulations and a thermodynamic integration method, we have constructed the potential-dependent free energetics of ORR on a single iron atom catalyst dispersed on nitrogen-doped graphene (Fe-N4/C) and further integrated these parameters into a microkinetic model. We demonstrate that the rate-determining step (RDS) of the ORR on SACs is potential-dependent rather than invariant within the operative potential range. Specifically, under the charge-neutral condition, the RDS is calculated to be water desorption with the highest barrier, while as the potential increases, it gradually transitions to the protonation of *OH species, O2* species, and O* species, regardless of the protonation of *OH species as the potential-determining step. Moreover, we reveal the critical role of the dynamic adsorption of axially adsorbed water in facilitating the release of the single-atom site, thus enhancing the ORR rate. Our work has resolved the long-standing controversies over the RDS of ORR on SACs and implies that the step with the lowest exothermicity is not always synonymous with the RDS, highlighting the importance of examining the kinetic barriers under realistic potential conditions for understanding the electrocatalytic performance.

A flexible piezoresistive three-dimensional strain sensor based on laser-induced graphene/nanosilver/MWCNTs for precise human all-range motion detection

Flexible piezoresistive strain sensors are crucial for monitoring human motion, but achieving the right balance between sensitivity and operating range has always been challenging. Additionally, the complexity of muscle movements across different body parts means that relying on sensors with limited dimensional sensing is insufficient. This paper presents a flexible piezoresistive three-dimensional strain sensor (FPTDSS) designed to address these challenges. The FPTDSS features a wide operating range capable of detecting various human movements and boasts a high sensitivity, with a maximum gauge factor of 20 479. It can capture strain information along both the X- and Y-axes, as well as small vibrations along the Z-axis, through its intrinsic stretching and vibration properties. The sensor's effectiveness comes from the synergy between laser-induced graphene, silver nanoparticles (a zero-dimensional nanomaterial), and multi-walled carbon nanotubes (a one-dimensional nanomaterial). The synergistic effect of nanomaterials with different dimensions enables the FPTDSS to perform three-dimensional strain sensing, allowing for accurate detection of a broad range of complex human motions without requiring intricate circuit designs or preparation processes. This approach moves beyond limited strain information to provide a comprehensive view of three-dimensional strain, making the sensor versatile for detecting everything from subtle pulse vibrations to significant joint movements.

Adaptive anomaly detection disruption prediction starting from first discharge on tokamak

Abstract Plasma disruption presents a significant challenge in tokamak fusion, especially in large-size devices like ITER, where it causes severe damage. While current data-driven machine learning methods perform well in disruption prediction, they require extensive discharge data for model training. However, future tokamaks will begin operations without any prior data, making it difficult to train data-driven disruption predictors and select appropriate hyperparameters during the early operation period. In this period disruption prediction also aims to support safe exploration of operation range and accumulate necessary data to develop advanced prediction models. Thus, predictors must adapt to evolving plasma states during this exploration phase. To address these challenges, this study further develops the Enhanced Convolutional Autoencoder Anomaly Detection (E-CAAD) predictor and proposes a cross-tokamak adaptive transfer method based on E-CAAD. By training the E-CAAD model on data from existing devices, the predictor can effectively distinguish between disruption precursor and non-disruption samples in new device, enabling disruption prediction from the first shot on the new device. Additionally, adaptive learning from scratch and alarm threshold adaptive adjustment strategies are proposed to enable model automatically adapt to changes in the discharge scenario. The adaptive learning strategy enables the predictor to fully use scarce data during the early operation of the new device while rapidly adapting to changes in the discharge scenario. The threshold adaptive adjustment strategy addresses the challenge of selecting alarm thresholds on new devices where the validation set is lacking, ensuring that the alarm thresholds adapt to changes in the discharge scenario. Finally, the experiment transferring the model from J-TEXT to EAST exhibit that this method enables disruption prediction from the first shot on EAST, allowing the predictor to adapt to changes in the discharge scenario and maintain high prediction performance.

Defect Chemistry Engineering to Regulate the Excellent ZTave Value of Nonstoichiometric Ca3-xCo4O9 (0 ≤ x ≤ 0.06) Ceramics.

Cobalt-based oxides have attracted significant attention as p-type thermoelectric materials due to their wide operational temperature range. However, their low average figure of merit (ZTave) value has hindered service performance. A series of cation vacancies as Ca-active sites were introduced into Ca3-xCo4O9 (0 ≤ x ≤ 0.06) by defect chemistry engineering to regulate the excellent ZTave value. The Ca-active sites of Ca3-xCo4O9 ceramics induced lattice distortion and point defects, which were unequivocally confirmed by the iDPC-STEM results. The power factor from 0.18 mW/(m·K2) to 0.38 mW/(m·K2) and the electrical conductivity from 54.8 to 108.3 S/cm were achieved for the Ca2.96Co4O9 sample. A notable ZT value of 0.32 was obtained at 1073 K. Furthermore, the high ZTave of approximately 0.166 reached within the temperature range of 323-1073 K, representing a 3.25 times improvement compared to pure Ca3Co4O9 ceramics. This study highlights defect chemistry engineering as an effective strategy for optimizing the thermoelectric performance of nonstoichiometric Ca3Co4O9 ceramics, offering promising prospects for the development of Ca3Co4O9-based thermoelectric materials.

A New Facet of a Decreasing Rearrangement Approach to Solving a Class of Urysohn Integral Equations

This article deals in an L 2 -setting with ill-posed nonlinear operator equations [ F ( x , κ ) ] ( s ) : = ∫ 0 1 x ( t ) κ − s dt = y ( s ) ( 0 ≤ s ≤ 1 ) . Here, a family of parameter-dependent specific integral equations of Urysohn type is considered, equipped with some exponent κ > 0 as parameter. As inverse problem, the decreasing rearrangement x ∗ of the uniformly bounded positive function x and the parameter κ are to be determined simultaneously from observations of the right-hand side y. Under some additional conditions, it can be shown that the pair ( x ∗ , κ ) of solutions is uniquely determined whenever y belongs to the range of the forward operator F. Exploiting the analytical and numerical results from [1] for the special exponent κ = 2 , one is able to get some solutions for general exponents in steps. Alternatively, by use of a classical regularization approach and a suitable discretization technique, computational results are presented in two example situations.