Search Results (10,093)

To address the degradation in he ranging accuracy of phase-sensitive radar systems caused by RF front-end group delay mismatch, this paper establishes a nonlinear group delay interference model. Using Monte Carlo simulations, we derive the group delay constraints required to achieve millimeter-level ranging accuracy, and, based on these constraints, we propose a novel negative group delay circuit (NGDC). The proposed NGDC attains a figure of merit (FoM) of 0.063, outperforming related designs while offering low insertion loss and high tuning flexibility. After cascading the NGDC, the group delay of a 200–400 MHz bandpass filter (BPF) was improved from $3.015\pm 1.135$ ns to $2.53\pm 0.54$ ns. When incorporated into the radar system, the NGDC reduces the root mean square (RMS) ranging error from 17.17 mm to 9.25 mm at $\mathrm{SNR}=16$ dB, approaching the theoretical limit of 5.07 mm. These results demonstrate that the proposed hardware provides effective support for high-precision phase linearization in radar systems and offers substantial engineering value. Full article

In the domain of engineering applications, this study addresses the challenge of achieving a unified estimation of the suspension relative velocity and road gradient during vehicle operation while mitigating the significant costs associated with automotive sensors. This paper proposes a simplified system model that integrates discretized vehicle vertical dynamics and longitudinal kinematics, intentionally excluding wheel dynamics. Utilizing the front axle vertical velocity, vehicle speed, and longitudinal and vertical accelerations as inputs, an estimator is employed in conjunction with the Extended Kalman filter algorithm to concurrently predict the relative velocity of the vehicle suspension, the sprung mass velocity, and the road gradient. The feasibility of the proposed methodology is corroborated through simulation experiments. Furthermore, real-world road tests validate the efficacy and timeliness of the joint estimation approach based on a “2 + 1” sensor arrangement. This methodology not only optimizes sensor system configuration and reduces engineering costs but also provides substantial technical support for further advancements in vehicle parameter estimation and suspension control applications. Full article

With the rapid development of artificial intelligence and robotics, the application of robotics in the chemical domain is driving a transformation toward intelligent and large-scale research in chemistry and material science. However, sample weighing and synthesis reactions constitute critical stages in chemical experiments, which presents significant challenges for robotic gripping of reagent tubes to achieve precise measurements and collision-free path planning autonomously. Therefore, this study aims to address automation of manipulation in chemical experiments, achieving collision-free path planning and optimization under multi-objective constraints. Specifically, the trajectory planning problem for such tasks is formulated as a multi-objective optimization to minimize motion time, joint jerk and energy consumption. Then, an improved optimized multi-objective particle swarm optimization (OMOPSO) algorithm that incorporates seventh-order polynomial interpolation is proposed to improve the smoothness of robotic motion trajectory. A uniform Pareto front is obtained through a reference vector-guided leader selection mechanism, and an update strategy based on $\epsilon$-domination, and inflection point selection is proposed to balance the convergence and diversity of the solution set. Finally, simulation results and demonstrations on a manipulation platform have fully validated the feasibility and practicality of the proposed method, which further provides a reference for robotic execution of chemical experiments. Full article

Background/Objectives: The front kick is among the most commonly used techniques in martial arts. This study aimed to analyze the range of motion during the mae-geri kick in advanced-level Kyokushin karate practitioners compared to an intermediate-level control group under three conditions: before warm-up, after warm-up, and after a shadow fight. Methods: The study group [N = 28, M: 27.6 years, body mass 81.9 kg, height 1.8 m] consisted of advanced-level Kyokushin karate practitioners (3rd kyu and higher), and the control group consisted of intermediate-level practitioners (6th to 4th kyu). A wireless surface electromyography (EMG) system was used to record muscle activity and an inertial measurement unit (IMU) was used to measure joint angles. Before the study began, the maximum voluntary contraction was determined for each muscle tested. Each participant performed three consecutive kicks in three conditions: before warm-up, after warm-up, and after a shadow fight. Results: The intermediate-level practitioners used the soleus muscle more than advanced practitioners during the front kick (48.92% vs. 35.94% before the warm-up kick, p = 0.042, η²_p = 0.27). After the warm-up, both groups began to use the soleus muscle more intensively (intermediate: 48.92% vs. 61.72% MVC, p = 0.046; advanced: 35.94% vs. 48.69% MVC, p = 0.045), and the advanced group’s activity in the medial gastrocnemius muscle increased compared to before the warm-up (58.23% vs. 39.20% MVC, p = 0.016). Conclusions: Advanced vs. intermediate Kyokushin karate practitioners display distinct neuro-muscular activation strategies in the mae-geri kick, particularly in soleus and gastrocnemius recruitment. Combined EMG and IMU systems can identify trends and in-form training feedback in Kyokushin karate training and effectively prepare the musculoskeletal system for rapid activity, which is important during sports competitions. Full article

Background: Early detection of dental caries is essential for effective oral health management. Current diagnostic workflows rely heavily on radiographic imaging, which involves infrastructure requirements, workflow coordination, and resource considerations that may limit frequent use in high-throughput or resource-constrained settings. These contextual factors motivate exploration of adjunct screening concepts that could support front-end triage decisions within existing care pathways. This study evaluates, in simulation, whether modeled tooth-percussion response signals contain sufficient discriminative information to justify further translational and managerial investigation. Implementation costs, workflow optimization, and economic outcomes are not evaluated directly; rather, the objective is to assess whether the technical preconditions for a potentially scalable screening concept are satisfied under controlled in silico conditions. Methods: An in silico model of tooth percussion was developed in which enamel, dentin, and pulp/root structures were represented as a simplified layered mechanical system. Impulse responses generated from simulated tapping were used to compute the modeled surface-vibration response (enamel-layer displacement), which served as a proxy for a measurable percussion-related signal (e.g., contact vibration), rather than a recorded acoustic waveform. Carious conditions were simulated through depth-dependent reductions in stiffness and effective mass and increases in damping to represent enamel and dentin demineralization. A synthetic dataset of labeled simulated signals was generated under varying structural parameters and measurement-noise assumptions. Machine-learning models using Mel-frequency cepstral coefficient (MFCC) features were trained to classify healthy teeth, enamel caries, and dentin caries at a screening (triage) level. Results: Under baseline simulation conditions, the classifier achieved an overall accuracy of 0.97 with balanced macro-averaged F1-score (0.97). Misclassifications occurred primarily between healthy and enamel-caries categories, whereas dentin-caries cases were most consistently identified. When measurement noise and structural variability were increased, performance declined gradually, reaching approximately 0.90 accuracy under the most challenging simulated scenario. These results indicate that discriminative information is present within the modeled signals at a screening (triage) level, meaning that higher-risk categories can be distinguished probabilistically rather than with definitive diagnostic certainty. Sensitivity and specificity trade-offs were not optimized in this study, as the objective was to assess separability rather than to define clinical decision thresholds. Conclusions: Within the constraints of the in silico model, simulated tooth-percussion response signals demonstrated discriminative patterns between healthy, enamel caries, and dentin caries categories at a screening (triage) level. These findings establish technical plausibility under controlled simulation conditions and support further investigation of percussion-based screening as a potential adjunct to clinical assessment. From a healthcare management perspective, the present results address a prerequisite question—whether such signals contain sufficient information to justify translational research, rather than demonstrating workflow optimization, cost reduction, or system-level impact. Clinical validation, threshold optimization, and implementation studies are required before managerial or operational benefits can be evaluated. Full article

Aiming to solve the persistent problem of edge cracking in magnesium alloy cast-rolling, this numerical simulation study introduces an innovative magnetic field-assisted approach. Utilizing Lorentz force, the process dynamically transforms the solidification front morphology from an arc-shaped (“Ɔ”) to a linear (“1”) configuration. Simulation results reveal that, while magnetic field-induced thermal effects minimally impact the solidification front, the Lorentz force fundamentally alters the flow field dynamics. This modification yields a more uniform temperature distribution and reduces velocity gradients between the symmetric center and edge regions, thereby promoting the transition to a linear solidification front essential for synchronous solidification and deformation across the entire plate width. Furthermore, variations in magnetic field intensity and frequency critically influence vortex flow position and density within the cast-rolling zone. The optimization goal was to maximize the angle α between the side surface and solidification front, which characterizes the linearity of the front. With optimized parameters of 0.49 T magnetic field intensity and 8 Hz frequency, angle α reaches 65°. This marks a 62.5% increase compared to the conventional (non-magnetic) cast-rolling scenario and achieves a near-linear (“1”) solidification profile. Full article

This study develops an integrated analytical framework to assess Russia’s green hydrogen demand potential and cost-competitiveness pathways across the steel production and road transport sectors. Using bottom-up sectoral analysis, we estimate Russia’s theoretical hydrogen demand potential at approximately 18.2 Mt/year. Three policy scenarios model demand realization trajectories under differentiated support regimes, calibrated to European alternative fuel vehicle diffusion patterns and Russian statistical data. A learning curve framework projects green hydrogen costs as an endogenous function of cumulative production, with learning rates of 5% and 10.1% representing conservative and optimistic technology development pathways. Results indicate that under realistic policy support and 10.1% learning rates, hydrogen costs decline from USD 15/kg to USD 7.23/kg by 2050, reaching the USD 10/kg competitiveness threshold by approximately 2035. However, Russia’s costs remain 2–4 times higher than global optimal-location projections due to scale disadvantages and infrastructure constraints. Policy recommendations emphasize front-loaded support mechanisms, export market integration with EAEU partners, and electrolyzer technology localization to accelerate learning effects and achieve cost competitiveness within mid-term planning horizons. Full article

Utah Lake is a large, shallow, highly eutrophic system that is naturally rich in phosphorus (P) and is prone to harmful algal blooms (HABs). While ongoing regulatory efforts often focus on reducing external anthropogenic P loads, particularly from wastewater treatment plants (WWTPs), accumulating evidence suggests that internal sediment P cycling and atmospheric deposition (AD) govern water column P concentrations and are the primary drivers of the lake’s trophic state. We synthesize the existing literature and present new data to demonstrate that (1) the lake’s P-rich, geologic sediments buffer the water column, rendering it largely insensitive to major changes in anthropogenic P inputs due to sorption dynamics, and (2) AD alone provides sufficient P to sustain the lake’s eutrophic status. New analyses on previous AD measurements combined with new active dust sampling data reinforce these conclusions by demonstrating no attenuation of dust deposition to the interior of Utah Lake. We conclude that efforts focused solely on limiting P inputs will have minimal impact on lowering the water column P concentration or improving the lake’s water quality, and that alternative physical and biological restoration methods, such as carp removal and shoreline restoration, are likely to be far more effective. Full article

Pawnshop buildings are places where pawn transactions are conducted. They are usually composed of a front shop and a back building, and their shape resembles a fortress. As a typical gambling city, pawnshops in Macau appeared as early as the Qing Dynasty. By the late Qing Dynasty (1644–1912) and early Republic of China (1912–1949), they had become a common market. They reached their peak during the Anti-Japanese War and were an important financial institution for the people to solve their urgent needs. Today, many pawnshop buildings have become architectural heritage sites and are distributed around the buffer zone of the World Heritage Site. Their location is consistent with the evolution of urban space and the development of gambling and tourism industries. However, existing research lacks systematic research based on spatial quantification technology and it has yet to be determined whether there is a spatial alignment relationship between pawnshop location and urban spatial structure. This paper takes the whole of Macau as the research area and combines DepthmapX space syntax, GIS analysis, and historical data comparison of pawnshop buildings to explore the path dependence characteristics of pawnshop building location and the service radius law in urban space. The study found that the location of pawnshop buildings in Macau has evolved through three stages: initially relying on traditional market spaces, then gathering around casino areas during a stable phase, and finally becoming closely tied to the core areas of gambling venues in the prosperous stage. It shows a path dependence that is continuously strengthened on nodes with low traffic resistance. The service radius of pawnshop buildings exhibits an unbalanced characteristic, with a dense core area and a blank peripheral area, forming a multi-level system of a 200 m core service circle, a 400 m extended service circle, and an 800 m radiation service circle. This study proposes pathways for the adaptive reuse and activation of traditional pawnbroking architectural heritage. For instance, by drawing on the operational model of the Tak Seng On Pawnshop, the integration of cultural exhibition and livelihood services can be realized, thereby providing practical references for the adaptive reuse and conservation of heritage assets. This study offers dual theoretical and practical support for the conservation of pawnbroking architectural heritage in Macau, the site selection and planning of modern pawnbroking establishments, and the optimization of the city’s urban spatial structure. Meanwhile, it enriches the research system on the spatial alignment between the peripheral financial industry and urban space. Full article

Background and Clinical Significance: Metastases of prostate adenocarcinoma most commonly involve the skeletal system, while orbital metastases, including those in the lacrimal gland, are extremely rare. Despite significant advances in the sensitivity of available imaging methods, their diagnosis is often delayed due to nonspecific clinical presentation and rarity of occurrence. Although exceedingly uncommon, orbital metastases have also been reported in other solid tumors, including certain gynecologic malignancies. Case presentation: A 49-year-old patient treated at our center for prostate adenocarcinoma with a Gleason score of 9, regional lymphadenopathy and bone metastases presented to the outpatient clinic with ptosis of the left eyelid, which had developed 7 days prior to examination (13 months after diagnosis of PC). Radiological diagnostics, including CT of the endocranium, revealed enlargement of the left lacrimal gland. An exploratory anterior orbitotomy was performed with an incisional biopsy of the tumor change under retrobulbar anesthesia, and histopathological analysis confirmed a metastatic tumor of the lacrimal gland originating from prostate adenocarcinoma. Despite the application of all available therapeutic measures, a fatal outcome occurred 6 months after the onset of ophthalmic symptoms. Discussion: Orbital involvement in metastatic prostate cancer remains poorly characterized due to its extreme rarity and nonspecific clinical presentation. This case emphasizes the need for a high index of suspicion for metastatic disease in patients with known advanced prostate cancer presenting with new orbital or lacrimal gland lesions, as imaging findings alone may be insufficient to distinguish metastases from primary orbital tumors. Conclusions: Metastasis of prostate adenocarcinoma to the lacrimal gland is an extremely rare clinical manifestation. Timely diagnosis and adequate radiological assessment are crucial for patient management and survival. The aims of this case report areto present a rare metastatic manifestation of prostate adenocarcinoma with orbital/lacrimal metastasis of prostate adenocarcinoma origin, and to highlight metastatic prostate disease as a potential differential diagnosis in orbital lesions and the importance of imaging methods in their detection. Full article

Old urban areas are often prone to waterlogging and sewage contamination owing to their haphazard spatial arrangements, extensive impervious surfaces, and insufficient drainage infrastructure, thereby posing significant risks to both public safety and aquatic ecosystems. Sponge City retrofitting offers a viable solution. Currently, the study area is facing issues of waterlogging and pollution caused by rainfall. Conventional modeling approaches for optimizing the spatial allocation of Low-Impact Development (LID) practices typically quantify only the overall retrofit proportion. However, these methods fail to specify the optimal placement of individual facilities to balance hydrological benefits against construction costs. To bridge this gap between theoretical optimization and practical implementation, this study proposes an iterative approximation framework. First, the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) was coupled with the Storm Water Management Model (SWMM) to generate a Pareto front, from which optimal solutions were selected using the Analytic Hierarchy Process (AHP). The configuration was further refined through multiple iterations of “exhaustive search combined with Euclidean distance” analysis to determine the optimal types and locations of LID facilities. The results show that: In Scenario 3, the Euclidean distance after LID retrofitting achieved a narrowing gap from 5 to 3 to 1. This indicates that the proposed progressive approximation solving process can be directly applied to specific retrofit targets, providing concrete construction guidance for LID retrofitting in older communities’ areas. Conclusions showed that (1) the specific locations for implementing LID facilities within sub-catchments become progressively clearer, ultimately defining precise retrofitting sites. (2) The proposed progressive approximation approach effectively and systematically reduces this disparity. (3) Retrofitted LID measures effectively managed stormwater and controlled pollution. Full article

This work presents a high-performance piezoelectric MEMS yaw gyroscope fabricated on a single-crystal silicon platform, which achieves a quality factor of 75 k—the highest reported to date among silicon-based piezoelectric gyroscopes. The device employs a wide annular resonator that operates at 132 kHz in the in-plane wineglass mode. To maximize transduction efficiency, we develop an analytical model that relates output charge to the area-integrated in-plane stress under modal deformation, and we use this model to guide parametric optimization of the annular width. The resulting geometry simultaneously enhances the mechanical quality factor and the piezoelectric coupling. A back-etching fabrication process is used to eliminate front-side release holes, thereby preserving structural continuity and suppressing thermoelastic damping. In open-loop rate mode operation with a native frequency split of 28 Hz, the gyroscope demonstrates an angle random walk of 0.34°/√h and a bias instability of 8.19°/h. These performance metrics are comparable to those of state-of-the-art lead zirconate titanate (PZT)-based annular gyroscopes, while the use of lead-free aluminum nitride as the transduction material ensures compliance with RoHS environmental regulations. Full article

The most severe premalignant lesion of glandular epithelium of the cervix is adenocarcinoma in situ (AIS). In most cases it is associated with persistent human papillomavirus (HPV) infection and most often occurs in women in the fourth decade of life. In most high-income countries, primary screening has shifted to HPV testing, while cytology is used for patient triage. Even with current robust screening protocols, their sensitivity for glandular lesions remains limited. Diagnosis of AIS obtained by biopsy, brushing or curettage is confirmed by excisional methods and pathohistological verification. Therapy depends on the patient’s lifestyle and reproductive age. In our case, we present a nulliparous patient with persistent ASC-US, multiple-type HPV infection without HPV 16 and 18 types, and AIS which was diagnosed after conization, follow-up and two biopsies with curettage of cervical canal. Our case report highlights limitations in detection of glandular lesions and need for caution in patients with persistent and seemingly low-grade cytological abnormalities, notably in young patients with high-risk HPV types. Full article

There is a strong demand for buried sensor networks in industries including mining, agriculture, geothermal energy, and oil/gas. However, the integration of these sensors is bottle-necked by the need for electric power which cannot be delivered by conventional means, i.e., cables, photocells, and batteries. To mitigate this bottle-neck, a recent technique was developed that utilizes conduction currents through the soil and subsurface (TTS) to transfer power wirelessly over large distances. The work presented here further investigates changes in conducted power signals as they flow over a 50m radius around a buried TTS Transmitter. An Active Front-End (AFE) converter in tandem with an integrated inverter output is used for creating signals with large spectral densities in order to study attenuation effects throughout the subsurface. The changes in the signals’ spectral content over distance are analyzed and discussed. The abilities to separate attenuation from current spread (divergence) from attenuation due to resistive loss are given, allowing the identification of frequencies best suited for long range power transfer. Full article

In this study, we present the design and development of a mobile, multi-modal electroencephalography and functional near-infrared spectroscopy (EEG/fNIRS) device for wireless neurophysiological monitoring. The system was engineered to achieve high signal fidelity, low power consumption, and a fully untethered operation suitable for ambulatory brain research. The device integrates four Texas Instruments ADS1299 24-bit biopotential amplifiers, providing up to 32 simultaneous acquisition channels. Signal control, processing, and local storage via an SD card are managed by an STM32H7 microcontroller, while an ESP32-S2 module handles Wi-Fi communication. Dual-wavelength light-emitting diodes and OPT101 photodiodes form the optical front-end, driven by digitally controlled constant-current sources for stable illumination. The design employs galvanic isolation, multi-rail power management, and a four-layer PCB layout to minimise interference between analogue, power, and digital domains. Data are captured by a deterministic, clock-driven STM32 acquisition loop and forwarded to the ESP32, which operates under an RTOS and streams packets over Wi-Fi for collection on a mobile phone or PC using the Lab Streaming Layer (LSL) framework. The STM32H7 architecture was chosen for its capability to support future embedded edge-machine-learning functions, enabling on-device signal quality assessment and artefact rejection. Validation demonstrations include 32-channel synchronised acquisition using the ADS1299 internal test signal, eyes-open/eyes-closed alpha modulation visualised in EEGLAB, a forehead fNIRS breath-hold response with physiological spectral content, and real-time ECG/optical pulse streaming via LSL. The resulting system provides a compact platform with explicitly defined acquisition and data interfaces for synchronised EEG/fNIRS acquisition, enabling scalable, low-cost mobile neuroimaging research. Full article