An Investigation of Real-Time Galileo/GPS Integrated Precise Kinematic Time Transfer Based on Galileo HAS Service.

GNSS Precise Point Positioning (PPP) technology has been extensively applied to post-processing international comparisons between UTC/TAI times and real-time time transfer, predominantly in static configurations. However, with the swift advancement of intelligent and unmanned systems, there is an urgent need for research into kinematic time transfer. This paper introduces a kinematic model Galileo/GPS integrated PPP time transfer approach leveraging the Galileo High Accuracy Service (HAS).

Experimental Verification of High-Temperature Resistance and High Resolution of Inductive Tip Clearance Measurement System.

An inductive clearance measurement sensor has advantages of good anti-interference, fast response speed, and high sensitivity, and it has obvious technical potential in aeroengine turbine tip clearance measurement. In this paper, a rotor dynamic tip clearance measurement experiment system was designed based on a high-resolution inductive measurement system. The high temperature calibration experiment, performance verification experiment, and dynamic clearance measurement experiment under varying operating conditions were used to verify the high-temperature dynamic measurement performance of the measurement system.

PuTMO systems crystal structures prediction and stability analysis based on first principles.

Based on particle swarm optimization algorithm and first-principle calculations, the most stable structures of 10 different PuTMO systems are predicted according to their thermodynamical, mechanical and dynamical properties. The results indicate firstly all selected 50 structures are thermodynamically stable based on formation enthalpy results. 29 of the 50 structures are then predicted to be mechanically stable according to mechanical stability criterion for different structures.

Robust two stages federated learning for sensor based human activity recognition with label noise.

Federated learning is widely used for collaborative training of human activity recognition models across multiple devices with limited local data. However, label noise caused by human and time constraints during data annotation is common and severely limits model performance. Existing studies mainly address this through client selection and sample filtering, but still face key limitations: (1) insufficient granularity in client quality evaluation; (2) aggregation methods ignoring data quality differences; (3) client drift under non-IID data distribution.

Liquid Carbon-Boron Cluster Additives for Mixed Amine-50.

Boron-containing compounds, known for their high calorific value, can significantly enhance the energy density of traditional liquid propellants. Through precise chemical modification of the C-H bonds in -carborane, a novel liquid cluster material was synthesized: C,C'-Bis(2-ethylhexanoylmethyl)--carborane (). This compound exhibits excellent stability, density, and energy properties.

Polymeric Desensitizer Fluororubber: A Good Binder to Improve the Thermal Stability and Mechanical Properties of 3,4-Dinitrofurazanfuroxan.

3,4-Dinitrofurazanfuroxan (DNTF) is characterized by its high energy, high detonation velocity, strong explosive power, and small critical diameter for detonation. However, its practical application is limited by poor thermal stability and mechanical properties. In this study, the polymeric desensitizer fluororubber (F2603) was introduced as a binder to enhance the overall performance of DNTF.

Theoretical stress mechanism and structural integrity of viscoelastic propellant grains with variable Poisson's ratio.

For the propellant grain of solid rocket motors (SRMs) with circular inner surfaces, the generalized Maxwell model (GMM) and the generalized Kelvin-Voigt model (GKV) are used to characterize the relaxation properties of the grain's elastic modulus and the creep properties of Poisson's ratio, respectively. Based on the elastic-viscoelastic correspondence principle, an analytical expression for viscoelastic stress that simultaneously considers the time-dependent nature of elastic modulus and Poisson's ratio is derived. Based on this, a parametric analysis of the stress distribution in the grain under internal pressure is conducted.

Controllable Preparation and Thermochemical Properties of Ultrafine FOX-7 by Microfluidic Crystallization Strategy.

The 1,1-diamino-2,2-dinitroethylene (FOX-7) has been adopted in high-energy explosives. To further improve the thermal safety and detonation performance of FOX-7, a microfluidic crystallization platform with a swirl-shaped chip was employed to prepare ultrafine FOX-7. Results show that the crystal structure of FOX-7 could be precisely controlled by adjusting the operational parameters of microfluidic.

Enhancing lower-limb motor imagery using a paradigm with visual and spatiotemporal tactile synchronized stimulation.

Vibrotactile stimulation (VS) has been widely used as an appropriate motor imagery (MI) guidance strategy to improve MI performance. However, most VS induced by a single vibrator cannot provide spatiotemporal information of tactile sensation associated with the visual guidance of the imagined motion process, not vividly providing MI guidance for subjects.This paper proposed a paradigm with visual and spatiotemporal tactile synchronized stimulation (VSTSS) to provide vivid MI guidance to help subjects perform lower-limb MI tasks and improve MI-based brain-computer interface (MI-BCI) performance, with a focus on poorly performing subjects.

Relation-based self-distillation method for 2D object detection.

The challenge of enhancing the detection accuracy of widely adopted and stable object detectors while maintaining cost-effectiveness has long been a topic of significant interest and concern within the industry. To address this challenge, this paper proposes a general relation-based self-distillation framework suitable for object detection to help existing detectors achieve a better balance between accuracy and overhead. Compared to existing self-distillation methods, the framework we propose focuses on integrating relation-based knowledge into the self-distillation framework.

Ultralight multifunctional aerogels with in situ enhanced chitosan networks at micro-/macroscale for super-efficiency electromagnetic metastructure absorbers.

Concurrently achieving lightweight, multifunctionality, excellent environmental adaptability, and broadband microwave absorption represents the inevitable trend in the development of microwave absorbing materials. Herein, an ultralight, elastic, multifunctional chitosan-based aerogel enhanced by carbon nanotubes (CNTs) and carbon fibers (CF) at micro-/macroscale is reported, and its super-efficiency microwave absorption is realized by the electromagnetic metastructure absorbers (EMAs) design. The resulting CF-C/C aerogel demonstrates ultra-low shrinkage (6.

Interpretable adaptive fault detection method for smart grid based on belief rule base.

An effective fault detection strategy has always been the focus of smart grid system research. Fast and accurate fault detection is the basis for complex systems to maintain reliability and security. However, traditional fault detection methods often ignore the interpretability of the model while pursuing high detection accuracy.

Remaining Useful Life Prediction Method for Stochastic Degrading Devices Considering Predictive Maintenance.

Predictive maintenance, recognized as an effective health management strategy for extending the lifetime of devices, has emerged as a hot research topic in recent years. A general method is to execute two separate steps: data-driven remaining useful life (RUL) prediction and a maintenance strategy. However, among the numerous studies that conducted maintenance and replacement activities based on the results of RUL prediction, little attention has been paid to the impact of preventive maintenance on sensor-based monitoring data, which further affects the RUL for repairable degrading devices.

Experimental and Eulerian-Lagrangian numerical investigation on cavitation erosion characteristics in Venturi pipes with different divergent angles.

Hydrodynamic cavitation (HC) is widely found in fluid machinery and has emerged as a significant technology in several engineering fields. To investigate the erosion characteristics caused by HC, experimental tests under varying conditions are conducted in this study using a Venturi test section with different divergent angles. The qualitative erosion risk distributions under different conditions are represented through paint experiments, showing that the erosion risk increases as the divergent angle decreases.

Recycling red mud with raw coal to low-cost Fe/C/ceramic composite for efficient microwave absorption.

To solve the urgent issue of electromagnetic (EM) wave radiation pollution and promote the resource utilisation of red mud (RM, a solid waste), Fe/C/ceramic composite EM wave-absorbing materials were constructed by recycling RM with raw coal (RC) through simple mechanical mixing and then carbothermal reduction between FeO in RM and carbon component in RC. It was found that the calcined temperature of 900 °C can be considered the optimal formation temperature for Fe. In addition, a tuneable EM wave absorption performance could be attained by regulating the mass ratio of RC to RM (denoted as :).

Maintenance Decision-Making Using Intelligent Prognostics Within a Single Spare Parts Support System.

Health management is the foothold of remaining useful life (RUL) prediction, known as 'prognostics'. However, sudden failures in complex systems can lead to increased downtime and maintenance costs, ultimately diminishing system health and availability. Considering intelligent prognostics of components, maintenance decision-making for spare parts ordering and replacement is proposed within a spare parts support system.

Synergistic Single-Atom and Clustered Cobalt Sites on N/S Co-Doped Defect Nano-Carbon for Efficient HO Electrosynthesis.

Non-noble-based single atomic catalysts have exhibited significant potential in electrochemical production of HO via two-electron oxygen reduction reactions (2e ORR). However, constructing highly efficient and acid-resistant catalysts remains a challenge but significant. In this work, fullerene (C) with abundant pentagonal inherent defects was employed as a carbon substrate to synthesize defect-rich nanocarbon electrocatalysts doped with NSCo single atoms and accompanied by metallic Co nanoparticles (CoSA/CoNP-NSDNC) for the first time.

Distributed communication interference resource scheduling using the master-slave parallel scheduling genetic algorithm.

With the increasing intelligence and diversification of communication interference in recent years, communication interference resource scheduling has received more attention. However, the existing interference scenario models have been developed mostly for remote high-power interference with a fixed number of jamming devices without considering power constraints. In addition, there have been fewer scenario models for short-range distributed communication interference with a variable number of jamming devices and power constraints.

Satellite Selection Strategy and Method for Signals of Opportunity Navigation and Positioning with LEO Communication Satellites.

Experts and scholars from various nations have proposed studying low Earth orbit (LEO) satellite signals as the space-based signals of opportunity (SOPs) for navigation and positioning. This method serves as a robust alternative in environments where global navigation satellite systems (GNSS) are unavailable or compromised, providing users with high-precision, anti-interference, secure, and dependable backup navigation solutions. The rapid evolution of LEO communication constellations has spurred the development of SOPs positioning technology using LEO satellites.

Independent and dynamic manipulation of surface waves radiation for quadruplex polarization channels enabled by programmable coding metasurface.

Flexible manipulation of surface waves (SWs) radiation has been continuously intriguing enormous interests of researchers due to its promising application prospects, and metasurfaces exhibit unparalleled capability to efficiently control SWs radiation. However, existing schemes still suffer from the bottlenecks of single radiation channel and immutable radiation pattern, which are difficult to satisfy the requirements of high-integration intelligent metadevices. Herein, an ingenious strategy of the SWs radiation metadevice is proposed to independently and dynamically manipulate SWs directional radiation in four polarization channels.

Experimental study on the mechanical properties of C30 molybdenum tailings concrete after high-temperature and sulfate corrosion.

In order to study the durability of molybdenum tailings concrete after a specific period of wet-dry cycle tests and exposure to high temperatures, this paper investigates the rule of change of the mechanical properties of molybdenum tailings concrete under the coupled influence of sulfate corrosion and high-temperature environmental conditions. A total of five C30 concrete prisms with molybdenum tailings content (0 %, 25 %, 50 %, 75 %, and 100 %) were considered in the tests, with sulfate solution concentrations of 0 g/L, 20 g/L, and 50 g/L, and exposure temperatures of 25° at room temperature and 400° at high temperature, respectively. The test results showed that the mass loss rate of concrete prisms with different molybdenum tailings substitution rates under sulfate corrosion and high temperature environment showed an increasing and then decreasing trend.

Single-Channel Sleep EEG Classification Method Based on LSTM and Hidden Markov Model.

Background: The single-channel sleep EEG has the advantages of convenient collection, high-cost performance, and easy daily use, and it has been widely used in the classification of sleep stages.

Methods: This paper proposes a single-channel sleep EEG classification method based on long short-term memory and a hidden Markov model (LSTM-HMM). First, the single-channel EEG is decomposed using wavelet transform (WT), and multi-domain features are extracted from the component signals to characterize the EEG characteristics fully.

Droplet impact dynamics on the surface of super-hydrophobic BNNTs stainless steel mesh.

The 'gas‒liquid‒solid' mechanism annealing method was used to create a superhydrophobic boron nitride nanotube (BNNT) stainless steel mesh in a tube furnace at 1250 °C in an NH environment. Fe powder was used as a catalyst, and B:BO = 4:1 was used as the raw material. The water droplets on the surface of the superhydrophobic material had a contact angle of approximately 150° and a slide angle of approximately 3°.

Enhanced Removal Performance and Economical Efficiency of Volatile Organic Sulfur Compounds by Silver-Modified ZSM-5 Zeolites under a High-Humidity Environment: A Mechanistic Study of the Adsorption-Plasma Catalytic Process.

Dimethyl sulfide (DMS) is a harmful volatile organic sulfur compound (VOSC), which must be effectively controlled. The adsorption-plasma catalytic (APC) process is an efficient and economical route for the elimination of low-concentration VOSCs; however, there are still many challenges in humid environment. In this study, a series of zeolites with different Si/Al ratios and Ag loadings were designed, and were performed for DMS removal by APC process.

Experimental and numerical studies on corrosion-resistant aluminium foam sandwich panel subject to low-velocity impact.

Aluminium foam sandwich panels (AFSPs) have a high impact resistance and are suitable for a wide range of engineering applications. To improve corrosion resistance, this paper proposes an anti-corrosion sandwich panel with stainless steel as the upper sheet. Drop hammer impact tests were performed on a total of ten AFSPs to investigate their dynamic response and failure patterns.