Beijing Research Institute of Mechanical and Electrical Technology

Abstract In complex electromagnetic environments, the stability of energetic materials (EMs) encounters substantial challenges. Revealing the evolution of charge structures in EMs under electromagnetic fields is crucial for enhancing their safety. EMs are generally non-magnetic, so the effect of magnetic fields in the system can usually be negligible, with the focus instead on the process of electric fields acting on EMs. To systematically investigate the response characteristics of EMs under electric field, this study employed density functional theory (DFT) to conduct quantitative calculations on the charge characteristics and chemical bond orders of RDX, TNT and their composites doped with single-walled carbon nanotubes (SWCNTs) of different sizes under different electric field conditions (strength and direction). A method based on the amount of charge transfer is proposed to assess the microwave-sensitivity of each system and estimate the threshold breakdown field strength. These predictions were subsequently validated through microwave resonant cavity ignition experiments conducted on RDX and TNT compositions. Under electric fields, the N-N bonds in the RDX molecule are weakened. The introduction of SWCNT molecules further weakens the C-N bonds, which may facilitate the formation of new reaction pathways. The breakdown field strength of each system can be ascertained based on the amount of charge displacement under an electric field. The threshold breakdown field strengths for RDX and TNT molecules respectively under a strong electric field are on the order of 1×10 -3 V/Å. After being doped with carbon nanotubes, TNT shows stronger microwave susceptibility than RDX. This enhanced effect, as well as the predictions about electromagnetic sensitivity, has been verified through experiments.

Organotin compounds (OTCs) are toxic pollutants threatening ecosystems and human health, among which dioctyltin (DOCT), widely used in skin-contact textiles, can induce immune dysfunction and metabolic disorders. Although DOCT levels in textiles are strictly regulated by international standards, traditional GC-MS suffers from cumbersome derivatization, unsatisfactory repeatability, and lengthy analysis, highlighting the urgent demand for a rapid and sensitive detection approach. Herein, we developed a fast SERS-based strategy for DOCT determination using size-optimized Au@Ag core-shell nanoparticles as the substrate, which offers simple pretreatment, high efficiency, good uniformity, and excellent reproducibility. The SERS spectra and functional group vibration modes of DOCT were elucidated by density functional theory (DFT) calculations combined with experimental validation, and the peak at 301 cm-1 was identified as the characteristic peak for quantitative analysis. After extractant optimization, the method achieved a low LOD of 0.1 μg/L in real textile samples, with recoveries ranging from 86% to 108% and good linearity from 0.1 to 1000 μg/L (R2 = 0.9804). This approach provides a reliable, high-sensitivity alternative for rapid monitoring of DOCT residues in textiles.

Electroencephalography (EEG)-based Rapid Serial Visual Presentation (RSVP) has steadily gained attention since 2015 as a paradigm to enhance image target detection in brain-computer interfaces (BCIs) used with healthy individuals. We reviewed the literature using Scopus and Web of Science as primary databases, covering publications from 2015 to 2024. After literature screening and filtering, a total of 86 papers on RSVP-BCI studies were analyzed over this decade-long period. The research categorizes RSVP into three dimensions: public datasets, paradigm encoding, and decoding methods, while exploring eight mode combinations involving target types, subject groups, and different modalities. Our literature search revealed a scarcity of studies addressing diverse target types across different subject groups or modality combinations, indicating a promising direction for future RSVP-BCI development. Future efforts should prioritize inclusivity across all age groups, the design of user-friendly stimulus interfaces, and the development of advanced algorithms, with the goal of creating a more widely accessible RSVP-BCI system. We have provided a comprehensive review of advances over the past decade in RSVP-based target detection, including datasets, encoding design, decoding methods and potential applications. The present work aims to articulate prospective trajectories for the continued advancement of the RSVP community.

This study examines the perceptions and expectations of diverse stakeholders in society with respect to contemporary fire management. By tracing the evolutionary trajectory of fire management practices in recent years, the paper proposes a progressive model that transitions from experience-based approaches to evaluation-driven upgrading, and ultimately toward comprehensive refinement, decomposition, and systematic implementation. In parallel, the study synthesizes the roles, responsibilities, and obligations undertaken by relevant parties during the design and construction phases [1], alongside practical insights derived from fire management during the operational phase. It is posited that the advancement of fire safety management across various organizational units necessarily depends on the adoption of a comprehensively refined and decomposed management model. This paradigm not only enhances operational precision but also serves as a foundational pathway for institutionalizing fire safety performance.

Abstract Molybdenum disulfide (MoS 2 ) is regarded as a promising next‐generation semiconductor material for high‐end microelectronic chips due to its excellent properties. However, due to the atomic thickness of two‐dimensional materials (2DMs), the interactions between these materials and their supporting substrates cannot be ignored, which affects the intrinsic properties of 2DMs. In this work, we investigated the influence of the substrate on the performance of MoS 2 devices. As compared to supported MoS 2 field‐effect transistors (FETs), the suspended MoS 2 FET exhibits more intrinsic properties of a threshold voltage ( V th ) shift toward 0 V and the current on/off ratio increases by 3 orders of magnitude. Moreover, by varying the trench/channel ratio in the MoS 2 FETs, we can effectively modulate the electrical performance of MoS 2 . An increase in the trench/channel ratio results in a shift of the V th from −40 to −5 V, approaching the ideal value. Concurrently, the subthreshold swing is reduced by approximately an order of magnitude to ~200 mV dec –1 (from ~3600 mV/dec), and the mobility is enhanced from ~1 to 100 cm 2 V −1 s −1 . To mitigate the effects of contact resistance and other extrinsic factors, we fabricated a suspended Hall‐bar MoS 2 device, achieving a mobility of 96.8 cm 2 V −1 s −1 , more than double the 37.0 cm 2 V −1 s −1 measured in a supported device. This work demonstrates a practical approach for enhancing the properties of 2D semiconductor devices, facilitating the development of high‐performance electronics. image