Surface Technology (表面技术)•2026•DOI: 10.16490/j.cnki.issn.1001-3660.2026.09.005
Polishing of BK7 optical glass suffers from rapid tool wear, low material removal rates, and unstable surface quality. This study introduces an internal-configuration optimization strategy for flexible polishing tools based on I-graph-wrapped package (IWP) triply periodic minimal surface unit cells. Two complementary architectures—skeletal lattice (IWP-1) and perforated lattice (IWP-2)—were fabricated via stereolithography (SLA) photocuring additive manufacturing at Shore A hardness levels of 35 A and 60 A. A corrected material removal function was developed by coupling Hertzian contact theory, the Preston equation, and effective abrasive count, with elastic-plastic deformation analysis of individual grains. Static finite element analysis revealed that IWP topologies homogenize contact pressure and reduce stress concentration. CFD-DPM/DEM fluid-structure interaction simulations showed that internal channels and surface depressions enhance slurry supply, circulation, and abrasive spatial distribution. Orthogonal polishing experiments (three factors, three levels) identified optimal parameters: IWP-1 at 2 mm compression and 60 A hardness achieved Ra = 0.033 μm, suitable for final polishing; IWP-2 at 2 mm compression and 35 A hardness achieved Ra = 0.075 μm with a material removal rate ηMRR = 0.0558 mm³/min, suitable for pre-polishing. These results demonstrate a tunable balance between removal efficiency and surface quality, providing a structural design framework for non-Newtonian hydrodynamic polishing of hard-brittle optical components.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2026•DOI: 10.1088/1674-4926/25060030
High gate oxide electric field (Eox,max) remains a critical failure mechanism in 4H-SiC MOSFETs, necessitating robust depletion layer engineering within the JFET region. This study fabricates 1200 V 4H-SiC MOSFETs with varying JFET widths (1.2, 1.6, 2.0 μm) and cell topologies (linear and hexagonal) to quantify depletion layer dynamics via an innovative Cg–Vg detection method. Experimental results establish a critical JFET width threshold of 1.4 μm: below this value, depletion is limited by lateral expansion; above 1.6 μm, hexagonal cells exhibit a larger effective JFET width, requiring more negative gate voltages for complete depletion. At identical JFET widths, linear cells demonstrate lower gate oxide electric field strength, attracting fewer charges to the interface. High-temperature gate reverse bias (HTGB−) tests reveal that increased JFET width leads to positive charge accumulation and voltage drift (ΔVg), with hexagonal cells showing reduced sensitivity to JFET width variations. Specifically, ΔVg ranges from −2.56 V (linear, 1.2 μm) to −4.2 V (hexagonal, 2.0 μm), corresponding to injected charge densities (ΔDot) of 1.1×10^12 cm^−2 to 1.81×10^12 cm^−2. These findings provide quantitative criteria for optimizing cell topology and JFET width to enhance gate voltage stability and mitigate reliability risks in SiC power devices.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2026-41-03-02)
Mesocarbon microbeads (MCMBs) are a high-performance carbon material that has been widely used in energy storage and as high-temperature structural materials due to their highly controllable microstructure and excellent electrical conductivity. However, with different energy storage mechanisms such as lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, and supercapacitors, MCMBs with a single structure cannot fully meet the different material performance requirements. We review the basic characteristics, preparation methods, formation mechanism and modification strategies of MCMBs, focusing on the relationship between its microstructure and electrochemical performance in various energy storage systems, and its application in other fields. The opportunities and challenges of using MCMBs in different energy storage applications are considered.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2025•DOI: 10.1088/1674-4926/25010027
Doping plays a pivotal role in enhancing the performance of organic semiconductors (OSCs) for advanced optoelectronic and thermoelectric applications. In this study, we systematically investigated the doping performance and applicability of the ionic dopant 4-isopropyl-4′-methyldiphenyliodonium tetrakis(penta-fluorophenyl-borate) (DPI-TPFB) as a p-dopant for OSCs. Using the p-type OSC PBBT-2T as a model system, we demonstrated that DPI-TPFB shows significant doping effect, as confirmed by ESR spectra, ultraviolet−visible−near-infrared (UV−vis−NIR) absorption, and work function analysis, and enhances the electronic conductivity of PBBT-2T films by over four orders of magnitude. Furthermore, DPI-TPFB exhibited broad doping applicability, effectively doping various p-type OSCs and even imparting p-type characteristics to the n-type OSC N2200, transforming its intrinsic n-type behavior into p-type. The application of DPI-TPFB-doped PBBT-2T films in organic thermoelectric devices (OTEs) was also explored, achieving a power factor of approximately 10 μW∙m−1∙K−2. These findings highlight the potential of DPI-TPFB as a versatile and efficient dopant for integration into organic optoelectronic and thermoelectric devices.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2025•DOI: 10.1088/1674-4926/25020006
The dynamic avalanche effect is a critical factor influencing the performance and reliability of the field-stop insulated gate bipolar transistors (FS-IGBT). Unclamped inductive switching (UIS) is the primary method for testing the dynamic avalanche capability of FS-IGBTs. Numerous studies have demonstrated that factors such as device structure, avalanche-generating current filaments, and electrical parameters influence the dynamic avalanche effect of the FS-IGBT. However, few studies have focused on enhancing the avalanche reliability of the FS-IGBT by adjusting circuit parameters during operation. In this paper, the dynamic avalanche effect of the FS-IGBT under UIS conditions is comprehensively investigated through a series of comparative experiments with varying circuit parameters, including bus voltage VDC, gate voltage VG, gate resistance Rg, load inductance L, and temperature TC. Furthermore, a method to enhance the dynamic avalanche reliability of the FS-IGBT under UIS by optimizing circuit parameters is proposed. In practical applications, reducing gate voltage, increasing load inductance, and lowering temperature can effectively improve the dynamic avalanche capability of the FS-IGBT.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01353-0
The huge impact kinetic energy cannot be quickly dissipated by the energy-absorbing structure and transferred to the other vehicle through the car body structure, which will cause structural damage and threaten the lives of the occupants. Therefore, it is necessary to understand the laws of energy conversion, dissipation and transfer during train collisions. This study proposes a multi-layer progressive analysis method of energy flow during train collisions, considering the characteristics of the train. In this method, the train collision system is divided into conversion, dissipation, and transfer layers from the perspective of the train, collision interface, and car body structure to analyze the energy conversion, dissipation and transfer characteristics. Taking the collision process of a rail train as an example, a train collision energy transfer path analysis model was established based on power flow theory. The results show that when the maximum mean acceleration of the vehicle meets the standard requirements, the jerk may exceed the allowable limit of the human body, and there is a risk of injury to the occupants of a secondary collision. The decay rate of the collision energy along the direction of train operation reaches 79%. As the collision progresses, the collision energy gradually converges in the structure with holes, and the structure deforms when the gathered energy is greater than the maximum energy the structure can withstand. The proposed method helps to understand the train collision energy flow law and provides theoretical support for the train crashworthiness design in the future.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01316-5
This study decouples the material microstructure into matrix and void phases. The undamaged constitutive is derived from the matrix phase, while the void phase contributes to damage evolution. A constitutive model is established by coupling the two. According to the void-phase evolution during damage, a damage sequence interaction model is proposed. Tests on new vehicles and vehicles in service materials yield stress-strain curves of materials without and with fatigue damage and measure the apparent elastic modulus. The damage sequence interaction model accurately predicts the residual mechanical properties of undamaged materials. A trolley collision test validates the constitutive model. Collision simulations at 25, 36, and 48 km/h reveal that compared with undamaged models, the maximum vertical lift heights of moving vehicles with fatigue damage are 4.54%, 3.74%, and 9.17% lower, respectively, and the maximum longitudinal compressions of stationary vehicles are 4.76%, 14.53%, and 33.15% higher respectively. This research emphasizes the importance of considering fatigue damage in vehicle design and maintenance. The damage sequence interaction model has high engineering application value, applicable to vehicle safety checks and design, and provides a reference for improving relevant standards.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-024-3031-4
Electrocatalytic N2 reduction reaction (NRR) has been considered as a promising and alternative strategy for the synthesis of NH3, which will contribute to the goal of carbon neutrality and sustainability. However, this process often suffers from the barrier for N2 activation and competitive reactions, resulting in poor NH3 yield and low Faraday efficiency (FE). Here, we report a two-dimensional (2D) ultrathin FeS nanosheets with high conductivity through a facile and scalable method under mild condition. The synthesized FeS catalysts can be used as the work electrode in the electrochemical NRR cell with N2-saturated Na2SO4 electrolyte. Such a catalyst shows a NH3 yield of 9.0 μg·h−1·mg−1 (corresponding to 1.47 × 10−4 μmol·s−1·cm−2) and a high FE of 12.4%, which significantly outperformed the other most NRR catalysts. The high catalytic performance of FeS can be attributed to the 2D mackinawite structure, which provides a new insight to explore low-cost and high-performance Fe-based electrocatalysts, as well as accelerates the practical application of the NRR.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-024-01607-x
The metal–carbon dioxide batteries, emerging as high-energy–density energy storage devices, enable direct CO2 utilization, offering promising prospects for CO2 capture and utilization, energy conversion, and storage. However, the electrochemical performance of M-CO2 batteries faces significant challenges, particularly at extreme temperatures. Issues such as high overpotential, poor charge reversibility, and cycling capacity decay arise from complex reaction interfaces, sluggish oxidation kinetics, inefficient catalysts, dendrite growth, and unstable electrolytes. Despite significant advancements at room temperature, limited research has focused on the performance of M-CO2 batteries across a wide-temperature range. This review examines the effects of low and high temperatures on M-CO2 battery components and their reaction mechanism, as well as the advancements made in extending operational ranges from room temperature to extremely low and high temperatures. It discusses strategies to enhance electrochemical performance at extreme temperatures and outlines opportunities, challenges, and future directions for the development of M-CO2 batteries.