Surface Technology (表面技术)•2026•DOI: 10.16490/j.cnki.issn.1001-3660.2026.08.010
Laser surface hardening of QT500-7 ductile cast iron was investigated through a coupled finite element–machine learning–multi-objective optimization framework. A phase-transformation heat-transfer finite element model screened process windows for laser power (100–400 W), scanning speed (5–15 mm·s⁻¹), and overlap rate (60%–90%). A three-factor, three-level Box-Behnken design yielded hardened layer depth and fused layer depth as response variables. Four predictive architectures were benchmarked: Random Forest (RF), XGBoost, RF-XGBoost ensemble, and Bayesian-optimized RF-XGBoost (BO-RF-XGBoost). The BO-RF-XGBoost model achieved superior accuracy, with relative errors of 6.52% for hardened layer depth and 9.09% for fused layer depth. Multi-objective optimization compared Advantage Actor-Critic (A2C), Multi-Objective Particle Swarm Optimization (MOPSO), and Non-dominated Sorting Genetic Algorithm II (NSGA-II). A TOPSIS-entropy weight method ranked the Pareto front, identifying optimal parameters: laser power 230 W, scanning speed 14 mm·s⁻¹, overlap rate 75%. Experimental validation at these parameters produced a hardened layer depth of 230 μm and fused layer depth of 66 μm, with finite element model errors of 9.13% and 3.03%, respectively. Microhardness measurements showed the fused layer at 940 ± 40 HV0.5 and the hardened layer at 630 ± 30 HV0.5, both significantly exceeding the substrate hardness of 166 ± 15 HV0.5. The framework provides a reliable tool for parameter optimization in laser surface hardening of ductile cast iron.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01835-9
Radiative cooling is a passive thermal management strategy that leverages the natural ability of materials to dissipate heat through infrared radiation. It has significant implications for energy efficiency, climate adaptation, and sustainable technology development, with applications in personal thermal management, building temperature regulation, and aerospace engineering. However, radiative cooling performance is susceptible to environmental aging and special environmental conditions, limiting its applicability in extreme environments. Herein, a critical review of extreme environmental radiative cooling is presented, focusing on enhancing environmental durability and cooling efficiency. This review first introduces the design principles of heat exchange channels, which are tailored based on the thermal flow equilibrium to optimize radiative cooling capacity in various extreme environments. Subsequently, recent advancements in radiative cooling materials and micro-nano structures that align with these principles are systematically discussed, with a focus on their implementation in terrestrial dwelling environments, terrestrial extreme environments, aeronautical environments, and space environments. Moreover, this review evaluates the cooling effects and anti-environmental abilities of extreme radiative cooling devices. Lastly, key challenges hindering the development of radiative cooling devices for extreme environmental applications are outlined, and potential strategies to overcome these limitations are proposed, aiming to prompt their future commercialization.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01753-w
Joint health is critical for musculoskeletal (MSK) conditions that are affecting approximately one-third of the global population. Monitoring of joint torque can offer an important pathway for the evaluation of joint health and guided intervention. However, there is no technology that can provide the precision, effectiveness, low-resource setting, and long-term wearability to simultaneously achieve both rapid and accurate joint torque measurement to enable risk assessment of joint injury and long-term monitoring of joint rehabilitation in wider environments. Herein, we propose a piezoelectric boron nitride nanotubes (BNNTs)-based, AI-enabled wearable device for regular monitoring of joint torque. We first adopted an iterative inverse design to fabricate the wearable materials with a Poisson’s ratio precisely matched to knee biomechanics. A highly sensitive piezoelectric film was constructed based on BNNTs and polydimethylsiloxane and applied to precisely capture the knee motion, while concurrently realizing self-sufficient energy harvesting. With the help of a lightweight on-device artificial neural network, the proposed wearable device was capable of accurately extracting targeted signals from the complex piezoelectric outputs and then effectively mapping these signals to their corresponding physical characteristics, including torque, angle, and loading. A real-time platform was constructed to demonstrate the capability of fine real-time torque estimation. This work offers a relatively low-cost wearable solution for effective, regular joint torque monitoring that can be made accessible to diverse populations in countries and regions with heterogeneous development levels, potentially producing wide-reaching global implications for joint health, MSK conditions, ageing, rehabilitation, personal health, and beyond.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2025•DOI: 10.1088/1674-4926/25030011
The optical soliton characteristics of GaSb-based ~2 μm wavelength integrated optical chips have broad application prospects in optoelectronic fields such as optical communications, infrared countermeasures, and gas environment monitoring. In the research of two-section integrated optical chips, more attention is paid to their passive mode-locked characteristics. The ability of its structure to generate stable soliton transmission has not yet been studied, which will limit its further application in high-performance near-mid infrared optoelectronic technology. In this paper, we design and prepare a GaSb-based ~2 μm wavelength two-section integrated semiconductor laser chip structure, and test and analyze its related properties of soliton, including power−injection current−voltage (P−I−V), temperature and mode-locked characteristics. Experimental results show that the chip can achieve stable mode-locked operation at nearly ~2 μm wavelength and present the working characteristics of near optical soliton states and multi-peak optical soliton states. By comparing and analyzing the measured optical pulse sequence curve with the numerical fitting based on the pure fourth order soliton approximation solution, it is confirmed that the two-section integrated optical chip structure can generate stable transmission of multi-peak optical soliton. This provides a research direction for developing near-mid infrared mode-locked integrated optical chips with high-performance property of optical soliton.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2025-40-01-10)
For rechargeable aqueous zinc-ion batteries (ZIBs), the design of nanocomposites comprised of electrochemically active materials and carbon materials with novel structures has great promise in addressing the issue of electrical conductivity and structural stability in the electrode materials during electrochemical cycling. We report the production of a novel flexible electrode material, by anchoring MnO2 nanosheets on a B,N co-doped carbon nanotube array (BNCNTs) grown on carbon cloth (BNCNTs@MnO2), which was fabricated by in-situ pyrolysis and hydrothermal growth. The generated BNCNTs were strongly bonded to the surface of the carbon fibers in the carbon cloth which provides both excellent electron transport and ion diffusion, and improves the stability and durability of the cathode. Importantly, the BNCNTs offer more active sites for the hydrothermal growth of MnO2, ensuring a uniform distribution. Electrochemical tests show that BNCNTs@MnO2 delivers a high specific capacity of 310.7 mAh g−1 at 0.1 A g−1, along with excellent rate capability and outstanding cycling stability, with a 79.7% capacity retention after 8000 cycles at 3 A g−1.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2026-41-01-02)
Photocatalysis is an important technology for using solar energy to produce hydrogen, convert CO2 to synthetic fuels, and decrease persistent pollutant. However, conventional photocatalysts have limitations, including poor spectral absorption, inefficient charge separation, and structural instability under operational stress, which demand innovative durable materials with tailored electronic properties. Nanodiamond (ND) has recently been recognized as a suitable material because of its exceptional chemical stability, superior charge carrier mobility, and possible surface functionalization. While its intrinsic wide bandgap limits its response to visible-light, different methods have been demonstrated to activate its catalytic potential. Here, several emerging strategies for improving the catalytic performance of ND-based photocatalytic systems are summarized, including surface functionalization, plasmonic hybridization, heteroatom doping, and heterostructure design. And the structure-activity relationship and design principle are proposed to improve the light harvesting, charge transport, and redox kinetics for constructing high efficiency ND-based photocatalysts used in the renewable energy and environmental industries.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2025•DOI: 10.1088/1674-4926/25030011
The optical soliton characteristics of GaSb-based ~2 μm wavelength integrated optical chips have broad application prospects in optoelectronic fields such as optical communications, infrared countermeasures, and gas environment monitoring. In the research of two-section integrated optical chips, more attention is paid to their passive mode-locked characteristics. The ability of its structure to generate stable soliton transmission has not yet been studied, which will limit its further application in high-performance near-mid infrared optoelectronic technology. In this paper, we design and prepare a GaSb-based ~2 μm wavelength two-section integrated semiconductor laser chip structure, and test and analyze its related properties of soliton, including power−injection current−voltage (P−I−V), temperature and mode-locked characteristics. Experimental results show that the chip can achieve stable mode-locked operation at nearly ~2 μm wavelength and present the working characteristics of near optical soliton states and multi-peak optical soliton states. By comparing and analyzing the measured optical pulse sequence curve with the numerical fitting based on the pure fourth order soliton approximation solution, it is confirmed that the two-section integrated optical chip structure can generate stable transmission of multi-peak optical soliton. This provides a research direction for developing near-mid infrared mode-locked integrated optical chips with high-performance property of optical soliton.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.08.011
To study the relationships between rock mass crack propagation and damage and confining pressure under blast impact loading during straight-hole cut blasting, tests were performed under different confining pressures. Then, the characteristics of rock mass crack development were analyzed, and the pressure resistance values of core samples before and after blasting were compared to study the trends of rock mass damage. Moreover, a three-dimensional numerical simulation model was established by LS-DYNA to analyze the stress wave propagation, cavity shape and crack propagation characteristics under different confining pressures. The propagation of rock blasting cracks is negatively correlated with the confining pressure. The greater the confining pressure, the shorter the crack development time. Additionally, the crack width is reduced from 0.4–1.7 to 0.04–1.4 mm, and the length is shortened from 280 to 120 mm. A comparison of the compressive strength revealed that blasting reduces the compressive strength of the rock mass. The greater the distance from the explosion source, the lower the degree of strength attenuation. An increase in the confining pressure can inhibit strength attenuation. Numerical simulations revealed that under the same confining pressure, the stress first peaks at the bottom of the blast hole. The greater the confining pressure, the longer the stress peak duration, the smaller the cavity volume, and the shorter the crack propagation length and depth. Under a confining pressure of 4 MPa, the longest crack was only 154.5 mm in length and 102 mm in depth. The research results provide a scientific basis for controlling rock damage and optimizing design in the excavation of deep rock roadways by blasting.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.08.003
This study proposes and systematically evaluates an optimized integration of warm surface seawater injection with depressurization for the long-term exploitation of marine natural gas hydrates. By employing comprehensive multiphysics simulations guided by field data from hydrate production tests in the South China Sea, we pinpoint key operational parameters—such as injection rates, depths, and timings—that notably enhance production efficiency. The results indicate that a 3-phase hydrate reservoir transitions from a free-gas-dominated production stage to a hydrate-decomposition-dominated stage. Moderate warm seawater injection supplies additional heat during the hydrate decomposition phase, thereby enhancing stable production; however, excessively high injection rates can impede the depressurization process. Only injection at an appropriate depth simultaneously balances thermal supplementation and the pressure gradient, leading to higher overall productivity. A “depressurization-driven sensible-heat supply window” is introduced, highlighting that timely seawater injection following initial depressurization prolongs reservoir dissociation dynamics. In this study area, commencing seawater injection at 170 d of depressurization proved optimal. This optimized integration leverages clean and renewable thermal energy, providing essential insights into thermal supplementation strategies with significant implications for sustainable, economically feasible, and efficient commercial-scale hydrate production.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01283-x
To effectively improve the adaptability and traversal abilities of a multi-terrain mobile robot under the dynamic excitation of multiple roads, we explore the mobile robot’s vibration and joint driving output stall caused by the dynamic excitation of the road spectrum function and analyze techniques for reducing the vibration and enhancing the driving moment of a four-wheel differential-speed mobile robot. A double-wishbone vibration reduction suspension and a moment compensator were designed for a multi-terrain mobile robot by theoretically describing its suspension-wheel-road dynamics. Also, the mobile robot’s road adaptability and traversal abilities were mathematically characterized under dynamic excitation. Co-simulation in ADAMS-MATLAB/Simulink is performed such as the harsh condition of in situ rotation and outdoor experimental schemes are implemented in which the experimental data are analyzed. The experimental result verifies the correctness of the theoretical analysis, as well as the effectiveness of the vibration reduction suspension and the moment compensator. The compatibility of the mobile robot’s driving mechanisms with road traversal abilities has been improved under various terrain conditions in complex field operation scenarios.
Journal of Central South University•2025•DOI: 10.1007/s11771-025-6133-x
Based on MTS Landmark 370.50 rock dynamic and static load fatigue test system and acoustic emission (AE) monitoring method, the damage characteristics and energy evolution law of high static load coal-rock combination (CRC) under the influence of dynamic load parameters were studied. The main results are as follows: 1) Dynamic load increases the rheological properties and damage fracture development of CRC. With the increase of the amplitude and frequency of the dynamic load, the number of dynamic load cycles required for the failure of the CRC decreases, the irreversible strain increases, and the failure of sample accelerates; 2) The AE positioning events during the loading process of the specimen decrease with the increase of the dynamic load amplitude, and increase with the increase of the dynamic load frequency; 3) The fractal dimension, total energy and cumulative elastic energy of the broken particles of the CRC increase with the increase of the amplitude and frequency of the dynamic load. The fractal dimension corresponding to the increase of the dynamic load frequency is larger, and the energy and cumulative elastic energy corresponding to the increase of the dynamic load amplitude are larger.