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3D-printable polyacrylamide/quaternary chitosan-based multifunctional hydrogel flexible sensors

Reactive and Functional Polymers 2025年 214卷

作者： Wang, Dingxin Mei, Lin Liu, Qian Zou, Xinhao Pan, Shaoshan Xu, Tianyu Zhao, Panfeng Luo, Tianzhi CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Hefei China State Key Laboratory of Fire Science University of Science and Technology of China Hefei China School of Nuclear Science and Technology University of Science and Technology of China Hefei230026 China School of Materials and Energy University of Electronic Science and Technology of China Chengdu China

Hydrogel-based wearable flexible pressure sensors show great potential for applications in human health and motion monitoring. However, fabricating hydrogel sensors with excellent mechanical properties, sensitivity, and stability remains challenging. In this study, we developed a poloxamer-quaternized chitosan-polyacrylamide (P407/QCS-PAAm) hydrogel with multifunctional capabilities. These hydrogels exhibit high strength, impact resistance, excellent electrical conductivity, hydrophilicity, and outstanding antimicrobial properties. Due to the dynamic hydrogen bonding provided by QCS, the mechanical properties of the hydrogel can be adjusted by regulating the QCS content, achieving tensile strengths ranging from 0.14 to 0.47 MPa and compressive strengths from 2.07 to 5.49 MPa. The quaternary ammonium groups carried by QCS enhance the gel's conductivity (0.29 S/m) and its bacteriostatic effects. Furthermore, the incorporation of P407 improves the hydrogel's hydrophilicity. These properties make the gel an excellent biosafety material for wearable devices. Notably, the hydrogel precursor exhibits rate-tunable sol-gel transition properties, enabling 3D printing. The 3D-printed P407/QCS-PAAm hydrogel sensors demonstrate high sensitivity (GF © 2025 Elsevier B.V.

关键词： Tensile strength

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Long-term effects of PM2.5 constituents on childhood attention deficit hyperactivity disorder: evidence from a large population-based study in the Pearl River Delta Region, China

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Environmental Research 2025年 277卷 121641页

作者： Zeng, Hui-Xian Meng, Wen-Jie Zeng, Qing-Guo Wei, Jing Liu, Lu-Sheng Wu, Qi-Zhen Zhao, Bin Oudin, Anna Yang, Mo Jalava, Pasi Dong, Guang-Hui Zeng, Xiao-Wen Joint International Research Laboratory of Environment and Health Ministry of Education Guangdong Provincial Engineering Technology Research Center of Environmental Pollution and Health Risk Assessment Department of Occupational and Environmental Health School of Public Health Sun Yat-sen University Guangzhou510080 China Department of Atmospheric and Oceanic Science Earth System Science Interdisciplinary Center University of Maryland College ParkMD United States State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing100084 China Department of Public Health and Clinical Medicine Umeå University Umeå Sweden Department of Environmental and Biological Science University of Eastern Finland Kuopio Finland

Background: Evidence linking fine particulate matter (PM2.5) constituents to childhood attention deficit hyperactivity disorder (ADHD) was limited. Objectives: To investigate the individual and joint effects of exposure to PM2.5 constituents on ADHD. Methods: We conducted a large population-based survey involving 110,818 school children aged 6–18 years across six cities in the Pearl River Delta region, China. The three-year average concentrations of PM2.5 constituents (black carbon (BC), organic matter (OM), sulfate, nitrate, and ammonium) were estimated using the ChinaHighAirPollutants dataset. Parents completed an ADHD checklist using the Diagnostic and Statistical Manual of Mental Disorders-IV criteria. The individual and joint associations between PM2.5 components and ADHD were estimated using generalized linear mixed models and the quantile g-computation regression model, respectively. Results: The exposure-response relationships between PM2.5 constituents and ADHD primarily exhibited a nonlinear pattern. Compared with the lowest tertile, the highest tertiles of PM2.5 and its components were linked to greater odds for ADHD (e.g., the adjusted odds ratio (OR) was 1.37 (95 % confidential interval (CI): 1.27, 1.47) for PM2.5, 1.51 (95 %CI: 1.40, 1.63) for OM, 1.29 (95 %CI: 1.20, 1.39) for BC, and 1.20 (95 %CI:1.08, 1.34) for sulfate). Similar positive associations were observed between BC and sulfate exposure and ADHD subtypes. Moreover, joint exposure to PM2.5 components was associated with ADHD (OR = 1.14, 95 % CI:1.10, 1.18), with OM and BC contributing more to the observed associations. Conclusions: These findings highlight the varying contributions of PM2.5 constituents to ADHD and underscore the importance of reducing specific PM2.5 component emissions to mitigate the burden of PM2.5-associated neurodevelopmental diseases. © 2025 Elsevier Inc.

关键词： Regression analysis

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Data-Driven Learning and Control with Event-Triggered Measurements

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IEEE Transactions on Automatic Control 2025年

作者： Feng, Shilun Shi, Dawei Chen, Tongwen Shi, Ling Beijing Institute of Technology State Key Laboratory of Intelligent Control and Decision of Complex Systems MIIT Key Laboratory of Servo Motion System Drive and Control School of Automation Beijing100081 China University of Alberta Department of Electrical and Computer Engineering EdmontonABT6G 1H9 Canada Hong Kong University of Science and Technology Department of Electronic and Computer Engineering Clear Water Bay Kowloon Hong Kong

Event-triggered control has attracted considerable attention for its effectiveness in resource-restricted applications. To make event-triggered control as an end-to-end solution, a key issue is how to effectively learn unknown system dynamics from event-triggered measurements and consequently, develop a learning-based event-triggered controller. Existing works learn system dynamics based on periodic time-triggered measurements, and it is yet to know how to learn a controller with performance guarantee based on event-triggered measurements. To address this issue, we consider the problem of learning an event-triggered state feedback controller for an unknown linear system based on event-triggered state measurements in this work. In particular, we first analyze the event-triggered measurements within a set-membership framework. We prove that the estimation error belongs to a bounded ellipsoid determined by the historical measurements and the event-triggering condition. Subsequently, we demonstrate that all admissible systems compatible with the collected data samples can be explicitly represented in the form of quadratic matrix inequalities using the state estimates. With the acquired set of admissible systems, a co-design problem for the data-driven controller and event-triggering condition is solved using the linear matrix inequality technique, with guaranteed closed-loop stability and L2-gain performance. Finally, numerical examples and comparisons are provided to illustrate the effectiveness of the proposed event-triggered learning and control approach. © 1963-2012 IEEE.

关键词： Networked control systems

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Disentangle the intrinsic line tension from the nano-corrugations induced by surface lateral roughness

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International Communications in Heat and Mass Transfer 2025年 164卷

作者： Long, Zhilin Yuan, Zifeng Wang, Hao Lab of Heat Mass Transfer and Carbon Cycling College of Engineering Peking University Beijing100871 China Center for Applied Physics and Technology Peking University Beijing100871 China Department of Mechanics and Engineering Science Peking University Beijing100871 China State Key Laboratory for Turbulence & Complex System Peking University Beijing100871 China

Line tension of the contact line plays an important role in microscopic wetting, but its understanding remains vague and the reported values are far from convergence. We note in most studies the contact lines are treated as smooth lines as the droplets are considered as smooth spherical caps. Here using helium ion microscopy, we confirm ubiquitous nano-corrugations along the contact lines even on smooth solids like mica. The corrugation size is correlated with the lateral roughness, which represents the lateral characteristic size of the solid roughness elements. A remodified Young's equation for line tension is therefore derived by including the corrugations and the droplet deformation in the surface energy calculations. By applying the remodified Young's equation, the nonlinear relationship between the apparent contact angle and the droplet radius reported in experiments can be well explained, and a converged line tension value is given around 10−10 J/m. © 2025 Elsevier Ltd

关键词： Linewidth

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Interfacial Thermal Transport and Energy Dissipation in Multilayer PdSe2 Field Effect Transistors

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Advanced Materials 2025年第0期 e2503264页

作者： Xie, Jiaqiu Yu, Zehao Sun, Yuanchen Gan, Qikang Liu, Chenhan Wang, Lei Zhang, Lifa Zhao, Yunshan Phonon Engineering Research Center of Jiangsu Province Ministry of Education Key Laboratory of NSLSCS Center for Quantum Transport and Thermal Energy Science Institute of Physics Frontiers and Interdisciplinary Sciences School of Physics and Technology Nanjing Normal University Nanjing210023 China National Laboratory of Solid-State Microstructures School of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China Micro- and Nano-scale Thermal Measurement and Thermal Management Laboratory Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex Systems School of Energy and Mechanical Engineering Nanjing Normal University Nanjing210046 China

The continuous miniaturization of 2D electronic circuits results in increased power density during device operation, leading to heat localization and placing higher demands on their performance thresholds. The risk to thermal breakdown and subsequent damage, due to the energy dissipation in the 2D semiconductor field-effect transistors (FETs) supported on the bulk substrates, represents a significant challenge in maintaining their optimal performance. Herein, this study investigates energy dissipation behavior in multilayer PdSe2 FETs for the first time. The high-field breakdown behavior is firstly studied in multilayer PdSe2 FETs on SiO2/Si substrates, where a maximum current density of ≈2.74 MA cm−2 is observed, which is comparable to that of multilayer black phosphorus FET and significantly higher—by about five times—than that of multilayer MoS2 FET. Additionally, the thermal boundary conductance (TBC) of PdSe2/SiO2 interface is measured at room temperature using Raman thermometry. The TBC is found to be ≈12–13 MW m−2 K−1, which is relatively low compared to the other known solid–solid interfaces, indicating that enhancing the performance of PdSe2 FETs can be possible by optimizing the TBC at the PdSe2/SiO2 interface. These findings provide valuable insights for design of high-quality and high-performance PdSe2 electronic and optoelectronic devices. © 2025 Wiley-VCH GmbH.

关键词： Multilayers

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DiffDual-AD: Diffusion-Based Dual-Stage Adversarial Defense Framework in Remote Sensing with Denoiser Constraint

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IEEE Transactions on Geoscience and Remote Sensing 2025年 63卷

作者： Lu, Zihao Sun, Hao Lei, Lin Xu, Yanjie Sun, Yuli Kuang, Gangyao National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System the College of Electronic Science and Technology Changsha410073 China National University of Defense Technology College of Aerospace Science and Engineering Changsha410073 China

Deep neural networks (DNNs), though highly effective in various Earth observation tasks with remote sensing images (RSIs), are vulnerable to adversarial attacks, threatening their reliability. Each maliciously attacked RSI potentially contains unique and critical information, but current defenses lack a unified framework for rapidly detecting adversarial RSIs and accurately restoring them to their natural state. To bridge this research gap, we propose a diffusion-based dual-stage adversarial defense (DiffDual-AD) framework. In the first stage, we propose a novel adversarial detection method based on the score expectation (AD-SE), which is integrated into the forward process of diffusion model with an improved denoiser constrained for adversarial defense. During the reverse process, the second stage introduces the distance and label-guided adversarial purification (DL-GAP) to restore adversarial RSIs to natural ones. With the help of two proposed guidelines and the specific denoiser, the DL-GAP effectively smooths out the adversarial perturbations from the detected adversarial RSIs while preserving semantic information and local key features. Finally, DL-GAP yields nonadversarial purified RSIs based on the results of AD-SE. Both stages are integrated within the diffusion models, complementing each other to form a pipelined operational mode. Extensive experiments across three RSI scene classification datasets have proven its efficacy in resisting adversarial RSIs in both whitebox and black-box scenarios, achieving an average adversarial detection accuracy of 87.02% with AD-SE and an average final classification accuracy of 81.50% with the entire DiffDual-AD. The performances of our proposed AD-SE and DL-GAP have surpassed other advanced adversarial detection and purification methods when applied to RSIs. Therefore, DiffDual-AD provides a unified and universal solution to preserve the utility and security of processing the adversarial RSIs, which advances the adversari

关键词： Deep neural networks

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An efficient adaptive space partitioning algorithm for electromagnetic scattering calculation of complex 3D models

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Journal of systems Engineering and Electronics 2021年第5期32卷 1071-1082页

作者： HUANG Minjie ZHOU Yaoming WANG Yongchao LIU Zhongtie School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Key Laboratory of Complex Aviation System Simulation Beijing 100076China

The space partitioning algorithm based on the rounding and addressing operations has been proved to be an efficient space partitioning algorithm with the potential for real-time *** improvement on this kind of space partitioning algorithms for solving complex 3D models is *** examples show that the efficiency of the improved algorithm is better than that of the original *** the size of most target elements is smaller than the size of spatial grids,the efficiency of the improved method can be more than four times of that of the original *** adaptive method of space partitioning based on the improved algorithm is developed by taking the surface element density or the curvature as the threshold for deep partitioning and conducting the deep partitioning using the octree method.A computer program implementation for applying the method in some typical applications is discussed,and the performance in terms of the efficiency,reliability,and resource use is *** testing shows that the results of the adaptive spacing partitioning are more convenient for the follow-up use than that of the basic uniform space ***,when it is used to calculate the electromagnetic scattering of complex targets by the ray tracing(RT)method,the adaptive space partitioning algorithm can reduce the calculation time of the RT process by more than 40%compared with the uniform space segmentation algorithm.

关键词： adaptive space partitioning computer graphics binary space partitioning ray tracing(RT)method stealth technology

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Evaluating the emission status of light-duty gasoline vehicles and motorcycles in Macao with real-world remote sensing measurement

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Journal of Environmental Sciences 2014年第11期26卷 2240-2248页

作者： Yu Zhou Ye Wu Shaojun Zhang Lixin Fu Jiming Hao School of Environment State Key Joint Laboratory of Environment Simulation and Pollution Control Tsinghua University State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex

Roadside remote sensing measurement was used to explore the real-world emission status of light duty gasoline vehicles （LDGVs） and motorcycles in Macao. Both fuel-based and distance-based emission factors were derived using the mass balance method. The emission concentration profile of LDGVs illustrated the benefits of tightening emission standards at the source country or region of import. The distance-based emission factors for CO, HC and NOx of LDGVs registered before 2000 were 8.00, 1.04 and 1.36 g/km, respectively. The distance-based emission factors for CO, HC and NOx of LDGVs registered in or after 2000 were 1.16, 0.15 and 0.18 g/km, respectively. The fuel-based CO emission factors of light duty motorcycles （LDMCs） and heavy duty motorcycles （HDMCs） registered before 2000 were about 10 times higher than those of LDGVs of the same age group. As the emissions of LDGVs decreased more quickly after 2000, the gap widens for newer vehicles. The distance-based HC emission factors of LDMCs and HDMCs registered before 2000 were 4.81 and 2.91 g/km, respectively. The distance-based HC emission factors of LDMCs and HDMCs registered in or after 2000 were 3.52 and 0.93 g/km, respectively. The poor emission performance of motorcycles and their larger share in the traffic flow will cause them to be the major contributor to traffic CO and HC emissions. LDMCs, especially two-stroke models, should be the priority for vehicle emission control efforts in Macao.

关键词： Emission Remote sensing Macao Motorcycle

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Lower bound for transient growth of inclined buoyancy layer

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Applied Mathematics and Mechanics(English Edition) 2017年第6期38卷 779-796页

作者： Xiangming XIONG Jianjun TAO Center for Applied Physics and Technology (CAPT)-MOE Key Laboratory of High Energy Density Physics Simulation (HEDPS) State Key Laboratory for Turbulence and Complex System (SKLTCS)Department of Mechanics and Engineering ScienceCollege ofEngineeringPeking University

The relationship between stabilities of the buoyancy boundary layers along an inclined plate and a vertical plate immersed in a stratified medium is studied theoretically and numerically. The eigenvalue problem of energy stability is solved with the method of descending exponentials. The disturbance energy is found to be able to grow to 11.62 times as large as the initial disturbance energy for Pr = 0.72 when the Grashof number is between the critical Grashof numbers of the energy stability and the linear stability. We prove that, with a weighted energy method, the basic flow of the vertical buoyancy boundary layer is stable to finite-amplitude streamwise-independent disturbances.

关键词： natural convection boundary layer energy method transient growth

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Water hammer prediction and control:the Green's function method

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Acta Mechanica Sinica 2012年第2期28卷 266-273页

作者： Li-Jun Xuan Feng Mao Jie-Zhi Wu State Key Laboratory of Turbulence and Complex System College of EngineeringPeking University100871 BeijingChina

By Green＇s function method we show that the water hammer （WH） can be analytically predicted for both laminar and turbulent flows （for the latter, with an eddy vis- cosity depending solely on the space coordinates）, and thus its hazardous effect can be rationally controlled and mini- mized. To this end, we generalize a laminar water hammer equation of Wang et al. （J. Hydrodynamics, B2, 51, 1995） to include arbitrary initial condition and variable viscosity, and obtain its solution by Green＇s function method. The pre- dicted characteristic WH behaviors by the solutions are in excellent agreement with both direct numerical simulation of the original governing equations and, by adjusting the eddy viscosity coefficient, experimentally measured turbulent flow data. Optimal WH control principle is thereby constructed and demonstrated.

关键词： Water hammer Two-dimensional analytical theory - Pressure transients Pipe-valve flow control

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