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Lightweight multifunctional metamaterial with low-frequency vibroacoustic reduction and load-bearing performances

Applied Mathematics and Mechanics(English Edition) 2025年第3期46卷 403-422页

作者： Qi JIA Dianlong YU Donghai HAN Jihong WEN National Key Laboratory of Equipment State Sensing and Smart Support College of Intelligence Science and TechnologyNational University of Defense TechnologyChangsha 410073China

Metamaterials can control and manipulate acoustic/elastic waves on a subwavelength scale using cavities or additional ***,the large cavity and weak stiffness components of traditional metamaterials may cause a conflict between vibroacoustic reduction and load-bearing capacity,and thus limit their ***,we propose a lightweight multifunctional metamaterial that can simultaneously achieve low-frequency sound insulation,broadband vibration reduction,and excellent load-bearing performance,named as vibroacoustic isolation and bearing metamaterial(VIBM).The advent of additive manufacturing technology provides a convenient and reliable method for the fabrication of VIBM *** results show that the compressive strength of the VIBM is as high as 9.71 MPa,which is nearly 87.81%higher than that of the conventional grid structure(CGS)under the same volume ***,the vibration and sound transmission are significantly reduced over a low and wide frequency range,which agrees well with the experimental data,and the reduction degree is obviously larger than that obtained by the *** design strategy can effectively realize the key components of metamaterials and improve their application scenarios.

关键词： multifunctional metamaterial low-frequency sound insulation broadband vibration reduction load bearing

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Evaluation of Long-Duration Fatigue Alleviation Effect of a Rocket Ejection Seat Installed at a 35° Angle Based on Heart Rate Variability 15

Evaluation of Long-Duration Fatigue Alleviation Effect of a ...

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15th Asia Conference on Mechanical and Aerospace Engineering, ACMAE 2024

作者： Li, Hui Li, Jun Key Laboratory of Science and Technology on Life-support Technology AVIC Aerospace Life-support Industries Ltd. No.1 AVIC Avenue Hubei Xiangyang China

ISBN: (纸本)9781643685892

Fatigue significantly impacts modern flight safety, leading to decreased pilot performance, judgment errors, flight illusions, and potentially severe accidents. Rocket ejection seat for emergency escape with additional 35° mounting angle design. To verify the fatigue improvement effect of this design for long-duration flights, a simulated long-duration flight test was conducted. The trial uses wearable wireless physiological monitoring equipment to collect ECG from trainees. Short-term heart rate variability (HRV) indicators reflecting fatigue state were selected from the time-domain, frequency-domain, and nonlinear characteristics of valid samples. Paired sample test results showed significant changes in short-term HRV indicators before and after resting with the rocket ejection seat installed at a 35° angle, indicating reduced sympathetic activity and increased parasympathetic activity, thus alleviating fatigue. © 2025 The Authors.

关键词： Heart

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Knockout of the fcsk gene in zebrafish causes neurodevelopmental defects

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Zoological Research 2025年第2期46卷 313-324页

作者： Zhen-Xing Liu Ting-Ting Zou Hui-Hui Liu Hai-Bo Jia Xian-Qin Zhang Key Laboratory of Molecular Biophysics of the Ministry of Education College of Life Science and Technology and Center for Human Genome ResearchHuazhong University of Science and TechnologyWuhanHubei 430074China

Congenital disorders of glycosylation(CDG)are a cluster of monogenic disorders resulting from defects in *** encodes fucokinase,an enzyme that catalyzes the phosphorylation of L-fucose to generate fucose-1-phosphate,an important step in *** in FCSK lead to CDG with an autosomal recessive inheritance pattern,primarily manifesting as developmental delay,hypotonia,and brain ***,no fcsk mutant animal models have yet been *** study constructed the first fcsk knockout(fcsk^(-/-))zebrafish model using CRISPR/Cas9 ***,fcsk^(-/-)zebrafish exhibited impaired growth,characterized by delayed epiboly and DNA accumulation during early embryonic development,as well as brain atrophy in ***-stage fcsk^(-/-)zebrafish displayed locomotor deficits and increased susceptibility to pentylenetetrazole-induced *** adulthood,fcsk^(-/-)zebrafish showed neurodevelopmental abnormalities,including increased anxiety,decreased aggression,reduced social preference,and impaired ***,total protein fucosylation was markedly reduced in fcsk^(-/-)zebrafish,accompanied by decreased expression of pofut2,which encodes protein Ofucosyltransferase 2,an enzyme involved in the fucosylation salvage *** activity was elevated in the midbrain-hindbrain boundary(MHB)of fcsk^(-/-)*** with GDP-L-fucose or the human FCSK gene restored developmental defects and total protein fucosylation in fcsk^(-/-)*** sequencing revealed dysregulated gene expression associated with glycosylation,apoptosis,and neurodegenerative *** findings suggest that fcsk^(-/-)zebrafish exhibit neurodevelopmental disorders,providing the first fcsk gene knockout animal model and offering a platform for investigating the molecular underpinnings of the disease and facilitating drug screening efforts.

关键词： Congenital disorders of glycosylation fcsk Zebrafish Behavior RNA sequencing

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Frame Generation Algorithm for Differentiated Services in Tactical Communication Networks

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Journal of Communications and Information Networks 2025年第1期10卷 15-25页

作者： Huaifeng Shi Chengsheng Pan Lishang Qin Yingzhi Wang Huangjie Lu Key Laboratory of Intelligent Support Technology for Complex Environments Ministry of EducationNanjing University of Information Science and TechnologyNanjing 210044China

In response to the complex and multidimensional nature of converged traffic on heterogeneous links in tactical communication networks,which leads to the difficulty in ensuring the quality of service(QoS)requirements for critical services,a frame generation algorithm for differentiated services(DS-FG)is ***-FG deploys an adaptive frame generation algorithm based on deep reinforcement learning(DRL-FG)for timesensitive service,while deploying a high efficient frame generation(HEFG)algorithm for non-time-sensitive ***-FG constructs a reward function by combining the queue status information of time-sensitive service and utilizes deep deterministic policy gradients(DDPG)to train a decision model for adaptive frame generation(AFG)algorithm ***,Gaussian noise sampling and prioritized experience replay strategies are employed to enhance model training efficiency and performance,achieving optimal matching between time-sensitive service QoS requirements and frame generation *** results demonstrate that DS-FG outperforms traditional algorithms,achieving up to 13%improvement in throughput and over 19.7%reduction in average queueing delay for time-sensitive service.

关键词： frame generation algorithm tactical communication network reinforcement learning differentiated services

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Swarming Magnetic Fe_(3)O_(4)@Polydopamine-Tannic Acid Nanorobots:Integrating Antibiotic-Free Superficial Photothermal and Deep Chemical Strategies for Targeted Bacterial Elimination

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Research 2025年第1期2024卷 840-853页

作者： Luying Si Shuming Zhang Huiru Guo Wei Luo Yuqin Feng Xinkang Du Fangzhi Mou Huiru Ma Jianguo Guan State Key Laboratory of Advanced Technology for Materials Synthesis and Processing International School of Materials Science and EngineeringWuhan University of TechnologyWuhanChina Wuhan Institute of Photochemistry and Technology WuhanChina School of Chemistry Chemical Engineering and Life ScienceWuhan University of TechnologyWuhanChina

Micro/nanorobots(MNRs)are envisioned to provide revolutionary changes to therapies for infectious diseases as they can deliver various antibacterial agents or energies to many hard-to-reach infection ***,existing MNRs face substantial challenges in addressing complex infections that progress from superficial to deep ***,we develop swarming magnetic Fe3O4@polydopamine-tannic acid nanorobots(Fe3O4@PDA-TA NRs)capable of performing targeted bacteria elimination in complicated bacterial infections by integrating superficial photothermal and deep chemical *** Fe3O4@PDA-TA nanoparticles(NPs),serving as building blocks of the nanorobots,are fabricated by in situ polymerization of dopamine followed by TA *** driven by alternating magnetic fields,Fe3O4@PDA-TA NPs can assemble into large energetic microswarms continuously flowing forward with tunable ***,the swarming Fe3O4@PDA-TA NRs can be navigated to achieve rapid broad coverage of a targeted superficial area from a distance and rapidly eradicate bacteria residing there upon exposure to near-infrared(NIR)light due to their efficient photothermal ***,they can concentrate at deep infection sites by traversing through confined,narrow,and tortuous passages,exerting sustained antibacterial action through their surface TA-induced easy cell adhesion and subsequent membrane ***,the swarming Fe3O4@PDA-TA NRs show great potential for addressing complex superficial-to-deep *** study may inspire the development of future therapeutic microsystems for various diseases with multifunction synergies,task flexibility,and high efficiency.

关键词： therapies infectious diseases complex infections chemical therapy magnetic nanoparticles polydopamine photothermal therapy targeted bacteria elimination tannic acid

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Molecular regulation of metal-organic frameworks for rapid and efficient extraction of uranium from seawater

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science China Chemistry 2025年第5期68卷 1906-1915页

作者： Jie Luo Xiao Luo Mo Xie Jia-Tong Lin Jie Pang Na Yin Yan-Yan Li Guo-Hong Ning Dan Li College of Chemistry and Materials Science Guangdong Provincial Key Laboratory of Supramolecular Coordination ChemistryJinan University Department of Biomedical Engineering College of Life Science and TechnologyJinan University

The development of novel metal-organic frameworks（MOFs） as solid adsorbents for rapid and efficient extraction of uranium from natural seawater is a long-term pursuit, yet remains challenging. In this work, we have prepared four two-dimensional（2D）vinylene-linked cyclic trinuclear units（CTUs） based MOFs. The metal nodes in the skeleton can be regulated, resulting in two Ag-CTU and two Cu-CTU-based MOFs with similar 2D hexagonal structures. These MOFs exhibit not only good stability in acid/base, γ-ray irradiation and natural seawater but also feature excellent anti-biofouling properties against five marine bacteria with inhibition rates as high as ～99%. Interestingly, the alteration of Ag（I） to Cu（I） remarkably enhances the uranium sorption capacity due to the reduction of soluble U（VI） to insoluble U（IV） triggered by the chemical and photo-redox reaction of *** to the multiple functions, the Cu-CTU-based MOF delivers the best overall performance for uranium extraction from natural seawater with a high adsorption capacity of 7.96 mg g-1and adsorption rate of ～1.00 mg g-1day-1, which is much higher than most of reported representative solid adsorbents. Our work paves a new way for rationally designing synergistic MOFs with superior performance for extracting uranium from natural seawater.

关键词： metal-organic frameworks uranium extraction photocatalytic reduction seawater

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SegNet4D: Efficient Instance-Aware 4D Semantic Segmentation for LiDAR Point Cloud

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IEEE Transactions on Automation science and Engineering 2025年 22卷 15339-15350页

作者： Wang, Neng Guo, Ruibin Shi, Chenghao Wang, Ziyue Zhang, Hui Lu, Huimin Zheng, Zhiqiang Chen, Xieyuanli National University of Defense Technology College of Intelligence Science and Technology National Key Laboratory of Equipment State Sensing and Smart Support Changsha410073 China

4D LiDAR semantic segmentation classifies the semantic category of each LiDAR point and detects whether it is dynamic, a critical ability for tasks like obstacle avoidance and autonomous navigation. Existing approaches often rely on computationally heavy 4D convolutions or recursive networks, which result in poor real-time performance. In this paper, we introduce SegNet4D, a novel real-time 4D semantic segmentation network, offering both efficiency and strong semantic understanding. SegNet4D addresses 4D segmentation as two tasks: single-scan semantic segmentation and moving object segmentation, each tackled by a separate network head. Both results are combined in a motion-semantic fusion module to achieve comprehensive 4D segmentation. Additionally, instance information is extracted from the current scan and exploited for instance-wise segmentation consistency. Extensive experiments on the SemanticKITTI and nuScenes datasets demonstrate that our method outperforms the state-of-the-art in both 4D semantic segmentation and moving object segmentation. Through detailed runtime analysis, our method shows greater efficiency, enabling real-time operation. Besides, its effectiveness and efficiency have also been validated on a real-world robotic platform. © 2004-2012 IEEE.

关键词： Semantic Segmentation

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Nonlinear dynamics of Nishimura model-based fractional-order vibration isolation system under the synergistic effect of aerodynamic lift and harmonic excitation

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Nonlinear Dynamics 2025年第11期113卷 12693-12717页

作者： Qu, Minghe Wang, Lianchun Jin, Qiduo Zhou, Danfeng Li, Jie College of Intelligence Science and Technology National University of Defense Technology Changsha410073 China National Key Laboratory of Equipment State Sensing and Smart Support National University of Defense Technology Changsha410073 China

The electromagnetic sled test platform exhibits complex nonlinear vibration characteristics under the excitation of synergistic effects due to the influence of self-excited vibration and aerodynamic lift from the test model. Metal plate and rubber combined structure vibration isolator are anticipated to deliver superior vibration attenuation performance for sled. However, the complex constitutive relation of rubber is always challenging to the change of excitation source. In this study, the nonlinear dynamics of metal-rubber-vibration subsystem is studied, and the dynamic characteristics under the synergistic effect of aerodynamic lift and harmonic excitation are emphatically discussed. A nonlinear Nishimura model-based on fractional-order is developed to describe the constitutive relationship of metal-rubber. The fractional order is defined by Caputo, the periodic solution is obtained by harmonic balance method, and the aperiodic response is numerically simulated. The amplitude-frequency characteristics of the system are obtained, and the complex nonlinear dynamic behavior of the system is verified by Poincaré mapping, phase diagram and spectrum diagram. The stability of dynamic response is further revealed by Lyapunov exponent and attraction basin. The multiplicity of amplitude-frequency response and the mechanism of periodic motion and chaotic transition are analyzed. The results show that the amplitude-frequency curve of the system exhibits a complex dynamic phenomenon with 5 coexisting solutions under combined excitation, and there are multiple types of bifurcations in the periodic motion and chaotic transition processes. The transition dynamics between periodic motion and chaos under varying excitation exhibit significant differences, and this transition process is inherently irreversible. The research in this paper provides theoretical guidance for the parameter design of metal-rubber vibration isolation system and its application in electromagnetic sled. © T

关键词： Lyapunov methods

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Structural design and controllable preparation of SiC NWs@Fe_(3)O_(4)@NC nanocomposites for electromagnetic wave absorption

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International Journal of Minerals,Metallurgy and Materials 2025年第3期32卷 520-533页

作者： Wenxin Zhao Meng Zhang Yukun Miao Chang Wang Anguo Cui Liying Yuan Zeqing Miao Xiaoqing Wang Zhibo Wang Haoyu Pang Alan Meng Zhenjiang Li Ting Wang College of Materials Science and Engineering Qingdao University of Science and TechnologyQingdao 266042China Shandong Engineering Laboratory for Preparation and Application of High-Performance Carbon-Materials College of Electromechanical EngineeringQingdao University of Science and TechnologyQingdao 266061China Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science MOEShandong Key Laboratory of Biochemical AnalysisCollege of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao 266042China College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042China

Using SiC nanowires(SiCNWs)as the substrate,reflux-annealing and electrodeposition-carbonization were sequentially applied to integrate SiC nanowires with magnetic Fe_(3)O_(4) nanoparticles and amorphous nitrogen-doped carbon(NC)for the fabrication of SiCNWs@Fe_(3)O_(4)@NC *** testing and characterization of this product provided valuable insights into the im-pact of structural and composition changes on its electromagnetic wave absorption *** optimized SiCNWs@Fe_(3)O_(4)@NC nanocomposite,which has 30wt%filler content and a corresponding thickness of 2.03 mm,demonstrates exceptional performance with the minimum reflection loss(RL_(min))of-53.69 dB at 11.04 GHz and effective absorption bandwidth(EAB)of 4.4 *** synergistic effects of the enhanced nanocomposite on electromagnetic wave absorption were thoroughly elucidated using the theories of multiple scattering,polarization relaxation,hysteresis loss,and eddy current ***,a multicomponent electromagnetic wave attenu-ation model was established,providing valuable insight into the design of novel absorbing materials and the enhancement of their absorp-tion *** research demonstrated the significant potential of the SiCNWs@Fe_(3)O_(4)@NC nanocomposite as a highly efficient electromagnetic wave-absorbing material with potential applications in various fields,such as stealth technology and microwave absorption.

关键词： electromagnetic attenuation mechanism multicomponent nanocomposite SiC nanowires structural design

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Copper-catalyzed C–H bond functionalization enabled by programmed alternating current

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science China Chemistry 2025年第1期68卷 10-11页

作者： Zhoumei Tan Kun Xu Chengchu Zeng Beijing Key Laboratory of Environmental and Viral Oncology College of Chemistry and Life ScienceBeijing University of TechnologyBeijing 100124China

Synthetic electrochemistry has been selected as one of the Top Ten Emerging Technologies in Chemistry in 2023 by International Union of Pure and Applied Chemistry(IUPAC)^([1]).It has emerged as a sustainable platform for organic synthesis and has exhibited a wide range of applications from academia to industry^([2]).However,electrosynthesis has been predominantly performed by using direct current(DC).

关键词： catalyzed Copper IUPAC

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