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多模光纤反馈半导体激光器产生无时延特征混沌

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中国激光 2024年第6期51卷 160-170页

作者：蔺玉雪高慧王龙生李腾龙赵彤常朋发王安帮王云才太原理工大学新型传感器与智能控制教育部/山西省重点实验室山西太原030024 中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室吉林长春130033 广东工业大学广东省信息光子技术重点实验室广东广州510006 中国工程物理研究院应用电子学研究所四川绵阳621900

提出了一种基于多模光纤模间色散的无时延特征混沌产生方案。在多模光纤长度为4.4 km、芯径为62.5μm、反馈强度为0.1的条件下,实验获得了无时延特征的混沌信号。进一步理论分析了多模光纤的纤芯直径、相对偏移、长度对混沌光模场的影响... 详细信息

提出了一种基于多模光纤模间色散的无时延特征混沌产生方案。在多模光纤长度为4.4 km、芯径为62.5μm、反馈强度为0.1的条件下,实验获得了无时延特征的混沌信号。进一步理论分析了多模光纤的纤芯直径、相对偏移、长度对混沌光模场的影响,结果显示:随着纤芯直径和相对偏移的增大,模式数量逐渐增多,模场分布变复杂;随着光纤长度的增加,模式分离程度(即模间色散)增大。最终探明了多模光纤相对偏移、反馈强度、长度对时延特征的抑制规律。结果表明,在与实验相同的纤芯直径和反馈强度下,消除时延特征的多模光纤的临界长度为1 km。

关键词：光纤光学半导体激光器混沌激光时延特征多模光纤

Integrated multi-scale approach combining global homogenization and local refinement for multi-field analysis of high-temperature superconducting composite magnets

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 747-762页

作者： Hanxiao GUO Peifeng GAO Xingzhe wang Key Laboratory of Mechanics on Western Disaster and Environment of Ministry of Education Key Laboratory of Special Function Materials and Structure Design of Ministry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting *** respect to epoxy-impregnated REBCO composite magnets that comprise multilayer components,the thermomechanical characteristics of each component differ considerably under extremely low temperatures and strong electromagnetic *** numerical models include homogenized orthotropic models,which simplify overall field calculation but miss detailed multi-physics aspects,and full refinement(FR)ones that are thorough but computationally ***,we propose an extended multi-scale approach for analyzing the multi-field characteristics of an epoxy-impregnated composite magnet assembled by HTS pancake *** approach combines a global homogenization(GH)scheme based on the homogenized electromagnetic T-A model,a method for solving Maxwell's equations for superconducting materials based on the current vector potential T and the magnetic field vector potential A,and a homogenized orthotropic thermoelastic model to assess the electromagnetic and thermoelastic properties at the macroscopic *** then identify“dangerous regions”at the macroscopic scale and obtain finer details using a local refinement(LR)scheme to capture the responses of each component material in the HTS composite tapes at the mesoscopic *** results of the present GH-LR multi-scale approach agree well with those of the FR scheme and the experimental data in the literature,indicating that the present approach is accurate and *** proposed GH-LR multi-scale approach can serve as a valuable tool for evaluating the risk of failure in large-scale HTS composite magnets.

关键词： epoxy-impregnated high-temperature superconducting(HTS)magnet multi-scale method global homogenization(GH) local refinement(LR) multi-field analysis

A Comparison of Four Neural Networks Algorithms on Locomotion Intention Recognition of Lower Limb Exoskeleton Based on Multi-source Information

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Journal of Bionic Engineering 2024年第1期21卷 224-235页

作者： Duojin wang Xiaoping Gu Hongliu Yu Institute of Rehabilitation Engineering and Technology University of Shanghai for Science and Technology516 Jungong RoadShanghai 200093China Shanghai Engineering Research Center of Assistive Devices 516 Jungong RoadShanghai 200093China

Lower Limb Exoskeletons(LLEs)are receiving increasing attention for supporting activities of daily *** such active systems,an intelligent controller may be *** this paper,we proposed a locomotion intention recognition system based on time series data sets derived from human motion *** of input data and Deep Learning(DL)algorithms,this framework enables the detection and prediction of users’movement *** makes it possible to predict the detection of locomotion modes,allowing the LLEs to provide smooth and seamless *** pre-processed eight subjects were used as input to classify four scenes:Standing/Walking on Level Ground(S/WOLG),Up the Stairs(US),Down the Stairs(DS),and Walking on Grass(WOG).The result showed that the ResNet performed optimally compared to four algorithms(CNN,CNN-LSTM,ResNet,and ResNet-Att)with an approximate evaluation indicator of 100%.It is expected that the proposed locomotion intention system will significantly improve the safety and the effectiveness of LLE due to its high accuracy and predictive performance.

关键词： Lower limb exoskeletons(LLEs) Locomotion intention ResNet Multi-source

Autonomous navigation method of satellite constellation based on adaptive forgetting factors

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Chinese Journal of Aeronautics 2024年第7期37卷 317-332页

作者： Dong wang Jing YANG Kai XIONG School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100094China

To address the problem that model uncertainty and unknown time-varying system noise hinder the filtering accuracy of the autonomous navigation system of satellite constellation,an autonomous navigation method of satellite constellation based on the Unscented Kalman Filter with Adaptive Forgetting Factors(UKF-AFF)is *** process noise covariance matrix is estimated online with the strategy that combines covariance matching and adaptive adjustment of forgetting *** adaptive adjustment coefficient based on squared Mahalanobis distance of state residual is employed to achieve online regulation of forgetting factors,equipping this method with more *** intersatellite direction vector obtained from photographic observations is introduced to determine the constellation satellite orbit together with the distance measurement to avoid rank deficiency *** that the number of available measurements varies online with intersatellite visibility in practical applications such as time-varying constellation configurations,the smooth covariance matrix of state correction determined by innovation and gain is adopted and constructed *** analysis of the proposed method is also *** effectiveness of the proposed method is verified by the Monte Carlo simulation and comparison *** estimation accuracy of constellation position and velocity of UKF-AFF is improved by 30%and 44%respectively compared to those of the extended Kalman filter,and the method proposed is also better than other several adaptive filtering methods in the presence of significant model uncertainty.

关键词： Constellation autonomous navigation Unscented Kalman filter Adaptive forgetting factor Model uncertainty Stability analysis

An Asynchronous Variational Integrator for Contact Problems Involving Elastoplastic Solids

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Acta Mechanica Solida Sinica 2024年第2期37卷 305-315页

作者： Zongwu Niu Zixiao wang Yongxing Shen University of Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong UniversityShanghai200240China School of Agriculture and Biology Shanghai Jiao Tong UniversityShanghai200240China Department of Biostatistics Johns Hopkins Bloomberg School of Public HealthBaltimoreMaryland21205USA

Simulations of contact problems involving at least one plastic solid may be costly due to their strong nonlinearity and requirements of *** this work,we develop an explicit asynchronous variational integrator(AVI)for inelastic non-frictional contact problems involving a plastic *** AVI assigns each element in the mesh an independent time step and updates the solution at the elements and nodes *** asynchrony makes the AVI highly efficient in solving such bi-material *** advantage of the AVI,the constitutive update is locally performed in one element at a time,and contact constraints are also enforced on only one *** time step of the contact element is subdivided into multiple segments,and the fields are updated *** a contact event,only one element involving a few degrees of freedom is considered,leading to high *** proposed formulation is first verified with a pure elastodynamics benchmark and further applied to a contact problem involving an elastoplastic solid with non-associative volumetric *** numerical results indicate that the AVI exhibits excellent energy behaviors and has high computational efficiency.

关键词： Asynchronous variational integrator Plasticity Contact Computational efficiency Finite element method

Dual-functional poly(2-methyl-2-oxazoline)/poly(2-(dimethylamine)ethyl methacrylate)mixed brushes with switchable protein adsorption and antibacterial properties

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Chinese Journal of Chemical Engineering 2024年第2期66卷 19-30页

作者： Kang He Liangyu Zhu Yanmei wang CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

Herein,binary mixed brushes consisting of poly(2-methyl-2-oxazoline)(PMOXA)and poly(2-(dimethylamine)ethyl methacrylate)(PDMAEMA)with different chain lengths were fabricated by successive grafting of NH_(2)-terminated PMOXA and SH-terminated PDMAEMA onto polydopamine-anchored *** mixed-brush coating was characterized by variable-angle spectroscopic ellipsometry,X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy,zeta potential measurements,water contact angle,and atomic force *** mixed brushes showed tunable surface charge,wettability,and surface roughness,depending on the degree of PDMAEMA swelling under varying pH and ionic strength(Ⅰ).Then the adsorption behaviors of pepsin,bovine serum albumin(BSA),γ-globulin,and lysozyme,four very different proteins with regard to isoelectric point,on the mixed brushes coating were studied by using fluorescence microscopy and surface plasmon *** the chain length of PDMAEMA was about twice as long as PMOXA,the mixed brushes not only had high adsorption capacity for pepsin,BSA,and y-globulin but also had a desorption efficiency of 86.9%,87.1%,and 93.5%,*** is explained that electrostatic attraction between the protonated PDMAEMA and positively charged acidic proteins(pepsin and BSA,whose isoelectric points were below the pK_(a) of PDMAEMA)would drive the intensive adsorption(at pH 3,I=10^(-3)mol·L^(-1)for pepsin,and pH 5,I=10^(-5)mol·L^(-1)for BSA),while desorption was dominated by the hydrophilic PMOXA when PDMAEMA was shrinking(at pH 7,I=10^(-1)mol·L^(-1)for pepsin,and pH 9,I=10^(-1)mol·L^(-1)for BSA).Furthermore,the isoelectric precipitation led to the adsorption of neutral protein(γ-globulin,whose isoelectric point was near the pK_a of PDMAEMA)at pH 7,I=10^(-5)mol·L^(-1),while electrostatic repulsion and antifouling PMOXA triggered the desorption of y-globulin at pH 3,I-10^(-1)mol·L^(-1).However,alkaline protein(lysozyme,whose isoelectric point was higher than

关键词： Switchable conformation transition Controllable protein adsorption Mixed brushes Isoelectric point Antibacterial surface

Recent Advance in Synaptic Plasticity Modulation Techniques for Neuromorphic Applications

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Nano-Micro Letters 2024年第10期16卷 403-434页

作者： Yilin Sun Huaipeng wang Dan Xie School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081People's Republic of China School of Integrated Circuits Beijing National Research Center for Information Science and Technology(BNRist)Tsinghua UniversityBeijing 100084People's Republic of China

Manipulating the expression of synaptic plasticity of neuromorphic devices provides fascinating opportunities to develop hardware platforms for artifi-cial ***,great efforts have been devoted to exploring biomimetic mechanisms of plasticity simulation in the last few *** progress in various plasticity modulation techniques has pushed the research of synaptic electronics from static plasticity simulation to dynamic plasticity modulation,improving the accuracy of neuromorphic computing and providing strategies for implementing neuromorphic sensing ***,several fascinating strategies for synap-tic plasticity modulation through chemical techniques,device structure design,and physical signal sensing are *** chemical techniques,the underly-ing mechanisms for the modification of functional materials were clarified and its effect on the expression of synaptic plasticity was also *** on device structure design,the reconfigurable operation of neuromorphic devices was well demonstrated to achieve programmable neuromorphic ***,integrating the sensory units with neuromorphic processing circuits paved a new way to achieve human-like intelligent perception under the modulation of physical signals such as light,strain,and ***,considering that the relevant technology is still in the basic exploration stage,some prospects or development suggestions are put forward to promote the development of neuromorphic devices.

关键词： Plasticity modulation Dynamic plasticity Chemical techniques Programmable operation Neuromorphic sensing

Long-term in vivo chimeric cells tracking in non-human primate

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Protein & Cell 2024年第3期15卷 207-222页

作者： Junmo Wu Yu Kang Xiang Luo Shaoxing Dai Yuxi Shi Zhuoyao Li Zengli Tang Zhenzhen Chen Ran Zhu Pengpeng Yang Zifan Li Hong wang Xinglong Chen Ziyi zhao Weizhi ji Yuyu Niu State Key Laboratory of Primate Biomedical Research Institute of Primate Translational MedicineKunming University of Science and TechnologyKunming 650500China Yunnan Key Laboratory of Primate Biomedical Research Kunming 650500China Faculty of Life Science and Technology Kunming University of Science and TechnologyKunming 650500China

Non-human primates(NHPs)are increasingly used in preclinical trials to test the safety and efficacy of biotech-nology ***,given the ethical issues and costs associated with this model,it would be highly advantageous to use NHP cellular models in clinical ***,developing and maintaining the naive state of primate pluripotent stem cells(PSCs)remains difficult as does in vivo detection of PSCs,thus limiting biotech-nology application in the cynomolgus ***,we report a chemically defined,xeno-free culture system for culturing and deriving monkey PSCs in *** cells display global gene expression and genome-wide hypometh-ylation patterns distinct from monkey-primed *** also found expression of signaling pathways components that may increase the potential for chimera *** for biomedical applications,we were also able to integrate bioluminescent reporter genes into monkey PsCs and track them in chimeric embryos in vivo and in *** engineered cells retained embryonic and extra-embryonic developmental ***,we generated a chimeric monkey carrying bioluminescent cells,which were able to track chimeric cells for more than 2 years in living *** study could have broad utility in primate stem cell engineering and in utilizing chimeric monkey models forclinical studies.

关键词： pluripotent stem cells bioluminescence imaging non-human primates

Room-temperature and atmospheric-pressure hydrogenation of lignin-derived phenol to KA oil by Pt/NiO@MOFs

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Nano Research 2024年第8期17卷 7053-7060页

作者： Fengbin Zheng Kun wang Yifei Ren Bohua wang Wenxing Chen Caoyu Yang Shengxian Shao Yinglong wang Zhiyong Tang Guodong Li College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042China CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100181China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing 100049China

Hydrogenation of lignin-derived phenol to KA oil(the mixture of cyclohexanone(K)and cyclohexanol(A))is attractive yet challenging in the sustainable upgrading of biomass derivatives under mild *** supported metal catalysts have been widely studied but the active components on supports often exhibit low recyclability due to their instability under experimental *** we show fabricating ultrasmall Pt/NiO in the pores of chromium terephthalate MIL-101 as catalysts for hydrogenation of ***,Pt/NiO@MIL-101 achieves catalytic phenol hydrogenation to KA oils of tunable K/A ratios and good reusability under room temperature and atmospheric hydrogen pressure,superior to contrast Pt@MIL-101 and Pt/NiO *** excellent performance mainly originates from the effective adsorption and activation of phenol by coordinatively unsaturated Cr sites and H2 activation on ultrasmall Pt/NiO as well as its effective spillover to the adsorbed phenol over Cr sites for hydrogenation ***,such catalyst also displays the excellent performances for hydrogenation of phenol’s derivatives under mild conditions.

关键词： ultrasmall Pt/NiO MIL-101 phenol hydrogenation KA oil