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Deformation and Locomotion of Untethered Small-Scale Magnetic Soft Robotic Turtle with Programmable Magnetization

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Journal of Bionic Engineering 2024年第2期21卷 754-763页

作者： Lin Xu liu yang Tao Li Xingbang Zhang Jianning Ding School of Mechanical Engineering Jiangsu UniversityZhenjiang212013China The Key Laboratory of Bionic Engineering(Ministry of Education) Jilin UniversityChangchun130012China Shanghai Tianchun Technology Co. LtdShanghai201802China School of Mechanical Engineering Yangzhou UniversityYangzhou225009China

Inspired by the way sea turtles rely on the Earth’s magnetic field for navigation and locomotion,a novel magnetic soft robotic turtle with programmable magnetization has been developed and investigated to achieve biomimetic locomotion patterns such as straight-line swimming and turning swimming.The soft robotic turtle(12.50 mm in length and 0.24 g in weight)is integrated with an Ecoflex-based torso and four magnetically programmed acrylic elastomer VHB-based limbs containing samarium-iron–nitrogen particles,and was able to carry a load more than twice its own weight.Similar to the limb locomotion characteristics of sea turtles,the magnetic torque causes the four limbs to mimic sinusoidal bending deformation under the influence of an external magnetic field,so that the turtle swims continuously forward.Significantly,when the bending deformation magnitudes of its left and right limbs differ,the soft robotic turtle switches from straight-line to turning swimming at 6.334 rad/s.Furthermore,the tracking swimming activities of the soft robotic turtle along specific planned paths,such as square-shaped,S-shaped,and double U-shaped maze,is anticipated to be utilized for special detection and targeted drug delivery,among other applications owing to its superior remote directional control ability.

关键词： Magnetic soft robotic turtle Programmable magnetization Untethered soft robotics Bending deformation

On the Probability of Generating a Primitive Matrix

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Journal of Systems Science & Complexity 2024年第4期37卷 1755-1771页

作者： CHEN Jingwei FENG Yong liu yang WU Wenyuan Chongqing Key Laboratory of Automated Reasoning and Cognition Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences Chongqing College University of Chinese Academy of Sciences Key Laboratory of Advanced Manufacturing Technology of Ministry of Education Guizhou Universityy Information Science and Engineering Chongqing Jiaotong University

Given a k × n integer primitive matrix A（i.e., a matrix can be extended to an n × n unimodular matrix over the integers） with the maximal absolute value of entries ‖A‖ bounded by an integer λ from above, the authors study the probability that the m × n matrix extended from A by appending other m-k row vectors of dimension n with entries chosen randomly and independently from the uniform distribution over {0, 1, · · ·, λ-1} is still primitive. The authors present a complete and rigorous proof of a lower bound on the probability, which is at least a constant for fixed m in the range[k + 1, n-4]. As an application, the authors prove that there exists a fast Las Vegas algorithm that completes a k × n primitive matrix A to an n × n unimodular matrix within expected ?（nωlog ‖A‖） bit operations, where ? is big-O but without log factors, ω is the exponent on the arithmetic operations of matrix multiplication.

关键词： Integer matrix matrix completion probabilistic algorithm unimodular matrix

Adaptive Observer-Based Finite-Time Fault Tolerant Control for Non-Strict Feedback Systems

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Journal of Systems Science & Complexity 2024年第4期37卷 1526-1544页

作者： SHENG Ning liu yang CHI Ronghu AI Zidong College of Automation and Electronic Engineering Qingdao University of Science and Technology

This paper considers the adaptive finite-time control and observer design method for a class of non-strict feedback systems with unmeasurable states, unknown nonlinear dynamics and actuator faults. In this paper, an observer is proposed to estimate the unmeasurable states in finite-time based on adaptive technique and neural networks, while the actuator faults are not included. Command filter is used to solve the computational explosion and singularity problems caused by the traditional backstepping and non-strict feedback structure, respectively. Since the fault efficiency indicators in real systems are not available, two-layer neural networks are adopted, where the first network is to estimate the unknown nonlinearities of systems and the second one is to estimate fault efficiency indicators and unknown nonlinear terms. The proposed scheme guarantees that states are bounded through stability theorem. Finally, two experiments including a numerical example and a spring-mass-damper system are given to verify the effectiveness of the proposed method.

关键词： Command filter fault tolerant control finite-time control non-strict systems two-layer neural networks

Generating a nanoscale blade-like optical field in a coupled nanofiber pair

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Photonics Research 2024年第1期12卷 154-162页

作者： YUXIN yang JIAXIN GAO HAO WU ZHANKE ZHOU liu yang XIN GUO PAN WANG LIMIN TONG Interdisciplinary Center for Quantum Information New Cornerstone Science LaboratoryState Key Laboratory of Extreme Photonics and InstrumentationCollege of Optical Science and EngineeringZhejiang UniversityHangzhou 310027China Jiaxing Key Laboratory of Photonic Sensing&Intelligent Imaging Intelligent Optics&Photonics Research CenterJiaxing Research Institute Zhejiang UniversityJiaxing 314000China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

An optical field with sub-nm confinement is essential for exploring atomic-or molecular-level light-matter interaction.While such fields demonstrated so far have typically point-like cross-sections,an optical field having a higher-dimensional cross-section may offer higher flexibility and/or efficiency in applications.Here,we propose generating a nanoscale blade-like optical field in a coupled nanofiber pair(CNP)with a 1-nm-width central slit.Based on a strong mode coupling-enabled slit waveguide mode,a sub-nm-thickness blade-like optical field can be generated with a cross-section down to~0.28 nm×38 nm at 1550 nm wavelength(i.e.,a thickness of~λ_(0)∕5000)and a peak-to-background intensity ratio(PBR)higher than 20 d B.The slit waveguide mode of the CNP can be launched from one of the two nanofibers that are connected to a standard optical fiber via an adiabatical fiber taper,in which a fundamental waveguide mode of the fiber can be converted into a high-purity slit mode with high efficiency(>98%)within a CNP length of less than 10μm at 1550 nm wavelength.The wavelengthdependent behaviors and group velocity dispersion in mode converting processes are also investigated,showing that such a CNP-based design is also suitable for broadband and ultrafast pulsed operation.Our results may open up new opportunities for studying light-matter interaction down to the sub-nm scale,as well as for exploring ultra-high-resolution optical technology ranging from super-resolution nanoscopy to chemical bond manipulation.

关键词： fiber waveguide optical

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Plant life form determines spatiotemporal variability and climate response of plant seed rain in subtropical forests

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Forest Ecosystems 2024年第2期11卷 193-201页

作者： Yuyang Xie Zehao Shen Xuejing Wang liu yang Jie Zhang MOE Laboratory for Earth Surface Processes Institute of EcologyCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China

Spatiotemporal variation of seed rain reflects the response of plants in terms of their reproductive strategy to environmental gradients.In this study,we collected seeds from four sites in the Dalaoling Nature Reserve,Hubei Province,China,between 2011 and 2014,measured seed output and seed mass as seed rain traits,and compared their interannual and elevational variation.Then,we ran phylogenetic generalized mixed linear models(PGLMMs) to explore the effects of temperature and precipitation as well as interspecific differences on seed rain,and fitted the best regression models for seed rain vs.weather of canopy and understory species.The results showed no correlation between values of seed output and seed mass.However,the variation of the two traits showed significantly positive correlation.Seed output of canopy species generally decreased with increasing elevation,and showed significant interannual difference;however,seed output of understory species and seed mass for both canopy and understory species did not show consistency tends along elevational or in interannual variation.Seed output was significantly affected by temperature and precipitation,while seed mass mainly varied due to interspecific differences.Weather explained more the variation of the seed output of canopy species than that of understory species,with R^(2) values of 43.0%and 29.9%,respectively.These results suggested that canopy plants contributed more to the reproductive dynamics of the whole communities,and the canopy's buffer effect on the underground weakened the response of understory plants to weather variation in terms of their reproductive strategy.

关键词： Seed rain Seed output Seed mass Elevation Interannual variation Lifeform

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Strong-coupling superconductivity with Tc above 70 K in Be-decorated monolayer T-graphene

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 99-105页

作者： liu yang Peng-Fei liu Hao-Dong liu Ya-Ping Li Na Jiao Hong-Yan Lu Bao-Tian Wang Ping Zhang School of Physics and Physical Engineering Qufu Normal UniversityQufu 273165China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China Institute of Applied Physics and Computational Mathematics Beijing 100088China

Using first-principles calculations,we predict a new type of two-dimensional(2D)beryllium(Be)-decorated T-graphene named BeC_(2),where Be atoms are inserted into C–C bonds linking the carbon tetrarings of T-graphene.The band structure shows that BeC_(2)is metallic,thus,the possible phonon-mediated superconductivity is explored based on the Eliashberg equation.The calculated electron-phonon coupling(EPC)constantλis up to 4.07,and the corresponding superconducting critical temperature(Tc)is 72.1 K,approaching the liquid nitrogen temperature.The reason for the high Tc is the strong EPC.And it is proved to be an anisotropic single-gap superconductor by analyzing the superconducting gap?kof BeC_(2).The electronic susceptibility calculation shows strong nesting effect in BeC_(2).Since rare 2D superconductors show such a strong EPC constantλwhich originates from the coupling between electrons in C-pzorbital and in-plane vibrations of Be and C atoms,the predicted BeC_(2)provides a new platform for investigating strong EPC 2D superconductor.

关键词： two-dimensional carbon-based superconductor electron-phonon coupling strong coupling high superconducting critical temperature

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Stabilizing semi-transparent perovskite solar cells with a polymer composite hole transport layer

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Nano Research 2024年第3期17卷 1500-1507页

作者： Yongbin Jin Huiping Feng Zheng Fang liu yang Kaikai liu Bingru Deng Jingfu Chen Xueling Chen Yawen Zhong Jinxin yang Chengbo Tian Liqiang Xie Zhanhua Wei Xiamen Key Laboratory of Optoelectronic Materials and Advanced Manufacturing Institute of Luminescent Materials and Information DisplaysCollege of Materials Science and EngineeringHuaqiao UniversityXiamen 361021China

Semi-transparent perovskite solar cells(ST-PSCs)have broad applications in building integrated photovoltaics.However,the stability of ST-PSCs needs to be improved,especially in n-i-p ST-PSCs since the doped 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene(Spiro-OMeTAD)is unstable at elevated temperatures and high humidity.In this work,aπ-conjugated polymer poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione)](PBDB-T)is selected to form a polymer composite hole transport layer(HTL)with Spiro-OMeTAD.The sulfur atom of the thiophene unit and the carbonyl group of the polymer interact with the undercoordinated Pb2+at the perovskite surface,which stabilizes the perovskite/HTL interface and passivates the interfacial defects.The incorporation of the polymer also increases the glass transition temperature and the moisture resistance of Spiro-OMeTAD.As a result,we obtain ST-PSCs with a champion efficiency of 13.71%and an average visible light transmittance of 36.04%.Therefore,a high light utilization efficiency of 4.94%can be obtained.Moreover,the encapsulated device can maintain 84%of the initial efficiency after 751 h under continuous one-sun illumination(at 30%relative humidity)at the open circuit and the unencapsulated device can maintain 80%of the initial efficiency after maximum power tracking for more than 1250 h under continuous one-sun illumination.

关键词： semi-transparent solar cells π-conjugated polymer composite hole transport layer building integrated photovoltaics

Water-soluble organic matter with various polarities in PM_(2.5) over Xi'an,China:Abundance,functional groups,and light absorption

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Particuology 2024年第1期84卷 281-289页

作者： Xueting yang Shasha Huang Dan Li Hongmei Xu Yaling Zeng liu yang Diwei Wang Ningning Zhang Junji Cao Zhenxing Shen Department of Environmental Science and Engineering Xi'an Jiaotong UniversityXi'an710049China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an710049China

Humic-like substances(HULIS)are a major component of brown carbon and consequently play a major role in climate change.In this study,70 PM_(2.5) samples were collected from Xi'an in winter 2019 and summer 2020.Neutral HULIS(HULIS-n),acidic HULIS(HULIS-a),and high-polarity water-soluble organic compounds(HP-WSOC)were analyzed to determine their carbon concentrations and measure their ultraviolet-visible absorption and infrared spectra.Of the three components,HULIS-n had the highest carbon content in both winter(3.29±1.45μg m^(-3))and in summer(1.38±1.10μg m^(-3)).The semi-quantitative results for the functional groups revealed that HP-WSOC was rich in carboxylic acids and had high aromaticity in winter,whereas HULIS-n was rich in carboxylic acids in summer.Moreover,HULJS-a was richer in nitrate esters and saturated aliphatic hydrocarbons in summer than in winter.The results for specific ultraviolet absorbance(SUVA)and E_(250)/E_(365) revealed that HULIS had higher molecular weight and aromaticity in winter than in summer.HULIS-n dominated in the total light absorption of HULIS+HP-WSOC in both winter(73.08%)and summer(48.57%).Overall,the results on the carbon content,optical properties,and functional groups of WSOCs with differing polarity can improve un-derstanding of environmental and climatic effects.

关键词： Humic-like substances(HULIS) Aromaticity Fourier-transform infrared(FTIR) spectroscopy Light absorbance

Early Growth Response Gene-1 Deficiency Interrupts TGFβ1 Signaling Activation and Aggravates Neurodegeneration in Experimental Autoimmune Encephalomyelitis Mice

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Neuroscience Bulletin 2024年第3期40卷 283-292页

作者： Yunyi Lan Xinyan Han Fei Huang Hailian Shi Hui Wu liu yang Zhibi Hu Xiaojun Wu Shanghai Key Laboratory of Compound Chinese Medicines The Ministry of Education Key Laboratory for Standardization of Chinese MedicinesThe State Administration of TCM Key Laboratory for New Resources and Quality Evaluation of Chinese MedicineInstitute of Chinese Materia MedicaShanghai University of Traditional Chinese MedicineShanghai201203China Central Laboratory Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese MedicineShanghai200021China

Early growth response protein 1(Egr-1)triggers the transcription of many genes involved in cell growth,differentiation,synaptic plasticity,and neurogenesis.However,its mechanism in neuronal survival and degeneration is still poorly understood.This study demonstrated that Egr-1 was down-regulated at mRNA and protein levels in the central nervous system(CNS)of experimental autoimmune encephalomyelitis(EAE)mice.Egr-1 knockout exacerbated EAE progression in mice,as shown by increased disease severity and incidence;it also aggravated neuronal apoptosis,which was associated with weakened activation of the BDNF/TGFβ1/MAPK/Akt signaling pathways in the CNS of EAE mice.Consistently,Egr-1 siRNA promoted apoptosis but mitigated the activation of BDNF/TGFβ1/MAPK/Akt signaling in SH-SY5Y cells.Our results revealed that Egr-1 is a crucial regulator of neuronal survival in EAE by regulating TGFβ1-mediated signaling activation,implicating the important role of Egr-1 in the pathogenesis of multiple sclerosis as a potential novel therapy target.

关键词： Early growth response protein 1 Transforming growth factor-beta 1 Multiple sclerosis Experimental autoimmune encephalomyelitis Neurodegeneration