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Biomimetic soft robotic wrist with 3-DOF motion and stiffness tunability based on ring-reinforced pneumatic actuators and a particle jamming joint

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Science China(Technological Sciences) 2024年第3期67卷 774-790页

作者： HU TeTe LU XinJiang YI Jian WAnG YuHui xu Du State Key Laboratory of Precision Manufacturing for Extreme Service Performance School of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China

The human wrist, a complex articulation of skeletal muscles and two-carpal rows, substantially contributes to improvements in maneuverability by agilely performing three-degree-of-freedom(3-DOF) orienting tasks and regulating stiffness according to variations in interaction forces. However, few soft robotic wrists simultaneously demonstrate dexterous 3-DOF motion and variable stiffness;in addition, they do not fully consider a soft-rigid hybrid structure of integrated muscles and two carpal *** this study, we developed a soft-rigid hybrid structure to design a biomimetic soft robotic wrist(BSRW) that is capable of rotating in the x and y directions, twisting around the z-axis, and possessing stiffness-tunable capacity. To actuate the BSRW, a lightweight soft-ring-reinforced bellows-type pneumatic actuator(SRBPA) with large axial, linear deformation(η_(lcmax)=70.6%,η_(lemax)=54.3%) and small radial expansion(η_(demax)=3.7%) is designed to mimic the motion of skeletal muscles. To represent the function of two-carpal rows, a compact particle-jamming joint(PJJ) that combines particles with a membrane-covered ballsocket mechanism is developed to achieve various 3-DOF motions and high axial load-carrying capacity(>60 n). By varying the jamming pressure, the stiffness of the PJJ can be adjusted. Finally, a centrally positioned PJJ and six independently actuated SRBPAs, which are in an inclined and antagonistic arrangement, are sandwiched between two rigid plates to form a flexible,stable, and compact BSRW. Such a structure enables the BSRW to have a dexterous 3-DOF motion, high load-carrying ability,and stiffness tunability. Experimental analysis verify 3-DOF motion of BSRW, producing force of 29.6 n and 36 n and torque of2.2 nm in corresponding rotations. Moreover, the range of rotational angle and stiffness-tuning properties of BSRW are studied by applying jamming pressure to the PJJ. Finally, a system combining a BSRW and a soft enclosing gripper is proposed to demo

关键词： pneumatic soft actuators particle jamming robotic wrist soft robotics stiffness-tunable

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Bioinspired supramolecular macrocycle hybrid membranes with enhanced proton conductivity

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nano Research 2024年第2期17卷 797-805页

作者： Pengfei Yang Linlin xu Panagiotis Trogadas Marc-Olivier Coppens Yang Lan Centre for nature Inspired Engineering Department of Chemical EngineeringUniversity College LondonLondon WC1E 7JEUK

Enhancing the proton conductivity of proton exchange membranes(PEMs)is essential to expand the applications of proton exchange membrane fuel cells(PEMFCs).Inspired by the proton conduction mechanism of bacteriorhodopsin,cucurbit[n]urils(CB[n],where n is the number of glycoluril units,n=6,7,or 8)are introduced into sulfonated poly(ether ether ketone)(SPEEK)matrix to fabricate hybrid PEMs,employing a nature-inspired chemical engineering(nICE)*** carbonyl groups of CB[n]act as proton-conducting sites,while the host–guest interaction between CB[n]and water molecules offers extra protonconducting ***,the molecular size of CB[n]aids in their dispersion within the SPEEK matrix,effectively bridging the unconnected proton-conducting sulfonic group domains within the SPEEK ***,all hybrid membranes exhibit significantly enhanced proton ***,the SPEEK membrane incorporating 1 wt.%CB[8](CB[8]/SPEEK-1%)demonstrates the highest proton conductivity of 198.0 mS·cm^(−1) at 60°C and 100%relative humidity(RH),which is 228%greater than that of the pure SPEEK membrane under the same ***,hybrid membranes exhibit superior fuel cell *** CB[8]/SPEEK-1%membrane achieves a maximum power density of 214 mW·cm^(−2),representing a 140%improvement over the pure SPEEK membrane(89 mW·cm^(−2))at 50°C and 100%*** findings serve as a foundation for constructing continuous proton-conducting pathways within membranes by utilizing supramolecular macrocycles as fuel cell electrolytes and in other applications.

关键词： supramolecular macrocycle proton conductivity cucurbit[n]uril proton exchange membrane fuel cell

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A COMPACT EMBEDDInG RESULT FOR nOnLOCAL SOBOLEV SPACES AnD MULTIPLICITY OF SIGn-CHAnGInG SOLUTIOnS FOR nOnLOCAL SCHRÖDInGER EqUATIOnS

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Acta Mathematica Scientia 2024年第5期44卷 1853-1876页

作者： xu ZHAnG Hao ZHAI Fukun ZHAO Department of Mathematics Wuhan University of TechnologyWuhan430070China Department of Mathematics Yunnan Normal UniversityKunming650500China

For any s∈(0,1),let the nonlocal Sobolev space X^(s)(ℝ^(n))be the linear space of Lebesgue measure functions fromℝn toℝsuch that any function u in X^(s)(ℝ^(n))belongs to L2(ℝn)and the function(x,y)\longmapsto\big(u(x)-u(y)\big)\sqrt{K(x-y)}is in L2(ℝn,ℝn).First,we show,for a coercive function V(x),the subspace E:=\bigg\{u\in X^s(\mathbb{R}^n):\int_{\mathbb{R}^n}V(x)u^2{\rm d}xnfty\bigg\}of X^(s)(ℝ^(n))is embedded compactly into L^(p)(ℝ^(n))for p\in[2,2_s^*),where 2_s^*is the fractional Sobolev critical *** terms of applications,the existence of a least energy sign-changing solution and infinitely many sign-changing solutions of the nonlocal Schrödinger equation-{\cal{L}_K}u+V(x)u=f(x,u),\x\in\\mathbb{R}^n are obtained,where-{\cal{L}_K}is an integro-differential operator and V is coercive at infinity.

关键词： sign-changing solution integro-differential operator least energy variational method

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A robust vector tracking loop structure based on potential bias analysis

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Chinese Journal of Aeronautics 2024年第4期37卷 405-420页

作者： qiongqiong JIA Yiran LUO Bing xu Li-Ta HSU Renbiao WU Tianjin Key Lab for Advanced Signal Processing Civil Aviation University of ChinaTianjin 300300China Interdisciplinary Division of Aeronautical and Aviation Engineering The Hong Kong Polytechnic University999077Hong KongChina Department of Geomatics Engineering University of CalgaryCalgary T2N1N4Canada

This paper proposes a robust vector tracking loop structure based on potential bias analysis. The influence of four kinds of biases on the existing two implementations of Vector Tracking Loops(VTLs) is illustrated by theoretical analysis and numerical simulations, and the following findings are obtained. Firstly, the initial user state bias leads to steady navigation solution bias in the relative VTL, while new measurements can eliminate it in the absolute VTL. Secondly, the initial code phase bias is transferred to the following navigation solutions in the relative VTL, while new measurements can eliminate it in the absolute VTL. Thirdly, the user state bias induced by erroneous navigation solution of VTLs can be eliminated by both of the two VTLs. Fourthly,the multipath/nLOS likely affects the two VTLs, and the induced tracking bias in the duration of the multipath/nLOS would decrease the performance of VTLs. Based on the above analysis,a robust VTL structure is proposed, where the absolute VTL is selected for its robustness to the two kinds of initialization biases;meanwhile, the instant bias detection and correction method is used to improve the performance of VTLs in the duration of the multipath/nLOS. numerical simulations and experimental results verify the effectiveness of the proposed robust VTL structure.

关键词： Global navigation Satellite System(GnSS) Vector Tracking Loop(VTL) Multipath non-Line-of-Sight(nLOS) Tracking bias propagation Least Absolute Shrinkage and Selection Operator(LASSO)

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Transfer learning framework for multi-scale crack type classification with sparse microseismic networks

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International Journal of Mining Science and Technology 2024年第2期34卷 167-178页

作者： Arnold Yuxuan Xie Bing qLi Department of Civil and Environmental Engineering Western UniversityLondon N6A 3K7Canada

Rock fracture mechanisms can be inferred from moment tensors(MT)inverted from microseismic ***,MT can only be inverted for events whose waveforms are acquired across a network of *** is limiting for underground mines where the microseismic stations often lack azimuthal ***,there is a need for a method to invert fracture mechanisms using waveforms acquired by a sparse microseismic ***,we present a novel,multi-scale framework to classify whether a rock crack contracts or dilates based on a single *** framework consists of a deep learning model that is initially trained on 2400000+manually labelled field-scale seismic and microseismic waveforms acquired across 692 *** learning is then applied to fine-tune the model on 300000+MT-labelled labscale acoustic emission waveforms from 39 individual experiments instrumented with different sensor layouts,loading,and rock types in *** optimal model achieves over 86%F-score on unseen waveforms at both the lab-and *** model outperforms existing empirical methods in classification of rock fracture mechanisms monitored by a sparse microseismic *** facilitates rapid assessment of,and early warning against,various rock engineering hazard such as induced earthquakes and rock bursts.

关键词： Multi-scale Fracture processes Microseismic Acoustic emission Source mechanism Deep learning

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Mechanical Behavior and Failure Mechanism of an As-Extruded Mg-11wt%Y Alloy at Elevated Temperature

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 969-981页

作者： Lan Zhang Dao-Kui xu Bao-Jie Wang Cui-Lan Lu Shuo Wang Xiang-Bo xu Dong-Liang Wang Xin Lv En-Hou Han School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Key Laboratory of nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang110159China Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang110819China Institute of Corrosion Science and Technology Guangdong510070China

Through carrying out the high-temperature tensile experiments on an as-extruded Mg-11wt%Y alloy at 350℃,400℃,450℃,500℃and 550℃,the mechanical behavior and fracture mechanisms at elevated temperatures are investigated and *** results show that with the increase of temperature,the yield strength and ultimate tensile strength of the alloy increase at first and then decrease,while that the elongation ratio decreases firstly and then *** the sample being tested at 350℃,the values of yield strength,ultimate tensile strength and the elongation ratio are 188 MPa,266 MPa and 11%,*** 400℃,the yield strength and ultimate tensile strength reach the maximum values of,respectively,198 MPa and 277 MPa,but the elongation ratio is the lowest and its value is only 8%.When the applied temperature is increased to 550℃,the values of yield strength and ultimate tensile strength,respectively,decrease to 140 MPa and 192 MPa and the elongation ratio increases to 38%.Failure analysis demonstrates that the fracture surfaces of different samples are mainly composed of plastic dimples and exhibit the typical characteristic of ductile *** observation to the fracture side surfaces indicates that at the temperatures of 350℃and 400℃,microcracks mainly initiate in the interior of Mg_(24)Y_(5)*** the temperatures are 450℃,500℃and 550℃,the cracks preferentially initiate at the Mg_(24)Y_(5)/α-Mg interfaces.

关键词： Mg-Y alloy High-temperature tensile properties Fracture mechanism Failure analysis

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A Ku-band image-rejection filtering LnA MMIC in 150-nm Gan-on-SiC technology

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Science China(Information Sciences) 2024年第1期67卷 318-319页

作者： Huiyang LI Jinxu xu Xiuyin ZHAnG School of Electronic and Information Engineering South China University of Technology School of Microelectronics South China University of Technology

The low noise amplifier (LnA) is one of the most important circuits in the transceiver. Many high-performance LnAs have been demonstrated based on Ga n processes. For instance, by using a hybrid-matching topology with...

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A highly sensitive electrochemical sensing platform based on Zn-CuGaO@CMK-3 signal amplification for simultaneous detection of the sunset yellow and tartrazine in foods

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Food Science and Human Wellness 2024年

作者： Yongfeng Chen Rui Gao Yufeng Sun Ruiqiang Wang Geoffrey I.n.Waterhouse xuguang qiao Zhixiang xu College of Food Science and Engineering， Shandong Agricultural University Shandong Cayon Testing Co.， LTD. School of Chemical Sciences， The University of Auckland

In this work， a highly sensitive electrochemical sensor based on Zn-doped copper gallium oxide@ordered mesoporous carbon (Zn-CuGaO2@CMK-3) for signal amplification was successfully developed for the simultaneous detection of sunset yellow （SY） and tartrazine （TZ） in foods. Compared with CuGaO2@CMK-3， Zn-CuGaO2@CMK-3 offered enhanced conductivity and catalytic properties owing to the improved carrier density， which was beneficial to the electrooxidation of SY and TZ. Under the optimal testing conditions， the constructed Zn-CuGaO2@CMK-3/GCE sensor offered a wide linear concentration range （0.25 to 100.00 μmol/L） for the detection of both SY and TZ. The limits of detection for SY and TZ were 0.044 μmol/L and 0.059 μmol/L， respectively. Recovery experiments were performed in milk， white vinegar and biscuit samples， yielding satisfactory recoveries （82.70%-114.80%）. Furthermore， the sensor was successfully applied to the determination of the SY and TZ residues in two kinds of carbonated drinks， and the results were nearly consistent with those detected by the high performance liquid chromatography （HPLC） method （P＞0.05）.

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pH-responsive metal nanoparticles as high contrast theranostic agents for selective imaging and synergistic cancer therapy

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Science China Chemistry 2024年第9期67卷 3063-3070页

作者： Sichao Tian Xiaofeng He Xiao Wu Dongxue Hu qing-Hua xu Department of Chemistry National University of SingaporeSingapore 117543Singapore national University of Singapore(Suzhou)Research Institute Suzhou 215123China Institute of Medicinal Plant Development Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China Department of Biological Sciences Faculty of ScienceNational University of SingaporeSingapore 117558Singapore

The low signal-to-noise ratio(S/n)and single functionality of fluorescence imaging agents have limited their practical *** two-photon excitation(2PE)imaging probes are highly desirable in vivo with larger imaging depth,minor autofluorescence background,and less ***,we developed responsive aggregated gold nanoparticles(Au nPs)as high contrast 2PE imaging agents,capable of emitting red fluorescence upon excitation of near-infrared(nIR)laser and possessing a high signal-to-noise ratio(S/n of 2,475).By forming aggregates in situ inside tumor tissue,doxorubicin hydrochloride(DOX)-loaded mix-charged gold nanoparticles(DOX-MC-Au nPs)were utilized to act as selective fluorescence imaging probes and precise therapy *** high-contrast theranostic agents offer a promising potential for precise cancer imaging and therapy,which might open a new venue to multifunctional and noninvasive theranostics.

关键词： metal nanoparticles two-photon excitation high contrast imaging agents fluorescence imaging cancer therapy

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Influence of topography on the fine structures of stratospheric gravity waves:An analysis using COSMIC-2 temperature data

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Earth and Planetary Physics 2024年第3期8卷 497-513页

作者： JiaRui Wei Xiao Liu JiYao xu qinZeng Li Hong Gao State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Institute of Electromagnetic Wave School of PhysicsHenan Normal UniversityXinxiang Henan 453000China

We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°n from December 2019 to november 2022 by using temperature profiles retrieved from the Constellation Observing System for Meteorology,Ionosphere,and Climate-2(COSMIC-2)*** to the dense sampling of COSMIC-2,in addition to the strong peaks of gravity wave potential energy(GWPE)above the Andes and Tibetan Plateau,we found weak peaks above the Rocky,Atlas,Caucasus,and Tianshan *** land-sea contrast is responsible for the longitudinal variations of the GWPE in the lower and upper *** 40°n/S,the peaks were mainly above the topographic regions during the *** 20°n/S,the peaks were a slight distance away from the topographic regions and might be the combined effect of nontopographic GWs and mountain *** the Equator,the peaks were mainly above the regions with the lowest sea level altitude and may have resulted from *** results indicate that even above the local regions with lower sea level altitudes compared with the Andes and Tibetan Plateau,the GWPE also exhibits fine structures in geographic *** found that dissipation layers above the tropopause jet provide the body force to generate secondary waves in the upper stratosphere,especially during the winter months of each hemisphere and at latitudes of greater than 20°n/S.

关键词： topography fine structures stratospheric gravity waves Constellation Observing System for Meteorology Ionosphere and Climate-2(COSMIC-2) dissipation layers

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