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A model reduction approach for discrete-time linear time-variant systems with delayed inputs

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Science China(Information Sciences) 2024年第4期67卷 197-217页

作者： Ai-guo WU Guang-Ren DUAN yu WANG Jie ZHANG School of Mechanical Engineering and Automation Harbin Institute of Technology(Shenzhen) HIT Wuhu Robot Technology Research Institute Center for Control Science and Technology Southern University of Science and Technology

A model reduction approach is presented for discrete-time linear time-variant input-delayed systems. According to this proposed approach, a dynamical variable is constructed by taking advantage of the current state and historical information of input. It is revealed that the behavior of this dynamical variable is governed by a discrete-time linear delay-free system. It is worth noting that the presented variable transformation does not require the system matrix to be invertible. Based on the reduced delay-free models,stabilizing control laws can be easily obtained for the original delayed system. For the case with a single input delay, the constructed variable is an exact prediction for the future state, and thus the stabilizing control law could be designed by replacing the future state with its prediction. Finally, three discrete-time periodic systems with delayed input are employed to illustrate how to utilize the presented model reduction approaches.

关键词： reduction approach predictor-based feedback time-varying systems delayed input periodic system

C_(60) as a metal-free catalyst for lithium-oxygen batteries

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Nano Research 2024年第5期17卷 3982-3987页

作者： Xinxin Zhang Jiaming Tian yu Wang Shaohua guo Yafei Li Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials School of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023China College of Engineering and Applied Sciences Jiangsu Key Laboratory of Artificial Functional MaterialsNational Laboratory of Solid State MicrostructuresCollaborative Innovation Center of Advanced MicrostructuresFrontiers Science Center for Critical Earth Material CyclingNanjing UniversityNanjing 210023China

Carbon materials have shown significant potential as catalysts for lithium-oxygen batteries(LOBs).However,the intrinsic carbon sites are typically inert,necessitating extensive modifications and resulting in a limited density of active *** we present C_(60) as a metal-free cathode catalyst for LOBs,using density functional theory calculations and experimental *** lithiation reactions on the pristine carbon sites of C_(60) are energetically favorable due to its curvedπ-conjugation over the pentagon-hexagon *** kinetic analysis specifically reveals low energy barriers for Li_(2)O_(2) decomposition and Li diffusion on C_(60).Consequently,C_(60) exhibits significantly higher catalytic activity than typical carbon materials such as graphene and carbon *** electrochemical measurements validate the predictions,notably demonstrating that the intrinsic activity of C_(60) is comparable to that of noble metals.

关键词： lithium-oxygen batteries C_(60) density functional theory(DFT)calculations metal-free cathode

Escape probability for isotropic emitters near Kerr black hole with astrometric

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Communications in Theoretical Physics 2024年第5期76卷 128-133页

作者： yu-Xuan Han Qing-Hua Zhu Qing-guo Huang CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesNo.19A Yuquan RoadBeijing 100049China Department of Physics Chongqing UniversityChongqing 401331China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study UCASHangzhou 310024China

The paper investigates the escape probability for isotropic emitters near a Kerr black *** propose a new approach to obtain the escape probability in a general manner,going beyond previous case-by-case *** approach is based on studies of the black hole shadow with astrometric observable and can be applied to emitters with an arbitrary 4-velocities and locations,even to the emitters outside of the equatorial *** also consider representative examples illustrating how escape probabilities vary with distance,velocity,and inclination ***,this new approach provides an effective method for studying escape probabilities near Kerr black holes.

关键词： Kerr black hole photon escape probability isotropic emitters

Comparative analyses of mitogenomes in the social bees with insights into evolution of long inverted repeats in the Meliponini

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Zoological Research 2024年第1期45卷 160-175页

作者： yu-Ran Li zheng-Wei Wang Richard T.Corlett Wen-Bin yu yunnan Key Laboratory for the Conservation of Tropical Rainforests and Asian Elephants&Center for Integrative Conservation Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan 666303China CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan 666303China Southeast Asia Biodiversity Research Institute Chinese Academy of SciencesMenglaYunnan 666303China University of Chinese Academy of Sciences Shijingshan DistrictBeijing 100049China

The insect mitogenome is typically a compact circular molecule with highly conserved gene ***,mitogenome structural variations have been reported in specific taxa,and gene rearrangements,usually the tRNAs,occur in different *** synapomorphies of mitogenome organizations can provide information for phylogenetic inferences,comparative analyses of mitogenomes have been given increasing ***,most studies use a very few species to represent the whole genus,tribe,family,or even order,overlooking potential variations at lower taxonomic levels,which might lead to some incorrect *** provide new insights into mitogenome organizations and their implications for phylogenetic inference,this study conducted comparative analyses for mitogenomes of three social bee tribes(Meliponini,Bombini,and Apini)based on the phylogenetic framework with denser taxonomic sampling at the species and population *** analyses revealed that mitogenomes of Apini and Bombini are the typical type,while those of Meliponini show diverse variations in mitogenome sizes and *** inverted repeats(IRs)cause significant gene rearrangements of protein coding genes(PCGs)and rRNAs in Indo-Malay/Australian stingless bee *** evolution analyses showed that the lineage with IRs have lower dN/dS ratios for PCGs than lineages without IRs,indicating potential effects of IRs on the evolution of mitochondrial *** finding of IRs and different patterns of gene rearrangements suggested that Meliponini is a hotspot in mitogenome *** conserved PCGs and rRNAs whose rearrangements were found only in the mentioned lineages within Meliponini,tRNA rearrangements are common across all three tribes of social bees,and are significant even at the species level,indicating that comprehensive sampling is needed to fully understand the patterns of tRNA rearrangements,and their implications for phylogenetic inference.

关键词： Social bees Phylogeny Mitogenome structure Gene rearrangement Inverted repeats

Suppression of low-frequency ultrasound broadband vibration using star-shaped single-phase metamaterials

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Defence Technology（防务技术） 2024年第4期34卷 217-224页

作者： Rui Zhao Jian zheng Jin guo yunbo Shi Hengzhen Feng Jun Tang Jun Liu Science and Technology on Electronic Test&Measurement Laboratory North University of ChinaTaiyuan 030051ShanxiChina School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties,which is configured by hybrid arc and sharp-angle convergent star-shaped *** effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and *** target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent *** proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity,and the simulation results verify a 99%vibration attenuation amplitude can be obtained in the frequency of20 k Hz—100 k *** the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique,the transmission loss experiments are performed,and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85%attenuation for the target *** results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation,which has capability for the vibration attenuation in the application of highprecise equipment.

关键词： Star-shaped metamaterials Broadband Vibration attenuation Low-frequency ultrasound vibration Transmission loss

Blade-Coated Porous 3D Carbon Composite Electrodes Coupled with Multiscale Interfaces for Highly Sensitive All-Paper Pressure Sensors

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Nano-Micro Letters 2024年第12期16卷 217-232页

作者： Bowen zheng Ruisheng guo Xiaoqiang Dou yueqing Fu Bingjun Yang Xuqing Liu Feng Zhou State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China Research Center of Resource Chemistry and Energy Materials State Key Laboratory of Solid LubricationLanzhou Institute of Chemical PhysicsChinese of Academy of SciencesLanzhou 730000People’s Republic of China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000People’s Republic of China Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai Yantai 264006People’s Republic of China

Flexible and wearable pressure sensors hold immense promise for health monitoring,covering disease detection and postoperative *** pressure sensors with high sensitivity,wide detection range,and cost-effectiveness is *** leveraging paper for its sustainability,biocompatibility,and inherent porous structure,herein,a solution-processed all-paper resistive pressure sensor is designed with outstanding performance.A ternary composite paste,comprising a compressible 3D carbon skeleton,conductive polymer poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate),and cohesive carbon nanotubes,is blade-coated on paper and naturally dried to form the porous composite electrode with hierachical micro-and nano-structured *** with screen-printed Cu electrodes in submillimeter finger widths on rough paper,this creates a multiscale hierarchical contact interface between electrodes,significantly enhancing sensitivity(1014 kPa-1)and expanding the detection range(up to 300 kPa)of as-resulted all-paper pressure sensor with low detection limit and power *** versatility ranges from subtle wrist pulses,robust finger taps,to large-area spatial force detection,highlighting its intricate submillimetermicrometer-nanometer hierarchical interface and nanometer porosity in the composite ***,this all-paper resistive pressure sensor,with its superior sensing capabilities,large-scale fabrication potential,and cost-effectiveness,paves the way for next-generation wearable electronics,ushering in an era of advanced,sustainable technological solutions.

关键词： Micro-and nano-structures PEDOT:PSS Flexible pressure sensors Health monitoring Multiscale interfaces

Tailoring Ni based catalysts by indium for the dehydrogenative coupling of ethanol into ethyl acetate

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Green Energy & Environment 2024年第8期9卷 1321-1331页

作者： Ming Yin Jifeng Pang Jin guo Xianquan Li yujia Zhao Pengfei Wu Mingyuan zheng CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences School of Materials Science and Engineering Dalian Jiaotong University

Exploring stable and robust catalysts to replace the current toxic CuCr based catalysts for dehydrogenative coupling of ethanol to ethyl acetate is a challenging but promising ***,novel NiIn based catalysts were developed by tailoring Ni catalysts with Indium （In） for this *** the optimal Ni0.1Zn0.7Al0.3InOx catalyst,the ethyl acetate selectivity reached 90.1%at 46.2%ethanol conversion under the conditions of 548 K and a weight hourly space velocity of 1.9 h-1in the 370 h time on ***,the ethyl acetate productivity surpassed1.1 gethyl acetateg-1catalysth-1,one of the best performance in current *** to catalyst characterizations and conditional experiments,the active sites for dehydrogenative coupling of ethanol to ethyl acetate were proved to be Ni4In *** presence of In tailored the chemical properties of Ni,and subsequently inhibited the C±C cracking and/or condensation reactions during ethanol *** Ni4In alloy sites,ethanol was dehydrogenated into acetaldehyde,and then transformed into acetyl species with the removal of H ***,the coupling between acetyl species and surface-abundant ethoxyde species into ethyl acetate was achieved,affording a high ethyl acetate selectivity and catalyst stability.

关键词： Dehydrogenative coupling Ethanol Ethyl acetate Nickel and indium alloys

Design,Simulation and Kinematic Validation of a Hip Prosthetic Mechanism with a Multimotor Function

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Journal of Bionic Engineering 2024年第3期21卷 1321-1333页

作者： Majun Song Zhongyi Li Jingjing Jiang Weihai Chen Sheng guo Hao zheng Lianzheng Niu Hangzhou Innovation Institute Beihang UniversityHangzhou310051China Hangzhou Huacheng Software Technology Co.Ltd. Hangzhou310051China School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China

We previously developed a powered hip prosthetic mechanism with kinematic functions of hip flexion-extension and abduction-adduction,and its theoretical and simulation-based kinematics were *** internal-external hip rotation has a positive effect on the movements of human lower limbs according to medical research,we developed a novel hip prosthetic mechanism based on a previous hip prosthesis that possesses motion characteristics similar to those of a human bionic hip,and the motion characteristics of multiple Degrees-of-Freedom(DoFs)were analyzed after kinematic ***,a walking model of the human‒machine model was established,and the walking stability of an amputee,which reflects the rehabilitation effect,was explored while the hip prosthetic mechanism considered the internal-external rotation of the ***,a prototype and its verification platform were built,and kinematic validation of the hip prosthetic mechanism was carried *** results showed that the designed Parallel Mechanism(PM)possesses human-like motion characteristics similar to those of a human bionic hip and can be used as a hip ***,the existing motion characteristic of internal-external hip rotation can enhance the walking stability of an amputee via this hip prosthetic mechanism.

关键词： Hip prosthetic mechanism Parallel mechanism Walking stability Kinematic validation

BL03HB: a Laue microdiffraction beamline for both protein crystallography and materials science at SSRF

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Nuclear Science and Techniques 2024年第7期35卷 68-78页

作者： Zhi-Jun Wang Si-Sheng Wang zheng-Huang Su Li yu yu-Zhu Wang Bo Sun Wen Wen Xing-yu Gao Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China University of Chinese Academy of Science Beijing100049China

A Laue microdiffraction beamline(BL03HB) was constructed at the Shanghai Synchrotron Radiation Facility(SSRF).This beamline features two consecutive focusing points in two different sectors within its end station, the first dedicated to protein crystallography and the other tailored to materials science applications. Based on a superbend dipole magnet with a magnetic field of 2.29 T, a two-stage focusing design was implemented with two sets of Kirkpatrick-Baez mirrors to achieve a micro white beam as small as 4.2 μ m ×4.3 μ m at the first sector and 0.9 μ m ×1.3 μ m at the second sector in the standard beamline operation mode at SSRF. The X-ray microbeam in the two sectors can be easily switched between monochromatic and white beams by moving a four-bounce monochromator in or out of the light path, respectively. In the protein crystallography sector, white-beam Laue microdiffraction was demonstrated to successfully determine the structure of protein crystals from only a few images of diffraction data collected by a Pilatus 2 M area detector. In the materials science sector,the white-beam Laue diffraction was collected in a reflection geometry using another Pilatus 2 M area detector, which could map the microstructural distribution on the sample surface by scanning the samples. In general, the BL03HB beamline promotes the application of Laue microdiffraction in both protein crystallography and materials science. This paper presents a comprehensive overview of the BL03HB beamline, end station, and the first commission results.

关键词： Crystallography White-beam Laue microdiffraction Beamline Synchrotron