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Improving Kinematic Flexibility and Walking Performance of a Six-legged Robot by Rationally Designing Leg Morphology

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Journal of Bionic Engineering 2019年第4期16卷 608-620页

作者： jie Chen Zhongchao Liang Yanhe Zhu jie Zhao School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

This paper explores the design of leg morphology in a six-legged *** by nature,where animals have different leg morphology,we examined how the difference in leg morphology influences behaviors of the *** this end,a systematic search was conducted by scanning over the parameter space consisting of default angles of leg joints of the six-legged robot,with two main objectives:to maximize the kinematic flexibility and walking performance of the *** show that(1)to have a high kinematic flexibility with both the torso and swing legs,the femur segment should tilt downwards by 5°-10°and the tibia segment should be vertically downwards or with a slight inward tilt;(2)to achieve relatively energy-efficient and steady walking,the tibia segment should be approximately vertically downwards,with the femur segment tilting upwards to lower the torso *** results of this study suggest that behaviors of legged robots can be passively enhanced by careful mechanical design choices,thereby leading to more competent legged machines.

关键词： six-legged robot leg morphology kinematic flexibility walking performance

Cachazo-Svrcek-Witten rules for tree-level gluonic amplitudes revisited

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Science China(Physics,Mechanics & Astronomy) 2022年第4期65卷 20-31页

作者： Wen-jie Zhang Jun-Bao Wu Chuan-jie Zhu Center for Joint Quantum Studies and Department of Physics School of ScienceTianjin UniversityTianjin 300350China Peng Huanwu Center for Fundamental Theory Hefei 230026China College of Mathematics and Physics Science Hunan University of Arts and ScienceChangde 415000China

We provide a new proof of Cachazo-Svrcek-Witten rules for tree-level gluonic *** a key step,we explicitly demonstrate the cancellation of spurious poles originating from the maximally helicity violating vertices in these *** achieve this,we introduce specially-defined two-off-shell-line sub-amplitudes and examine their residues at spurious poles.

关键词： general properties of perturbation theory perturbative calculations dualities in gauge field theories

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The development,performances and applications of the monochromatic X-rays facilities in(0.218–301)keV at NIM,China

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Nuclear Science and Techniques 2021年第6期32卷 108-121页

作者： Si-Ming Guo Jin-jie Wu Dong-jie Hou National Institute of Metrology BeijingChina

Space scientific exploration is rapidly becoming the primary battlefield for humankind to explore the *** worldwide have launched numerous space exploration *** calibration of the detectors on the ground is a crucial element for space science satellites to obtain observational *** the purpose of providing calibration for various satellite-borne detectors,multiple monochromatic X-rays facilities have been built at the National Institute of Metrology,***(NIM).These facilities mainly pertain to grating diffraction and Bragg diffraction,and the energy range of the produced monochromatic X-rays is 0.218–301 ke *** facilities have a high performance in terms of energy stability,monochromaticity,and flux *** monochromaticity was greater than 3.0%.The energy stability of the facility is 0.02%at 25 ke V over 8 h,and the flux stability was within 1.0%at 25 ke V over 8 *** experiments on the properties of satellite-borne detectors,such as energy linearity,energy resolution,detection efficiency,and temperature response,can be conducted at the *** far,the calibration of two satellites has been completed by the authors,and the work on three other satellites is in *** study will contribute to the advancement of X-ray astronomy the development of Chinese space science.

关键词： Monochromatic X-rays Monochromator Bragg diffraction Energy spectra Calibration

Optical whispering-gallery mode barcodes for high-precision and wide-range temperature measurements

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Light(Science & Applications) 2021年第2期10卷 278-288页

作者： jie Liao Lan Yang Department of Electrical&Systems Engineering Washington University in St.LouisMO 63130 St.LouisUSA Department of Physics Washington University in St.LouisMO 63130 St.LouisUSA

Temperature is one of the most fundamental physical properties to characterize various physical,chemical,and biological *** a slight change in temperature could have an impact on the status or dynamics of a ***,there is a great need for high-precision and large-dynamic-range temperature *** temperature sensors encounter difficulties in high-precision thermal sensing on the submicron ***,optical whispering-gallery mode(WGM)sensors have shown promise for many sensing applications,such as thermal sensing,magnetic detection,and ***,despite their superior sensitivity,the conventional sensing method for WGM resonators relies on tracking the changes in a single mode,which limits the dynamic range constrained by the laser source that has to be fine-tuned in a timely manner to follow the selected mode during the ***,we cannot derive the actual temperature from the spectrum directly but rather derive a relative temperature ***,we demonstrate an optical WGM barcode technique involving simultaneous monitoring of the patterns of multiple modes that can provide a direct temperature readout from the *** measurement relies on the patterns of multiple modes in the WGM spectrum instead of the changes of a particular *** can provide us with more information than the single-mode spectrum,such as the precise measurement of actual *** the high sensitivity of WGMs and eliminating the need to monitor particular modes,this work lays the foundation for developing a high-performance temperature sensor with not only superior sensitivity but also a broad dynamic range.

关键词： mode high spectrum

Approximating Special Social Influence Maximization Problems

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Tsinghua Science and Technology 2020年第6期25卷 703-711页

作者： jie Wu Ning Wang the Department of Computer and Information Sciences Temple University.PhiladelphiaPA 19122USA the Department of Computer Science Rowan UniversityGlassboroNJ 08028USA

Social Influence Maximization Problems(SIMPs)deal with selecting k seeds in a given Online Social Network(OSN)to maximize the number of eventually-influenced *** is done by using these seeds based on a given set of influence probabilities among neighbors in the *** the SIMP has been proved to be NP-hard,it has both submodular(with a natural diminishing-return)and monotone(with an increasing influenced users through propagation)that make the problem suitable for approximation ***,several special SIMPs cannot be modeled as submodular or monotone *** this paper,we look at several conditions under which non-submodular or non-monotone functions can be handled or *** is a profit-maximization SIMP where seed selection cost is included in the overall utility function,breaking the monotone *** other is a crowd-influence SIMP where crowd influence exists in addition to individual influence,breaking the submodular *** then review several new techniques and notions,including double-greedy algorithms and the supermodular degree,that can be used to address special *** main results show that for a specific SIMP model,special network structures of OSNs can help reduce its time complexity of the SIMP.

关键词： influence maximization online social networks submodular function

Some notes on a conjecture of Zygmund

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Applied Mathematics(A Journal of Chinese Universities) 2008年第2期23卷 213-218页

作者： CHEN jie-cheng ZHANG Chun-jie Dept. of Math. Zhejiang Univ. Hangzhou 310027 China

In this paper, some classes of differentiation basis are investigated and several positive answers to a conjecture of Zygmund on differentiation of integrals are presented.

关键词： Zygmund's conjecture differentiation of integrals maximal function.

The midas touch on copper into palladium

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Science China Chemistry 2020年第12期63卷 1740-1741页

作者： jie Zeng Hefei National Laboratory for Physical Sciences at the Microscale Department of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026China

The catalytic semi-hydrogenation of alkynes(C≡C) to alkenes(C=C) has long been a crucial and challenging step in industry as it restrains the tendency of over-hydrogenation towards substrates [1]. Up to now, Pd-based catalysts show ultrahigh activity and selectivity towards the semihydrogenation of alkynes and are commonly used in industry, while metals such as Cu, Ag and Au exhibit relatively low activity due to their poor hydrogen activation ability.

关键词： hydrogenation palladium semi

Structural engineering of high-entropy alloys for advanced electrocatalytic reactions

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Tungsten 2025年第1期 1-31页

作者： Qiao Xie Ying-jie Yu Hai-Jun Zhang Ya-Ping Deng Wen Lei The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology Department of Chemical Engineering Waterloo Institute for Sustainable Energy Waterloo Institute for Nanotechnology University of Waterloo

High-entropy alloys(HEAs) have emerged as promising candidates to replace traditional precious metal catalysts,owing to their unique chemical and physical *** review commences by revisiting the fundamental concepts of HEAs,including their synthesis methods and structural control strategies in *** underscores the critical role of meticulously manipulating both macroscopic and microscopic structures of the HEAs to optimize their catalytic performance.A deep understanding of the structure-activity relationship in HEAs across various configurations is pivotal in developing more effective *** review methodically encapsulates the research progress of structural control strategies for HEAs in achieving efficient energy conversion,with the aim of gaining a better understanding of the relationship between structure and *** review concludes by summarizing the current achievements and challenges,and suggestions for potential future directions of HEAs in the fields of energy conversion and environmental purification.

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Practical Exponential Stability of Two Dimensional Nonlinear Switched Positive Systems in the Roesser Model

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Journal of Systems Science & Complexity 2023年第3期36卷 1103-1115页

作者： ZHANG jie SUN Yuangong School of Mathematical Sciences University of JinanJinan 250022China

This paper deals with the practical exponential stability of two-dimensional(2-D)nonlinear switched positive systems with impulse,disturbance and all modes *** the mode-dependent interval dwell time switching,new criteria such that 2-D nonlinear switched positive systems achieve practical exponential stability are ***,the explicit upper bound and convergence rate of the system state are estimated *** examples indicate the correctness and effectiveness of the obtained results.

关键词： Disturbance impulse mode-dependent interval dwell-time(MDIDT)switching practical exponential stability roesser model