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A Neuro-Muscular Elasto-Dynamic Model of the Human Arm Part 2:Musculotendon Dynamics and Related Stress Effects

作者： G.H.·布朗(G.M. brownm.

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Journal of Bionic Engineering 2009年第2期6卷 108-119页

作者： Cody B.Moody Alan A.Barhorst lawrence Schovanec Texas Tech University Department of Mechanical Engineering Texas Tech University Department of Mathematics and Statistics

In this paper we develop an elasto-dynamic model of the human arm that includes effects of neuro-muscular control upon elastic deformation in the *** elasto-dynamic model of the arm is based on hybrid parameter multiple body system variational projection principles presented in the companion *** the technique is suitable for detailed bone and joint modeling,we present simulations for simplified geometry of the bones,discretized as Rayleigh beams with elongation,while allowing for large *** of the upper extremity is simulated by incorporating muscle forces derived from a Hill-type model of musculotendon *** effects of muscle force are modeled in two *** one approach,an effective joint torque is calculated by multiplying the muscle force by a joint moment ann.A second approach models the muscle as acting along a straight line between the origin and insertion sites of the *** arm motion is simulated by utilizing neural feedback and feedforward *** illustrate the combined effects of neural control strategies, models of muscle force inclusion,and elastic assumptions on joint trajectories and stress and strain development in the bone and tendon.

关键词： elasto-dynamics hybrid parameter system musculo skeletal model neuro-muscular model

Neuronal avalanches:Sandpiles of self-organized criticality or critical dynamics of brain waves?

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Frontiers of physics 2023年第4期18卷 337-348页

作者： Vitaly L.Galinsky lawrence R.Frank Center for Scientific Computation in Imaging University of California at San DiegoLa JollaCA 92037-0854USA Center for Functional MRI University of California at San DiegoLa JollaCA 92037-0677USA

Analytical expressions for scaling of brain wave spectra derived from the general nonlinear wave Hamiltonian form show excellent agreement with experimental“neuronal avalanche”*** theory of the weakly evanescent nonlinear brain wave dynamics[*** 2,023061(2020);*** Neurosci.32,2178(2020)]reveals the underlying collective processes hidden behind the phenomenological statistical description of the neuronal avalanches and connects together the whole range of brain activity states,from oscillatory wave-like modes,to neuronal avalanches,to incoherent spiking,showing that the neuronal avalanches are just the manifestation of the different nonlinear side of wave processes abundant in cortical *** a more broad way these results show that a system of wave modes interacting through all possible combinations of the third order nonlinear terms described by a general wave Hamiltonian necessarily produces anharmonic wave modes with temporal and spatial scaling properties that follow scale free power *** the best of our knowledge this has never been reported in the physical literature and may be applicable to many physical systems that involve wave processes and not just to neuronal avalanches.

关键词： nonlinear waves critical exponent Hamiltonian system neuronal avalanches critical dynamics

Experimental Dynamic Analysis of a Breathing Cracked Rotor

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Chinese Journal of Mechanical Engineering 2017年第5期30卷 1177-1183页

作者： Chao-Zhong Guo Ji-Hong Yan lawrence A.Bergman School of Mechatronics Engineering Harbin Institute of Technology Department of Aerospace Engineering University of Illinois at Urbana-Champaign

Crack fault diagnostics plays a critical role for rotating machinery in the traditional and Industry 4.0 fac- tory. In this paper, an experiment is set up to study the dynamic response of a rotor with a breathing crack as it passes through its 1/2, 1/3, 1/4 and 1/5 subcritical speeds. A cracked shaft is made by applying fatigue loads through a three-point bending apparatus and then placed in a rotor testbed. The vibration signals of the testbed during the coasting-up process are collected. Whirl orbit evolution at these subcritical speed zones is analyzed. The Fourier spectra obtained by FFF are used to investigate the internal frequencies corresponding to the typical orbit characteris- tics. The results show that the appearance of the inner loops and orientation change of whirl orbits in the experiment are agreed well with the theoretical results obtained previously. The presence of higher frequencies 2X, 3X, 4X and 5X in Fourier spectra reveals the causes of subharmonic reso- nances at these subcritical speed zones. The experimental investigation is more systematic and thorough than previ- ously reported in the literature. The unique dynamic behavior of the orbits and frequency spectra are feasible features for practical crack diagnosis. This paper provides a critical technology support for the self-aware health man- agement of rotating machinery in the Industry 4.0 factory.

关键词： Industry 4.0 Fault diagnosis Cracked rotor FFT spectra

Activity origin and design principles for atomic vanadium anchoring on phosphorene monolayer for nitrogen reduction reaction

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Nano Research 2020年第11期13卷 2925-2932页

作者： Xiongyi Liang Xiangxuan Deng Chen Guo Chi-Man lawrence Wu Department of Materials Science and Engineering City University of Hong KongHong KongChina

Conversion of inert N2 molecules into NH3 via electrochemical methods is an environmentally friendly alternative to replace the traditional Haber-Bosch ***,the development of highly efficient catalyst is still ***,we report a density functional theory(DFT)based high-throughput screening to investigate the potential of 23 atomic transition metals(Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Y,Zr,Nb,Mo,Tc,Ru,Rh,Pd,Ag,Cd,W,Pt and Au)supported on phosphorene monolayer as electrocatalyst for nitrogen reduction reaction(NRR).Our theoretical results demonstrate that V single atom anchoring on phosphorene monolayer exhibits good thermal stability,selectivity and excellent catalytic activity with a low overpotential of 0.18 ***,rational design principles and electronic descriptor between the intrinsic electronic properties and activation barrier have been *** work offers a new promising noble metal-free catalyst for NRR and reveals profound insights into the activity origin to guide further design.

关键词： high-throughput screening density functional theory phosphorene electronic descriptor single atomic catalyst transition metal

Update on cell therapy for stroke

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Stroke & Vascular Neurology 2017年第2期2卷 59-64页

作者： Cynthia L Kenmuir lawrence R Wechsler Department of Neurology University of Pittsburgh Medical CenterPittsburghPennsylvaniaUSA

Ischaemic stroke remains a leading cause of death and *** stroke treatment options aim to minimise the damage from a pending stroke during the acute stroke period using intravenous thrombolytics and endovascular thrombectomy;however,there are no currently approved treatment options for reversing neurological damage once a stroke is *** studies suggest that cell therapy may be safe and effective in improving functional *** recent clinical trials have reported safety and some improvement in outcomes following cell therapy administration in ischaemic stroke,which are *** therapy may provide a promising new treatment for stroke reducing stroke-related *** investigation is needed to determine specific effects of cell therapy and to optimise cell delivery methods,cell dosing,type of cells used,timing of delivery,infarct size and location of infarct that are likely to benefit from cell therapy.

关键词： damage acute treatment

On the algorithmic construction of classifying spaces and the isomorphism problem for biautomatic groups

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Science China Mathematics 2011年第8期54卷 1533-1545页

作者： BRIDSON Martin R. REEVES lawrence Mathematical Institute University of Oxford Department of Mathematics and Statistics University of Melbourne

We show that the isomorphism problem is solvable in the class of central extensions of word-hyperbolic groups,and that the isomorphism problem for biautomatic groups reduces to that for biautomatic groups with finite *** describe an algorithm that,given an arbitrary finite presentation of an automatic group Γ,will construct explicit finite models for the skeleta of K(Γ,1) and hence compute the integral homology and cohomology of Γ.

关键词： geometric group theory automatic groups isomorphism problem

Current issues in endoscope reprocessing and infection control during gastrointestinal endoscopy

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World Journal of Gastroenterology 2006年第25期12卷 3953-3964页

作者： Douglas B Nelson lawrence F Muscarella Staff Physician in Gastroenterology Minneapolis VA Medical Center University of MinnesotaMinneapolisMN 55417United States Director Research and Development ChiefInfection ControlCustom UltrasonicsInc

The purpose of this article is to review the evidence regarding transmission of infection during gastrointestinal endoscopy, factors important in endoscope reprocessing and infection control, areas to focus on to impr... 详细信息

关键词： Endoscopy Infection Disinfection Reprocessing Infection control

国际二语自我调节学习研究二十年回顾:基于文献计量与范围综述的融通方法

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浙江大学学报（人文社会科学版） 2024年第4期54卷 145-159页

作者：滕琳杨玉鑫张雨阳 [英]内森·托马斯张军浙江大学外国语学院浙江杭州310058 伦敦大学学院应用语言学中心伦敦WC1H 0AL 奥克兰大学教育学院奥克兰92019

创新运用文献计量与范围综述相融合的方法,揭示出近二十年来国际二语自我调节学习研究的现状及其不足。在理论层面,自我调节学习存在概念界定不清及相关术语使用混淆两大问题。此外,现有研究以社会认知理论为主导,缺乏从多元理论视角对... 详细信息

创新运用文献计量与范围综述相融合的方法,揭示出近二十年来国际二语自我调节学习研究的现状及其不足。在理论层面,自我调节学习存在概念界定不清及相关术语使用混淆两大问题。此外,现有研究以社会认知理论为主导,缺乏从多元理论视角对自我调节学习的深入探究。在研究群体上,多聚焦高等教育阶段的外语学习者,而对不同年龄段和文化背景下学习者的自我调节机制了解不足。在研究话题上,主要集中在写作任务情景,而对听力、阅读、口语及词汇等其他语言技能的自我调节学习过程探讨不足。在研究方法上,主要是问卷调查和访谈,缺乏对自我调节学习过程和能力发展的历时研究。因此,未来研究需要厘清自我调节学习的概念内涵;拓宽理论视角;扩大研究对象范围;全面探讨不同语言技能的自我调节学习过程;开展实验和历时性追踪研究,运用多种方法收集过程性数据,以便深入了解二语自我调节学习的过程和发展轨迹,为二语教学提供更为有益的指导。

关键词：自我调节学习二语/外语文献计量范围综述可视化分析

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