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Practical Prescribed Time Tracking Control With Bounded Time-Varying Gain Under Non-Vanishing Uncertainties

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 219-230页

作者： Dahui Luo Yujuan Wang Yongduan Song the Key Laboratory of Dependable Service Computing in Cyber physical Society Ministry of EducationChongqing UniversityChongqing 400044 the School of Automation Chongqing UniversityChongqing 400044 the Star Institute for Intelligent Systems Chongqing 400044 IEEE

This paper investigates the prescribed-time control(PTC) problem for a class of strict-feedback systems subject to non-vanishing uncertainties. The coexistence of mismatched uncertainties and non-vanishing disturbances makes PTC synthesis nontrivial. In this work, a control method that does not involve infinite time-varying gain is proposed, leading to a practical and global prescribed time tracking control solution for the strict-feedback systems, in spite of both the mismatched and nonvanishing uncertainties. Different from methods based on control switching to avoid the issue of infinite control gain that involves control discontinuity at the switching point, in our method a softening unit is exclusively included to ensure the continuity of the control action. Furthermore, in contrast to most existing prescribed-time control works where the control scheme is only valid on a finite time interval, in this work, the proposed control scheme is valid on the entire time interval. In addition, the prior information on the upper or lower bound of gi is not in need,enlarging the applicability of the proposed method. Both the theoretical analysis and numerical simulation confirm the effectiveness of the proposed control algorithm.

关键词： Adaptive control prescribed time control(PTC) strict-feedback systems tracking control

Enhanced conductivity and weakened magnetism in Pb-doped Sr2IrO4

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Chinese Physics B 2024年第1期33卷 696-701页

作者：岳智来甄伟立牛瑞焦珂珂朱文卡皮雳张昌锦 High Magnetic Field Laboratory Hefei Institutes of Physical ScienceChinese Academy of Sciences Science Island Branch of graduate School University of Science and Technology of China Collaborative Innovation Center of Advanced Microstructures Nanjing University

Group IV element Pb has been selected as the dopant to dope at the Sr site of Sr2IrO4. It is exciting to find that the single-phase crystal structure could be maintained with a high Pb doping level of up to x=0.3 in Sr2-xPbxIrO4. The mapping data obtained from energy-dispersive x-ray spectroscopy analyses give solid evidence that the Pb ions are uniformly distributed in the Sr2IrO4matrix. The incorporation of Pb leads to a moderate depression of the canted antiferromagnetic ordering state. The electrical conductivity could be greatly enhanced when the Pb doping content is higher than x=*** present results give a fresh material base to explore new physics in doped Sr2IrO4systems.

关键词： iridates doping conductivity magnetism

Power transfer efficiency in an air-breathing radio frequency ion thruster

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Chinese Physics B 2024年第7期33卷 430-438页

作者：黄高煌李宏高飞王友年 Key Laboratory of Materials Modification by Laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024China College of physical Science and Technology Dalian UniversityDalian 116622China

Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.

关键词： radio frequency ion thruster inductively coupled plasma power transfer efficiency analytic solution

Go to the back before going forward:Addressing psychological responses in anterior cruciate ligament reconstruction rehabilitation

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Journal of Sport and Health Science 2024年第5期13卷 666-669页

作者： Terese L.Chmielewski Adam Meierbachtol Rick Aberman Travis Gunderson Jonathon Sikorski Kathleen Cummer TRIA Orthopedic Center BloomingtonMN 55431USA Rehabilitation Science graduate program Department of Family Medicine and Community HealthMedical SchoolUniversity of MinnesotaMinneapolisMN 55455USA Optum Inc. Clinical OperationsPhysical Health DivisionEden PrairieMN 55344USA Dr.Rick Aberman Consulting MinnetonkaMN 55305USA Department of Rehabilitation Medicine Division of Physical TherapyUniversity of WashingtonSeattleWA 98195USA

Helping athletes return to sports participation is a primary goal of anterior cruciate ligament(ACL)reconstruction *** facilitate the achievement of this goal,decades of research studies have sought to identify knee impairments that reduce knee function as well as interventions to resolve them.1Yet,over the past 10 years,research pertaining to psychological responses(i.e.,cognitions and emotions)after ACL reconstruction has grown exponentially—a phenomenon that can be visualized by entering the search terms"psychological"and"anterior cruciate ligament reconstruction"into the PubMed search engine.

关键词： ligament return psychological

The Link between Psychomotor Disorders and physical Therapy

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Open Journal of Medical Psychology 2024年第1期13卷 1-10页

作者： Ramona Delia Arsani Marius Stoica National University of physical education and Sports Bucharest Romania

The evolution of the individual in ontogenesis has been studied throughout life and on all sides of development. Studies in the field based on medical rehability performed by a full team such as doctors, physiotherapists and psychologists and not only have shown that the link between the patient’s psychological state and exercise are factors in full dependence and any imbalance can trigger irreparable effects. Psychology is the science that studies the laws of formation, development, functioning and deficiencies related to psychism;it includes a series of fundamental concepts that include: psychic processes, psychic phenomena, psychic attributes, psychic states or psychic activities. Psychic phenomena are the component elements of psychism. In a sense, the psychic phenomena are manifested by external facts, by our behavior, by the motor actions started, by gestures or verbal actions;in the other sense, psychic phenomena are manifested by inner deeds, as the form of ideas, images, feelings, and desires. The motor acts without psychism would be only simple automatisms, without human specifications of adaptation, while the psychism without motor acts would be deprived of the fundamentals of formation and functioning as well as of its production mechanisms. Objective: The objective of this study is to highlight the causal problems of delayed medical recovery in relation to the psychological and emotional factors. This desktop review aims to identify psychoemotional disorders in the case of subjects with operated lumbar disc herniation and aims to adapt a specialized physiotherapeutic protocol by adapting to CIF. The result of this study will be found in the percentage of socio-professional reintegration of the subjects with operated lumbar disc herniation and implicitly the increase in the quality of life. Conclusions: 1) For an effective functional recovery, a psycho-emotional balance is needed;2) A positive attitude actively influences medical rehabilitation;3) Regain

关键词： Hyperkinesia Hypokinesia Tics Body Schema Disorders Apraxia

Development of D_α band symmetrical visible optical diagnostic for boundary reconstruction on EAST tokamak

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Plasma Science and Technology 2024年第2期26卷 44-53页

作者：陈明沈飊 Shinichiro KADO 郭笔豪陈大龙蔡福瑞肖炳甲 Hefei Institutes of physical Science Chinese Academy of SciencesHefei 230031People's Republic of China Science Island Branch Graduate School of University of Science and Technology of ChinaHefei 230026People's Republic of China Institute of Advanced Energy Kyoto UniversityUji 611-0011Japan graduate School of Energy Science Kyoto UniversityUji 611-0011Japan

To investigate the potential of utilizing visible spectral imaging for controlling the plasma boundary shape during stable operation of plasma in future tokamak, a D_α band symmetric visible light diagnostic system was designed and implemented on the Experimental Advanced Superconducting Tokamak(EAST). This system leverages two symmetric optics for joint plasma imaging. The optical system exhibits a spatial resolution less than 2 mm at the poloidal cross-section, distortion within the field of view below 10%, and relative illumination of 91%.The high-quality images obtained enable clear observation of both the plasma boundary position and the characteristics of components within the vacuum vessel. Following system calibration and coordinate transformation, the image coordinate boundary features are mapped to the tokamak coordinate system. Utilizing this system, the plasma boundary was reconstructed, and the resulting representation showed alignment with the EFIT(Equilibrium Fitting) results. This underscores the system's superior performance in boundary reconstruction applications and provides a diagnostic foundation for boundary shape control based on visible spectral imaging.

关键词： visible optical diagnostic plasma boundary reconstruction EAST

Neutrophil extracellular traps mediate neuro-immunothrombosis

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Neural Regeneration Research 2024年第8期19卷 1734-1740页

作者： Jianbo Lou Jianning Zhang Quanjun Deng Xin Chen Department of Neurosurgery Tianjin Medical University General HospitalTianjinChina Tianjin Neurological Institute Key Laboratory of Post-Trauma Neuro-Repair and Regeneration in Central Nervous SystemMinistry of EducationTianjin Key Laboratory of InjuriesVariations and Regeneration of Nervous SystemTianjinChina

Neutrophil extracellular traps are primarily composed of DNA and histones and are released by neutrophils to promote inflammation and thrombosis when stimulated by various inflammato ry *** extracellular trap formation occurs through lytic and non-lytic pathways that can be further classified by formation ***,von Willebrand factor,fibrin,and many other factors participate in the interplay between inflammation and *** summarizes the intricate interplay between inflammation and thrombosis during neural development and the pathogenesis of neurological diseases,providing cutting-edge insights into post-neurotrauma thrombotic *** blood-brain barrier defends the brain and spinal cord against external assaults,and neutrophil extracellular trap involvement in blood-brain barrier disruption and immunothrombosis contributes substantially to secondary injuries in neurological *** research is needed to understand how neutrophil extracellular traps promote blood-brain barrier disruption and immunothrombosis,but recent studies have demonstrated that neutrophil extracellular traps play a crucial role in immunothrombosis,and identified modulators of ***,these neurological diseases occur in blood vessels,and the mechanisms are unclear by which neutrophil extracellular traps penetrate the blood-brain barrier to participate in immunothrombosis in traumatic brain *** review discusses the role of neutrophil extracellular traps in neuro-immunothrombosis and explores potential therapeutic interventions to modulate neutrophil extracellular traps that may reduce immunothrombosis and improve traumatic brain injury outcomes.

关键词： inflammation neuro-immunothrombosis neurologic diseases neurotrauma neutrophil extracellular traps platelet thrombosis traumatic brain injury

Negative Stiffness Mechanism on An Asymmetric Wave Energy Converter by Using A Weakly Nonlinear Potential Model

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China Ocean Engineering 2024年第4期38卷 689-700页

作者： Sunny Kumar POGULURI Dongeun KIM Yoon Hyeok BAE Department of Ocean Engineering IIT MadrasChennaiIndia Multidisciplinary graduate School program for Wind Energy Jeju National UniversityJejuRepublic of Korea Mechanical and System Design Engineering Hongik UniversitySeoulRepublic of Korea

Salter's duck,an asymmetrical wave energy converter(WEC)device,showed high efficiency in extracting energy from 2D regular waves in the past;yet,challenges remain for fluctuating wave *** can potentially be addressed by adopting a negative stiffness mechanism(NSM)in WEC devices to enhance system efficiency,even in highly nonlinear and steep 3D waves.A weakly nonlinear model was developed which incorporated a nonlinear restoring moment and NSM into the linear formulations and was applied to an asymmetric WEC using a time domain potential flow *** model was initially validated by comparing it with published experimental and numerical computational fluid dynamics *** current results were in good agreement with the published *** was found that the energy extraction increased in the range of 6%to 17%during the evaluation of the effectiveness of the NSM in regular *** irregular wave conditions,specifically at the design wave conditions for the selected test site,the energy extraction increased by 2.4%,with annual energy production increments of approximately *** findings highlight the potential of NSM in enhancing the performance of asymmetric WEC devices,indicating more efficient energy extraction under various wave conditions.

关键词： asymmetric wave energy converter negative stiffness mechanism weakly nonlinear potential flow power

Spatio-temporal coupled mode theory for nonlocal metasurfaces

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Light(Science & Applications) 2024年第2期13卷 267-282页

作者： Adam Overvig Sander A.Mann Andrea Alù Photonics Initiative Advanced Science Research CenterCity University of New YorkNew YorkNY10031USA Physics program Graduate Center of the City University of New YorkNew YorkNY10016USA

Diffractive nonlocal metasurfaces have recently opened a broad range of exciting developments in nanophotonics research and applications,leveraging spatially extended—yet locally patterned—resonant modes to control light with new degrees of *** conventional grating responses are elegantly captured by temporal coupled mode theory,current approaches are not well equipped to capture the arbitrary spatial response observed in the nascent field of nonlocal ***,we introduce spatio-temporal coupled mode theory(STCMT),capable of elegantly capturing the key features of the resonant response of wavefront-shaping nonlocal *** framework can quantitatively guide nonlocal metasurface design while maintaining compatibility with local metasurface frameworks,making it a powerful tool to rationally design and optimize a broad class of ultrathin optical *** validate this STCMT framework against full-wave simulations of various nonlocal metasurfaces,demonstrating that this tool offers a powerful semi-analytical framework to understand and model the physics and functionality of these devices,without the need for computationally intense full-wave *** also discuss how this model may shed physical insights into nonlocal phenomena in photonics and the functionality of the resulting *** a relevant example,we showcase STCMT’s flexibility by applying it to study and rapidly prototype nonlocal metasurfaces that spatially shape thermal emission.

关键词： theory resonant spatially