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Pattern control for large-scale spacecraft swarms in elliptic orbits via density fields

Chinese Journal of Aeronautics 2022年第3期35卷 367-379页

作者： Chihang yang hao zhang Weida FU Key Laboratory of Space Utilization Technology and Engineer Center for Space UtilizationChinese Academy of SciencesBeijing 100094China University of Chinese Academy of Sciences Beijing 100049China DFH Satellite Co. LtdBeijing 100094China

Space swarms,enabled by the miniaturization of spacecraft,have the potential capability to lower costs,increase efficiencies,and broaden the horizons of space *** formation control problem of large-scale spacecraft swarms flying around an elliptic orbit is *** objective is to drive the entire formation to produce a specified spatial *** relative motion between agents becomes complicated as the number of agents ***,a density-based method is adopted,which concerns the density evolution of the entire swarm instead of the trajectories of *** density-based method manipulates the density evolution with Partial Differential Equations(PDEs).This density-based control in this work has two aspects,global pattern control of the whole swarm and local collision-avoidance between nearby *** global behavior of the swarm is driven via designing velocity *** each spacecraft,the Q-guidance steering law is adopted to track the desired velocity with accelerations in a distributed ***,the final stable velocity field is required to be zero in the classical density-based approach,which appears as an obstacle from the viewpoint of astrodynamics since the periodic relative motion is always *** solve this issue,a novel transformation is constructed based on the periodic solutions of Tschauner-Hempel(TH)*** relative motion in Cartesian coordinates is then transformed into a new coordinate system,which permits zero-velocity in a stable *** local behavior of the swarm,such as achieving collision avoidance,is achieved via a carefully-designed local density estimation *** simulations are provided to demonstrate the performance of this approach.

关键词： Collision avoidance Density-based feedback control Distributed control Formation flight Large-scale swarms Pattern generation PDE-based control TH equation

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Close relative motion on distant retrograde orbits

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Chinese Journal of Aeronautics 2023年第3期36卷 335-356页

作者： Chihang yang Ming WANG hao zhang University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Space Utilization Technology and Engineering Center for Space UtilizationChinese Academy of SciencesBeijing 100094China

Distant Retrograde Orbits(DROs)in the Earth-Moon system have great potential to support varieties of missions due to the favorable stability and orbital ***,the close relative motion on DROs should be analyzed to design formations to assist or extend the DRO ***,as the reference DROs are obtained through numerical methods,the close relative motions on DROs are non-analytical,which severely limits the design of relative *** this paper,a novel approach is proposed to construct the analytical solution of bounded close relative motion on *** linear dynamics of relative motion on DRO is established at *** preliminary forms of the general solutions are obtained based on the Floquet *** the general solutions are classified as different modes depending on their periodic components.A new parameterization is applied to each mode,which allows us to explore the geometries of quasi-periodic modes in *** each mode,the solutions are integrated as a uniform expression and their periodic components are expanded as truncated Fourier *** this way,the analytical bounded relative motion on DRO is *** on the analytical expression,the characteristics of different modes are comprehensively *** natural periodic mode is always located on the single side of the target spacecraft on DRO and is appropriate to be the parking orbits of the rendezvous and *** the basis of quasi-periodic modes,quasi-elliptical fly-around relative trajectories are designed with the assistance of only two impulses per *** fly-around formation can support observations to targets on DRO from multiple viewing *** the fly-around formation is validated in a more practical ephemeris model.

关键词： Distant retrograde orbits Ephemeris model Floquet theory Formation flight Relative motion Spacecraft Three-body problem Transfer singularity

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Fault tolerant attitude control of under-actuated spacecraft:Theory and experiment

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Chinese Journal of Aeronautics 2023年第5期36卷 465-474页

作者： Zejun zhang hao yang Bin JIANG College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

This paper investigates fault tolerant attitude control theory and experiment for underactuated spacecraft with one reaction wheel completely broken and two others suffering actuator faults of partial loss of effectiveness or bias.A non-smooth robust adaptive fault tolerant control law is proposed under the zero-momentum and input saturation *** shows that the available reaction wheels need to produce sufficient control torque for the fault *** a new control method is implemented in a semi-physical simulation system of an air-bearing *** results show the effectiveness of the proposed method in spacecraft practical engineering.

关键词： Actuator fault Air-bearing platform Fault tolerant control Semi-physical experiment Under-actuated spacecraft

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Metabolic reprogramming: a new option for the treatment of spinal cord injury

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Neural Regeneration Research 2025年第4期20卷 1042-1057页

作者： Jiangjie Chen Jinyang Chen Chao Yu Kaishun Xia Biao yang Ronghao Wang Yi Li Kesi Shi Yuang zhang Haibin Xu Xuesong zhang Jingkai Wang Qixin Chen Chengzhen Liang Department of Orthopedics The Second Affiliated Hospital of Zhejiang University School of MedicineHangzhouZhejiang ProvinceChina Orthopedics Research Institute of Zhejiang University Zhejiang UniversityHangzhouZhejiang ProvinceChina Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province HangzhouZhejiang ProvinceChina Clinical Research Center of Motor System Disease of Zhejiang Province HangzhouZhejiang ProvinceChina Qiandongnan Prefecture People’s Hospital KailiGuizhou ProvinceChina Department of Orthopedics Fourth Medical CenterChinese PLA General HospitalBeijingChina

Spinal cord injuries impose a notably economic burden on society,mainly because of the severe after-effects they *** the ongoing development of various therapies for spinal cord injuries,their effectiveness remains ***,a deeper understanding of metabolism has opened up a new therapeutic opportunity in the form of metabolic *** this review,we explore the metabolic changes that occur during spinal cord injuries,their consequences,and the therapeutic tools available for metabolic *** spinal cord metabolism is characterized by independent cellular metabolism and intercellular metabolic ***,spinal cord injury results in metabolic disorders that include disturbances in glucose metabolism,lipid metabolism,and mitochondrial *** metabolic disturbances lead to corresponding pathological changes,including the failure of axonal regeneration,the accumulation of scarring,and the activation of *** rescue spinal cord injury at the metabolic level,potential metabolic reprogramming approaches have emerged,including replenishing metabolic substrates,reconstituting metabolic couplings,and targeting mitochondrial therapies to alter cell *** available evidence suggests that metabolic reprogramming holds great promise as a next-generation approach for the treatment of spinal cord *** further advance the metabolic treatment of the spinal cord injury,future efforts should focus on a deeper understanding of neurometabolism,the development of more advanced metabolomics technologies,and the design of highly effective metabolic interventions.

关键词： axons glycolysis metabolic reprogramming metabolism mitochondria neural regeneration neuroprotection oxidative phosphorylation spinal cord injury therapy

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Nomogram for overall survival in ampullary adenocarcinoma using the surveillance,epidemiology,and end results database and external validation

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World Journal of Clinical Oncology 2025年第2期16卷 36-51页

作者： Jia yang Zi-Yi Wang Jing Chen Yao zhang Lei Chen Department of Gastroenterology The First Affiliated Hospital of Army Medical UniversityChongqing 400038China Department of Epidemiology College of Preventive MedicineArmy Medical UniversityChongqing 400038China

BACKGROUND Ampullary adenocarcinoma is a rare malignant tumor of the gastrointestinal ***,only a few cases have been reported,resulting in limited information on *** To develop a dynamic nomogram using internal and external validation to predict survival in patients with ampullary *** Data were sourced from the surveillance,epidemiology,and end results stat *** patients in the database were randomized in a 7:3 ratio into training and validation *** Cox regression univariate and multivariate analyses in the training group,we identified independent risk factors for overall survival and cancer-specific survival to develop the *** nomogram was validated with a cohort of patients from the First Affiliated Hospital of the Army Medical *** For overall and cancer-specific survival,12(sex,age,race,lymph node ratio,tumor size,chemotherapy,surgical modality,T stage,tumor differentiation,brain metastasis,lung metastasis,and extension)and 6(age;surveillance,epidemiology,and end results stage;lymph node ratio;chemotherapy;surgical modality;and tumor differentiation)independent risk factors,respectively,were incorporated into the *** area under the curve values at 1,3,and 5 years,respectively,were 0.807,0.842,and 0.826 for overall survival and 0.816,0.835,and 0.841 for cancer-specific *** internal and external validation cohorts indicated good consistency of the *** The dynamic nomogram offers robust predictive efficacy for the overall and cancer-specific survival of ampullary adenocarcinoma.

关键词： Ampullary adenocarcinoma Dynamic nomogram Gastrointestinal tract Surveillance Epidemiology End results database Survival rate

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Glucocorticoid receptor signaling in the brain and its involvement in cognitive function

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Neural Regeneration Research 2025年第9期20卷 2520-2537页

作者： Chonglin Su Taiqi Huang Meiyu zhang Yanyu zhang Yan Zeng Xingxing Chen Brain Science and Advanced Technology Institute Hubei Province Key Laboratory of Occupational Hazard Identification and ControlSchool of MedicineWuhan University of Science and TechnologyWuhanHubei ProvinceChina

The hypothalamic-pituitary-adrenal axis regulates the secretion of glucoco rticoids in response to environmental *** the brain,a nuclear receptor transcription fa ctor,the glucocorticoid recepto r,is an important component of the hypothalamicpituitary-a d renal axis's negative feedback loop and plays a key role in regulating cognitive equilibrium and *** glucoco rticoid receptor influences cognitive processes,including glutamate neurotransmission,calcium signaling,and the activation of brain-derived neurotrophic factor-mediated pathways,through a combination of genomic and non-genomic *** interactions within the central nervous system can alter the expression and activity of the glucocorticoid receptor,there by affecting the hypothalamic-pituitary-a d renal axis and stress-related cognitive *** appropriate level of glucocorticoid receptor expression can improve cognitive function,while excessive glucocorticoid receptors or long-term exposure to glucoco rticoids may lead to cognitive *** with cognitive impairment-associated diseases,such as Alzheimer's disease,aging,depression,Parkinson's disease,Huntington's disease,stroke,and addiction,often present with dysregulation of the hypothalamic-pituitary-adrenal axis and glucocorticoid receptor *** review provides a comprehensive overview of the functions of the glucoco rticoid receptor in the hypothalamic-pituitary-a d renal axis and cognitive *** emphasizes that appropriate glucocorticoid receptor signaling fa cilitates learning and memory,while its dysregulation can lead to cognitive *** provides clues about how glucocorticoid receptor signaling can be targeted to ove rcome cognitive disability-related disorders.

关键词： brain-derived neurotrophic factor calcium signaling glucocorticoid receptor glucocorticoid glutamate transmission hypothalamic-pituitary-adrenal axis long-term potentiation neurocognitive disorders neuroplasticity stress

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Programmable shape memory polymers:Intermolecular and interfacial interaction mechanisms

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Science China Materials 2023年第11期66卷 4519-4520页

作者： Diling yang hao zhang Hongbo Zeng Department of Chemical and Materials Engineering University of AlbertaEdmontonAlberta T6G 1H9Canada

Shape memory polymers(SMPs)have long been at the forefront of the field of stimulus-responsive shape-shifting *** possess a unique ability to recall and return to their original shapes after undergoing temporary deformations triggered by specific external stimuli,including heat,light,or changes in the surrounding environment,such as alterations in p H conditions^([1-4]).

关键词： interfacial shifting interaction

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Numerical Study of Flow and Heat Transfer Characteristics of Impingement/Effusion Cooling

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Chinese Journal of Aeronautics 2009年第4期22卷 343-348页

作者： zhang Jingzhou Xie hao yang Chengfeng College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China College of Power Engineering Nanjing Normal University Nanjing 210042 China

Three-dimensional numerical simulation is carried out to investigate the flow and heat transfer characteristics of impingement/effusion cooling systems. The impingement/effusion holes are arranged on two parallel perforated plates respectively in a staggered manner. Every effusion hole has an inclined angle of 30° with respect to the surface. The two parallel plates are spaced three times the diameter of the effusion hole. The ratio of center-to-center spacing of adjacent holes to the diameter of the effusion hole is set to be 3.0, 4.0 and 5.0 respectively. The flow field, temperature field and wall film cooling effectiveness are calculated for different blowing ratios ranging from 0.5 to 1.5. In general, the wall cooling effectiveness increases as the center-to-center spacing of adjacent holes decreases or the blowing ratio increases.

关键词： impingement/effusion blowing ratio cooling effectiveness heat transfer numerical simulation

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Structural integration of solar desalination system

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Science China Materials 2024年第6期67卷 2039-2041页

作者： Diling yang hao zhang Hongbo Zeng School of Materials and Environmental Engineering Hunan University of HumanitiesScience and TechnologyLoudi 417000China Department of Chemical and Materials Engineering University of AlbertaEdmontonAlberta T6G 1H9Canada

As population grow and climate change place significant water stress on numerous regions,the demand for efficient and environmentally friendly water resource solutions becomes increasingly *** address this challenge,desalination technology has received much attention and is widely employed,with a recent emphasis on solar-powered solutions driven by the global push for carbon neutrality.

关键词： neutral system integration

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Fault-tolerant flocking control against multiple malicious agents under geometric configuration containment

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Science China(Information Sciences) 2024年第10期67卷 261-282页

作者： Chencheng zhang hao yang Bin JIANG College of Automation Engineering Nanjing University of Aeronautics and Astronautics Institute of Engineering and Technology (ENTEG) University of Groningen

Flocking control in the presence of malicious decisions is a crucial research topic since agents in swarms are likely to suffer from security issues in practice. This paper considers a swarm containing malicious agents that deliberately alter their controller parameters and disrupt the swarm by causing collisions,divisions, and escapes. Two possible malicious scenarios are considered. The first is that one malicious agent acts selectively on a subset of its neighbors and the second is that multiple malicious agents are either scattered or clustered together. To achieve the flocking control objective:(1) containment conditions based on specific geometric configurations are established;(2) hierarchical fault-tolerant flocking control methods based on those containment conditions are proposed. Compared to existing research dealing with malicious agents in swarms, our approach aims to contain rather than remove them. This guarantees the completeness of the task and takes agents' motions into consideration. Simulations show the effectiveness of the proposed methods.

关键词： flocking control fault-tolerant control multiple malicious agents geometric configuration

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