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Distance Estimates for Simple Choreographic Solutions of the Three-body Problem

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Acta Mathematica Sinica,English Series 2022年第10期38卷 1823-1830页

作者： kuo chang chen Bo Yu PAN Department of Mathematics “National Tsing Hua University”HsinchuTaiwanChina Department of Applied Mathematics “National Chung Hsing University”TaichungTaiwanChina

In this article we estimate mutual distances of simple choreographic solutions for the Newtonian three-body *** formulas will be proved and our applications include the famous figure-8 orbit.

关键词： n-body problem variational method mutual distance

Keplerian Action,Convexity Optimization,and the 4-Body Problem

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Analysis in Theory and Applications 2021年第1期37卷 24-58页

作者： kuo-chang chen Department of Mathematics National Tsing Hua UniversityHsinchuTaiwan

In this paper we introduce a method to construct periodic solutions for the n-body problem with only boundary and topological *** approach is based on some novel features of the Keplerian action functional,constraint convex optimization techniques,and variational *** demonstrate the strength of this method by constructing relative periodic solutions for the planar four-body problem within a special topological class,and our results hold for an open set of masses.

关键词： n-body problem variational methods periodic solutions convex optimization

From ore to MOF: A case of MIL-100(Fe) production from iron ore concentrates

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Progress in Natural Science:Materials International 2024年第1期34卷 66-73页

作者： Miao chang Chiyao Tang Chong-chen Wang chen Zhao Beijing Key Laboratory of Functional Materials for Building Structure and Environment Remediation School of Environment and Energy Engineering Beijing University of Civil Engineering and Architecture

Within this work, iron ore concentrates instead of elemental iron Fe0and iron salts like Fe（NO3）3and FeCl3were selected as iron source to prepare MIL-100（Fe）(labeled as MIL-100（Fe）-ore). The corresponding synthesis cost is reduced to half of the MIL-100（Fe） produced from elemental iron and iron salts. As well, the unreacted iron ore concentrates can be easily separated from the as-prepared MIL-100（Fe）-ore by magnetic to facilitate the purification process, free of the strong acids to wash the residual iron. The as-obtained MIL-100（Fe）-ore with Langmuir surface area up to 2281.6 m2g-1displayed long-term chemical stability. Furthermore, the sorption capacity of MIL-100（Fe）-ore towards malachite green（MG） is up to 522.3 mg g-1at 25℃ and initial pH = 3.2, higher than that of MIL-100（Fe） yielded by conventional hydrothermal process. Finally, the production cost and life cycle assessment of MIL-100（Fe）-ore were compared with other traditional production procedures. The results revealed that our work greatly reduced the synthesis cost and enhanced the environmental sustainability.

关键词： Metal-organic framework Iron ore concentrates Adsorption Life cycle assessment

Ten- year follow- up investigation of stroke risk in systemic lupus erythematosus

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Stroke & Vascular Neurology 2024年第1期9卷 1-7页

作者： Jin-An Huang Ching-Heng Lin Ming-Ju Wu Yi-Hsing chen kuo-cheng chang Chung-Wei Hou Division of Neurology Neurological InstituteTaichung Veterans General HospitalTaichungTaiwan Department of Health Business Administration Hungkuang UniversityTaichungTaiwan Department of Medical Research Taichung Veterans General HospitalTaichungTaiwan Division of Nephrology Department of Internal MedicineTaichung Veterans General HospitalTaichungTaiwan School of Medicine Chung Shan Medical UniversityTaichungTaiwan College of Medicine National Chung Hsing UniversityTaichungTaiwan Division of Allergy Immunology and RheumatologyDepartment of Internal MedicineTaichung Veterans General HospitalTaichungTaiwan School of Medicine National Yang-Ming Chiao Tung UniversityTaichungTaiwan

Background and purpose To analyse the long-term risk of ischaemic stroke and the clinical effects of antithrombotics on the risk of haemorrhagic stroke in patients with systemic lupus erythematosus(SLE).Methods A retrospective cohort study was conducted using a population-based database taken from Taiwan National Health Insurance Research *** with SLE between 2000 and 2008 were registered and matched with two controls by the index date,age,gender and Charlson Comorbidity Index(CCI).These subjects were followed until either stroke event or 31 December *** HRs(aHRs)for strokes were estimated with Cox regression models,and the cumulative incidence of ischaemic stroke was analysed by log-rank test and Kaplan-Meier survival *** In total,8310 patients with SLE and 16620 patients without SLE were *** general,patients with SLE had higher rates of ischaemic stroke(5.4%vs 3.3%)and haemorrhagic stroke(1.5%vs 0.6%)than in *** multivariate analysis adjusted to age,gender,CCI,urbanisation level and antithrombotics uses,aHRs of all strokes,ischaemic stroke and haemorrhagic stroke were 1.73(95%CI:1.54 to 1.94),1.65(95%CI:1.45 to 1.87)and 2.24(95%CI:1.71 to 2.95),respectively,in patients with *** with SLE were significantly more likely to suffer ischaemic stroke than patients without SLE,even 10 years after SLE diagnosis(6.12%vs 3.50%,p<0.001).Antiplatelet use increased the risk of haemorrhagic stroke in SLE group(aHR=1.74,95%CI:1.18 to 2.57).Conclusions Patients with SLE are at greater risk of developing ischaemic stroke that lasts for 10 *** should be carefully administered to prevent cardiovascular events in patients with SLE due to the risk of haemorrhagic stroke.

关键词： erythematosus diagnosis likely

Spin-orbit interaction induced Casimir-Lifshitz torque between two-dimensional electron gases

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 134-142页

作者： Jia-Nan Rong Liang chen Kai chang State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China School of Mathematics and Physics North China Electric Power UniversityBeijing 102206China School of Physics Zhejiang UniversityHangzhou 310027China College of Materials Science and Opto-electronic Technology University of Chinese Academy of SciencesBeijing 100049China

We investigate theoretically the Casimir interaction between two parallel two-dimensional electron gases(2DEGs)with Rashba and Dresselhaus spin-orbit interactions(SOIs),based on the quantum field *** derive an analytical expression for the polarization tensor and obtain the solution to the motion equation of the electromagnetic(EM)*** calculate the CasimirLifshitz torque(CLT)between two parallel 2DEGs with Rashba and Dresselhaus SOIs,which can be tuned by changing the relative strength between two *** anisotropic Casimir energy between 2DEGs caused by the interplay between the SOIs of 2DEGs offers a new origin of CLT and a new type of optoelectronic device.

关键词： Casimir torque two-dimensional electron gas spin-orbit interaction

Converting an O-vacancy-rich oxide into a multifunctional separator modifier for long-lifespan lithium metal batteries

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Journal of Energy Chemistry 2024年第10期97卷 371-378,I0007页

作者： Juntao Si Xiaoying Li Yixuan Li kuo Cao Yiran Zhu Chunhua chen CAS Key Laboratory of Precision and Intelligent Chemistry Department of Materials Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026AnhuiChina

The lithium metal anode is hailed as the desired "holy grail" for the forthcoming generation of highenergy-density batteries,given its astounding theoretical capacity and low ***,the formation and growth of dendrites seriously compromise battery life and ***,an yttriastabilized bismuth oxide(YSB) layer is fabricated on the polypropylene(PP) separator,where YSB reacts with Li anode in-situ in the cell to form a multi-component composite interlayer consisting of Li_(3)Bi,Li_(2)O,and Y_(2)O_(3).The interlayer can function not only as a redistributor to regulate Li^(+) distribution but also as an anion adsorber to increase the Li^(+) transference number from 0.37 to 0.79 for suppressing dendrite nucleation and ***,compared with the cell with a baseline separator,those with modified separators exhibit prolonged lifespan in both Li/Li symmetrical cells and Li/Cu ***,the full cells coupled with ultrahigh-loading LiFePO_(4) display an excellent cycling performance of 1700 cycles with a high capacity retention of ~80% at 1 C,exhibiting great potential for practical *** work provides a feasible and effective new strategy for separator modification towards building a much-anticipated dendrite-free Li anode and realizing long-lifespan lithium metal batteries.

关键词： Lithium metal battery Separator Dendrite-free Multifunctional interlayer Conversion-alloying reaction

Atomically Dispersed Ruthenium Catalysts with Open Hollow Structure for Lithium-Oxygen Batteries

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Nano-Micro Letters 2024年第2期16卷 154-164页

作者： Xin chen Yu Zhang chang chen Huinan Li Yuran Lin Ke Yu Caiyun Nan chen chen Beijing Advanced Innovation Center for Materials Genome Engineering Institute of Solid State ChemistryUniversity of Science and Technology BeijingBeijing 100083People’s Republic of China Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084People’s Republic of China Beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875People’s Republic of China

Lithium–oxygen battery with ultrahigh theoretical energy density is considered a highly competitive next-generation energy storage device,but its practical application is severely hindered by issues such as difficult decomposition of discharge products at ***,we have developed N-doped carbon anchored atomically dispersed Ru sites cathode catalyst with open hollow structure(h-RuNC)for Lithium–oxygen *** one hand,the abundance of atomically dispersed Ru sites can effectively catalyze the formation and decomposition of discharge products,thereby greatly enhancing the redox *** the other hand,the open hollow structure not only enhances the mass activity of atomically dispersed Ru sites but also improves the diffusion efficiency of catalytic ***,the excellent activity from atomically dispersed Ru sites and the enhanced diffusion from open hollow structure respectively improve the redox kinetics and cycling stability,ultimately achieving a high-performance lithium–oxygen battery.

关键词： Atomically dispersed Open hollow structure Discharge product Lithium Oxygen battery

A methodology for laser tool setters calibration and its precise mathematical model

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Chinese Journal of Aeronautics 2024年第7期37卷 564-581页

作者： Tao FANG Zixi FANG Ze Zhong chen Zhiyong chang School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Gina Cody School of Engineering and Computer Science Concordia UniversityMontrealQuebec H3G 1M8Canada changsha Optimum CNC Corporation Changsha 410221China Institute for Aero-engine Smart Assembly of Shaanxi Province Xi’an 710072China

On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine *** tool setters play a crucial role in precisely measuring the dimensions of cutting tools during the part machining process,focusing on tool length and *** a measuring instrument,the positions of the laser axis of the laser tool setter need to be accurately calibrated before ***,in actual calibration scenarios,traditional calibration methods face challenges due to installation errors in the tool setter and geometric errors in the measuring *** address this issue,this study proposes a novel calibration ***,the calibration mechanism of the laser beam axis is *** on the accurate mathematical model of the laser beam and the measuring rod,and using the polygon clipping algorithm,the mathematical mechanism of the laser tool setter’s work is ***,a novel method is introduced to calculate the compensation distance between the laser beam reference point and the rod bottom center point at each moment during ***,by utilizing the kinematic chain of the tool setter calibration system,a new calibration method is developed to accurately calibrate the position of the laser beam axis in the machine tool coordinate ***,the accuracy of the calibration method is verified through simulation experiments and calibration *** method improves the calibration accuracy of the tool setter,and the mathematical model of the laser tool setter can be extended to the measurement of tools,thereby improving the precision of tool *** research significantly improves the efficient production performance of smart machine tools.

关键词： On-machine tool setting Smart machine tools Mathematical model Calibration method Laser tool sette

Aerodynamic Performance of Three Flapping Wings with Unequal Spacing in Tandem Formation

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Journal of Bionic Engineering 2024年第4期21卷 1662-1676页

作者： Min chang Ziyi Xu Zengshuang chen Li Li Xueguang Meng Unmanned System Research Institute National Key Laboratory of Unmanned Aerial Vehicle TechnologyNorthwestern Polytechnical UniversityXi’an710072People’s Republic of China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an710049People’s Republic of China Xi’an Aeronautics Computing Technique Research Institute Aviation Industry Corporation of ChinaXi’an710076People’s Republic of China

To better understand the aerodynamic reasons for highly organized movements of flying organisms,the three-flapping wing system in tandem formation was studied numerically in this *** from previous relevant studies on the multiple flapping wings that are equally spaced,this study emphasizes the impact of unequal spacing between individuals on the aerodynamics of each individual wing as well as the whole *** is found that swapping the distance between the first and second wing with the distance between the second wing and the rearmost wing does not affect the overall aerodynamic performance,but significantly changes the distribution of aerodynamic benefits across each *** the whole flapping cycle,three effects are at *** narrow channel effect and the downwash effect can promote and weaken the wing lift,respectively,while the wake capture effect can boost the *** also shows that these effects could be manipulated by changing the spacing between adjacent *** findings provide a novel way for flow control in tandem formation flight and are also inspiring for designing the formation flight of bionic aircraft.

关键词： Three flapping wings Unequal spacing Aerodynamic performance Tandem formation