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Coordinated Robust PID-based Damping Control of Permanent Magnet Synchronous Generators for Low-frequency Oscillations Considering Power System Operational Uncertainties

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1042-1051页

作者： Rehan Sadiq Zhen Wang chi Yung Chung Deqiang Gan Cunzhi Tong College of Electrical Engineering Zhejiang UniversityHangzhou 310058China The Hong Kong Polytechnic University Hong KongChina State Grid Zhejiang Electric Power Company Hangzhou 310007China

In recent years, with the growth of wind energy resources,the capability of wind farms to damp low-frequency oscillations(LFOs) has provided a notable advantage for the stabilityenhancement of the modern power grid. Meanwhile, owingto variations in the power system operating point (OP), thedamping characteristics of LFOs may be affected adversely. Inthis respect, this paper presents a coordinated robust proportional-integral-derivative (PID) based damping control approachfor permanent magnet synchronous generators (PMSGs)to effectively stabilize LFOs, while considering power system operationaluncertainties in the form of a polytopic model constructedby linearizing the power system under a given set ofOPs. The proposed approach works by modulating the DC-linkvoltage control loop of the grid-side converter (GSC) via a supplementaryPID controller, which is synthesized by transformingthe design problem into H-infinity static output feedback(SOF) control methodology. The solution of H-infinity SOF controlproblem involves satisfying linear matrix inequality (LMI)constraints based on the parameter-dependent Lyapunov functionto ensure asymptotic stability such that the minimal H-infinityperformance objective is simultaneously accomplished forthe entire polytope. The coordinated damping controllers forthe multiple wind farms are then designed sequentially by usingthe proposed approach. Eigenvalue analysis confirms the improveddamping characteristics of the closed-loop system forseveral representative OPs. Afterward, the simulation results, includingthe performance comparison with existing approaches,validate the higher robustness of the proposed approach for awide range of operating scenarios.

关键词： Permanent magnet synchronous generator(PMSG) low-frequency oscillation(LFO) proportional-integralderivative(PID) robust control H-infinity static output feed-back control linear matrix inequality(LMI)

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Tendency to Avoid Physical Activity and Sport:Associations with Weight Stigma,and Psychological Distress in a Two-Wave Longitudinal Study

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International Journal of Mental Health Promotion 2024年第8期26卷 633-641页

作者： Saffari Mohsen Yi-ching Lin Po-ching Huang Yu-Ting Huang Ru-Yi Huang chi Hsien Huang Jung-Sheng Chen wai Chuen Poon Mark D.Griffiths Chung-Ying Lin Health Research Center Life Style InstituteBaqiyatallah University of Medical SciencesTehran***Iran Health Education Department Faculty of HealthBaqiyatallah University of Medical SciencesTehran***Iran Department of Early childhood and Family Education National Taipei University of EducationTaipei106TaiwanChina School of Physical Therapy Graduate Institute of Rehabilitation ScienceCollege of MedicineChang Gung UniversityTaoyuan333TaiwanChina Institute of Allied Health Sciences College of MedicineNational Cheng Kung UniversityTainan701TaiwanChina Division of Family Medicine Taipei Tzu Chi HospitalBuddhist Tzu Chi Medical Foundationand School of MedicineTzu Chi UniversityHualienTaiwanChina Data Science Degree Program National Taiwan University and Academia SinicaTaipeiTaiwanChina Department of Family Medicine and Community Medicine E-Da HospitalI-Shou UniversityKaohsiung824TaiwanChina College of Medicine I-Shou UniversityKaohsiung840Taiwan Department of Medical Research E-Da HospitalI-Shou UniversityKaohsiung840TaiwanChina Sunway Business School Sunway UniversitySelangor47500Malaysia International Gaming Research Unit Psychology DepartmentNottingham Trent UniversityNottinghamNG14BUUK Department of Public Health College of MedicineNational Cheng Kung UniversityTainan701TaiwanChina Biostatistics Consulting Center National Cheng Kung University HospitalCollege of MedicineNational Cheng Kung UniversityTainan704TaiwanChina Department of Occupational Therapy College of MedicineNational Cheng Kung UniversityTainan701TaiwanChina

Background:Physical inactivity is a major public health problem worldwide that results in physical and mental health *** major issue for physical inactivity is weight stigma(WS),especially perceived WS,which could lead to a tendency to avoid physical activity(PA).To better understand the association between perceived WS and PA,knowledge of the likely mediators in this association such as weight bias internalization(WBI)and psychological distress were investigated in the present ***:Using a two-wave longitudinal study and convenient sampling,388 Taiwan residents participants(55%females;mean age=29.7 years[SD±6.3])completed two surveys six months *** mass index(BMI),Perceived Weight Stigma Scale(PWSS),Weight Bias Internalization Scale(WBIS),Depression,Anxiety,Stress Scale(DASS-21),and Tendency to Avoid Physical Activity and Sport Scale(TAPAS)were ***:A mediation model controlling for age,gender,and BMI with 5000 bootstrapping resamples was *** WS exerted significant direct effects on WBI(β=0.25;p<0.001),psychological distress(β=0.15;p=0.003),and tendency to avoid PA(β=0.10;p=0.027);WBI exerted a significant direct effect on tendency to avoid PA(β=0.47;p<0.001).Standardized indirect effects of WBI and psychological distress on the association between perceived WS and tendency to avoid PA were 0.12 and 0.01,***:Given the direct association of perceived WS on the tendency to avoid PA and the mediating role of WBI in this association,interventions addressing perceived WS and WBI may contribute to promoting ***,health interventionists(both when planning and executing PA programs)need to consider weight stigmawhen encouraging physical activity.

关键词： Mediation model physical activity psychological distress weight stigma young adults

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Cobalt-nitrogen co-doped porous carbon sphere as highly efficient catalyst for liquid-phase cyclohexane oxidation with molecular oxygen and the active sites investigation

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 101-112页

作者： Lei Chen Yuan Sun Jinshan chi Wei Xiong Pingle Liu Fang Hao College of Chemical Engineering National&Local United Engineering Research Centre for Chemical Process Simulation and IntensificationXiangtan UniversityXiangtan411105China

The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol(KA oil)is a challenging issue in the chemical *** present the industrial conversion of cyclohexane to cyclohexanone and cyclohexanol is normally controlled at less than 5%***,the development of highly active and stable catalysts for the aerobic oxidation of cyclohexane is necessary to overcome this low-efficiency ***,we have developed a cobalt-nitrogen co-doped porous sphere catalyst,Co-NC-x(x is the Zn/Co molar ratio,where x=0,0.5,1,2,and 4)by pyrolyzing resorcinol-formaldehyde resin *** achieved 88.28%cyclohexanone and cyclohexanol selectivity and a cyclohexane conversion of 8.88%under *** results showed that the introduction of zinc effectively alleviated the aggregation of Co nanoparticles and optimized the structural properties of the *** addition,Co0 and pyridinic-N are proposed to be the possible active species,and their proportion efficiently increased in the presence of Zn^(2+)*** this study,we developed a novel strategy to design highly active catalysts for cyclohexane oxidation.

关键词： KA oil production cyclohexane selective oxidation cobalt-nitrogen co-doped porous carbon spheres metal-organic framework

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Optimized scheduling of integrated energy systems for low carbon economy considering carbon transaction costs

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Global Energy Interconnection 2024年第4期7卷 377-390页

作者： Chao Liu Weiru Wang Jing Li Xinyuan Liu Yongning chi china Electric Power Research Institute Beijing 100192P.R.China State Grid Shanxi Electric Power Research Institute Taiyuan 030001P.R.China

With the introduction of the“dual carbon”goal and the continuous promotion of low-carbon development,the integrated energy system(IES)has gradually become an effective way to save energy and reduce *** study proposes a low-carbon economic optimization scheduling model for an IES that considers carbon trading *** the goal of minimizing the total operating cost of the IES and considering the transferable and curtailable characteristics of the electric and thermal flexible loads,an optimal scheduling model of the IES that considers the cost of carbon trading and flexible loads on the user side was *** role of flexible loads in improving the economy of an energy system was investigated using examples,and the rationality and effectiveness of the study were verified through a comparative analysis of different *** results showed that the total cost of the system in different scenarios was reduced by 18.04%,9.1%,3.35%,and 7.03%,respectively,whereas the total carbon emissions of the system were reduced by 65.28%,20.63%,3.85%,and 18.03%,respectively,when the carbon trading cost and demand-side flexible electric and thermal load responses were considered *** electrical and thermal loads did not have the same impact on the system *** the analyzed case,the total cost and carbon emissions of the system when only the flexible electrical load response was considered were lower than those when only the flexible thermal load response was taken into *** have an excess of carbon trading credits and can profit from selling them,whereas other devices have an excess of carbon trading and need to buy carbon credits.

关键词： Demand response Combined cooling Heating and power system Carbon transaction costs Flexible electric and thermal loads Optimal scheduling

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Space debris environment engineering model 2019:Algorithms improvement and comparison with ORDEM 3.1 and MASTER-8

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chinese Journal of Aeronautics 2024年第5期37卷 392-409页

作者： Yuyan LIU Runqiang chi Baojun PANG HU Diqi Wuxiong CAO Dongfang WANG School of Astronautics Harbin Institute of TechnologyHarbin 150001China College of Safety Science&Engineering Civil Aviation University of ChinaTianjin 300300China

As an essential tool for realistic description of the current or future debris environment,the Space Debris Environment Engineering Model(SDEEM)has been developed to provide support for risk assessment of *** contrast with SDEEM2015,SDEEM2019,the latest version,extends the orbital range from the Low Earth Orbit(LEO)to Geosynchronous Orbit(GEO)for the years *** this paper,improved modeling algorithms used by SDEEM2019 in propagating simulation,spatial density distribution,and spacecraft flux evaluation are *** debris fluxes of SDEEM2019 are compared with those of three typical models,i.e.,SDEEM2015,Orbital Debris Engineering Model 3.1(ORDEM 3.1),and Meteoroid and Space Debris Terrestrial Environment Reference(MASTER-8),in terms of two assessment *** orbital cases,including the Geostationary Transfer Orbit(GTO),Sun-Synchronous Orbit(SSO)and International Space Station(ISS)orbit,are selected for the spacecraft assessment mode,and the LEO region is selected for the spatial density assessment *** analysis indicates that compared with previous algorithms,the variable step-size orbital propagating algorithm based on semi-major axis control is more precise,the spatial density algorithm based on the second zonal harmonic of the non-spherical Earth gravity(J_(2))is more applicable,and the result of the position-centered spacecraft flux algorithm is more *** comparison shows that SDEEM2019 and MASTER-8 have consistent trends due to similar modeling processes,while the differences between SDEEM2019 and ORDEM 3.1 are mainly caused by different modeling approaches for uncatalogued debris.

关键词： SDEEM2019 Space debris propagating algorithm Spatial density algorithm ORDEM 3.1 MASTER-8

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Performance Study of a Novel Ejector-Cascade Refrigeration System with Regenerator

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Journal of Thermal Science 2024年第5期33卷 1618-1629页

作者： chi Weikai YANG Qichao CHEN Xiaonan LIU Guangbin ZHAO Yuanyang LI Liansheng College of Electromechanical Engineering Qingdao University of Science and TechnologyQingdao 266061China

In this paper,a novel NH_(3)/CO_(2)ejector-cascade refrigeration system with regenerator is proposed,which can recycle the waste heat at the outlet of the *** establishing the mathematical model of the system,the theoretical energy and exergy analysis are carried out and compared with the conventional cascade refrigeration *** is concluded that compared with the conventional cascade refrigeration system,the novel ejector-cascade refrigeration system with regenerator has the advantages of less power consumption of the compressor,less component exergy destruction,high system performance,and is more suitable for working at a lower *** the working conditions studied in this paper,compared with the conventional cascade refrigeration system,the COP of the novel ejector-cascade refrigeration system with regenerator is increased by9.58%;the exergy efficiency is increased by 9.50%,and the optimal evaporation temperature is about-45℃.

关键词： cascade refrigeration system ejector regenerator system performance thermodynamic analysis

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Broadband absorption performance of 3D-printed polyetheretherketone-based electromagnetic wave-absorbing composites

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chinese Journal of Aeronautics 2024年第8期37卷 547-558页

作者： Lin BAI Nan chanG Meiying ZHAO chi HOU Yi CAO Dichen LI School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Chengdu Aircraft Design and Research Institute Chengdu 610091China Xi’an Key Laboratory of Advanced Structure Design and Application of Aircraft Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory for Manufacturing System Engineering Xi’an Jiaotong UniversityXi’an 710054China

The rapid development of additive manufacturing technology has offered a new avenue for designing and fabricating high wave-absorbing meta *** this study,the mechanical properties and broadband absorption performance of Poly-Ether-Ether-Ketone(PEEK)–based electromagnetic wave–absorbing composite materials was *** high-performance polymer PEEK was used as the matrix,and the materials with electromagnetic wave loss,such as reduced graphene oxide,Carbonyl Iron(CI),and Flake CI(FCI),were used as *** on the theory of impedance matching,a wave-absorbing structure with a gradual impedance gradient was designed and *** test results showed that at the 2.0–18.0 GHz frequency band,the coverage rate of the effective absorption bandwidth was up to 72.0%,the average optimal reflectivity was–18.09 dB,and the wide-angle absorption range was 0°–30°.The advantages of additive manufacturing technology in designing and fabricating wave-absorbing structures are presented,demonstrating that the technology is an effective method for creating broadband absorbing structures.

关键词： Absorption performance Additive manufacturing Electromagnetic absorption PEEK composite materials Gradual structure Broadband absorption

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Application of surfactant for improving leaching process of weathered crust elution-deposited rare earth ores

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Journal of Rare Earths 2024年第1期42卷 181-190,I0007页

作者： Fang Zhou Lisen Zhang Zhiwei Wang Yixin Zhang Ru'an chi Xiaoyan Wu Key Laboratory for Green Chemical Process of Ministry of Education Wuhan Institute of TechnologyWuhan430073China

Weathered crust elution-deposited rare earth ores(WREOs)in china are the main source of medium and heavy rare earths in the *** order to improve the seepage and the mass transfer of traditional ammonium salt leaching process of WREOs,surfactants were added in the ammonium sulfate leaching solution and the ammonium chloride leaching *** leaching kinetics,the mass transfer process,and the adhesion work reduction factor calculated from the interfacial properties were studied to reveal the strengthening mechanism of *** the presence of the tested five surfactants,cetyl trimethyl ammonium bromide(CTAB),dodecyl trimethyl ammonium bromide(DTAB),sodium dodecyl sulfate(SDS),sodium oleate and oleic acid,the permeability of WREOs is improved,the rare earth(RE)leaching efficiency increase and the impurity aluminum(Al)leaching efficiency decrease,indicating its promotional effect on the leaching process of ***,CTAB shows a better leaching enhancement,and the optimal addition dosage is 0.4 g/L for the two ammonium salt leaching agent *** kinetics analysis shows the internal diffusion controls model of RE and Al leaching process,and the leaching kinetics equations of RE and Al related to CTAB concentration were obtained for the two ammonium salt leaching *** to the chromatographic plate theory,the mass transfer efficiency of RE increases with the CTAB concentration increasing until 0.4 g/L,which confirms that the optimal CTAB addition is 0.4 g/*** adhesion work and adhesion work reduction factor indicate more favorable permeation as well as the leaching process.

关键词： Weathered crust elution-deposited rare earth ores Surfactant Kinetics Mass transfer

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Theoretical screening of cooperative N-bridged dual-atom sites for efficient electrocatalytic nitrogen reduction with remolding insight

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Nano Research 2024年第4期17卷 3413-3422页

作者： Huimei Chen Yan Yang chi Jiao Zhiwen Zhuo Junjie Mao Yan Liu Key Laboratory of Functional Molecular Solids Ministry of EducationCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China

The electrocatalytic nitrogen reduction reaction(e-NRR)is a promising alternative method for the Haber–Bosch ***,it still faces many challenges in searching for high activity,stability,and selectivity catalysts and ascertaining the catalytic mechanism with complete ***,a series of graphene-based N-bridged dual-atom catalysts(M1-N-M2/NC)are systematically investigated via first-principle calculation and a high-throughput screening *** result unveils that N_(2) adsorption on M1-N-M2/NC in bridge-on adsorption mode can effectively break the scaling relationship on single-atom catalysts(SACs).Moreover,V-N-Ru/NC and V-N-Os/NC are systematically screened out as promising e-NRR catalysts,with extremely low limiting potentials of-0.20 and-0.18 V,***,the adsorption site competition between*N_(2) and*H,as well as the competitive twin reactions of hydrogen evolution reaction(HER)on intermediates(N_(n)H_(m))during the e-NRR process,is systematically evaluated to form a remodeling insight for the reactions in mechanism,and the e-NRR of new proposed dual-atom catalysts(DACs)is strategically optimized for its high-efficiency performance potential via our remolding insight in e-NRR *** work provides new ideas and insights for the design and mechanism of e-NRR catalysts and an effective strategy for rapidly screening highly efficient e-NRR catalysts.

关键词： nitrogen reduction dual-atom catalysts high-throughput screening hydrogen evolution reaction density functional theory calculations

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Magnetically controllable multimode interference in topological photonic crystals

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Light(Science & Applications) 2024年第5期13卷 998-1005页

作者： Weiyuan Tang Mudi Wang Shaojie Ma Che Ting chan Shuang Zhang New Cornerstone Science Laboratory Department of PhysicsThe University of Hong KongHong KongChina. Department of Physics The Hong Kong University of Science and TechnologyHong KongChina. Department of Optical Science and Engineering Fudan UniversityShanghai 200433China

Topological photonic insulators show promise for applications in compact integrated photonic circuits due to their ability to transport light robustly through sharp *** number of topological edge states relies on the difference between the bulk Chern numbers across the boundary,as dictated by the bulk edge *** interference among multiple topological edge modes in topological photonics systems may allow for controllable functionalities that are particularly desirable for constructing reconfigurable photonic *** this work,we demonstrate magnetically controllable multimode interference based on gyromagnetic topological photonic insulators that support two unidirectional edge modes with different *** successfully achieve controllable power splitting in experiments by engineering multimode interference with the magnetic field intensity or the frequency of *** work demonstrates that manipulating the interference among multiple chiral edge modes can facilitate the advancement of highly efficient and adaptable microwave devices.

关键词： multimode controllable microwave

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