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Decentralized Primary Frequency Regulation for Hybrid Multi-terminal Direct Current Power Systems Considering Multi-source Enhancement

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 958-970页

作者： Jialiang Wu Zhen Wang Ruixu Liu yu.shan Chenxuan Wang the College of Electrical Engineering Zhejiang UniversityHangzhou 310027China the Economic Research Institute of State Grid Zhejiang Electric Power Co. Ltd.Hangzhou 310016China

Hybrid multi-terminal direct current(MTDC)transmission technology has been a research focus,and primary frequency regulation(FR)improvement in the receiving-end system is one of the problems to be *** paper presents a decentralized primary FR scheme for hybrid MTDC power systems considering multi-source enhancement to help suppress frequency disturbance in the receiving-end *** the converters only need local frequency or DC voltage signal input to respond to system disturbance without communication or a control center,i.e.,a decentralized control *** proposed scheme can activate appropriate power sources to assist in FR in various system disturbance severities with fine-designed thresholds,ensuring sufficient utilization of each power *** better balance FR performance and FR resource participation,an evaluation index is proposed and the parameter optimization problem is further ***,the validity of the proposed scheme is verified by simulations in MATLAB/Simulink.

关键词： Decentralized control scheme primary frequency regulation(FR) rate of change of frequency(ROCOF) system frequency disturbance

Polymer-to-Monomers Chemically Recyclable Poly(imide-imine)Plastics with Extreme-Condition Resistance and Flame Retardancy

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Chinese Journal of Polymer Science 2024年第10期42卷 1525-1535,I0012页

作者： Zhen-yu.Wang xiao-Kong Liu State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun130012China

Polyimides are a family of high-tech plastics that have irreplaceable applications in the fields of aerospace,defense,and opto-electronics,but polyimides are difficult to be reprocessed and recycled at the end of their service life,resulting in a significant waste of ***,it is of great significance to develop recyclable polyimides with comparable properties to the commercial ***,we report a novel polymer-to-monomers chemically recyclable poly(imide-imine)(PtM-CR-PII)plastic,synthesized by cross-linking the amine-terminated aromatic bisimide monomer and the hexa-vanillin terminated cyclophosphazene monomer via dynamic imine *** PtM-CR-PII plastic exhibits comparable mechanical and thermal properties as well as chemical stability to the commercial *** PtM-CR-PII plastic possesses a high Young’s modulus of≈3.2 GPa and a tensile strength as high as≈108 MPa,which also exhibits high thermal stability with a glass transition temperature of≈220℃.Moreover,the PtM-CR-PII plastic exhibits outstanding waterproofness,acid/alkali-resistance,and solvent-resistance,its appearance and mechanical properties can be well maintained after long-term soaking in water,highly concentrated acid and base,and various organic ***,the cyclophosphazene moieties endow the PtM-CR-PII plastic with excellent flame *** PtM-CR-PII plastic exhibits the highest UL-94 flame-retarding rating of V-0 and a limiting oxygen index(LOI)value of 45.5%.Importantly,the PtM-CR-PII plastic can be depolymerized in an organic solvents-acid mixture medium at room temperature,allowing easy separation and recovery of both monomers in high *** recovered pure monomers can be used to regenerate new PtM-CR-PII plastics,enabling sustainable polymer-monomers-polymer circulation.

关键词： Chemical recyclability Polyimides Polyimines Dynamic imine bonds Mechanical properties Chemical stability

Direct numerical simulation of shock wave/boundary layer interaction controlled by steady microjet in a compression ramp

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Chinese Journal of Aeronautics 2024年第10期37卷 83-102页

作者： Ruoye xiao Dong SUN Jian yu School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Aerodynamics Mianyang 621000China

Shock wave/boundary layer interaction in a 24°turning angle of the compression ramp at Mach number 2.9 controlled by steady microjet is investigated using direct numerical *** different jet spacings which are termed as sparse,moderate and dense are considered,and the induced vortex system and shock structures are compared.A moderate jet spacing configuration is found to generate counter-rotating vortex pairs that transport high-momentum fluid towards the vicinity of wall and strengthen the boundary layer to resist separation,reducing the separation *** dense jet spacing configuration creates a larger momentum deficit region,reducing the friction downstream of the *** of pressure and pressure gradient reveals that dense jet spacing configuration reduces the intensity of separation *** impact of varying jet spacings on the turbulent kinetic energy transport mechanism is also investigated by decomposing the budget terms in the transport ***,the spectral characteristics of the separation region are studied using power spectral density and dynamic mode decomposition methods,revealing that moderate jet spacing configuration suppresses low-frequency fluctuations in the separation region.

关键词： Shock wave/boundary layer interaction Compression ramp Steady microjet Different jet spacings Direct numerical simulation

Thermodynamic nature of black holes in coexistence region

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： Shao-Wen Wei yu.xiao Liu Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of Theoretical Physics&Research Center of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a thermodynamic ***,there is no effective method to study thermodynamic nature of the coexistence black hole regions for the failure of the equation of *** at these coexistence states,in this work,we develop a general approach by introducing two new ratio *** first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule *** demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase *** study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and *** results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. thermodynamic

Data-driven modeling on anisotropic mechanical behavior of brain tissue with internal pressure

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Defence Technology（防务技术） 2024年第3期33卷 55-65页

作者： Zhiyu.n Tang yu.Wang Khalil I.Elkhodary Zefeng yu.shan Tang Dan Peng State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of Technology116023DalianPR China The Department of Mechanical Engineering The American University in CairoNew Cairo11835Egypt Department of Neurology The Second Hospital of Dalian Medical UniversityDalian116023PR China

Brain tissue is one of the softest parts of the human body,composed of white matter and grey *** mechanical behavior of the brain tissue plays an essential role in regulating brain morphology and brain ***,traumatic brain injury(TBI)and various brain diseases are also greatly influenced by the brain's mechanical *** white matter or grey matter,brain tissue contains multiscale structures composed of neurons,glial cells,fibers,blood vessels,etc.,each with different mechanical *** such,brain tissue exhibits complex mechanical behavior,usually with strong nonlinearity,heterogeneity,and directional *** a constitutive law for multiscale brain tissue using traditional function-based approaches can be very ***,this paper proposes a data-driven approach to establish the desired mechanical model of brain *** focus on blood vessels with internal pressure embedded in a white or grey matter matrix material to demonstrate our *** matrix is described by an isotropic or anisotropic nonlinear elastic model.A representative unit cell(RUC)with blood vessels is built,which is used to generate the stress-strain data under different internal blood pressure and various proportional displacement loading *** generated stress-strain data is then used to train a mechanical law using artificial neural networks to predict the macroscopic mechanical response of brain tissue under different internal ***,the trained material model is implemented into finite element software to predict the mechanical behavior of a whole brain under intracranial pressure and distributed body *** with a direct numerical simulation that employs a reference material model,our proposed approach greatly reduces the computational cost and improves modeling *** predictions made by our trained model demonstrate sufficient ***,we find that the level of internal blood pressur

关键词： Data driven Constitutive law Anisotropy Brain tissue Internal pressure

Cable-driven legged landing gear for unmanned helicopter:Prototype design,optimization and performance assessment

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Science China(Technological Sciences) 2024年第4期67卷 1196-1214页

作者： TIAN BaoLin GAO HaiBo yu.HaiTao shan HaoMin HOU JunChen yu.HongYing DENG ZongQuan State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China China Academy of Aerospace Science and Innovation Beijing 100048China

Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging *** study presents a novel cable-driven legged landing gear(CLG)with differential transmission for unmanned helicopters in complex landing *** obtain the preferred configuration of the legged mechanism,a multi-objective optimization framework for the CLG is constructed by concurrently considering terrain adaptability,landing stability and reasonable linkage of internal *** non-dominated sorting genetic algorithmⅡis employed to numerically acquire the optimal scale parameters that guide the mechanical design of the *** unmanned helicopter prototype equipped with the devised CLG is developed with key performance *** results show that the devised CLG can provide energy-efficient support over uneven terrains(totally driven torque demand less than 0.1 N m)in quasi-static landing tests,and favorable terrain adaptability(posture fluctuation of the fuselage less than±1°)in unknown slope landing *** exhibited merits give the proposed CLG the potential to enhance the landing performance of future aircraft in extreme environments.

关键词： unmanned helicopter adaptive landing gear experimental verification

Network meta-analysis of combination strategies in metastatic hormone-sensitive prostate cancer

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Asian Journal of Andrology 2024年第4期26卷 402-408页

作者： shan-shan Wang xiao-Jie Bian Jun-Long Wu Bei-He Wang Sheng Zhang Ding-Wei Ye Department of Urology Fudan University Shanghai Cancer CenterShanghai 200032China Department of Oncology Shanghai Medical CollegeFudan UniversityShanghai 200032China Department of Medical Oncology Fudan University Shanghai Cancer CenterShanghai 200032China.

This study compared different doublet and triplet therapies for efficacy and safety in metastatic hormone-sensitive prostate cancer(mHSPC).PubMed,EMBASE,and the Cochrane Library were comprehensively searched for eligible randomized controlled trials(RCTs)published from inception to October *** included abiraterone,apalutamide,enzalutamide,docetaxel,darolutamide,and androgen deprivation therapy(ADT),either as doublet or triplet *** outcomes examined were overall survival(OS),progression-free survival(PFS),castration-resistant prostate cancer(CRPC)-free survival,time to symptomatic skeletal event(SSE),and *** surface under the cumulative ranking curve(SUCRA)was determined to identify the preferred *** RCTs were *** combination of darolutamide,docetaxel,and ADT had the highest SUCRA of 84.3 for OS,followed by combined abiraterone,docetaxel,and ADT(SUCRA=71.6).The highest SUCRAs for PFS were observed for triplet therapies(abiraterone,docetaxel,and ADT[SUCRA=74.9],followed by enzalutamide,docetaxel,and ADT[SUCRA=74.3])and other androgen receptor axis-targeted therapy-based doublet therapies(SUCRAs:26.5–59.3).Darolutamide,docetaxel,and ADT had the highest SUCRAs,i.e.,80.8 and 84.0 regarding CRPC-free survival and time to SSE,*** Grade>3 adverse events(AEs),the SUCRAs of triplet therapies(SUCRAs:14.8–31.5)were similar to that of docetaxel and ADT(SUCRA=39.5).Three studies had a low risk of bias in all categories;the remaining studies had at least an unclear risk of bias in at least one *** therapy demonstrated potentially enhanced effectiveness than doublet therapy in mHSPC,with acceptable safety *** might be the optimal option for triplet therapy in combination with docetaxel and ADT.

关键词： androgen antagonist androgen receptor antagonist docetaxel meta-analysis prostatic neoplasm

Oleuropein alleviates sepsis-induced acute lung injury via the AMPK/Nrf-2/HO-1 signaling

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Asian Pacific Journal of Tropical Biomedicine 2024年第5期14卷 187-198页

作者： shan-Hu Wang Yang-Yang Wu xiao-Jiao Xia Department of Pediatrics The Second Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang 325027China

Objective:To explore the effect of oleuropein on sepsis-induced acute lung injury(ALI)in vitro and in vivo and investigate the underlying ***:In an lipopolysaccharide(LPS)-mediated cell model of sepsis-induced ALI and a cecal ligation and puncture-induced mouse model of septic ALI,CCK-8 assay and flow cytometry analysis were used to detect cell activity and *** and relevant assay kits were used to measure the levels of inflammatory cytokines and oxidative stress,*** blot was applied to determine the expression of apoptosis-and AMP-activated protein kinase(AMPK)/nuclear factor erythroid 2-related factor-2(Nrf-2)/heme oxygenase-1(HO-1)signaling-associated ***-1 staining,adenosine triphosphate(ATP)assay kit,and MitoSOX Red assays were performed to detect mitochondrial membrane potential,ATP content,and mitochondrial ROS formation,***,lung injury was evaluated by measuring lung morphological alternations,lung wet-to-dry ratio,myeloperoxidase content,and total protein ***:Oleuropein reduced inflammatory reaction,oxidative damage,and apoptosis,and ameliorated mitochondrial dysfunction in LPS-exposed BEAS-2B cells and mice with septic ***,oleuropein activated the AMPK/Nrf-2/HO-1 signaling ***,these effects of oleuropein were abrogated by an AMPK inhibitor compound ***:Oleuropein can protect against sepsis-induced ALI in vitro and in vivo by activating the AMPK/Nrf-2/HO-1 signaling,which might be a potential therapeutic agent for the treatment of sepsis-induced ALI.

关键词： AMPK/Nrf-2/HO-1 signaling Inflammatory response Lung damage Mitochondrial dysfunction Oleuropein Oxidative stress Sepsis

Embracing the age of artificial intelligence:paradigm shifts,opportunities,and challenges in the treatment of acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

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Science China(Life Sciences) 2024年第6期67卷 1302-1304页

作者： Zhuo-yu.An xiao-Hui Zhang Peking University People’s Hospital Peking University Institute of HematologyBeijing 100044China Collaborative Innovation Center of Hematology Peking UniversityBeijing 100044China Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation Beijing 100044China National Clinical Research Center for Hematologic Disease Beijing 100044China

Allogeneic hematopoietic stem cell transplantation(allo-HSCT)is an important medical development in treating hematological ***,the risk of acute graft-versus-host disease(a GVHD)severely limits its use.a GVHD is a sev... 详细信息

关键词： hematopoietic graft artificial