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A hybrid-stress element based on Hamilton principle

Acta Mechanica Sinica 2010年第4期26卷 625-634页

作者： Song Cen Tao Zhang Chen-Feng li xiang-Rong Fu Yu-Qiu long Department of Engineering Mechanics School of Aerospace Tsinghua University Beijing 100084 China Civil and Computational Engineering Centre School of Engineering Swansea University Swansea SA2 8PP UK College of Water Conservancy and Civil Engineering China Agriculture University Beijing 100083 China Department of Civil Engineering Tsinghua University Beijing 100084 China

A novel hybrid-stress finite element method is proposed for constructing simple 4-node quadrilateral plane elements, and the new element is denoted as HH4-3fl here. Firstly, the theoretical basis of the traditional hybrid-stress elements, i.e., the Hellinger-Reissner variational principle, is replaced by the Hamilton variational principle, in which the number of the stress variables is reduced from 3 to 2. Secondly, three stress parameters and corresponding trial functions are introduced into the system equations. Thirdly, the displacement fields of the conventional bilinear isoparametric element are employed in the new models. Finally, from the stationary condition, the stress parameters can be expressed in terms of the displacement parameters, and thus the new element stiffness matrices can be obtained. Since the required number of stress variables in the Hamilton variational principle is less than that in the Hellinger-Reissner variational principle, and no additional incompatible displacement modes are considered, the new hybrid-stress element is simpler than the traditional ones. Furthermore, in order to improve the accuracy of the stress solutions, two enhanced post-processing schemes are also proposed for element HH4-3β. Numerical examples show that the proposed model exhibits great improvements in both displacement and stress solutions, implying that the proposed technique is an effective way for developing simple finite element models with high performance.

关键词： Finite element Hamilton variational principle Hybrid-stress element Post-processing schemes

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Abscisic acid negatively regulates post-penetration resistance of Arabidopsis to the biotrophic powdery mildew fungus

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Science China(life Sciences) 2017年第8期60卷 891-901页

作者： xiang Xiao Xi Cheng Kangquan Yin Huali li Jin-long Qiu State Key Laboratory of Plant Genomics Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Pytohormone abscisic acid （ABA） plays important roles in defense responses. Nonetheless, how ABA regulates plant resistance to biotrophic fungi remains largely unknown. Arabidopsis ABA-deficient mutants, aba2-1 and aba3-1, displayed enhanced resistance to the biotrophic powdery mildew fungus Golovinomyces cichoracearum. Moreover, exogenously administered ABA increased the susceptibility of Arabidopsis to G. cichoracearum. Arabidopsis ABA perception components mutants, abil-1 and abi2-1, also displayed similar phenotypes to ABA-deficient mutants in resistance to G. cichoracearum. However, the resistance to G. cichoracearum is not changed in downstream ABA signaling transduction mutants, abi3-1, abi4-1, and abi5-1. Microscopic examination revealed that hyphal growth and conidiophore production of G. cichoracearum were compromised in the ABA deficient mutants, even though pre-penetration and penetration growth of the fimgus were not affected. In addition, salicylic acid （SA） and MPK3 are found to be involved in ABA-regulated resistance to G. cichoracearurn. Our work demonstrates that ABA negatively regulates post-penetration resistance of Arabidopsis to powdery mildew fungus G. cichoracearum, probably through antagonizing the function of SA.

关键词： abscisic acid powdery mildew biotrophic fungus disease resistance salicylic acid

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基于元件组合的配电可靠性评估算法

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电气开关 2017年第3期55卷 44-46页

作者：陈军万侃余湘张进龙李嘉林国网湖北省电力公司黄冈供电公司湖北黄冈438000 国网四川省电力公司遂宁供电公司四川遂宁629000

本文对配电设备和负荷进行简化,并把配电线路分为主线、分支线和配变;采用故障扩散法定义的隔离范围来确定各网段,利用线路可靠性指标分别计算各网段的可靠性,从而计算系统的指标。

关键词：配电系统可靠性故障扩散法

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Dynamic Properties of Steel Catenary Riser near Touchdown Point Under Coplanar Vessel Heave and Vortex Induced Vibration

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China Ocean Engineering 2023年第2期37卷 288-298页

作者： ZHANG xiang-rui WANG Kun-peng JIANG Da-peng TANG Kai li Yu-long Marine Design and Research Institute of China Shanghai 200011China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 510275China

The present study establishes a simple numerical model for the coupled response of a steel catenary riser(SCR) subjected to coplanar vessel motion and vortex-induced vibration(VIV). Owing to the large deflection of the SCR, the geometric nonlinearity is considered in this model. The hydrodynamic force comprises the excitation force and hydrodynamic damping, where the excitation force that only exists when the non-dimensional frequency is located in the lock-in range, is associated with the VIV. The hydrodynamic force model is validated based on the published VIV test *** for the seabed resistance at the touchdown zone(TDZ), integrated with an initial seabed trench, the hysteretic feature is modeled. Based on the model, the study emphasizes on the coupled response characteristics near the touchdown point(TDP) induced by coplanar vessel heave and VIV, and analyzes the sensitivity of the coupled response to the heaving amplitude and frequency. It is found that with the increase of the heave amplitude and frequency, the VIV can be obviously mitigated, but the heave-related response in the coupled analysis seems to be close to that in the heave-only simulation. Finally, the fatigue damage near TDP is parametrically investigated based on the separate analysis and the coupled analysis. The results demonstrate that the coupled effect plays a significant role in the fatigue assessment near TDP. Besides, the proportion of the coupled effect accounting for the total fatigue damage decreases with the increasing seabed stiffness, while increases with the increasing seabed trench depth.

关键词： vessel heave vortex induced vibration coupled effect steel catenary riser(SCR)-seabed interaction seabed trench

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Targeting epigenetic mechanisms in amyloid-β-mediated Alzheimer’s pathophysiology:unveiling therapeutic potential

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Neural Regeneration Research 2025年第1期20卷 54-66页

作者： Jennie Z.li Nagendran Ramalingam Shaomin li Ann Romney Center for Neurologic Diseases Brigham and Women’s Hospital and Harvard Medical SchoolBostonMAUSA

Alzheimer’s disease is a prominent chronic neurodegenerative condition characterized by a gradual decline in memory leading to *** evidence suggests that Alzheimer’s disease is associated with accumulating various amyloid-βoligomers in the brain,influenced by complex genetic and environmental *** memory and cognitive deficits observed during the prodromal and mild cognitive impairment phases of Alzheimer’s disease are believed to primarily result from synaptic *** life,environmental factors can lead to enduring changes in gene expression and the emergence of brain *** changes,known as epigenetic modifications,also play a crucial role in regulating the formation of synapses and their adaptability in response to neuronal *** this context,we highlight recent advances in understanding the roles played by key components of the epigenetic machinery,specifically DNA methylation,histone modification,and microRNAs,in the development of Alzheimer’s disease,synaptic function,and activity-dependent synaptic ***,we explore various strategies,including enriched environments,exposure to non-invasive brain stimulation,and the use of pharmacological agents,aimed at improving synaptic function and enhancing long-term potentiation,a process integral to epigenetic ***,we deliberate on the development of effective epigenetic agents and safe therapeutic approaches for managing Alzheimer’s *** suggest that addressing Alzheimer’s disease may require distinct tailored epigenetic drugs targeting different disease stages or pathways rather than relying on a single drug.

关键词： Alzheimer’s disease DNA methylation enriched environments histone modification microRNAs non-invasive brain stimulation synaptic plasticity

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Epigenetic regulation of the inflammatory response in stroke

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Neural Regeneration Research 2025年第11期20卷 3045-3062页

作者： Jingyi liang Fei Yang Zixiao li Qian li School of Basic Medical Sciences Capital Medical UniversityBeijingChina Department of Neurobiology School of Basic Medical SciencesCapital Medical UniversityBeijingChina Laboratory for Clinical Medicine Beijing Key Laboratory of Neural Regeneration and RepairCapital Medical UniversityBeijingChina Department of Neurology Beijing Tiantan HospitalCapital Medical UniversityBeijingChina China National Clinical Research Center for Neurological Diseases Beijing Tiantan HospitalCapital Medical UniversityBeijingChina National Center for Healthcare Quality Management in Neurological Diseases Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Chinese Institute for Brain Research BeijingChina Research Unit of Artificial Intelligence in Cerebrovascular Disease Chinese Academy of Medical SciencesBeijingChina Beijing Engineering Research Center of Digital Healthcare for Neurological Diseases BeijingChina Department of Biochemistry and Molecular Biology School of Basic Medical SciencesCapital Medical UniversityBeijingChina Beijing Key Laboratory of Cancer Invasion and Metastasis Research Capital Medical UniversityBeijingChina

Stroke is classified as ischemic or hemorrhagic,and there are few effective treatments for either *** mechanisms play a critical role in secondary brain injury following a stroke,which manifests as cytokine release,blood–brain barrier disruption,neuronal cell death,and ultimately behavioral *** the inflammatory response has been shown to mitigate this cascade of events in experimental stroke ***,in clinical trials of anti-inflammatory agents,longterm immunosuppression has not demonstrated significant clinical benefits for *** may be attributable to the dichotomous roles of inflammation in both tissue injury and repair,as well as the complex pathophysiologic inflammatory processes in *** acute harmful inflammatory responses or inducing a phenotypic shift from a pro-inflammatory to an anti-inflammatory state at specific time points after a stroke are alternative and promising therapeutic *** agents that can modulate inflammation requires a detailed understanding of the inflammatory processes of ***,epigenetic reprogramming plays a crucial role in modulating post-stroke inflammation and can potentially be exploited for stroke *** this review,we summarize current findings on the epigenetic regulation of the inflammatory response in stroke,focusing on key signaling pathways including nuclear factor-kappa B,Janus kinase/signal transducer and activator of transcription,and mitogen-activated protein kinase as well as inflammasome *** also discuss promising molecular targets for stroke *** evidence to date indicates that therapeutic targeting of the epigenetic regulation of inflammation can shift the balance from inflammation-induced tissue injury to repair following stroke,leading to improved post-stroke outcomes.

关键词： DNA methylation histone modification intracerebral hemorrhage ischemic stroke neuroinflammation neuroprotection non-coding RNA RNA methylation subarachnoid hemorrhage treatment

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Theoretical research on gas seepage in the formations surrounding bedded gas storage salt cavern

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Petroleum Science 2022年第4期19卷 1766-1778页

作者： xiang-Sheng Chen Yin-Ping li Ya-long Jiang Yuan-Xi liu Tao Zhang State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013Jiangxi China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071 HubeiChina University of Chinese Academy of Sciences Beijing 100049China

When constructing salt cavern gas or petroleum storage in lacustrine sedimentary salt formations rich in mudstone interlayers, the influence of the sealing performance of interlayers and salt-mud interface on the storage tightness should be considered adequately. In order to reveal the gas seepage in deep formations surrounding bedded salt cavern underground storage, a leakage analysis model was established based on the characteristics of a low dip angle and the interbedded structure of bedded rock salt. The gas seepage governing equations for one-dimensional and plane radial flow were derived and solved. A gas seepage simulation experiment was conducted to demonstrate the accuracy and reliability of the theoretical calculation results. The error of the seepage range was approximately 6.70%, which is acceptable. The analysis and calculation results indicate that the motion equation of gas in deep formations satisfies a non-Darcy's law with a threshold pressure gradient and slippage effect. The sufficient condition for the gas flow to stop is that the pressure gradient is equal to the threshold pressure *** relationship between the leakage range and operating time is a positive power function, that is, the leakage range gradually increases with time and eventually stabilizes. As the seepage range increases, the seepage pressure decreases sharply during the early stage, and then decreases gradually until the flow *** the research results with engineering applications, three quantitative evaluation indexes named the maximum admissible leakage range, leakage volume and leakage rate are proposed for the tightness evaluation of gas storage salt cavern during their operating stage. These indexes can be used directly in actual engineering applications and can be compared with the key design parameters stipulated in the relevant specifications. This work is expected to provide theoretical and technical support for the gas loss and tightness evaluation of

关键词： Gas storage salt cavern Seepage Tightness Non-Darcy's law Leakage

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Soil contamination with antibiotics in a typical peri-urban area in eastern China: Seasonal variation, risk assessment, and microbial responses

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Journal of Environmental Sciences 2019年第5期31卷 200-212页

作者： Fangkai Zhao Lei Yang liding Chen Qian xiang Shoujuan li long Sun Xinwei Yu li Fang State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province Zhoushan Municipal Center For Disease Control and Prevention

The prevalence and persistence of antibiotics in soils has become an emerging environmental issue and an increasing threat to soil security and global public health. The problem is more severe in areas undergoing rapid urbanization; however, the ecological risks of antibiotics,seasonal variability, and associated soil microbial responses in peri-urban soils have not been well-explored. The seasonal soil sampling campaigns were conducted in a typical peri-urban watershed in eastern China to investigate distribution of antibiotics. The results demonstrated higher mean concentrations of most antibiotic compounds in winter than in summer in periurban soils. The seasonal variations of norfloxacin, enrofloxacin, and ciprofloxacin were more significant than those of other antibiotics, due to their higher migration ability and *** ecological risk assessment demonstrated that chlortetracycline, ciprofloxacin, doxycycline,and ofloxacin can pose high risks to soil microorganisms. Furthermore, the coexistence of multiple antibiotics obviously poses higher risks than individual compounds. A redundancy analysis demonstrated that tetracyclines mainly showed negative correlations with Firmicutes and Chloroflexi, and quinolones showed obviously negative correlations with Acidobacteria,Gemmatimonadetes, and Nitrospirae, suggesting potential inhibition from antibiotics on biological activities or biodegradation processes. However, the persistence of antibiotics in soil results in a significant decrease in bacterial diversity and a change in dominant *** results provide an overview of the seasonal variability of antibiotics and the associated effects on bacterial communities in peri-urban soils. The results can provide scientific guidance on decreasing soil contamination with antibiotics to enhance soil security in similar areas.

关键词： Antibiotics Soil Seasonal variation Ecological risks Bacterial community

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Design strategies of performance-enhanced Se cathodes for li-Se batteries and beyond

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Journal of Energy Chemistry 2023年第1期76卷 528-546,I0013页

作者： Weiling Qiu xiang long Huang Ye Wang Chi Feng Haining Ji Hua Kun liu Shi Xue Dou Zhiming Wang Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054SichuanChina Institute for Superconducting and Electronic Materials Australian Institute for Innovative MaterialsUniversity of WollongongNSW 2500Australia School of Materials and Energy.University of Electronic Science and Technology of China Chengdu 610054SichuanChina Institute for Advanced Study Chengdu UniversityChengdu 610106SichuanChina Institute of Energy Materials Science University of Shanghai for Science and TechnologyShanghai 200093China

lithium-selenium(li-Se)batteries are deemed as an emerging high energy density electrochemical energy storage system owing to their high specific capacity and volume *** to their practicality,a series of critical challenges from the Se cathode side need to be overcome including low reactivity of bulk Se,shuttle effect of intermediates,sluggish redox kinetics of polyselenides,and volume change *** this review,recent progress on design strategies of functional Se cathodes are comprehensively summarized and *** the significance and key challenges,various efficient functionalized strategies for Se cathodes are presented,encompassing covalent bonding,nanostructure construction,heteroatom doping,component hybridization,and solid solution ***,the universality of these functional strategies are successfully extended into Na-Se batteries,K-Se batteries,and Mg-Se *** last,a brief summary is made and some perspectives are offered with the goal of guiding future research advances and further exploration of these strategies.

关键词： Metal-selenium batteries Se cathodes Carbons Nanostructure Materials design

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Enhancing li cycling coulombic efficiency while mitigating “shuttle effect” of li-S battery through sustained release of liNO_(3)

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Journal of Energy Chemistry 2023年第9期84卷 22-29页

作者： Qi Jin Kaixin Zhao lili Wu Lu li long Kong Xitian Zhang Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal UniversityHarbin 150025HeilongjiangChina Frontiers Science Center for Flexible Electronics and Xi’an Institute of Flexible Electronics(IFE) Northwestern Polytechnical UniversityXi’an 710129ShaanxiChina

In practical lithium-sulfur batteries(LSBs),the shuttle effect and li cycling coulombic efficiency(CE) are strongly affected by the physicochemical properties of solid electrolyte interphase(SEI).liNO_(3) is widely used as an additive in electrolytes to build a high-quality SEI,but its self-sacrificial nature limits the ability to mitigate the shuttle effect and stabilize li anode during long-term *** counteract liNO_(3) consumption during long-term cycling without using a high initial concentration,inspired by sustainedrelease drugs,we encapsulated liNO_(3) in lithiated Nafion polymer and added an electrolyte co-solvent(1,1,2,2-tetrafluoroethylene 2,2,2-trifluoromethyl ether) with poor liNO_(3) solubility to construct highquality and durable F-and N-rich *** calculations,experiments,multiphysics simulations,and in-situ observations confirmed that the F-and N-rich SEI can modulate lithium deposition behavior and allow persistent repair of SEI during prolonged ***,the F-and N-rich SEI improves the li anode cycling CE to 99.63% and alleviates the shuttle effect during long-term *** lithium anode with sustainable F-and N-rich SEI shows a stable li plating/stripping over 2000 h at 1 mA cm^(-2).As expected,li‖S full cells with this SEI achieved a long lifespan of 250 cycles,far exceeding cells with a routine *** li‖S pouch cell based on F-and N-rich SEI also can achieve a high energy density of about300 Wh kg^(-1) at initial *** strategy provides a novel design for high-quality and durable SEls in LSBs and may also be extendable to other alkali metal batteries.

关键词： lithium-sulfur battery Solid electrolyte interphase liNO_(3) Coulombic efficiency Shuttle effect

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