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Applied mathematics and Mechanics(English Edition) 2020年第5期41卷 805-818页

作者： Weichao CHI s.j.ma j.Q.sUN College of science Northeastern UniversityShenyang 100819China Key Laboratory of Ministry of Education on safe Mining of Deep Metal Mines Northeastern UniversityShenyang 100819China Department of Mechanical Engineering School of EngineeringUniversity of CaliforniaMercedCA 95343U.S.A.

The hybrid vibration isolation, which takes advantages of both the passive and active approaches, has been an important solution for space missions. The objective of this paper is to design a vibration isolation platform for payloads on spacecrafts with the robust, wide bandwidth, and multi-degree-of-freedom(MDOF). The proposed solution is based on a parallel mechanism with six voice-coil motors(VCMs) as the actuators. The linear active disturbance resistance control(LADRC) algorithm is used for the active control. Numerical simulation results show that the vibration isolation platform performs effectively over a wide bandwidth, and the resonance introduced by the passive isolation is eliminated. The system robustness to the uncertainties of the structure is also verified by simulation.

关键词： hybrid vibration isolation stewart platform linear active disturbance rejection control(LADRC) stability robustness

Universal insertion of molecules in ionic compounds under pressure

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National science Review 2024年第1期11卷 120-128页

作者： Feng Peng Yanming ma Chris j.Pickard Hanyu Liu maosheng Miao College of Physics and Electronic Information Luoyang Normal University Department of Chemistry and Biochemistry California State University Northridge state Key Laboratory of superhard materials & Key Laboratory of material simulation Methods and software of Ministry of Education College of Physics Jilin University International Center of Future science Jilin University Department of materials science & Metallurgy University of Cambridge Advanced Institute for materials Research Tohoku University Department of Earth science University of California Santa Barbara

Using first-principles calculations and crystal structure search methods, we found that many covalently bonded molecules such as H2, N2, CO2, NH3, H2O and CH4may react with NaC l, a prototype ionic solid,and form stable compounds under pressure while retaining their molecular structure. These molecules,despite whether they are homonuclear or heteronuclear, polar or non-polar, small or large, do not show strong chemical interactions with surrounding Na and Cl ions. In contrast, the most stable molecule among all examples, N2, is found to transform into cyclo-N5-anions while reacting with NaC l under high pressures. It provides a new route to synthesize pentazolates, which are promising green energy materials with high energy density. Our work demonstrates a unique and universal hybridization propensity of covalently bonded molecules and solid compounds under pressure. This surprising miscibility suggests possible mixing regions between the molecular and rock layers in the interiors of large planets.

关键词： molecule-solid hybrid materials high-pressure crystal structure prediction density functional theory planet interior

Uniform decomposition of velocity gradient tensor

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journal of Hydrodynamics 2024年第1期36卷 24-34页

作者： Chenxi ma Chaoqun Liu Department of mathematics University of Texas at ArlingtonArlingtonTXUSA

In this paper,the principal decomposition of the velocity gradient tensor[∇v]is discussed in 3 cases based on the discriminant∆:∆0 with 3 distinct real eigen values,and∆=0 with 1 or 2 distinct real eigen *** velocity ... 详细信息

In this paper,the principal decomposition of the velocity gradient tensor[∇v]is discussed in 3 cases based on the discriminant∆:∆jugate complex eigen values,∆>0 with 3 distinct real eigen values,and∆=0 with 1 or 2 distinct real eigen *** velocity gradient tensor can also be classified as rotation point,which can be decomposed into three parts,i.e.,rotation[R],shear[s]and stretching/compression[sC],and non-rotation point,we defined a new resistance term[L],and the tensor can be decomposed into three parts,i.e.,resistance[L],shear[s]and stretching/compression[sC].Example matric are also displayed to demonstrate the new *** of principal decomposition between 3 different cases,and between Resistance and Liutex will also be discussed.

关键词： Velocity gradient Liutex resistance fluid kinematics

Generalized Hopf Bifurcation in a Delay Model of Neutrophil Cells Model

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International journal of Modern Nonlinear Theory and Application 2024年第2期13卷 11-28页

作者： suqi ma s. j. Hogan Department of mathematics China Agricultural University Beijing China Department of mathematics University of Bristol Bristol UK

The DDE-Biftool software is applied to solve the dynamical stability and bifurcation problem of the neutrophil cells model. Based on Hopf point finding with the stability property of the equilibrium solution loss, the continuation of the bifurcating periodical solution starting from Hopf point is exploited. The generalized Hopf point is tracked by seeking for the critical value of free parameter of the switching phenomena of the open loop, which describes the lineup of bifurcating periodical solutions from Hopf point. The normal form near the generalized Hopf point is computed by Lyapunov-schimdt reduction scheme combined with the center manifold analytical technique. The near dynamics is classified by geometrically different topological phase portraits.

关键词： Generalized Hopf Bifurcation DDE-Biftool software Norm Form

Potential secretory Transporters and Biosynthetic Precursors of Biological Nitrification Inhibitor 1,9-Decanediol in Rice as Revealed by Transcriptome and Metabolome Analyses

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Rice science 2024年第1期31卷 87-102页

作者： DI Dongwei ma Mingkun ZHANG Xiaoyang LU Yufang Herbert j.KRONZUCKER sHI Weiming state Key Laboratory of soil and sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China school of Food science and Engineering Foshan UniversityFoshan 528000China school of Biosciences The University of MelbourneParkvilleVIC 3010Australia University of Chinese Academy of sciences Beijing 100049China

Biological nitrification inhibitors(BNIs)are released from plant roots and inhibit the nitrification activity of microorganisms in soils,reducing NO_(3)^(‒)leaching and N2O emissions,and increasing nitrogenuse efficiency(NUE).several recent studies have focused on the identification of new BNIs,yet little is known about the genetic loci that govern their biosynthesis and *** applied a combined transcriptomic and metabolomic analysis to investigate possible biosynthetic pathways and transporters involved in the biosynthesis and release of BNI 1,9-decanediol(1,9-D),which was previously identified in rice root *** results linked four fatty acids,icosapentaenoic acid,linoleate,norlinolenic acid,and polyhydroxy-α,ω-divarboxylic acid,with 1,9-D biosynthesis and three transporter families,namely the ATP-binding cassette protein family,the multidrug and toxic compound extrusion family,and the major facilitator superfamily,with 1,9-D release from roots into the soil *** finding provided candidates for further work on the genes implicated in the biosynthesis and secretion of 1,9-D and pinpoint genetic loci for crop breeding to improve NUE by enhancing 1,9-D secretion,with the potential to reduce NO_(3)^(‒)leaching and N2O emissions from agricultural soils.

关键词： 1,9-decanediol biological nitrification inhibitor metabolomic analysis nitrogen-use efficiency transcriptomic analysis

Numerical investigation on characteristics of interfacial wave of liquid film in gas-liquid two-phase flow using OpenFOAM

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Chinese journal of Aeronautics 2024年第2期37卷 233-248页

作者： Xiaoqi ma Yueshe WANG jiaming TIAN state Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Liquid film cooling as an advanced cooling technology is widely used in space *** operation of liquid film along the rocket combustion inner wall is crucial for thermal protection of rocket *** stability of liquid film is mainly determined by the characteristics of interfacial wave,which is rarely investigated right *** to improve the stability of thin film has become a hot *** view of this,an advanced model based on the conventional Volume of Fluid(VOF)model is adopted to investigate the characteristics of interfacial wave in gas-liquid flow by using OpenFOAM,and the mechanism of formation and development of wave is revealed intuitively through numerical *** effects from gas velocity,surface tension and dynamic viscosity of liquid(three factors)on the wave are studied *** can be found that the gas velocity is critical to the formation and development of wave,and four modes of droplets generation are illustrated in this ***,a gas vortex near the gas-liquid interface can induce formation of wave easily,so changing the gas vortex state can regulate formation and development of ***’s more,the change rules of three factors influencing on the interfacial wave are obtained,and the surface tension has a negative effect on the formation and development of wave only when the surface tension coefficient is above the critical value,whereas the dynamic viscosity has a positive effect in this ***,the maximum height and maximum slope angle of wave will level off as the gas velocity ***,the maximum slope angle of wave is usually no more than 38°,no matter what happens to the three factors.

关键词： Interfacial wave Gas-liquid Two-phase flow VOF model OpenFOAM

Transient Response and Ionic Dynamics in Organic Electrochemical Transistors

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Nano-Micro Letters 2024年第11期16卷 191-223页

作者： Chao Zhao jintao Yang Wei ma state Key Laboratory for Mechanical Behavior of materials Xi’an Jiaotong UniversityXi′an 710049People’s Republic of China

The rapid development of organic electrochemical transistors(OECTs)has ushered in a new era in organic electronics,distinguishing itself through its application in a variety of domains,from high-speed logic circuits to sensitive biosensors,and neuromorphic devices like artificial synapses and organic electrochemical random-access *** recent strides in enhancing OECT performance,driven by the demand for superior transient response capabilities,a comprehensive understanding of the complex interplay between charge and ion transport,alongside electron–ion interactions,as well as the optimization strategies,remains *** review aims to bridge this gap by providing a systematic overview on the fundamental working principles of OECT transient responses,emphasizing advancements in device physics and optimization *** review the critical aspect of transient ion dynamics in both volatile and non-volatile applications,as well as the impact of materials,morphology,device structure strategies on optimizing transient *** paper not only offers a detailed overview of the current state of the art,but also identifies promising avenues for future research,aiming to drive future performance advancements in diversified applications.

关键词： Organic electrochemical transistors Transient response Ion dynamics Electronic dynamics Volatility and non-volatility

Extreme precipitation detection ability of four high-resolution precipitation product datasets in hilly area:a case study in Nepal

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Advances in Climate Change Research 2024年第3期15卷 390-405页

作者： sunil subba Yao-Ming ma Wei-Qiang ma Cun-Bo Han Land-Atmosphere Interaction and its Climatic Effects Group State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China College of Earth and Planetary sciences University of Chinese Academy of SciencesBeijing 100049China College of Atmospheric science Lanzhou UniversityLanzhou 730000China National Observation and Research station for Qomolongma special Atmospheric Processes and Environmental Changes Dingri 858200China Kathmandu Center of Research and Education Chinese Academy of SciencesBeijing 100101China China-Pakistan joint Research Center on Earth sciences Chinese Academy of SciencesIslamabad 45320Pakista

Given Nepal's vulnerability to extreme precipitation(EP),it is imperative to conduct a comprehensive analysis to comprehend the historical trends of such ***,acquiring precise precipitation data for EP remains challenging in mountainous countries like Nepal owing to the scarcity of densely gauged *** limitation impedes the dissemination of knowledge pertaining to EP variability events in *** current research on this topic is deficient for two main reasons:1)there is a lack of studies leveraging recently released high-resolution precipitation products to identify their EP detection capabilities,which further hinders the usability of those products in data-scarce regions like Nepal,and 2)most studies have focused on the characterisation of EP events in Nepal rather than their spatial and temporal *** address these issues,this study evaluated the EP detection capabilities of four high-resolution precipitation product datasets(PPDs)across Nepal from 1985 to *** datasets include the ERA5 Land reanalysis data,satellite-based precipitation data(PERsIANN_CCs_CDR and CHIRPs_V2.0)and a merged dataset(TPHiPr).We used various statistical and categorical indices to assess their ability to capture the spatial and temporal variability of EP *** annual EP events were characterised by 11 indices divided into frequency and intensity *** TPHiPr merged dataset offered a robust depiction of monthly precipitation estimates,achieving the highest critical success index,accuracy,probability of detection and a low false alarm ratio for daily precipitation detection of 0.1 mm in ***,the PERsIANN_CCs_CDR dataset exhibited poor *** PPDs showed increasing trends in EP ***,the TPHiPr dataset showcased those trends with fewer errors and stronger correlations for many frequency(R10mm,R20mm and R25mm)and intensity(RX1day,RX5day,PRCPTOT and R99p)*** results indicate that TPHiPr outperformed ot

关键词： Extreme precipitation Precipitation product Nepal TPHiPr ERA5 land PERsIANN_CCs_CDR CHIRPs_V2.0

Nuance of inward rectifying potassium(Kir)channel dysfunctions in neurodegenerative diseases

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Neural Regeneration Research 2024年第6期19卷 1195-1196页

作者： Benjamin Garland Linlin ma Griffith Institute for Drug Discovery&school of Environment and science Griffith UniversityNathanBrisbaneQLDAustralia

Neurodegenerative disorders are highly prevalent and diverse in *** manifestation largely depends on the cell types involved,with aberrant inflammatory episodes progressively inducing a constellation of phenotypes that are classified into specific diseases based on their neuropathological *** two most prevalent neurodegenerative diseases worldwide,Alzheimer’s disease(AD)and Parkinson’s disease(PD),for example,share notable similarities,yet they differ in terms of the specific cell types lost within the central nervous system(CNs).The significant and progressive loss of cortical and certain subcortical neurons in various regions is a major defining trait of *** contrast,the specific loss of dopaminergic neurons(DA)within the substantial nigra pars compacta(sNpc)is sufficient to cause motor symptoms associated with *** devastating condition arising from neurodegeneration within the CNs,amyotrophic lateral sclerosis(ALs),results in the progressive death of upper and lower motor *** degeneration originates in oligodendrocytes,whose defective myelination abilities lead to the denervation of the anterior horn,aggravating motor neuron death.

关键词： diseases degenerative degeneration

Time-inconsistent stochastic linear-quadratic control problem with indefinite control weight costs

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science China mathematics 2024年第1期67卷 211-236页

作者： Qi Lü Bowen ma school of mathematics Sichuan UniversityChengdu 610064China

A time-inconsistent linear-quadratic optimal control problem for stochastic differential equations is *** introduce conditions where the control cost weighting matrix is possibly *** such conditions,we obtain a family of closed-loop equilibrium strategies via multi-person differential *** result extends Yong’s work(2017) in the case of stochastic differential equations,where a unique closed-loop equilibrium strategy can be derived under standard conditions(namely,the control cost weighting matrix is uniformly positive definite,and the other weighting coefficients are positive semidefinite).

关键词： linear-quadratic optimal control problem time-inconsistent cost functional generalized Riccati equation indefinite control weight cost closed-loop equilibrium strategy