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Resilient Event-Triggered Control of Connected Automated Vehicles Under Cyber Attacks

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IEEE/CAA Journal of Automatica Sinica 2023年第12期10卷 2300-2302页

作者： ning Zhao xudong Zhao Ning XU Liang Zhang the College of Control Science and Engineering Bohai UniversityJinzhou 121013China the Institute of Ocean Research Bohai UniversityJinzhou 121013China the Faculty of Electronic Information and Electrical Engineering Dalian University of TechnologyDalian 116024China the College of Information Science and Technology Bohai UniversityJinzhou 121013China

Dear Editor,This letter contributes to designing a resilient event-triggered controller for connected automated vehicles under cyber attacks,including denial-of-service(DoS)and deception attacks.To characterize the ef... 详细信息

关键词： DoS service automated

Phase Behaviors of Soft-core Particle Systems

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Chinese Journal of Polymer Science 2019年第11期37卷 1065-1082页

作者： Ning XU Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Soft Matter Chemistry and Department of Physics University of Science and Technology of China

This paper reviews some of our recent works on phase behaviors of particulate systems with a soft-core interaction potential. The potential is purely repulsive and bounded, i.e., it is finite even when two particles completely overlap. The one-sided linear spring (harmonic) potential is one of the representatives. This model system has been successively employed to study the jamming transition, i.e., the formation of rigid and disordered packings of hard particles, and establish the jamming physics. This is actually based on the "hard" aspect of the potential, because at low densities and when particle overlap is tiny the potential resembles the hard sphere limit. At high densities, the potential exhibits its "soft" aspect: with the increase of density, there are successive reentrant crystallizations with many types of solid phases. Taking advantage of the dual nature of the potential, we investigate the criticality of the jamming transition from different perspectives, extend the jamming scenario to high densities, reveal the novel density evolution of two-dimensional melting, and find unexpected formation of quasicrystals. It is surprising that such a simple potential can exhibit so rich and unexpected phenomena in phase transitions. The phase behaviors discussed in this paper are also highly regarded in polymer science, which may thus shed light on our understanding of polymeric systems or inspire new ideas in studies of polymers.

关键词： Phase transitions Soft-core particles Jamming Two-dimensional melting Quasicrystals

Recent Advances of Covalent Organic Frameworks in Chemical Sensing

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Chemical Research in Chinese Universities 2022年第2期38卷 339-349页

作者： xu Kai HUANG ning Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of EducationState Key Laboratory of Silicon MaterialsDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027P.R.China

With the rapid development of reticular chemistry,an increasing number of covalent organic frameworks(COFs)have been designed and synthesized over the past decades.Owing to the large surface areas,numerous active sites,and high chemical stability,recent effects gradually were made to investigate the interaction with various small molecules.Among the reported application areas,sensorics is an attractive field,where COFs have exhibited tremendous potential and acquired high-performance sensitivity and selectivity due to their structural merits.In this review,we highlighted the recent progress of COFs as sensors for the detection of various analytes,mainly depending on the analysis of change of fluorescence signals.The basic principles of physics for fluorescence-based sensors were briefly discussed for better understanding of the relationship between structures and functions of COFs.Moreover,we reviewed various classes of small molecule analytes that have been successfully detected by COFs,including explosives,gases,humidity,metal ions,pH,and biological molecules.In this work,we detailedly discussed the components of COFs,functional sites,and sensing performance in each sensing application,aiming to disclose their intrinsic connection.This review also concluded with several issues to be solved and provided the outlook for the future development direction for practical applications.

关键词： Covalent organic framework(COF) Sensing Fluorescence Porous polymer

Preparation of CeO_(2) abrasives by reducing atmosphere-assisted molten salt method for enhancing their chemical mechanical polishing performance on SiO_(2)substrates

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Journal of Rare Earths 2023年第10期41卷 1627-1635,I0006页

作者： Ning XU Jiahui Ma Qi Liu Yuxin Luo Yongping Pu School of Material Science and Engineering Shaanxi University of Science&TechnologyXi'an710021China Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials Xi'an710021China

Ce^(3+)as the active site on the CeO_(2)abrasive surface is the key to enhancing the material removal rate(MRR).The CeO_(2)abrasives with high chemical activity were prepared by the molten salt method under a reducing atmosphere.The crystal structure and morphology of CeO_(2)abrasive s were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FT-IR),ultraviolet—visible diffuse reflectance spectroscopy(UV-Vis DRS),and X-ray photoelectron spectroscopy(XPS).The CeO_(2)abrasives were obtained under different atmospheres(Air,Ar,and Ar/H_(2)).With the enhancement of the reducing atmosphere,the morphology of the abrasives transforms from spherical to octahedral,while more oxygen vacancies and Ce^(3+)are generated on the surface of CeO_(2)abrasives.The CMP experiments show that the MRRs of the CeO_(2)-Air,CeO_(2)-Ar,and CeO_(2)-Ar/H_(2)abrasives on SiO_(2)substrates are 337.60,578.74,and 691.28 nm/min,respectively.Moreover,as confirmed by atomic force microscopy(AFM),the substrate surfaces exhibit low roughness(20.5 nm)after being polished using all of the prepared samples.Especially,the MRR of CeO_(2)-Ar/H_(2)abrasives is increased by 104.76%compared with CeO_(2)-air abrasives.The improved CMP performance is attributed to the increased Ce^(3+)concentration and the octahedral morphology of the abrasives enhancing the chemical reaction and mechanical removal at the abrasive-substrate interface.

关键词： CeO_(2) Chemical mechanical polishing(CMP) Reducing atmosphere Material removal rate(MRR) Molten salt method Rare earths

Effect of relaxation time on the squeezed correlations of bosons for evolving sources in relativistic heavy-ion collisions

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Nuclear Science and Techniques 2022年第2期33卷 87-92页

作者： Wei-ning Zhang Peng-Zhi xu School of Physics Dalian University of TechnologyDalian 116024China College of Computer Science and Technology Jilin Normal UniversitySiping 136000China

The squeezed back-to-back correlation(SBBC)of a boson-antiboson pair is sensitive to the time distribution of the particle-emitting source,and the SBBC function for an evolving source is expected to be affected by the relaxation time of the system.In this study,we investigated the effect of relaxation time on the SBBC function.We propose a method for calculating the SBBC function with relaxation-time approximation for evolving sources.SBBC functions of D^(0)D^(-0)in relativistic heavy-ion collisions were investigated using a hydrodynamic model.We found that the relaxation time reduces the amplitudes of the SBBC functions.This becomes apparent for long relaxation times and large initial relative deviations of the chaotic and squeezed amplitudes from their equilibrium values in the temporal steps.

关键词： Relaxation time Squeezed back-to-back correlation Evolving source Relativistic heavy-ion collisions

Microstructures and micromechanical behaviors of high -entropy alloys investigated by synchrotron X-ray and neutron diffraction techniques: A review

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1333-1349页

作者： Yubo Huang Ning XU Huaile Lu Yang Ren Shilei Li Yandong Wang Beijing Advanced Innovation Center of Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China AnSteel Beijing Research Institute Co.Ltd. Beijing 102200China Spallation Neutron Source Science Center Dongguan 523803China Department of Physics City University of Hong KongHong Kong 999077China Institute for Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Extensive studies on the deformation mech-anisms of HEAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural materials.Synchrotron X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on materials.Recently,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of HEAs,such as variable-temperature,high-pressure,and hydrogenation processes.In this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of HEAs are discussed.The factors that influence the deformation mechanisms of HEAs are also outlined.This review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress changes.Perspectives on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed.

关键词： high-entropy alloys microstructures micromechanical behaviors synchrotron X-ray diffraction neutron diffraction

Blowing-ups and Valuations on Surfaces

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Acta Mathematica Sinica,English Series 2011年第7期27卷 1305-1314页

作者： Ning XU Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 P. R. China

In this paper, we show that all the nontrivial valuations on surfaces can be given by the infinite sequences of blowing-ups, and give the process of blowing-ups.

关键词： Valuation height rank totally ordered group blowing-ups

Paired-Pd(Ⅱ) centers embedded in HKUST-1 framework: Tuning the selectivity from dimethyl carbonate to dimethyl oxalate

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Journal of Energy Chemistry 2022年第4期31卷 233-240页

作者： Hong-Zi Tan Zhe-ning Chen Kai-Qiang Jing Jing Sun Yu-Ping xu ning-ning Zhang Zhong-Ning XU Guo-Cong Guo State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002FujianChina School of Chemistry&Chemical Engineering Shandong University of TechnologyZibo 255049ShandongChina School of Chemistry and Chemical Engineering Liaocheng UniversityLiaocheng 252000ShandongChina

CO oxidative coupling to dimethyl oxalate(DMO) is the most crucial step in coal to ethylene glycol. Pdbased supported catalysts have been verified effective for generating DMO, but concomitant generation of dimethyl carbonate(DMC) is always unavoidable. It is generally accepted that Pd(0) is the active species for producing DMO, while Pd(II) for DMC. However, density functional theory calculations have proposed that the selectivity to DMO or DMC highly depends on the space state of Pd species rather than its oxidative state. It is thus urgently desired to develop high-efficient catalysts with well-defined structure,and further to elucidate the structure-performance relationship. In this work, HKUST-1 with unique structure of paired-Cu(Ⅱ) centers was chosen as ideal support to construct the catalysts with respective paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers via in situ Pd species doping. In despite of featuring Pdδ+(δ≈2) oxidation state, the synthesized paired-Pd(Ⅱ)/HKUST-1 catalyst still exhibited DMO as dominant product(90.8% of DMO selectivity). For isolated-Pd(Ⅱ)/HKUST-1 catalyst, however, the main product was DMC(84.8% of DMC selectivity). Based on catalyst characterizations, the structures of paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers were determined. DMO was generated from the coupling of adjacent *COOCH;intermediates adsorbed on paired-Pd(Ⅱ) centers, while DMC was produced from the reaction between methyl nitrite and the *COOCH;intermediates formed on isolated-Pd(Ⅱ) centers. Current work is the first MOFs-based catalyst with well-defined structure being applied in CO oxidative coupling reaction, which not only sheds light on the structure-performance relationship, but also inspires the potential of using MOFs as tunable platform to design high-efficient catalysts in heterogeneous catalysis.

关键词： CO Methyl nitrite Oxidative coupling Dimethyl oxalate Paired-Pd(Ⅱ)centers HKUST-1

Numerical investigation of the dynamics of flexible vegetations in turbulent open-channel flows

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Journal of Hydrodynamics 2022年第4期34卷 681-699页

作者： Dong xu Jia-ning Liu Yun-feng Wu Chun-ning Ji State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Aquatic vegetations widely exist in natural rivers and play an essential role in the evolution of the water environment and ecosystem by changing the river’s hydrodynamic characteristics and transporting sediments and nutrition.In reality,most aquatic vegetations are highly flexible,which invalidates the“rigid-cylinder”assumption widely adopted in many literatures.To explore the dynamics of submerged flexible vegetation in open-channel flows and its feedback to turbulent flow structures,numerical simulations are carried out using an in-house fluid-structure interaction(FSI)solver.In the simulations,the geometry of vegetation plants is grid-resolved,the turbulent flow is simulated using the large eddy simulation(LES),the dynamics of the flexible plants are solved using the vector form intrinsic finite element(VFIFE)method,and the turbulent flow and the plants are two-way coupled using the immersed boundary(IB)method.The dynamic responses of the flexible vegetation with different plant flexibility,spacing,and submergence are investigated.Simulation results show that flexible plants are subjected to complex flow-induced vibrations(FIVs)rather than static bending.The FIV involves both streamwise and cross-flow motions driven by the small-scale vortex shedding around the plants and the large-scale Kelvin-Helmholtz(K-H)vortices developed in the vegetation canopy layer.The vegetations exhibit pulsive wave motion of different patterns in relatively long and narrow open channels.Compared with the open-channel flows with static plants with equivalent bending deformation,the dynamic responses of flexible plants may increase the turbulent Reynolds stress of the open-channel flow by 70%–100%and increase the invasion depth of the K-H vortices by 30%–50%.

关键词： Flexible vegetation dynamic responses flow-induced vibration(FIV) fluid-structure interaction(FSI)