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An Upper Bound for the Transversal Number of Connected k-Uniform Hypergraphs

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Journal of the Operations Research Society of China 2024年第3期12卷 829-835页

作者： Zi-An chen Bin chen Center for Discrete Mathematics Fuzhou UniversityFuzhou350108FujianChina

Let H be a hypergraph with vertex set V(H)and hyperedge set E(H).We call a vertex set R ■V(H)a transversal if it has a nonempty intersection with every hyperedge of *** transversal number,denoted by τ(H),is the minimum cardinality of *** 2021,Diao verified that the upper bound of transversal number for any connected 3-uniform hypergraph H is at most 2m+1/3,that is,τ(H)≤2m+1/3, where m is the size of ***,they gave the necessary and sufficient conditions to reachthe upper bound,namely τ(H)≤2m+1/3,if and only if H is a hypertreewitha 3 perfect *** this paper,we investigate the transversal number of connected kunifom hypergraphs for k≥*** confrm that τ(H)≤(k-1)m+1/k for any k-unifom hypegraphH with size ***,we show that τ(H)≤(k-1)m+1/k if and only if H is a hypertree with a perfect matching,which generalizes the results of Diao.

关键词： Transversal number k-uniform hypergraph Perfect matching

Advances in the application of hydrogel-based scaffolds for tendon repair

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genes & Diseases 2024年第4期11卷 296-313页

作者： Renqiang chen Fanglin chen Kenian chen Jian Xu Department of Orthopedics The First Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang 310003China Department of Orthopedics The Fourth Affiliated Hospital of Guangxi Medical UniversityLiuzhou Guangxi 545005China

Tendon injuries often lead to joint dysfunction due to the limited self-regeneration capacity of *** tendons is a major challenge for surgeons and imposes a signif-icant financial burden on ***,there is an urgent need to develop effective stra-tegies for repairing injured *** tissue engineering using hydrogels has emerged as a promising approach that has attracted considerable *** possess excellent biocompatibility and biodegradability,enabling them to create an extracellular matrix-like growth environment for *** can also serve as a carrier for cells or other substances to accelerate tendon *** the past decade,numerous studies have made significant prog-ress in the preparation of hydrogel scaffolds for tendon *** review aims to provide an overview of recent research on the materials of hydrogel-based scaffolds used for tendon tis-sue engineering and discusses the delivery systems based on them.

关键词： Application Hydrogel-based Repairscaffolds Review Tendon injury Tissue engineering

Thin paints for durable and scalable radiative cooling

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Journal of Energy Chemistry 2024年第3期90卷 176-182,I0006页

作者： Shanquan Liu Fei Zhang Xingyu chen Hongjie Yan Wei chen Meijie chen School of Energy Science and Engineering Central South UniversityChangsha 410083HunanChina School of Intelligent Manufacturing Ecosystem Xi'an Jiaotong-Liverpool UniversitySuzhou 215400JiangsuChina

Passive daytime radiative cooling(PDRC) is environment-friendly without energy input by enhancing the coating's solar reflectance(R_(solar)) and thermal emittance(ε_(LWIR)) in the atmosphere's long-wave infrared transmission ***,high R_(solar) is usually achieved by increasing the coating's thickness,which not only increases materials' cost but also impairs heat ***,the desired high R_(solar) is vulnerable to dust pollution in the *** this work,a thin paint was designed by mixing hBN plates,PFOTS,and IPA. R_(solar)=0.963 and ε_(LWIR)=0.927 was achieved at a thickness of 150 μm due to the high backscattering ability of scatters.A high through-plane thermal conductivity(~1.82 W m^(-1) K^(-1)) also can be *** addition,the porous structure coupled with the binder PFOTS resulted in a contact angle of 154°,demonstrating excellent durability under dust *** experiments showed that the thin paint can obtain a 2.3℃ lower temperature for sub-ambient cooling than the reference PDRC coating in the ***,the above-ambient heat dissipation performance can be enhanced by spraying the thin paint on a 3D heat sink,which was 15.7℃ lower than the reference 1D structure,demonstrating excellent performance for durable and scalable PDRC applications.

关键词： Radiative cooling Heat dissipation Solar reflectance Thermal emittance Contact angle

Evaluation of 3D crustal seismic velocity models in southwest China:Model performance,limitation,and prospects

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Science China Earth Sciences 2024年第2期67卷 604-619页

作者： Xin WANG Ling chen Qi-Fu chen Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China

Southwest China is a tectonically and seismically active region,witnessing strong deformation due to the collision between the Indian and Eurasian *** the subsurface velocity structure of this region is thus important in understanding the tectonics and geodynamic processes of continental collision and in mitigating seismic *** studies have provided various 3D seismic velocity models in southwest ***,discrepancies exist among these models,and less effort has been made to quantify the reliability and accuracy of these existing velocity *** this study,we use regional 3D waveform simulation to evaluate the performance of various regional crustal 3D velocity models in reproducing observed *** particularly focus on two recent earthquake sequence in the region,the 2021 Yunnan Yangbi MS_(6.4) earthquake sequence and the 2022 Sichuan Luding MS_(6.8) earthquake *** tested 3D velocity models include the Southwest China Community Velocity model V1.0,the Unified Seismic Tomography Models for Continental China Lithosphere V2.0,the adjoint full waveform tomography model of the crustal and upper mantle beneath Eastern Tibetan Plateau,and the shallow seismic structure model beneath continental *** results show that the tested 3D velocity models generally capture well long-period(geneities are not well *** shallow velocity structures(<10 km)can improve the waveform fitting,emphasizing the importance of incorporating shallow structures in waveform *** full-waveform tomography model shows a slighter better performance than the other models,especially for the body-waves,highlighting the advantages

关键词： Southwest China Seismic tomography models Shallow Structures Waveform simulation Model evaluation

Self-aligned dual-beam superresolution laser direct writing with a polarization-engineered depletion beam

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Photonics Research 2024年第6期12卷 1194-1200页

作者： GUOLIANG chen DEWEI MO JIAN chen QIWEN ZHAN School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai 200093China Shanghai Key Laboratory of Modern Optical System University of Shanghai for Science and TechnologyShanghai 200093China Zhangjiang Laboratory Shanghai 201204China

A fiber-based,self-aligned dual-beam laser direct writing system with a polarization-engineered depletion beam is designed,constructed,and *** system employs a vortex fiber to generate a donut-shaped,cylindrically polarized depletion beam while simultaneously allowing the fundamental mode excitation beam to pass *** results in a co-axially self-aligned dual-beam source,enhancing stability and mitigating assembly *** size of the central dark spot of the focused cylindrical vector depletion beam can be easily adjusted using a simple polarization rotation *** a depletion wavelength of 532 nm and an excitation wavelength of800 nm,the dual-beam laser direct writing system has demonstrated a single linewidth of 63 nm and a minimum line spacing of 173 *** optimization of this system may pave the way for practical superresolution photolithography that surpasses the diffraction limit.

关键词： polarization beam depletion

Computing Persistent Homology by Spanning Trees and Critical Simplices

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Research 2024年第2期2023卷 519-527页

作者： Dinghua Shi Zhifeng chen Chuang Ma Guanrong chen Department of Mathematics Cllege of ScienceShanghai UniversityShanghaiChina School of Big Data Fuzhou University of International Studies and TradeFuzhouChina Department of Data Science and Big Data Technology School of InternetAnhui UniversityHefeiChina Department of Electrical Engineering City University of Hong KongHong KongChina

Topological data analysis can extract effective information from higher-dimensional *** mathematical basis is persistent *** persistent homology can calculate topological features at different spatiotemporal scales of the dataset,that is,establishing the integrated taxonomic relation among points,lines,and ***,the simplicial network composed of all-order simplices in a simplicial complex is *** the sequence of nested simplicial subnetworks can be regarded as a discrete Morse function from the simplicial network to real values,a method based on the concept of critical simplices can be developed by searching all-order spanning *** this new method,not only the Morse function values with the theoretical minimum number of critical simplices can be obtained,but also the Betti numbers and composition of all-order cavities in the simplicial network can be calculated ***,this method is used to analyze some examples and compared with other methods,showing its effectiveness and feasibility.

关键词： Morse establishing topological

An improved interval model updating method via adaptive Kriging models

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 497-514页

作者： Sha WEI Yifeng chen Hu DING Liqun chen Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

Interval model updating(IMU)methods have been widely used in uncertain model updating due to their low requirements for sample ***,the surrogate model in IMU methods mostly adopts the one-time construction *** makes the accuracy of the surrogate model highly dependent on the experience of users and affects the accuracy of IMU ***,an improved IMU method via the adaptive Kriging models is *** method transforms the objective function of the IMU problem into two deterministic global optimization problems about the upper bound and the interval diameter through universal grey *** optimization problems are addressed through the adaptive Kriging models and the particle swarm optimization(PSO)method to quantify the uncertain parameters,and the IMU is *** the construction of these adaptive Kriging models,the sample space is gridded according to sensitivity *** sampling is then performed in key subspaces based on the maximum mean square error(MMSE)*** interval division coefficient and random sampling coefficient are adaptively adjusted without human interference until the model meets accuracy *** effectiveness of the proposed method is demonstrated by a numerical example of a three-degree-of-freedom mass-spring system and an experimental example of a butted cylindrical *** results show that the updated results of the interval model are in good agreement with the experimental results.

关键词： interval model updating(IMU) non-probabilistic uncertainty adaptive Kriging model surrogate model grey number

Photodegradation of xylene isomers:Kinetics,mechanism,secondary pollutant formation potential and health risk evaluation

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Journal of Environmental Sciences 2024年第2期136卷 658-669页

作者： Xiaoyan chen Weikun Zhu Sufen Feng Jiangyao chen Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and HealthSchool of Environmental Science and EngineeringGuangdong University of TechnologyGuangzhou 510006China

Photodegradation technology has been widely applied in the purification of industrial aromatic ***,whether this technology efficiently removes the pollutants to prevent secondary pollution and health risk is still ***,the photodegradation processes of three xylenes were compared under designed reaction atmospheres and light *** lamp showed poor photodegradation ability toward xylenes,no matter in N_(2) or N_(2)+O_(2)system,while much higher photodegradation performance of xylenes were obtained under ultraviolet(UV)and vacuum ultraviolet(VUV)irradiation,especially in N_(2)+O_(2)+VUV system,where 97.9%of m-xylene,99.0%of o-xylene or 87.5%of p-xylene with the initial concentration of 860 mg/m^(3) was removed within 240 *** xylenes underwent three processes of photo-isomerization,photodecomposition and photo-oxidation to produce intermediates of aromatics,alkanes and *** them,the photo-isomerization products showed the highest concentration percentage(e.g.,≥50%in o-xylene system),confirming that photo-isomerization reaction was the dominated photodegradation process of ***,these isomerized products not only contributed about 97%and91%to the formation potential of O3(OFP)and secondary organic aerosols(SOAFP),but also displayed obvious non-carcinogenic risk,although one of photodecomposition product—benzene showed the highest occupational exposure ***,the secondary pollution and health risks of photodegradation products of xylenes were non-ignorable,although the OFP,SOAFP and health risks of the generated products reduced at least 4.5 times in comparison with that of the degraded *** findings are helpful for the appropriate application of this technology in the purification of industrial organic waste gas.

关键词： Isomer aromatics Photodegradation Ozone formation Secondary organic aerosols Health risk

An ionic liquid-assisted strategy for enhanced anticorrosion of low-energy PEO coatings on magnesium–lithium alloy

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Journal of Magnesium and Alloys 2024年第6期12卷 2380-2396页

作者： You Zhang Chuping chen Haoyue Tian Shuqi Wang chen Wen Fei chen College of New Materials and Chemical Engineering Hydrogen Energy Research CentreBeijing Institute of Petrochemical TechnologyBeijing 102617China Key Laboratory of Advanced Structure-Function Integrated Materials and Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China Beijing Spacecrafts China Academy of Space TechnologyBeijing 100190China

A low-energy plasma electrolytic oxidation(LePEO)technique is developed to simultaneously improve energy efficiency and *** liquids(1-butyl-3-methylimidazole tetrafluoroborate(BmimBF_(4)))as sustainable corrosion inhibitors are chosen to investigate the corrosion inhibition behavior of ionic liquid(ILs)during the LePEO process for LA91 magnesium-lithium(Mg-Li)*** show that the ionic liquid BmimBF_(4)participates in the LePEO coating formation process,causing an increment in coating thickness and surface *** low conductivity of the ionic liquid is responsible for the voltage and breakdown voltage increases during the LePEO with IL process(LePEO-IL).After adding BmimBF_(4),corrosion current density decreases from 1.159×10^(−4)A·cm^(−2)to 8.143×10^(−6)A·cm^(−2).The impedance modulus increases to 1.048×10^(4)Ω·cm^(−2)and neutral salt spray remains intact for 24 *** superior corrosion resistance of the LePEO coating assisted by ionic liquid could be mainly attributed to its compact and thick barrier layer and physical absorption of ionic *** ionic liquid-assisted LePEO technique provides a promising approach to reducing energy consumption and improving film performance.

关键词： Magnesium-lithium alloy Plasma electrolytic oxidation Low energy Ionic liquid Corrosion resistance