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A lubrication model for bubbly oil lubrication with interfacial effect and thermal effect using the theory of multiphase mixtures

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Friction 2024年第2期12卷 271-290页

作者： shaohua LI Xiaohui lin shuyun JIANG school of Mechanical Engineering Southeast UniversityNanjing 211189China

Bubbly oil lubrication is a type of lubrication ***,the lubrication model of the bubbly oil has not been thoroughly *** paper aims to investigate the modelling for bubbly oil lubrication considering the interfacial effect and thermal effect,and a theoretical model is established based on the theory of multiphase *** interfacial and thermal effects on the static characteristics of a thrust bearing are analyzed.A test rig for the thrust bearing is developed to measure the static characteristics of the bearing under bubbly oil *** results show that the bearing static characteristics,*** temperature rise,film thickness,friction torque,and volume flow,increase with consideration of three interfacial effects;the bearing temperature rise increases but the film thickness,friction torque,and volume flow rate decrease with consideration of the three thermal effects;the thermal effect on the bearing static characteristics is greater than the interfacial effect.

关键词： bubbly oil lubrication theory of multiphase mixtures interfacial effect thermal effect fluid bearing

Flocking Effects of the stochastic Cucker-smale system with Noise

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Journal of systems science & Complexity 2024年第5期37卷 1978-1994页

作者： HAN Ning GE Bin LI lin school of Mathematical sciences Harbin Engineering UniversityHarbin 150001China

In this paper,the flocking behavior of a Cucker-smale model with a leader and noise is studied in a finite *** authors present a Cucker-smale system with two nonlinear controls for a complex network with stochastic synchronization in *** on the finite-time stability theory of stochastic differential equations,the sufficient conditions for the flocking of stochastic systems in a finite time are obtained by using the Lyapunov function ***,the numerical simulation of the particle system is carried out for the leader and noise,and the correctness of the results is verified.

关键词： Cucker-smale model flocking behavior leader noise

Realizing the excellent oxidation resistance of an environmental barrier coating through aluminum surface modification

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Journal of Advanced Ceramics 2024年第7期13卷 976-986页

作者： lin Dong Wen-Qi yang lin Chen Guan-Jun yang Chang-Jiu Li state Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Xi’an Aerospace Engine Company Limited in China Aerospace science and Technology Corporation Xi’an 710065China

The lifetime of si-based environmental barrier coatings(EBCs)is constrained by thermally grown siO_(2)oxidelayer(siO_(2)-TGO),which can cause premature cracking and *** address this issue,a new approach for surfacemodification using aluminum is *** oxidation performance was examined in a 50 vol%H_(2)O-50 vol%O_(2)environment at 1350℃for up to 300 *** results indicate that a dense ytterbium aluminum garnet(ybAG)layer wasformed after modification,decreasing the porosity by 80%.Due to the elimination of fast diffusion channels and the lowoxygen permeability of ybAG,aluminum modification significantly reduced the growth rate of siO_(2)-TGO by nearly twoorders of ***,its thickness decreased by more than 70%after 300 h of exposure.A diffusioncontrolled oxidation mechanism indicates that the modified dense surface is equivalent to an initial siO_(2)layer with a specificthickness,causing a shift in the oxidation time and increasing the oxidation *** research provides valuableinsights for designing si-based EBC with improved lifetimes.

关键词： environmental barrier coating(EBC) oxidation modification diffusion cracking

Distribution of per-and polyfluoroalkyl substances in blood,serum,and urine of patients with liver cancer and associations with liver function biomarkers

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Journal of Environmental sciences 2024年第5期139卷 418-427页

作者： Cao Dai lin Peng yanjie Li Zhendong Li Da Chen Fei Wang Nan lin Department of Hepatobiliary surgery The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510630China school of Environment Guangdong Key Laboratory of Environmental Pollution and HealthJinan UniversityGuangzhou 510632China state Key Laboratory of Environmental and Biological Analysis Department of ChemistryHong Kong Baptist UniversityHong Kong 999077China south China Institute of Environmental sciences MEEGuangzhou 510655China

studies have shown that per-and polyfluoroalkyl substances(PFAss)may be hepatotoxic in animals or ***,data on clinical epidemiology are very *** this study,21PFAss were determined in patients with liver diseases,with the highest median concentrations detected in the serum sample(26.7 ng/mL),followed by blood(10.7 ng/mL)and urine(5.02 ng/mL).Higher total PFAs concentrations were found in hepatocellular carcinoma(HCC)patients compared to non-HCC patients,with significant discrepancies in serum and blood ***,significant correlations were also found among PFAs concentrations and age,gender,body mass index(BMI),and liver function biomarkers *** example,PFAs concentrations are significantly higher in males than in females;several serum PFAss concentrations increase with age and BMI,while the serum perfluorohexane sulfonic acid(PFHxs)concentrations are negatively correlated with *** addition,multiple regression models adjusted for age,gender and BMI found that increased serum perfluorobutane sulfonic acid(PFBs),perfluoroheptane sulfonic acid(PFHps)and perfluorohexylphosphonic acid(PFHxPA)conentrations are correlated with elevated alkaline phosphatase(ALP),aspartate aminotransferase(AsT),and alpha-fetoprotein(AFP)(psults provide epidemiological support for the future study on the potential clinical hepatotoxicity of PFAs.

关键词： Per-and polyfluoroalkyl substances(PFAss) Liver cancer serum Blood Urine Liver function biomarkers

The Minimum Centroid Branch spanning Tree Problem

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Journal of the Operations Research society of China 2024年第2期12卷 528-539页

作者： Hao lin Cheng He school of science Henan University of TechnologyZhengzhou450001HenanChina

For a spanning tree T of graph G,the centroid of T is a vertex v for which the largest component of T-v has as few vertices as *** number of vertices of this component is called the centroid branch weight of *** minimum centroid branch spanning tree problem is to find a spanning tree T of G such that the centroid branch weight is *** application to design of communication networks,the loads of all branches leading from the switch center should be as balanced as *** this paper,we prove that the problem is strongly NP-hard even for bipartite ***,the problem is shown to be polynomially solvable for split graphs,and exact formulae for special graph familis,say Kn_(1),n_(2),...,n_(k)and P_(m)×P_(n),are presented.

关键词： spanning tree optimization Centroid branch-NP-hardness Polynomial-time algorithm

semi-derived Ringel-Hall algebras and Hall algebras of odd-periodic relative derived categories

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science China Mathematics 2024年第8期67卷 1735-1760页

作者： Ji lin Liangang Peng Department of Mathematics and statistics Fuyang Normal UniversityFuyang 236037China school of Mathematics Sichuan UniversityChengdu 610064China

Let t be a positive integer and A be a hereditary abelian category satisfying some finiteness *** define the semi-derived Ringel-Hall algebra of A from the category C_(Z/t)(A)of Z/t-graded complexes and obtain a natural basis of the semi-derived Ringel-Hall ***,we describe the semiderived Ringel-Hall algebra by the generators and defining *** particular,if t is an odd integer,we show an embedding of the derived Hall algebra of the odd-periodic relative derived category in the extended semi-derived Ringel-Hall algebra.

关键词： hereditary abelian categories the categories of Z/t-graded complexes semi-derived Ringel-Hall algebras derived Hall algebras

The character of Thurston's circle packings

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science China Mathematics 2024年第7期67卷 1623-1640页

作者： Huabin Ge Aijin lin school of Mathematics Renmin University of ChinaBeijing100872China Department of Mathematics National University of Defense TechnologyChangsha410073China

We introduce the character of Thurston's circle packings in the hyperbolic background ***, some quite simple criteria are obtained for the existence of hyperbolic circle packings. For example,if a closed surface X admits a circle packing with all the vertex degrees d_(i)≥7, then it admits a unique complete hyperbolic metric so that the triangulation graph of the circle packing is isotopic to a geometric decomposition of X. This criterion is sharp due to the fact that any closed hyperbolic surface admits no triangulations with all d_(i)≤6. As a corollary, we obtain a new proof of the uniformization theorem for closed surfaces with genus g≥2;moreover, any hyperbolic closed surface has a geometric decomposition. To obtain our results, we use Chow-Luo's combinatorial Ricci flow as a fundamental tool.

关键词： character circle packings combinatorial Ricci flow

Optical Modeling of sea salt Aerosols Using in situ Measured size Distributions and the Impact of Larger size Particles

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Advances in Atmospheric sciences 2024年第10期41卷 1917-1935页

作者： Wushao lin Lei BI Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province School of Earth SciencesZhejiang UniversityHangzhou 310058China

sea salt aerosols play a critical role in regulating the global climate through their interactions with solar *** size distribution of these particles is crucial in determining their bulk optical *** this study,we analyzed in situ measured size distributions of sea salt aerosols from four field campaigns and used multi-mode lognormal size distributions to fit the *** employed super-spheroids and coated super-spheroids to account for the particles’non-sphericity,inhomogeneity,and hysteresis effect during the deliquescence and crystallization *** compute the singlescattering properties of sea salt aerosols,we used the state-of-the-art invariant imbedding T-matrix method,which allows us to obtain accurate optical properties for sea salt aerosols with a maximum volume-equivalent diameter of 12μm at a wavelength of 532 *** results demonstrated that the particle models developed in this study were successful in replicating both the measured depolarization and lidar ratios at various relative humidity(RH)***,we observed that large-size particles with diameters larger than 4μm had a substantial impact on the optical properties of sea salt aerosols,which has not been accounted for in previous ***,excluding particles with diameters larger than 4μm led to underestimating the scattering and backscattering coefficients by 27%−38%and 43%−60%,respectively,for the ACE-Asia field ***,the depolarization ratios were underestimated by 0.15 within the 50%−70%RH *** findings emphasize the necessity of considering large particle sizes for optical modeling of sea salt aerosols.

关键词： sea salt aerosol particle size distribution lidar optical property

Aubry-Mather theory for contact Hamiltonian systems Ⅲ

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science China Mathematics 2024年第11期67卷 2541-2570页

作者： Panrui Ni lin Wang shanghai Center for Mathematical sciences Fudan University school of Mathematics and statistics Beijing Institute of Technology

By exploiting the contact Hamiltonian dynamics（T*M × R,Φ_t） around the Aubry set of contact Hamiltonian systems,we provide a relation among the Mather set,the Φ_t-recurrent set,the strongly static set,the Aubry set,the Ma?é set,and the Φ_t-non-wandering ***,we consider the strongly static set,as a new flow-invariant set between the Mather set and the Aubry set in the strictly increasing *** show that this set plays an essential role in the representation of certain minimal forward weak Kolmogorov-Arnold-Moser（KAM） solutions and the existence of transitive orbits around the Aubry set.

关键词： Aubry-Mather theory weak KAM theory contact Hamiltonian systems Hamilton-Jacobi equations