检索结果-南通市图书馆

Yet More Elementary Proof of Matrix-Tree Theorem for Signed Graphs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

代数集刊:英文版 2023年第3期30卷 493-502页

作者： Shu Li Jianfeng Wang School of Mathematics and Statistics Shandong University of TechnologyZiboShandong 255049China

A signed graph G˙=(G,σ)is a graph G=(V(G),E(G))with vertex set V(G)and edge set E(G),together with a functionσ:E→{+1,−1}assigning a positive or negative sign to each edge.In this paper,we present a more elementary proof for the matrix-tree theorem of signed graphs,which is based on the relations between the incidence matrices and the Laplcians of signed graphs.As an application,we also obtain the results of Monfared and Mallik about the matrix-tree theorem of graphs for signless Laplacians.

关键词： signed graph matrix-tree theorem Laplacian signless Laplacian incidence matrix

A case of massive hemoptysis after radiofrequency catheter ablation for atrial fibrillation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2022年第1期13卷 78-80页

作者： Zhen Ren Shu Li Qing-bian Ma Department of Emergency Medicine Peking University Third HospitalBeijing 100191China

Dear editor,Massive hemoptysis(MH)sometimes causes a fatal condition;[1]thus,prompt diagnosis and treatment for MH are crucial.However,a wide range of diseases(e.g.,infectious diseases,malignancies,and systemic autoimmune diseases)is associated with the development of MH,[2]which occasionally causes difficulty with identifying the specific etiology.

关键词： diagnosis diseases al.

Joint offloading strategy based on quantum particle swarm optimization for MEC-enabled vehicular networks

在线全文

学校读者我要写书评

暂无评论

Digital Communications and Networks 2023年第1期9卷 56-66页

作者： Wanneng shu Yan li College of Computer Science South-Central University for NationalitiesWuhan430074China College of Science Huazhong Agricultural UniversityWuhan430070China

With the development of the mobile communication technology,a wide variety of envisioned intelligent transportation systems have emerged and put forward more stringent requirements for vehicular communications.Most of computation-intensive and power-hungry applications result in a large amount of energy consumption and computation costs,which bring great challenges to the on-board system.It is necessary to exploit traffic offloading and scheduling in vehicular networks to ensure the Quality of Experience(QoE).In this paper,a joint offloading strategy based on quantum particle swarm optimization for the Mobile Edge Computing(MEC)enabled vehicular networks is presented.To minimize the delay cost and energy consumption,a task execution optimization model is formulated to assign the task to the available service nodes,which includes the service vehicles and the nearby Road Side Units(RSUs).For the task offloading process via Vehicle to Vehicle(V2V)communication,a vehicle selection algorithm is introduced to obtain an optimal offloading decision sequence.Next,an improved quantum particle swarm optimization algorithm for joint offloading is proposed to optimize the task delay and energy consumption.To maintain the diversity of the population,the crossover operator is introduced to exchange information among individuals.Besides,the crossover probability is defined to improve the search ability and convergence speed of the algorithm.Meanwhile,an adaptive shrinkage expansion factor is designed to improve the local search accuracy in the later iterations.Simulation results show that the proposed joint offloading strategy can effectively reduce the system overhead and the task completion delay under different system parameters.

关键词： Computation offloading MEC-enabled vehicular networks Mobile edge computing Task scheduling

The membrane-associated ubiquitin ligases MARCH2 and MARCH3 target IL-5 receptor alpha to negatively regulate eosinophilic airway inflammation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2022年第10期19卷 1117-1129页

作者： lin-Wen Zeng Lu Feng Rui liu Heng lin Hong-Bing shu Shu Li Department of Infectious Diseases Zhongnan Hospital of Wuhan UniversityMedical Research InstituteFrontier Science Center for Immunology and MetabolismResearch Unit of Innate Immune and Inflammatory Diseases(2019RU063)Chinese Academy of Medical SciencesWuhan UniversityWuhan430071China

Interleukin 5(IL-5)plays crucial roles in type 2-high asthma by mediating eosinophil maturation,activation,chemotaxis and survival.Inhibition of IL-5 signaling is considered a strategy for asthma treatment.Here,we identified MARCH2 and MARCH3 as critical negative regulators of IL-5-triggered signaling.MARCH2 and MARCH3 associate with the IL-5 receptorαchain(IL-5Rα)and mediate its K27-linked polyubiquitination at K379 and K383,respectively,and its subsequent lysosomal degradation.Deficiency of MARCH2 or MARCH3 modestly increases the level of IL-5Rαand enhances IL-5-induced signaling,whereas double knockout of MARCH2/3 has a more dramatic effect.March2/3 double knockout markedly increases the proportions of eosinophils in the bone marrow and peripheral blood in mice.Double knockout of March2/3 aggravates ovalbumin(OVA)-induced eosinophilia and causes increased inflammatory cell infiltration,peribronchial mucus secretion and production of Th2 cytokines.Neutralization of Il-5 attenuates OVA-induced airway inflammation and the enhanced effects of March2/3 double deficiency.These findings suggest that MARCH2 and MARCH3 play redundant roles in targeting IL-5Rαfor degradation and negatively regulating allergic airway inflammation.

关键词： MARCH2/3 IL-5Rα Polyubiquitination Eosinophil Airway inflammation

Residual stress analysis of multi-pass cold spinning process

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第3期35卷 259-271页

作者： Zixuan li Xuedao shu Faculty of Mechanical Engineering&Mechanics Ningbo UniversityNingbo 315211China Zhejiang Provincial Key Laboratory of Part Rolling Technology Ningbo UniversityNingbo 315211China

Uncontrolled residual stresses have significant effects on the service time and defects of the spun parts.Nowadays,X-Ray Diffraction(XRD)method has been widely used in the residual stress measurement of industry products with different forming processes.The calculated residual stress is usually obtained from the data fitting slope of strain and angle with Ordinary Least Squares(OLS)method.But this fitting method is not always suitable for the big fluctuant data.In this paper,the Weighted Least Square(WLS)method is used for the data fitting and compared with the OLS method.The nickel-based superalloy GH3030 and iron-based superalloy GH1140 are applied in the multi-pass cold spinning experiments.The residual stress distributions of normal,potential crack and wrinkle workpieces are discussed with the grain structure.The results show that WLS method has better goodness of fit compared with OLS method.The residual stress distributions have special relationship with potential crack,wrinkle workpiece and grain structure.

关键词： Cold spinning process Data fitting Grain structure Potential crack Residual stress Weighted least square method

Aging of PVDF and PES ultrafiltration membranes by sodium hypochlorite:Effect of solution pH

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2021年第6期33卷 444-455页

作者： Kai li Qian Su Shu Li Gang Wen Tinglin Huang Key Laboratory of Northwest Water Resource Environment and EcologyMOEXi’an University of Architecture and TechnologyXi’an 710055China Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

Sodium hypochlorite(NaClO)is a commonly applied cleaning agent for ultrafiltration membranes in water and wastewater treatment.Long-term exposure to NaClO might change the properties and performance of polymeric membranes,and ultimately shorten membrane lifespan.Active species in NaClO solution vary with solution pH,and the aging effects can change depending on the membrane material.In this study,the aging of polyvinylidene fluoride(PVDF)and polyethersulfone(PES)membranes by NaClO at pH 3–11 was investigated by examining variations in chemical composition,surface charge,surface morphology,mechanical strength,permeability,and retention ability.Polyvinyl pyrrolidone(PVP),which was blended in both membranes,was oxidized and dislodged due to NaClO aging at all investigated pH values,but the oxidation products and dislodgement ratio of PVP varied with solution pH.For the PVDF membrane,NaClO aging at pH 3–11 caused a moderate increase in permeability and decreased retention due to the oxidation and release of PVP.The tensile strength decreased only at pH 11 because of the defluorination of PVDF molecules.For the PES membrane,NaClO aging at all investigated pH resulted in chain scission of PES molecules,which was favored at pH 7 and 9,potentially due to the formation of free radicals.Therefore,a decrease in tensile strength and retention ability,as well as an increase in permeability,occurred in the PES membrane for NaClO aging at pH 3–11.Overall,the results can provide a basis for selecting chemical cleaning conditions for PVDF and PES membranes.

关键词： Polymeric ultrafiltration(UF)membrane Membrane aging Sodium hypochlorite(NaClO) Membrane properties Performance factors

Magnesium isotope geochemistry of the carbonate-silicate system in subduction zones

在线全文

学校读者我要写书评

暂无评论

National Science Review 2022年第6期9卷 23-33页

作者： shui-Jiong Wang shu-Guang li State Key Laboratory of Geological Processes and Mineral Resources and Institute of Earth SciencesChina University of Geosciences (Beijing) CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of China

The lighter magnesium(Mg) isotopic signatures observed in intraplate basalts are commonly thought to result from deep carbonate recycling, provided that the sharp difference in Mg isotopic composition between surface carbonates and the normal mantle is preserved during plate subduction. However, deep subduction of carbonates and silicates could potentially fractionate Mg isotopes and change their chemical compositions. Subducting silicate rocks that experience metamorphic dehydration lose a small amount of Mg, and preserve the original Mg isotopic signature of their protoliths. When the dehydrated fluids dissolve carbonate minerals, they may evolve into lighter Mg isotopic compositions. The solubility of carbonate minerals in fluids decreases in the order of calcite, aragonite, dolomite, magnesite and siderite, leading to selective and partial dissolution of carbonate minerals along the subduction path. At the island arc depth(70–120 km), the metamorphic fluid dissolves mainly Mg-poor calcites, and thus the fluid has difficulty modifying the Mg isotopic system of the mantle wedge and associated arc basalts. At the greater depth of the back arc system or continental margin(>150 km), the supercritical fluid can dissolve Mg-rich carbonate minerals, and its interaction with the mantle wedge could significantly imprint the light Mg isotopic signature onto the mantle rocks and derivatives. Meanwhile, the carbonate and silicate remaining within the subducting slab could experience elemental and isotopic exchange, during which the silicate can obtain a light Mg isotopic signature and high CaO/Al2O3, whereas the carbonates, particularly the Ca-rich limestone, shift Mg isotopes and Mg O contents towards higher values. If this isotopic and elemental exchange event occurs widely during crustal subduction, subducted Ca-rich carbonates can partially transform into being Mg-rich, and a portion of recycled silicates(e.g. carbonated eclogites) can have light Mg isotopic composition alongside carbonates. Both serve as the low-δ26M

关键词： magnesium isotope fractionation deep carbon cycle subduction carbonate

Simulation of gas-solid adsorption process considering particle-size distribution

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2023年第2期54卷 331-342页

作者： Jihui li Bingjian Zhang Yidan shu School of Materials Science and Engineering Sun Yat-sen UniversityGuangzhou 510006China

The particle-size distribution of adsorbents usually plays an important role on the adsorption performance. In this study, population balance equation(PBE) is utilized in the simulation of an adsorption process to model the time-dependent adsorption amount distribution on adsorbent particles of a certain size distribution. Different adsorption kinetics model can be used to build the adsorption rate function in PBE according to specific adsorption processes. Two adsorption processes, including formaldehyde on activated carbon and CO_(2)/N_(2)/CH_(4) mixture on 4A zeolite are simulated as case studies, and the effect of particle-size distribution of adsorbent is analyzed. The simulation results proved that the influence of particle-size distribution is significant. The proposed model can help consider the influence of particlesize distribution of adsorbents on adsorption processes to improve the prediction accuracy of the performance of adsorbents.

关键词： Adsorption Population balance equations Particle-size distribution

Inorganic nanomaterial lubricant additives for base fluids,to improve tribological performance:Recent developments

在线全文

学校读者我要写书评

暂无评论

Friction 2022年第5期10卷 645-676页

作者： Junhai WANG Weipeng ZHUANG Wenfeng liANG Tingting YAN Ting li lixiu ZHANG Shu Li School of Mechanical Engineering Shenyang Jianzhu UniversityShenyang 110168China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

In this paper,we review recent research developments regarding the tribological performances of a series of inorganic nano-additives in lubricating fluids.First,we examine several basic types of inorganic nanomaterials,including metallic nanoparticles,metal oxides,carbon nanomaterials,and"other"nanomaterials.More specifically,the metallic nanoparticles we examine include silver,copper,nickel,molybdenum,and tungsten nanoparticles;the metal oxides include CuO,ZnO,Fe_(3)O_(4),TiO_(2),ZrO,Al_(2)O_(3),and several double-metal oxides;the carbon nanomaterials include fullerene,carbon quantum dots,carbon nanotubes,graphene,graphene oxides,graphite,and diamond;and the"other"nanomaterials include metal sulfides,rare-earth compounds,layered double hydroxides,clay minerals,hexagonal boron nitride,black phosphorus,and nanocomposites.Second,we summarize the lubrication mechanisms of these nano-additives and identify the factors affecting their tribological performance.Finally,we briefly discuss the challenges faced by inorganic nanoparticles in lubrication applications and discuss future research directions.This review offers new perspectives to improve our understanding of inorganic nano-additives in tribology,as well as several new approaches to expand their practical applications.

关键词： antifriction mechanism inorganic additives nanomaterials tribological performances