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Accumulation of localized charge on the surface of polymeric carbon nitride boosts the photocatalytic activity

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Journal of Materials Science & Technology 2022年第16期111卷 9-16页

作者： Yabin Jiang Lei Zeng Chi Cao Wensheng Yang Limin Huang School of Materials Sun Yat-Sen UniversityShenzhen 518107China Department of Chemistry Southern University of Science and TechnologyShenzhenGuangdong 518055China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China Institute of Molecular Plus Tianjin UniversityTianjin 300072China

The random mobility of charge carriers is a main factor causing the low photocatalytic efficiency of gCN.Thus,the controllable migration of charge carriers is a rational strategy to suppress the charge recombination and facilitate charge separation.Herein,an ethylenediamine modified g-C_(3)N_(4)displays improved photocatalytic activity.The excellent charge separation efficiency is confirmed to be a key factor for the enhancement.The TEM observation after photo-depositing Pt nanoparticles and DFT calculations verify the accumulation of electrons on some areas of g-C_(3)N_(4)surface.The increased-NH_(2)groups significantly tune the electronic structure of g-C_(3)N_(4)after the modification.The generation of midgap states also affects the charge separation.Our reports provide a simple method to manage the migration of charge carriers and enable electrons directional transfer,which suppresses the recombination and improves the photocatalytic activity.

关键词： g-C_(3)N_(4) Charge separation Photocatalytic H2 evolution Directional migration

Metal-based nanoparticles for cardiovascular disease diagnosis and therapy

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Particuology 2023年第1期72卷 94-111页

作者： lei Li Yun zeng Gang Liu State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics Center for Molecular Imaging and Translational MedicineSchool of Public HealthXiamen UniversityXiamen 361102China Department of Pharmacy Xiamen Medical CollegeXiamen 361023China

Cardiovascular diseases (CVDs) are the most prominent cause of disability and mortality in the world. Although there have been a variety of therapeutic options for the management of CVDs, most of the traditional therapeutic strategies could not sufficiently stop or reduce the progression of these diseases and may result in some side effects. With the advance in nanotechnology, a number of metal-based nanoparticles have been developed and shown promising potentials in the treatment of CVDs. In this review, we provide a comprehensive review of researches on recent development of metal-based nanoparticles in diagnosis and therapy in CVDs as biomedical materials. We also discuss the challenges in the clinical translation and potential risks in their application of CVD therapy. Based on the ongoing research and applications, we can conclude metal-based nanoparticles are expected to become potential therapeutics for the treatment of CVDs. But their application is still in its infancy and much more efforts should be made to enforce a clinical breakthrough.

关键词： Metal-based nanoparticles Nanomedicine Cardiovascular diseases Diagnosis Therapy

Intraspecific variations in fine root N and P and factors affecting their concentrations in Masson pine plantations across subtropical China

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林业研究:英文版 2023年第5期34卷 1463-1473页

作者： Zunji Jian Jin Xu Yanyan Ni lei lei Lixiong zeng Wenfa Xiao Ecology and Nature Conservation Institute Chinese Academy of ForestryKey Laboratory of Forest Ecology and Environment of National Forestry and Grassland AdministrationBeijing 100091People’s Republic of China Co-Innovation Center for Sustainable Forestry in Southern China Nanjing Forestry UniversityNanjing 210037JiangsuPeople’s Republic of China Wuhan Botanical Garden Chinese Academy of SciencesWuhan 430074HubeiPeople’s Republic of China

Fine roots(<2 mm)play vital roles in water and nutrient uptake.However,intraspecific variations in their chemical traits and their controlling mechanisms remain poorly understood at a regional scale.This study examined these intraspecific variations in fine roots in Masson pine(Pinus massoniana Lamb.)plantations across subtropical China and their responses to environmental factors.Root nitrogen(N)and phosphorus(P)concentrations and their mass ratios(N:P)ranged from 3.5 to 11.7 g kg^(-1),0.2 to0.9 g kg^(-1),and 7.8 to 51.6 g kg^(-1),respectively.These three chemical traits were significantly different between sites and in longitudinal patterns across subtropical China.Mean annual temperature was positively related to root N concentration but negatively related to root P concentration.There were significant,negative relationships between clay content and root P concentration and between pH and root N concentration.Available N had no significant relationship with root N concentration,while available P was a significantly positive relationship with root P concentration.The combined effects of altitude,climate(temperature and precipitation)and soil properties(pH,clay content,available N and P)explained 26%and 36%of the root N and P concentrations variations,respectively.These environmental variables had direct and indirect effects and exhibited disproportionate levels of total effects on root N and P concentrations.Root N and P concentrations explained 35%and 65%variations in their mass ratios,respectively.The results highlight different spatial patterns of chemical traits and various environmental controls on root N and P concentrations in these ecosystems.More cause-effect relationships of root chemical traits with abiotic and biotic factors are needed to understand nutrient uptake strategies and the mechanisms controlling intraspecific variations in plant traits.

关键词： Fine root Chemical traits Environmental variables Pinus massoniana Subtropical China

Two-dimensional Metal-Organic Frameworks as Electrocatalysts for Oxygen Evolution Reaction

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Chemical Research in Chinese Universities 2020年第4期36卷 504-510页

作者： lei Jia zeng Mengqi FU lei College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072P.R.China

Oxygen evolution reaction(OER)plays an important role in many electrochemical systems.However,its sluggish kinetics severely limits the development of next-generation energy technologies.Recently,two-dimensional(2D)metal-organic frameworks(MOFs)have attracted much attention as a class of promising electrocatalysts.Their diverse components and tunable structures provide a new platform to design and explore ideal eleclrocatalysts.The ultrathin characteristics including high specific surface area,abundant exposed metal sites and fast electronic transfer further promote the electrocatalytic performance of 2D MOFs.Therefore,many attempts have been made in svntliesizing 2D MOF-based electrocatalysts in recent years.This review focuses on the strategies to fabricate 2D MOFs with high electrocatalytic performances for OER.The discussion on challenge and development of their electrocatalytic application is also presented.

关键词： Two-dimensional Metal-organic framework Oxygen evolution reaction(OER) Electrocatalysis

General Synthetic Iterative Scheme for Unsteady Rarefied Gas Flows

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Communications in Computational Physics 2023年第6期33卷 173-207页

作者： Jianan zeng Wei Su lei Wu Department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhen 518055China Division of Emerging Interdisciplinary Areas The Hong Kong University of Science and TechnologyClear Water BayHong KongChina Department ofMathematics The Hong Kong University of Science and TechnologyClear Water BayHong KongChina Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Mechanics and Engineering Applications Southern University of Science and TechnologyShenzhen 518055China

In rarefied gas flows,the spatial grid size could vary by several orders of magnitude in a single flow configuration(e.g.,inside the Knudsen layer it is at the order of mean free path of gas molecules,while in the bulk region it is at a much larger hydrodynamic scale).Therefore,efficient implicit numerical method is urgently needed for time-dependent problems.However,the integro-differential nature of gas kinetic equations poses a grand challenge,as the gain part of the collision operator is non-invertible.Hence an iterative solver is required in each time step,which usually takes a lot of iterations in the(near)continuum flow regime where the Knudsen number is small;worse still,the solution does not asymptotically preserve the fluid dynamic limit when the spatial cell size is not refined enough.Based on the general synthetic iteration scheme for steady-state solution of the Boltzmann equation,we propose two numerical schemes to push the multiscale simulation of unsteady rarefied gas flows to a new boundary,that is,the numerical solution not only converges within dozens of iterations in each time step,but also asymptotically preserves the Navier-Stokes-Fourier limit in the continuum flow regime,when the spatial grid is coarse,and the time step is large(e.g.,in simulating the extreme slow decay of two-dimensional Taylor vortex,the time step is even at the order of vortex decay time).The properties of fast convergence and asymptotic preserving of the proposed schemes are not only rigorously proven by the Fourier stability analysis for simplified gas kinetic models,but also demonstrated by several numerical examples for the gas kinetic models and the Boltzmann equation.

关键词： Unsteady rarefied gas flow general synthetic iterative scheme fast convergence asymptotic Navier-Stokes preserving

OPTIMAL CONTROL FOR MULTISCALE ELLIPTIC EQUATIONS WITH ROUGH COEFFICIENTS

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Journal of Computational Mathematics 2023年第5期41卷 841-865页

作者： Yanping Chen Xinliang Liu Jiaoyan zeng lei Zhang School of Mathematical Sciences South China Normal UniversityGuangzhou 510631China King Abdullah University of Science and Technology Thuwal 23955Saudi Arabia School of Mathematics and Statistics Guangdong University of FinanceGuangzhou 510631China School of Mathematical Sciences Institute of Natural Sciencesand MOE-LSCShanghai Jiao Tong UniversityShanghai 200240China

This paper concerns the convex optimal control problem governed by multiscale elliptic equations with arbitrarily rough L∞coefficients,which has not only complex coupling between nonseparable scales and nonlinearity,but also important applications in composite materials and geophysics.We use one of the recently developed numerical homogenization techniques,the so-called Rough Polyharmonic Splines(RPS)and its generalization(GRPS)for the efficient resolution of the elliptic operator on the coarse scale.Those methods have optimal convergence rate which do not rely on the regularity of the coefficients nor the concepts of scale-separation or periodicity.As the iterative solution of the nonlinearly coupled OCP-OPT formulation for the optimal control problem requires solving the corresponding(state and co-state)multiscale elliptic equations many times with different right hand sides,numerical homogenization approach only requires one-time pre-computation on the fine scale and the following iterations can be done with computational cost proportional to coarse degrees of freedom.Numerical experiments are presented to validate the theoretical analysis.

关键词： Optimal control Rough coefficients Multiscale elliptic equations Numerical homogenization Rough polyharmonic splines Iterative algorithm

Probabilistic Lane-Change Decision-Making and Planning for Autonomous Heavy Vehicles

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IEEE/CAA Journal of Automatica Sinica 2022年第12期9卷 2161-2173页

作者： Wen Hu Zejian Deng Dongpu Cao Bangji Zhang Amir Khajepour Lei Zeng Yang Wu State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China Department of Mechanical and Mechatronics Engineering University of WaterlooWaterloo ON N2L3G1Canada IEEE School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China

To improve the safety and driving stability of the autonomous heavy truck, it is necessary to consider the differences of driving behavior and drivable trajectories between the heavy trucks and passenger cars. This study proposes a probabilistic decision-making and trajectory planning framework for the autonomous heavy trucks. Firstly, the driving decision process is divided into intention generation and feasibility evaluations, which are realized using the utility theory and risk assessment, respectively. Subsequently the driving decision is made and sent to the trajectory planning module. In order to reflect the greater risks of the truck to other surrounding vehicles, the aggressiveness index(AI) is proposed and quantified to infer the asymmetrical risk level of lane-change maneuver. In the planning stage, the lateral and roll dynamics stability domains are developed as the constraints to exclude the candidate trajectories that would cause vehicle instability. Finally, the simulation results are compared between the proposed model and the artificial potential filed model in the scenarios extracted from the naturalistic driving data. It is shown that the proposed framework can provide the human-like lane-change decisions and truck-friendly trajectories, and performs well in dynamic driving environments.

关键词： Autonomous heavy truck decision-making driving aggressiveness risk assessment trajectory planning

A unified pre-training and adaptation framework for combinatorial optimization on graphs

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Science China Mathematics 2024年第6期67卷 1439-1456页

作者： Ruibin zeng Minglong lei Lingfeng Niu Lan Cheng School of Computer Science and Technology University of Chinese Academy of SciencesBeijing100049China Faculty of Information Technology Beijing University of TechnologyBeijing100124China School of Economics and Management University of Chinese Academy of SciencesBeijing100190China School of Mathematics and Statistics Central South UniversityChangsha410075China

Combinatorial optimization(CO)on graphs is a classic topic that has been extensively studied across many scientific and industrial fields.Recently,solving CO problems on graphs through learning methods has attracted great attention.Advanced deep learning methods,e.g.,graph neural networks(GNNs),have been used to effectively assist the process of solving COs.However,current frameworks based on GNNs are mainly designed for certain CO problems,thereby failing to consider their transferable and generalizable abilities among different COs on graphs.Moreover,simply using original graphs to model COs only captures the direct correlations among objects,which does not consider the mathematical logicality and properties of COs.In this paper,we propose a unified pre-training and adaptation framework for COs on graphs with the help of the maximum satisfiability(Max-SAT)problem.We first use Max-SAT to bridge different COs on graphs since they can be converted to Max-SAT problems represented by standard formulas and clauses with logical information.Then we further design a pre-training and domain adaptation framework to extract the transferable and generalizable features so that different COs can benefit from them.In the pre-training stage,Max-SAT instances are generated to initialize the parameters of the model.In the fine-tuning stage,instances from CO and Max-SAT problems are used for adaptation so that the transferable ability can be further improved.Numerical experiments on several datasets show that features extracted by our framework exhibit superior transferability and Max-SAT can boost the ability to solve COs on graphs.

关键词： combinatorial optimization graph neural networks domain adaptation maximum satisfiability problem

Paleoclimate evolution and aridification mechanism of the eastern Tethys during the Callovian–Oxfordian: evidence from geochemical records of the Qiangtang Basin, Tibetan Plateau

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Acta Geochimica 2021年第2期40卷 199-211页

作者： Yongyao zeng lei Gao Wenqing Zhao Lanzhou Resources and Environment Voc-Tech College Lanzhou 730000China

Global climate during the Jurassic has been commonly described as a uniform greenhouse climate for a long time.However,the climate scenario of a cool episode during the Callovian-Oxfordian transition following by a warming trend during the Oxfordian(163.53 to157.4 Ma)is documented in many localities of the western Tethys.It is still unclear if a correlatable climate scenario also occurred in the eastern Tethys during the same time interval.In this study,a detailed geochemical analysis on the 1060 m thick successions(the Xiali and Suowa formations)from the Yanshiping section of the Qiangtang Basin,located in the eastern Tethys margin during the Callovian-Oxfordian periods,was performed.To reveal the climate evolution of the basin,carbonate content and soluble salt concentrations(SO_(4)^(2-),Cl^(-))were chosen as climatic indices.The results show that the overall climate patterns during the deposition of the Xiali and Suowa formations can be divided into three stages:relatively humid(164.0 to 160.9 Ma),dry(160.9 to159.6 Ma),semi-dry(159.6 to 156.8 Ma).A similar warming climate scenario also occurred in eastern Tethys during the Callovian-Oxfordian transition(160.9 to159.6 Ma).Besides,we clarify that the Jurassic True polar wander(TPW),the motion of the lithosphere and mantle with respect to Earth’s spin axis,inducing climatic shifts were responsible for the aridification of the Qiangtang Basin during the Callovian-Oxfordian transition with a review of the paleolatitude of the Xiali formation(19.7+2.8/-2.6°N)and the Suowa formation(20.7+4.1/-3.7°N).It is because the TPW rotations shifted the East Asia blocks(the North and South China,Qiangtang,and Qaidam blocks)from the humid zone to the tropical/subtropical arid zone and triggered the remarkable aridification during the Middle-Late Jurassic(ca.165-155 Ma).

关键词： Qiangtang basin The Callovian–Oxfordian Geochemistry Paleolatitude Paleoclimate