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A review of gas-phase chemical mechanisms commonly used in atmospheric chemistry modelling

Journal of Environmental sciences 2023年第1期123卷 522-534页

作者： Yanhui Liu Jiayin Li Yufang Ma Ming Zhou Zhaofeng Tan Limin Zeng Keding Lu Yuanhang Zhang State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Science and EngineeringPeking UniversityBeijing 100871China Institute of Energy and Climate Research IEK-8:TroposphereForschungszentrum Jülich GmbHJülich 52428Germany

The atmospheric chemical mechanism is an essential component of airshed models used for investigating the chemical behaviors and impacts of *** the first tropospheric chemical mechanism was proposed in the 1960s,various mechanisms including Master Chemical Mechanism(MCM),Carbon Bond Mechanism(CBM),Statewide Air Pollution Research Center(SAPRC)and Regional Atmospheric Chemistry Mechanism(RACM)have been developed for different research *** work summarizes the development and applications of these mechanisms,introduces their compositions and lumping methods,and compares the ways the mechanisms treat radicals with box model *** can reproduce urban pollution events with relatively low cost compared to SAPRC and RACM,whereas the chemical behaviors of radicals and the photochemical production of ozone are described in detail in *** photolysis rates of some oxygenated compounds are low in SAPRC07,which may result in underestimation of radical *** an explicit chemical mechanism,MCM describes the chemical processes of primary pollutants and their oxidation products in *** can be used to investigate certain chemical processes;however,due to its large size,it is rarely used in regional model simulations.A box model case study showed that the chemical behavior of OH and HO_(2)radicals and the production of ozone were well described by all *** and SAPRC underestimated the radical levels for different chemical treatments,leading to low ozone production values in both *** and RACM are widely used in box model studies,while CBM and SAPRC are often selected in regional simulations.

关键词： Atmospheric chemistry Gas-phase chemical mechanism Ozone Box model

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Kernel-learning parameter prediction and evaluation in algebraic multigrid method for several PDEs

arXiv

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arXiv 2025年

作者： Zhang, Juan Luo, Junyue Zhang, Fangfang Yue, Xiaoqiang Hunan Key Laboratory for Computation and Simulation in Science and Engineering Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education School of Mathematics and Computational Science Xiangtan University Hunan Xiangtan411105 China

This paper explores the application of kernel learning methods for parameter prediction and evaluation in the Algebraic Multigrid Method (AMG), focusing on several Partial Differential Equation (PDE) problems. AMG is an efficient iterative solver for large-scale sparse linear systems, particularly those derived from elliptic and parabolic PDE discretizations. However, its performance heavily relies on numerous parameters, which are often set empirically and are highly sensitive to AMG’s effectiveness. Traditional parameter optimization methods are either computationally expensive or lack theoretical support. To address this, we propose a Gaussian Process Regression (GPR)-based strategy to optimize AMG parameters and introduce evaluation metrics to assess their effectiveness. Trained on small-scale datasets, GPR predicts nearly optimal parameters, bypassing the time-consuming parameter sweeping process. We also use kernel learning techniques to build a kernel function library and determine the optimal kernel function through linear combination, enhancing prediction accuracy. In numerical experiments, we tested typical PDEs such as the constant-coefficient Poisson equation, variable-coefficient Poisson equation, diffusion equation, and Helmholtz equation. Results show that GPR-predicted parameters match grid search results in iteration counts while significantly reducing computational time. A comprehensive analysis using metrics like mean squared error, prediction interval coverage, and Bayesian information criterion confirms GPR’s efficiency and reliability. These findings validate GPR’s effectiveness in AMG parameter optimization and provide theoretical support for AMG’s practical application. © 2025, CC BY.

关键词： Poisson equation

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High energy storage performance in AgNbO_(3) relaxor ferroelectric films induced by nanopillar structure

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Journal of Materials science & Technology 2023年第24期155卷 160-166页

作者： Xiang Li Jing Wang Xingyuan San Ning Wang Lei Zhao Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province College Physics Science and Technology Hebei University Baoding 071002 China State Key Laboratory of Mechanics and Control of Mechanical Structures College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Huangpu Hydrogen Energy Innovation Center School of Chemistry and Chemical Engineering Guangzhou University Guangzhou 510006 China

Inspired by the increasing demand for energy-storage capacitors in electrical and electronic systems, dielectrics with high energy-storage performance have attracted more and more attention. AgNbO_(3) -based lead-free ceramics serve as one of the most promising environmental-friendly candidates. However, their energy storage optimization is seriously limited by the low breakdown strength. Fortunately, thin film as a form of AgNbO3 materials can effectively improve the breakdown strength. In this work, AgNbO_(3)film with ∼550 nm in thickness was deposited on SrRuO_(3 )/(001)SrTiO_(3) using pulsed laser deposition. The AgNbO_(3) film reveals typical relaxor ferroelectric hysteresis loops due to the new nanopillar structure, which contributes to high breakdown strength of up to 1200 kV cm^(-1) . Benefiting from the high breakdown strength, a recoverable energy storage density of 10.3 J cm^(-3) and an energy efficiency of 72.2% are obtained in the AgNbO_(3) film, which demonstrates the promising prospect of AgNbO_(3) film for energy storage applications.

关键词： AgNbO3 film Relaxor ferroelectrics Energy storage performance Nanopillar structure

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Design of Multi-Coupled Laminates with Extension-Twisting Coupling for Application in Adaptive Structures

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Computer Modeling in engineering & sciences 2022年第1期130卷 415-441页

作者： Da Cui Daokui Li Shiming Zhou College of Aerospace Science and Engineering National University of Defense TechnologyChangsha410073China Hunan Key Laboratory of Intelligent Planning and Simulation for AerospaceMissions Changsha410073China

The multiple coupling of composite laminates has a unique advantage in improving the macro mechanical properties of composite structures.A total of three hygro-thermally stablemulti-coupled laminates with extensiontwisting coupling were presented,which were conducive to the formation of passive adaptive ***,the multi-coupled laminates were used to design the bending-twisting coupled box structure,in which the configuration of laminate and box structure could be extended to variable cross-section *** optimal design of stacking sequence was realized,the optimization objectives of which were to maximize bending-twisting coupling of box structure and extension-twisting coupling of laminate,*** effects of multiple coupling on hygro-thermal stability,coupling,failure strength,buckling load,robustness and other comprehensive mechanical properties of laminates and box structures were analyzed by parametric modeling *** results show that the extension-twisting coupling of laminate and the bending-twisting coupling of box structures can be greatly improved by 450%and 260%at maximum,***,it would have a negative impact on the failure strength and buckling load,which,however,can be minimized by a reasonable paving *** laminates have good robustness,and the bending-twisting coupling helps improve ***,the hygro-thermal stability and mechanical properties were verified by numerical simulation with finite element method.

关键词： Multi-coupled laminate passive adaptive structures optimal design mechanical properties numerical simulation

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MPC-based strategy for longitudinal and lateral stabilization of a vehicle under extreme conditions

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science China(Information sciences) 2022年第7期65卷 263-264页

作者： Zihan LI Ping WANG Chaojie ZHU Yunfeng HU Hong CHEN State Key Laboratory of Automotive Simulation and Control Jilin University Department of Control Science and Engineering School of Communication Engineering Jilin University Clean Energy Automotive Engineering Center Tongji University

Dear editor, In recent decades, active safety-control systems have been developed to assist drivers. Wheel slip ratio, yaw rate, and side-slip angle are commonly considered as the control indices of longitudinal and lateral vehicle stabilities [1]. However, if systems that only contain vehicle dynamics in longitudinal or lateral directions work simultaneously, the system objectives may conflict.

关键词： model predictive control stability control combined-slip characteristics LuGre tire model extreme driving conditions

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Catalytic urea hydrolysis by composite metal oxide catalyst towards efficient urea-based SCR process:performance evaluation and mechanism investigation

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Frontiers of Environmental science & engineering 2023年第5期17卷 67-80页

作者： Yuchen Li Zhen Chen Xiangyu Zhang Kun Yang Lidong Wang Junhua Li MOE Key Laboratory of Resources and Environmental Systems Optimization Department of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China Xi’an Thermal Power Research Institute Co. Xi’an 710032China

As a promising option to provide gaseous NH_(3) for SCR system,catalytic urea hydrolysis has aroused great attention,and improving surface area and activity of catalysis are the crucial issues to be solved for efficient urea ***,a composite metal oxide(TiO_(2)@Al_(2)O_(3))catalyst was prepared by a simple hydrothermal method,with mesoporous alumina(γ-Al_(2)O_(3))as *** results verify the mesoporous structure and submicron cluster of TiO_(2)@Al_(2)O_(3),with exposed crystal faces of(101)and(400)for TiO_(2)andγ-Al_(2)O_(3),*** electronegativity difference of Ti4+and Al3+changes the charge distribution scheme around the interface,which provides abundant acid/base sites to boost the urea ***,for an optimal proportioning with nano TiO_(2)content at 10 wt.%,the hydrolysis efficiency can reach up to 35.2%at 100℃ in 2 h,increasing by~7.1%than that of the blank experiment.^(13)C NMR spectrum measurements provide the impossible intermediate species during urea *** calculations are performed to clarify the efficient H_(2)O decomposition at the interface of TiO_(2)@Al_(2)O_(3).The result offers a favorable technology for energy-efficiency urea hydrolysis.

关键词： SCR Urea hydrolysis Catalytic Water dissociation Electronegativity

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Deciphering decadal urban ozone trends from historical records since 1980

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National science Review 2024年第11期11卷 117-129页

作者： Haolin Wang Xiao Lu Paul I.Palmer Lin Zhang Keding Lu Ke Li Tatsuya Nagashima Ja-Ho Koo Hiroshi Tanimoto Haichao Wang Meng Gao Cheng He Kai Wu Shaojia Fan Yuanhang Zhang School of Atmospheric Sciences Sun Yat-sen University and Key Laboratory of Tropical Atmosphere-Ocean System Ministry of Education Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) School of Geo Sciences University of Edinburgh National Centre for Earth Observation University of Edinburgh Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking University State Key Joint Laboratory of Environmental Simulation and Pollution Control The State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution ControlCollege of Environmental Sciences and Engineering Peking University Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science &Technology National Institute for Environmental Studies Department of Atmospheric Sciences Yonsei University Department of Geography Hong Kong Baptist University Department of Civil and Environmental Engineering University of California

Ozone pollution is a major environmental threat to human health. Timely assessment of ozone trends is crucial for informing environmental policy. Here we show that for the most recent decade（2013–2022） in the northern hemisphere, warm-season（April–September） mean daily 8-h average maximum ozone increases much faster in urban regions with top ozone levels(mainly in the North China Plain, 1.2 ± 1.3 ppbv year-1) than in other, low-ozone regions(0.2 ± 0.9 ppbv year-1). These trends widen the ozone differences across urban regions, and increase extreme pollution levels and health threats from a global perspective. Comparison of historical trends in different urban regions reveals that ozone increases in China during 2013–2022 differ in magnitude and mechanisms to historical periods in other regions since *** reflects a unique chemical environment characterized by exceptionally high nitrogen oxides and aerosol concentrations, where reducing ozone precursor emissions leads to substantial ozone *** increase in China has slowed down in 2018–2022 compared to 2013–2017, driven by ongoing emission reductions, but with ozone-favorable weather conditions. Historical ozone evolution in Japan and South Korea indicates that ozone increases should be suppressed with continuous emission *** temperature and associated wildfires have also reversed ozone decreases in the USA and Europe,with anthropogenic ozone control slowing down in recent decades.

关键词： air quality surface ozone trends

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A Sparse Optical Flow Method for Camera Tracking under Fisheye Camera Models 5

A Sparse Optical Flow Method for Camera Tracking under Fishe...

引用

5th International Conference on Frontiers Technology of Information and Computer, ICFTIC 2023

作者： Zhang, Zuoming Wang, Xin College of Computer Science and Technology Jilin China College of Computer Science and Technology Key Laboratory of Symbolic Computation and Knowledge Engineering Ministry of Education Jilin China

ISBN: (纸本)9798350309034

In computer image processing, optical flow is a classic task used to track the motion of pixels. In the field of robotics, methods like SLAM extensively employ sparse optical flow as a substitute for time-consuming feature point matching methods, enabling rapid and stable camera tracking. However, the widespread use of fisheye cameras introduces distortion issues in practical applications. Traditional sparse optical flow struggles to accurately track pixel positions in such scenarios, affecting the precision of camera pose tracking. Therefore, we introduce a sparse optical flow method designed for fisheye camera models, which correctly utilizes prior information obtained during camera tracking to enhance the accuracy of sparse optical flow. Finally, we propose a scheme for constructing a semi-distortion lookup table to accelerate distortion operations and reduce memory requirements. We conducted extensive testing on simulated datasets with various camera motion scenarios, and the experimental results demonstrate that our method outperforms OpenCV in terms of accuracy and versatility. © 2023 IEEE.

关键词： camera tracking component distortion fisheye camera model optical flow

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Designing hard wear-resistant conductors by introducing high-plasma-energy heterogeneous metals into transition metal nitrides

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Journal of Materials science & Technology 2023年第26期157卷 213-219页

作者： Yuankai Li Chaoquan Hu Yao Wu Zhenan Qiao Yifan Cheng Zhiqing Gu Gang Gao Weitao Zheng State Key Laboratory of Superhard Materials Key Laboratory of Automobile Materials of Ministry of EducationSchool of Materials Science and EngineeringJilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy MaterialsJilin UniversityChangchun 130012China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China SINOPEC Star Co.Ltd. Beijing 100083China Key Laboratory of Medical Electronics and Digital Health of Zhejiang Province College of Information Science and EngineeringJiaxing UniversityJiaxing 314001China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150080China State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130025China

*** Hard and wear-resistant conductors(HWCs)refer to functional films with simultaneously high hardness,high wear resistance,and good electrical *** have important applica-tions such as next-generation sliding electrical contacts,high-end conductive probe-tip,and oval hole guides for the precision rolling mill[1-4],which has drawn extensive research ***,it is still challenging to integrate high hardness,super wear resis-tance,and high electrical conductivity in one ***-ally,researchers have mainly alloyed the highly conductive met-als Cu,Au,and Pt to improve their hardness and wear resistance.

关键词： wear high electrical

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New digital drilling process monitoring: Instrumentation, validation and calibration

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Journal of Rock Mechanics and Geotechnical engineering 2025年第1期17卷 31-54页

作者： Yanpeng Sun Zuyu Chen Fangcai Xu Yufei Zhao Ruilang Cao Dong Li State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi'an University of TechnologyXi'an710048China State Key Laboratory of Simulation and Regulation of the Water Cycle in River Basins China Institute of Water Resources and Hydropower ResearchBeijing100048China Sinohydro Foundation Engineering Co. Ltd.Tianjin301700China North China Institute of Science&Technology Langfang065201China

This study aims to enhance the digital drilling process monitoring(DPM)or monitoring while drilling(MWD)technique,which is a widely recognized method in geological exploration for evaluating rock mass ***,robust displacement and torque measurement facilities for rotary-core drilling are *** conventional cable encoder for displacement measurement is replaced with a magnetostrictive displacement sensor,which is more reliable in harsh field drilling *** enables the measurement of the bit position with an accuracy of<1 *** importantly,this new instrument is proven to be successful in improving the detection of structural discontinuities with thicknesses>1 *** addition,by measuring the electric current of the driving motor,the torque applied to the bit is conveniently and accurately *** innovations ensure high-quality data collection for DPM ***,two indices derived from DPM are proposed to quantitatively describe rock mass *** specific energy index(SEI)and specific penetration index(SPI)are based on the principles of energy conservation and Mohr-Coulomb failure criterion,*** field tests conducted in a dam grouting area confirm a linear relationship between the thrust force and penetration per rotation,and between the torque and penetration per *** correlation ratios of the related regressions are typically>*** two indices allow for the quantitative interpretation of DPM data into rock mechanics characteristics,such as uniaxial compressive strength,rock quality designation(RQD),and rock mass permeability,eliminating the need for subjective judgment normally involved in the currently used rock mass quality rating approaches.

关键词： Drilling process monitoring Specific penetration index Specific energy index Fracture identification

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