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Mixing states and secondary formation processes of organic nitrogen-containing single particles in Guangzhou,China

Journal of Environmental Sciences 2024年第4期138卷 62-73页

作者： Lijun Yun Chunlei cheng Suxia Yang Zaihua Wang Mei Li Qi En Zhong LiyuanMao Sulin Liu Xiaoya cheng Duanying Chen Fan Yang Zhen Zhou Institute of Mass Spectrometry and Atmospheric Environment Guangdong Provincial Engineering Research Center for on-line source apportionment system of air pollutionJinan UniversityGuangzhou 510632China Guangdong-Hongkong-Macao Joint Laboratory of Collaborative Innovation for Environmental Quality Guangzhou 510632China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy ScienceXi’an 710061China Institute for Environment and Climate Research Jinan UniversityGuangzhou 510632China Guangdong Academy of Sciences Institute of Resources Utilization and Rare Earth DevelopmentGuangzhou 510650China Environmental Monitoring Station of Pudong New District Shanghai 201200China

Organic nitrogen(ON)compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols,however,the mixing state,secondary formation processes,and influencing factors of ON compounds are still unclear.This paper reports on the mixing state of ON-containing particles based on measurements obtained using a highperformance single particle aerosol mass spectrometer in January 2020 in Guangzhou.The ON-containing particles accounted for 21% of the total detected single particles,and the particle count and number fraction of the ON-containing particles were two times higher at night than during the day.The prominent increase in the content of ON-containing particles with the enhancement of NO_xmainly occurred at night,and accompanied by high relative humidity and nitrate,which were associated with heterogeneous reactions between organics and gaseous NO_(x)and/or NO_(3)radical.The synchronous decreases in ON-containing particles and the mass absorption coefficient of water-soluble extracts at 365 nm in the afternoon may be associated with photo-bleaching of the ON species in the particles.In addition,the positive matrix factorization analysis found five factors dominated the formation processes of ON particles,and the nitrate factor(33%)mainly contributed to the production of ON particles at night.The results of this study provide unique insights into the mixing states and secondary formation processes of the ON-containing particles.

关键词： Organic nitrogen compounds Single particles Mixing state Secondary formation Nighttime chemistry

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Early prediction and prevention of infected pancreatic necrosis

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World Journal of Gastroenterology 2024年第9期30卷 1005-1010页

作者： cheng Lv Zi-Xiong Zhang Lu Ke Department of Critical Care Medicine Jinling HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing 210000Jiangsu ProvinceChina Research Institute of Critical Care Medicine and Emergency Rescue Nanjing UniversityNanjing 210000Jiangsu ProvinceChina

Approximately 20%-30%of patients with acute necrotizing pancreatitis develop infected pancreatic necrosis(IPN),a highly morbid and potentially lethal complication.Early identification of patients at high risk of IPN may facilitate appropriate preventive measures to improve clinical outcomes.In the past two decades,several markers and predictive tools have been proposed and evaluated for this purpose.Conventional biomarkers like C-reactive protein,procalcitonin,lymphocyte count,interleukin-6,and interleukin-8,and newly developed biomarkers like angiopoietin-2 all showed significant association with IPN.On the other hand,scoring systems like the Acute Physiology and Chronic Health Evaluation II and Pancreatitis Activity Scoring System have also been tested,and the results showed that they may provide better accuracy.For early prevention of IPN,several new therapies were tested,including early enteral nutrition,anti-biotics,probiotics,immune enhancement,etc.,but the results varied.Taken together,several evidence-supported predictive markers and scoring systems are readily available for predicting IPN.However,effective treatments to reduce the incidence of IPN are still lacking apart from early enteral nutrition.In this editorial,we summarize evidence concerning early prediction and prevention of IPN,providing insights into future practice and study design.A more homo-geneous patient population with reliable risk-stratification tools may help find effective treatments to reduce the risk of IPN,thereby achieving individualized treatment.

关键词： Acute pancreatitis Infected pancreatic necrosis Biomarker Scoring system Nutrition therapy Selective digestive decontamination Probiotics Antibiotics Immune enhancement therapy

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Microstructure recognition of steels by machine learning based on visual attention mechanism

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Journal of Iron and Steel Research(International) 2024年第4期31卷 909-923页

作者： Xing-yu Chen Lin cheng cheng-yang Hu Yu-peng Zhang Kai-ming Wu The State Key Laboratory of Refractories and Metallurgy Hubei Province Key Laboratory of Systems Science on Metallurgical ProcessingInternational Research Institute for Steel TechnologyCollaborative Center on Advanced SteelsWuhan University of Science and TechnologyWuhan 430081HubeiChina Metals Valley and Band(Foshan)Metallic Composite Materials Co. Ltd.Foshan 528000GuangdongChina

U-Net has achieved good performance with the small-scale datasets through skip connections to merge the features of the low-level layers and high-level layers and has been widely utilized in biomedical image segmentation as well as recent microstructure image segregation of the materials.Three representative visual attention mechanism modules,named as squeeze-and-excitation networks,convolutional block attention module,and extended calibration algorithm,were intro-duced into the traditional U-Net architecture to further improve the prediction accuracy.It is found that compared with the original U-Net architecture,the evaluation index of the improved U-Net architecture has been significantly improved for the microstructure segmentation of the steels with the ferrite/martensite composite microstructure and pearlite/ferrite composite microstructure and the complex martensite/austenite island/bainite microstructure,which demonstrates the advantages of the utilization of the visual attention mechanism in the microstructure segregation.The reasons for the accuracy improvement were discussed based on the feature maps analysis.

关键词： Microstructure recognition-Steel Machine learning Visual attention mechanism Visualization

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Ytterbium modified birnessite MnO_(2) for improving deep oxidation of toluene

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Journal of Rare Earths 2024年第4期42卷 668-675页

作者： Linjiang Sun Yan cheng Yujie Liu Can Yi Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengdu611756China

A series of rare earth metals modified birnessite manganese dioxides(RE-Mn)was synthesized by hydrothermal method and their catalytic degradation of toluene was investigated.Yb-Mn shows the best toluene oxidation activity with the conversion of T50%and T99%at 196 and 226℃,respectively.The physiochemical characterizations identified that the high catalytic performance and excellent stability of Yb-Mn are mainly associated with its higher molar ratios of Mn^(4+)/Mn^(3+),more lattice oxygen(Olatt),and better mobility of surface adsorbed oxygen(O_(ads)).Moreover,it is confirmed that introduction of Yb into birnessite MnO_(2) facilitates the production of acetic acid at lower temperature.These results can aid the design of high-efficiency manganese oxide catalysts for the catalytic combustion of VOCs.

关键词： Manganese oxide Rare earth metal doping Toluene Catalytic combustion

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Modelling the formation and dissolution behavior of alumina agglomerate in the cryolite

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Particuology 2024年第3期86卷 211-222页

作者： Jiaqi Wang Mao Li Benjun cheng Hesong Li School of Energy Science and Engineering Central South UniversityChangsha410083China

The presence of alumina agglomerates seriously affects the current efficiency of the aluminum electrolysis process.Clarify the dynamic dissolution process of agglomerates is essential to improve the current efficiency of aluminum electrolysis.A mathematical model is proposed to describe the different phenomena from the formation until complete dissolution of agglomerates.Considering permeation and solidification processes of cryolite,a semi-analytical mathematical model is developed to formulate the formation,melting and dissolution processes of agglomerates,and the time duration for each stage is deduced.Porosity and heat mass transfer of agglomerates are explored based on the packing theory and mechanism of heat mass transfer in wet porous media.Dimensionless approach is applied to investigate the main factors affecting the dissolution stages and porosity of agglomerates.The results show that the superheat has a great influence on the formation and melting stage,the diameter of agglomerates can reach 14.93 mm for 200 particles agglomerated.The density decreases with the increase of agglomerated particle number,which varies in the range of 2.27-2.28 g/cm^(3).The average dissolution rate of agglomerates is about 1.83×10^(-5)-2.95×10^(-5) kg/s within the range of alumina concentration in this study.

关键词： Mathematical model Alumina agglomerate Porous media Packing theory Heatand mass transfer

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Compound Product of Hypermatrices

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Journal of Systems Science & Complexity 2024年第1期37卷 169-183页

作者： cheng Daizhan MENG Min ZHANG Xiao JI Zhengping Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China Department of Control Science and Engineering School of Electronics and Information EngineeringTongji UniversityShanghai 201210China National Center for Mathematics and Interdisciplinary Sciences Chinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100149China.

The semi-tensor product(STP)of matrices is generalized to multidimensional arrays,called the compound product of hypermatrices.The product is first defined for three-dimensional hypermatrices with compatible orders and then extended to general cases.Three different types of hyperdeterminants are introduced and certain properties are revealed.The Lie groups and Lie algebras corresponding to the hypermatrix products are constructed.Finally,these results are applied to dynamical systems.

关键词： Compound semi-tensor product hyperdeterminants hypereigenvalues and hypereigenvectors hypergeneral linear groups hypermatrices.

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Bioinspired designs in active metal-based batteries

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Nano Research 2024年第2期17卷 587-601页

作者： Fan Zhang Ting Liao cheng Yan Ziqi Sun School of Chemistry and Physics Queensland University of TechnologyGeorge StreetBrisbaneQLD 4000Australia School of Mechanical Medical and Process Engineering Queensland University of TechnologyGeorge StreetBrisbaneQLD 4000Australia QUT Centre for Materials Science Queensland University of TechnologyGeorge StreetBrisbaneQLD 4000Australia

Active metal-based batteries are drawing increased attention because of their inherent high energy density and specific capacity.Some grand challenges,such as dendrite growth,electrode degradation,rapid performance fading,etc.,have limited their practical application.Bioinspiration,which involves taking cues from the structures and functions of the natural world,can lead to a wealth of conceptually fresh approaches to regulator the metal ion transportation to achieve a dendrite-free metal plating,thwart the side-reaction reactions,and retard the structural distortions,for a more reliable and secure operation of active metal-based batteries.In this review,we concentrate on the fabrication and application of bioinspired designs in active metal-based batteries with enhanced performance,along with discussion on the challenges and opportunities associated with this promising topic.We anticipate that this review can offer some insights into the development of functional materials by learning from nature and provide some approaches for the innovations of either the battery structures or the energy materials for metal-based batteries.

关键词： bioinspired materials energy storage devices metal-based batteries

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Effect of boundary conditions on shakedown analysis of heterogeneous materials

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 39-68页

作者： Xiuchen GONG Yinghao NIE Gengdong cheng Kai LI State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentInternational Research Center for Computational MechanicsDepartment of Engineering MechanicsDalian University of TechnologyDalian 116023Liaoning ProvinceChina

The determination of the ultimate load-bearing capacity of structures made of elastoplastic heterogeneous materials under varying loads is of great importance for engineering analysis and design. Therefore, it is necessary to accurately predict the shakedown domains of these materials. The static shakedown theorem, also known as Melan's theorem, is a fundamental method used to predict the shakedown domains of structures and materials. Within this method, a key aspect lies in the construction and application of an appropriate self-equilibrium stress field(SSF). In the structural shakedown analysis, the SSF is typically constructed by governing equations that satisfy no external force(NEF) boundary conditions. However, we discover that directly applying these governing equations is not suitable for the shakedown analysis of heterogeneous materials. Researchers must consider the requirements imposed by the Hill-Mandel condition for boundary conditions and the physical significance of representative volume elements(RVEs). This paper addresses this issue and demonstrates that the sizes of SSFs vary under different boundary conditions, such as uniform displacement boundary conditions(DBCs), uniform traction boundary conditions(TBCs), and periodic boundary conditions(PBCs). As a result, significant discrepancies arise in the predicted shakedown domain sizes of heterogeneous materials. Built on the demonstrated relationship between SSFs under different boundary conditions, this study explores the conservative relationships among different shakedown domains, and provides proof of the relationship between the elastic limit(EL) factors and the shakedown loading factors under the loading domain of two load vertices. By utilizing numerical examples, we highlight the conservatism present in certain results reported in the existing literature. Among the investigated boundary conditions, the obtained shakedown domain is the most conservative under TBCs.Conversely, utilizing PBCs to construct an SSF for the shakedown analysis lea

关键词： heterogeneous material self-equilibrium stress field(SSF) shakedown analysis effect of boundary conditions

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Honeycomb-like biochar framework coupled with Fe_(3)O_(4)/FeS nanoparticles as efficient heterogeneous Fenton catalyst for phenol degradation

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Journal of Environmental Sciences 2024年第2期136卷 390-399页

作者： Aihua cheng Yi He Xiaohe Liu Chi He Department of Environmental Engineering College of Geology and EnvironmentXi’an University of Science and TechnologyXi’an 710054China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China National Engineering Laboratory for VOCs Pollution Control Material and Technology University of Chinese Academy of SciencesBeijing 101408China

Achieving an efficient and stable heterogeneous Fenton reaction over a wide pH range is of great significance for wastewater treatment.Here,a pollen-derived biochar catalyst with a unique honeycomb-like structure,coupled with the dispersion of magnetic Fe_(3)O_(4)/FeS(Fe/S)nanoparticles,was synthesized by simple impregnation precursor,followed by pyrolysis.The prepared Fe/S-biochar catalyst demonstrated outstanding phenol degradation efficiency across a wide pH range,with 98%of which eliminated even under neutral conditions(pH 7.0).The high catalytic activity was due to the multilevel porous structure of pollenderived biochar provided enough active sites and allowed for better electron transfer,then increases oxidation ability to promote the reaction.Moreover,the acid microenvironment formed by SO_(4)^(2-)group from Fe/S composite extended the pH range for Fenton reaction,and S^(2-)facilitated the conversion of≡Fe^(3+)to≡Fe^(2+),resulting in remarkable degradation efficiency.Further,biochar can effectively promote cycling stability by limiting Fe leaching.This work may provide a general strategy for designing 3D framework biochar-based Fe/S catalysts with excellent performance for heterogeneous Fenton reactions.

关键词： Biomass Biochar Fenton reaction Fe_(3)O_(4)/FeS(Fe/S) Phenol degradation

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Effects of Additives on the Microstructure and Tribology Performance of Ta-12W Alloy Micro-Arc Oxidation Coating

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 142-149页

作者：刘玲 HU Changgang cheng Wendong 刘兴泉 School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 610054China

Oxide ceramic coatings were fabricated on tantalum alloys by micro-arc oxidation (MAO) to improve their hardness and tribological properties. The MAO coatings were manufactured in a mixed silicatephosphate electrolyte containing NaF and/or EDTA (ethylene diamine tetraacetic acid). The surface morphology,cross-sectional view, chemical composition, hardness, and wear performance of the coatings were analysed. As revealed by the scanning electron microscopy, silica-rich nodules appear on the MAO coating obtained in the silicate-phosphate electrolyte, but the formation of nodules is inhibited with NaF and/or EDTA in the electrolyte.Also, they reduce the roughness and improve the compactness of the coatings, which are composed of Ta_(2)O_(5),(Ta, O), and TaO. A thick and hard coating is obtained in the NaF-containing electrolyte, and the tribology performance is effectively improved. With additives, the nodule structure is detached from the coating surface and dissolved in the electrolyte. By using NaF as an electrolyte additive, the abrasion performance of the MAO coating is enhanced by decreasing the nodule structure, increasing the size of micropores, and improving the coating hardness.

关键词： micro-arc oxidation tantalum alloy additives tribology performance

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