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Abundance and sources of particulate polycyclic aromatic hydrocarbons and aromatic acids at an urban site in central China

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Journal of Environmental Sciences 2024年第8期142卷 155-168页

作者： Luqi Shang Zhe Dong Zihan li Mingkai Wang Zihan Kong xiao li Ruiqin Zhang School of Ecology and Environment Zhengzhou UniversityZhengzhou 450001China College of Chemistry Zhengzhou UniversityZhengzhou 450001China Institute of Environmental Sciences Zhengzhou UniversityZhengzhou 450001China

We conducted a simultaneous field study of PM_(2.5)-bound particulate polycyclic aromatic hydrocarbons(PAHs)and aromatic acids(AAs)in a polluted city Zhengzhou to explore the concentration,sources and potential conversion pathways between PAHs and AAs in different seasons.The average concentrations of PM_(2.5),28PAHs and 8AAs during the sampling period were 77μg/m^(3),75 ng/m^(3),and 283 ng/m^(3),respectively.The concentration of both28PAHs and 8AAs were highest in winter and lowest in summer with ratios of 6.3 and 2.3,respectively.PAHs with 5-7 rings were the main components of PAHs(52%),followed by 4rings PAHs(30%)and 2-3 rings PAHs(18%).According to the source appointment results obtained by positive matrix factorization,the main sources of PAHs were combustion and vehicle emissions,which account for 37%and 34%,respectively.8AAs were divided into three groups,including four benzene dicarboxylic acids(B2CAs),three benzene tricarboxylic acids(B3CAs)and one benzene tetracarboxylic acid(B4CA).And interspecies correlation analysis with PM_(2.5)source markers were used to investigate potential sources.Phthalic acid(o-Ph)was the most abundant specie of 8AAs(157 ng/m^(3),55%of 8AAs),which was well correlated with sulfate.Meanwhile,B3CAs and B4CA were highly correlated with sulfate and weakly correlated with levoglucosan,suggesting that secondary formation was their main source.As logical oxidation products of PAHs,o-Ph and B3CAs showed good correlations with a number of PAHs,indicating possible photochemical oxidation pathway by PAHs.In addition,O_(3),NO_(2),temperature and relative humidity have positive effects on the secondary formation of B3CAs.

关键词： Polycyclic aromatic hydrocarbons Aromatic acids Source appointment Secondary formation

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Double stabilizations and convergence analysis of a second-order linear numerical scheme for the nonlocal Cahn-Hilliard equation

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Science China Mathematics 2024年第1期67卷 187-210页

作者： xiao li Zhonghua Qiao Cheng Wang Department of Applied Mathematics The Hong Kong Polytechnic UniversityHong KongChina Department of Mathematics The University of MassachusettsNorth DartmouthMA 02747USA

In this paper,we study a second-order accurate and linear numerical scheme for the nonlocal CahnHilliard equation.The scheme is established by combining a modified Crank-Nicolson approximation and the Adams-Bashforth extrapolation for the temporal discretization,and by applying the Fourier spectral collocation to the spatial discretization.In addition,two stabilization terms in different forms are added for the sake of the numerical stability.We conduct a complete convergence analysis by using the higher-order consistency estimate for the numerical scheme,combined with the rough error estimate and the refined estimate.By regarding the numerical solution as a small perturbation of the exact solution,we are able to justify the discrete?^(∞)bound of the numerical solution,as a result of the rough error estimate.Subsequently,the refined error estimate is derived to obtain the optimal rate of convergence,following the established?∞bound of the numerical solution.Moreover,the energy stability is also rigorously proved with respect to a modified energy.The proposed scheme can be viewed as the generalization of the second-order scheme presented in an earlier work,and the energy stability estimate has greatly improved the corresponding result therein.

关键词： nonlocal Cahn-Hilliard equation second-order stabilized scheme higher-order consistency analysis rough and refined error estimate

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Understanding the failure mechanism towards developing high-voltage single-crystal Ni-rich Co-free cathodes

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Green Energy & Environment 2024年第6期9卷 1045-1057页

作者： Jixue Shen Bao Zhang Changwang Hao xiao li Zhiming xiao Xinyou He Xing Ou Engineering Research Center of the Ministry of Education for Advanced Battery Materials School of Metallurgy and EnvironmentCentral South UniversityChangsha410083China Zhejiang Power New Energy Co. Ltd.Zhuji311899China Material Science and Chemistry Engineering College China University of GeosciencesWuhan430074China

Benefited from its high process feasibility and controllable costs,binary-metal layered structured liNi_(0.8)Mn_(0.2)O_(2)(NM)can effectively alleviate the cobalt supply crisis under the surge of global electric vehicles(EVs)sales,which is considered as the most promising nextgeneration cathode material for lithium-ion batteries(liBs).However,the lack of deep understanding on the failure mechanism of NM has seriously hindered its application,especially under the harsh condition of high-voltage without sacrifices of reversible capacity.Herein,singlecrystal liNi_(0.8)Mn_(0.2)O_(2) is selected and compared with traditional liNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM),mainly focusing on the failure mechanism of Cofree cathode and illuminating the significant effect of Co element on the li/Ni antisite defect and dynamic characteristic.Specifically,the presence of high li/Ni antisite defect in NM cathode easily results in the extremely dramatic H2/H3 phase transition,which exacerbates the distortion of the lattice,mechanical strain changes and exhibits poor electrochemical performance,especially under the high cutoff voltage.Furthermore,the reaction kinetic of NM is impaired due to the absence of Co element,especially at the single-crystal architecture.Whereas,the negative influence of li/Ni antisite defect is controllable at low current densities,owing to the attenuated polarization.Notably,Co-free NM can exhibit better safety performance than that of NCM cathode.These findings are beneficial for understanding the fundamental reaction mechanism of single-crystal Ni-rich Co-free cathode materials,providing new insights and great encouragements to design and develop the next generation of liBs with low-cost and high-safety performances.

关键词： li/Ni antisite defect Dynamic characteristic High-voltage Single-crystal Ni-rich Co-free cathodes lithium-ion batteries

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A Denoiser for Correlated Noise Channel Decoding: Gated-Neural Network

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China Communications 2024年第2期21卷 122-128页

作者： xiao li ling Zhao Zhen Dai Yonggang Lei School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Beijing Institute of Tracking and Telecommunications Technology BITTT

This letter proposes a sliced-gated-convolutional neural network with belief propagation(SGCNN-BP) architecture for decoding long codes under correlated noise. The basic idea of SGCNNBP is using Neural Networks(NN) to transform the correlated noise into white noise, setting up the optimal condition for a standard BP decoder that takes the output from the NN. A gate-controlled neuron is used to regulate information flow and an optional operation—slicing is adopted to reduce parameters and lower training complexity. Simulation results show that SGCNN-BP has much better performance(with the largest gap being 5dB improvement) than a single BP decoder and achieves a nearly 1dB improvement compared to Fully Convolutional Networks(FCN).

关键词： belief propagation channel decoding correlated noise neural network

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Cell metabolism pathways involved in the pathophysiological changes of diabetic peripheral neuropathy

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Neural Regeneration Research 2024年第3期19卷 598-605页

作者： Yaowei Lv Xiangyun Yao xiao li Yuanming Ouyang Cunyi Fan Yun Qian Department of Orthopedics Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghaiChina Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration ShanghaiChina Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine ShanghaiChina College of Fisheries and life Science Shanghai Ocean UniversityShanghaiChina

Diabetic peripheral neuropathy is a common complication of diabetes mellitus.Elucidating the pathophysiological metabolic mechanism impels the generation of ideal therapies.However,existing limited treatments for diabetic peripheral neuropathy expose the urgent need for cell metabolism research.Given the lack of comprehensive understanding of energy metabolism changes and related signaling pathways in diabetic peripheral neuropathy,it is essential to explore energy changes and metabolic changes in diabetic peripheral neuropathy to develop suitable treatment methods.This review summarizes the pathophysiological mechanism of diabetic peripheral neuropathy from the perspective of cellular metabolism and the specific interventions for different metabolic pathways to develop effective treatment methods.Various metabolic mechanisms(e.g.,polyol,hexosamine,protein kinase C pathway)are associated with diabetic peripheral neuropathy,and researchers are looking for more effective treatments through these pathways.

关键词： cell metabolism diabetic peripheral neuropathy peripheral nerve injury protein kinase C pathway reactive oxygen species.

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Intake of tobacco nitrosamines of smokers in various provinces of China and their cancer risk:A meta-analysis

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Journal of Environmental Sciences 2024年第7期141卷 249-260页

作者： xiao li Zhiwei Ye Jun Wang Pengfei lin xiaojin Zhang Shuguang Xie Chao Chen Research Institute for Environmental Innovation(Suzhou) TsinghuaSuzhouJiangsu 215163China State Key Joint Laboratory of Environmental Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China Shenzhen Key Laboratory of Organic Pollution Prevention and Control State Key Laboratory of Urban Water Resource and EnvironmentHarbin Institute of TechnologyShenzhen 518055China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Science and EngineeringPeking UniversityBeijing 100871China

Nitrosamines are a class of carcinogens which have been detected widely in food,water,some pharmaceuticals as well as tobacco.The objectives of this paper include reviewing the basic information on tobacco consumption and nitrosamine contents,and assessing the health risks of tobacco nitrosamines exposure to Chinese smokers.We searched the publications in English from“Web of Science”and those in Chinese from the“China National Knowledge Infrastructure”in 2022 and collected 151 literatures with valid information.The content of main nitrosamines in tobacco,including 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone(NNK),N-nitrosonornicotine(NNN),N-nitrosoanatabine(NAT),N-nitrosoanabasine(NAB),total tobacco-specific nitrosamines(TSNA),and N-nitrosodimethylamine(NDMA)were summarized.The information of daily tobacco consumption of smokers in 30 provinces of China was also collected.Then,the intakes of NNN,NNK,NAT,NAB,TSNAs,and NDMA via tobacco smoke were estimated as 1534ng/day,591 ng/day,685 ng/day,81 ng/day,2543 ng/day,and 484 ng/day by adult smokers in30 provinces,respectively.The cancer risk(CR)values for NNN and NNK inhalation intake were further calculated as 1.44×10^(-5)and 1.95×10^(-4).The CR value for NDMA intake via tobacco smoke(inhalation:1.66×10^(-4))indicates that NDMA is similarly dangerous in tobacco smoke when compared with the TSNAs.In China,the CR values caused by average nitrosamines intake via various exposures and their order can be estimated as the following:smoke(3.75×10^(-4))>food(1.74×10^(-4))>drinking water(1.38×10^(-5)).Smokers in China averagely suffer 200%of extra cancer risk caused by nitrosamines in tobacco when compared with non-smokers.

关键词： N-nitrosamine Tobacco Cancer risk Tobacco specific nitrosamines(TSNAs) N-nitrosodimethylamine(NDMA)

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Accurate Quantification of Pure Thiacloprid with Mass Balance and Quantitative H-NMR

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Journal of Analysis and Testing 2024年第1期8卷 1-8页

作者： Mengling Tu Wei Zhang Yunxiao Zhu Wen Ma xiao li Shukun Zhou Hongmei li Xianjiang li Key Laboratory of Chemical Metrology and Applications on Nutrition and Health for State Market Regulation Division of Metrology in ChemistryNational Institute of MetrologyBeijing 100029China State Key Laboratory of Heavy Oil Processing College of Chemical Engineering and EnvironmentChina University of PetroleumBeijing 102249China State Key Laboratory of Natural and Biomimetic Drugs School of Pharmaceutical SciencesPeking UniversityBeijing 100191China

Thiacloprid is the first-generation neonicotinoid insecticide,which is widely used in modern agriculture.Reference materials are essential for sound measurement and traceability of results in chemical analysis.Pure thiacloprid was comprehensively assessed by two orthonormal methods:mass balance(MB) and quantitative nuclear magnetic resonance spectroscopy(qNMR).From MB,its mass fraction value was 998.4 mg/g with the subtraction of structurally related impurities(99.87%),inorganic impurities(0.006 mg/g),water(0.33 mg/g),and volatile organic solvent(0 mg/g).To guarantee sufficient separation of structurally related purity,peak purity of thiacloprid was evaluated by five points of UV spectra.From the qNMR of hydrogen,its mass fraction value was 995.7 mg/g which was traced to the internal standard(methyl sulfone).Finally,the certified value was assigned to 997 mg/g,together with an expanded uncertainty of 3 mg/g(k=2).This high-purity thiacloprid can be applied to routine monitoring in agriculture and the food fields.

关键词： Mass balance Quantitative nuclear magnetic resonance spectroscopy Reference material Thiacloprid

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Effect of Y substitution on the microstructure,magneto-optical,and thermal properties of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)transparent ceramics

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Journal of Advanced Ceramics 2024年第4期13卷 529-538页

作者： lixuan Zhang Dianjun Hu xiao li Ziyu liu Chen Hu Lexiang Wu Tingsong li Dariusz Hreniak Jiang li Transparent Ceramics Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 201899China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China Institute of Low Temperature and Structure Research Polish Academy of SciencesWroclaw 50-422Poland

Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam,so they are important elements in laser systems.As magneto-optical materials are the most important component in Faraday isolators,the studies on magneto-optical materials have attracted much attention these years.Tb_(3)Al_(5)O_(12)(TAG)ceramics are considered to be one of the most promising magneto-optical materials for visible to near-infrared wavelength band application because of their outstanding comprehensive magneto-optical performance.However,the optical quality of TAG ceramics needs further optimization to meet the application requirements.In this work,high optical quality(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)(x=0,0.05,0.1,0.2,and 0.3)magneto-optical ceramics were fabricated successfully by solid-state reaction sintering combined with hot isostatic pressing(HIP)post-treatment.All the ceramics obtained showed a single garnet phase for different values of x in the range studied.The addition of Y2O3 was found to suppress the secondary phase and improve optical quality significantly.The ceramic samples obtained had clear grain boundaries and possessed the in-line transmittance values of 82.9%at 1064 nm and 82.2%at 633 nm,respectively.The Verdet constants of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)ceramics with x=0,0.05,0.1,0.2,and 0.3 were−188.1,−175.4,−168.5,−143.0,and−119.9 rad/(T·m),respectively.The thermal conductivity of TAG ceramics was found to be 5.23 W/(m·K)at 25℃,and when 20%Y was substituted in place of Tb,the thermal conductivity decreased by only 9.4%.

关键词： (Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)ceramics magneto-optical materials optical quality thermal properties

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Pushing the frontiers: Chip-based detection based on micro-and nano-structures

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Chinese Chemical Letters 2024年第4期35卷 86-98页

作者： Meihui liu Xinyuan Zhou xiao li Zhenjie Xue Tie Wang Tianjin Key Laboratory of life and Health Detection Life and Health Intelligent Research InstituteTianjin University of TechnologyTianjin 300384China

Changes in trace substances in human metabolites, which are related to disease processes and health status, can serve as chemical markers for disease diagnosis and symptom monitoring. Real-time online detection is an inevitable trend for the future of health monitoring, and the construction of chips for detection faces major challenges. The response of sensors often fails to meet the requirements for chipbased detection of trace substances due to the low efficiency of interfacial heterogeneous reactions, necessitating a rational design approach for micro-and nano-structures to improve sensor performance with respect to sensitivity and detection limits. This review focuses on the influence of micro-and nanostructures that used in chip on sensing. Firstly, this review categorizes sensors into chemiresistors, electrochemical sensors, fluorescence sensors, and surface enhanced Raman scattering(SERS) sensors based on their sensing principle, which have significant applications in disease diagnosis. Subsequently, commencing from the application requirements in the field of sensing, this review focuses on the different structures of nanoparticle(NP) assemblies, including wire, layered, core-shell, hollow, concave and deformable structures. These structures change in the size, shape, and morphology of conventional structures to achieve characteristics such as ordered alignment, high specific surface area, space limitation,vertical diffusion, and swaying behavior with fluid, thereby addressing issues such as poor signal transmission efficiency, inadequate adsorption and capture capacity, and slow mass transfer speed during sensing. Finally, the design direction of micro-and nano-structures, and possible obstacles and solutions to promote chip-based detection have been discussed. It is hope that this article will inspire the exploration of interface micro-and nano-structures modulated sensing methods.

关键词： Chip-based detection Micro-and nano-structures Real-time online detection Sensing Health monitoring

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Robust Estimation of Average Treatment Effects with Observational Studies

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Wuhan University Journal of Natural Sciences 2024年第2期29卷 117-124页

作者： xiao li YU Peichao Department of Physical Education Guilin University of Aerospace TechnologyGuilin 541004GuangxiChina School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan 430073HubeiChina

Estimating treatment effects has always been one of the hot issues in empirical research.It brings great challenges to estimating treatment effects because heterogeneity exists in the distribution of covariates between treated and controlled groups.Propensity score methods have been widely used to adjust for heterogeneity in observational studies.However,the propensity score is usually unknown and needs to be estimated.In this article,we propose a generalized single-index model to estimate the propensity score and use the propensity score residuals to reduce the estimation bias.The finite-sample performance of the proposed method is evaluated through simulation stud-ies.We use the proposed method to evaluate the policy of"Sunshine Running"and find that the physical test scores of college students par-ticipating in the"Sunshine Running"can be improved by 3.72 points.

关键词： treatment effect propensity score generalized single-index model partial linear model

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