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Ambient particle composition and toxicity in 31 major cities in China

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Fundamental research 2024年第3期4卷 505-515页

作者： Lu Zhang Maosheng Yao State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China

Current assessment of air quality or control effectiveness is solely based on particulate matter(PM)mass levels,without considering their toxicity differences in terms of health ***,we collected a total of 465 automo-bile air conditioning filters from 31 major Chinese cities to study the composition and toxicity of PM at a national *** assay showed that normalized PM toxicity(NIOG)in different Chinese cities varied greatly from the highest 4.99×10^(-3)for Changsha to the lowest 7.72×10^(-4)for ***0G values were observed to have significant correlations with annual PM_(10) concentration(r=-0.416,p=0.020)and some PM components(total fungi,so.2-and calcium element).The concentrations of different elements and water-soluble ions in PM also varied by several orders of magnitude for 31 cities in *** concentrations in PM analyzed using limulus amebocyte lysate assay ranged from 2.88 EU/mg PM(Hangzhou)to 62.82 EU/mg PM(Shijiazhuang)among 31 Chinese ***,real-time qPCR revealed 10~100-fold differences in total bacterial and fungal levels among 31 Chinese *** concentrations of chemical(water soluble ions and trace elements)and bi-ological(fungi,bacteria and endotoxin)components in PM were found to be significantly correlated with some meteorological factors and gaseous pollutants such as SO_(2).Our results have demonstrated that PM toxicity from 31 major cities varied greatly up to 6.5 times difference;and components such as fungi and SO_(4)^(2-)in PM could play important roles in the observed PM *** city-specific air pollution control strategy that integrates toxicity factors should be enacted in order to maximize health and economic *** work also provides a comprehensive view on the overall PM pollution situation in China.

关键词： PM toxicity Oxidative potential Biologicals Chemical components Endotoxin

Retrospective and prospective review of the generalized nonlinear strength theory for geomaterials

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1767-1787页

作者： Shunchuan Wu Jiaxin Wang Shihuai Zhang Shigui Huang Lei Xia Qianping Zhao Faculty of Land Resource Engineering Kunming University of Science and TechnologyKunming 650093China Key Laboratory of Geohazard Forecast and Geoecological Restoration in Plateau Mountainous Area MNRKunming 650093China Yunnan Key Laboratory of Geohazard Forecast and Geoecological Restoration in Plateau Mountainous Area Kunming 650093China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China

Strength theory is the basic theory for calculating and designing the strength of engineering materials in civil,hydraulic,mechanical,aerospace,military,and other engineering ***,the comprehensive study of the generalized nonlinear strength theory(GNST)of geomaterials has significance for the construction of engineering rock *** paper reviews the GNST of geomaterials to demonstrate the research status of nonlinear strength characteristics of geomaterials under complex stress ***,it systematically summarizes the research progress of GNST(classical and empirical criteria).Then,the latest research the authors conducted over the past five years on the GNST is introduced,and a generalized three-dimensional(3D)nonlinear Hoek‒Brown(HB)criterion(NGHB criterion)is proposed for practical *** criterion can be degenerated into the existing three modified HB criteria and has a better prediction *** strength prediction errors for six rocks and two in-situ rock masses are 2.0724%-3.5091%and 1.0144%-3.2321%,***,the development and outlook of the GNST are expounded,and a new topic about the building strength index of rock mass and determining the strength of in-situ engineering rock mass is *** summarization of the GNST provides theoretical traceability and optimization for constructing in-situ engineering rock mass strength.

关键词： rock mechanics rock mass strength strength theory failure criterion Hoek-Brown criterion intermediate principal stress deviatoric plane smoothness and convexity

Long-term thinning decreases the contribution of heterotrophic respiration to soil respiration in subalpine plantations

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Journal of Forestry research 2024年第3期35卷 189-204页

作者： Longfei Chen Zhibin He Wenzhi Zhao Xi Zhu Qin Shen Mingdan Song Zhengpeng Li Junqia Kong Shuping Yang Yuan Gao Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000People's Republic of China State Forestry Administration Key Laboratory of Forest Resources and Environmental Management Beijing Forestry UniversityBeijing 100083People's Republic of China Academy of Agriculture and Forestry Sciences Qinghai UniversityXining 810000People's Republic of China College of Landscape Architecture Zhejiang A&F UniversityHangzhou 310000People's Republic of China

Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental ***,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on Rs,Rn and R_(a).Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning *** significantly decreased winter R,because of the reduction in R_(n) but had no significant effect on *** temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to R_(n) and R_(a) *** increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial *** results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term ***,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) *** increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.

关键词： Heterotrophic respiration Autotrophic respiration Long-term thinning impacts Cold seasons Subalpine plantations Temperature sensitivity

A Web-like Three-dimensional Binder for Silicon Anode in Lithium-ion Batteries

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Energy & Environmental Materials 2024年第1期7卷 21-27页

作者： Liyuan Li Tao Li Yifan Sha Baozeng Ren Lan Zhang Suojiang Zhang CAS Key Laboratory of Green Process and Engineering Beijing Key Laboratory of Ionic Liquids Clean ProcessState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China Langfang Green Industrial Technology Center Langfang 065001China Henan Key Laboratory of Energy Storage Materials and Processes Zhengzhou Institute of Emerging Industrial TechnologyZhengzhou 450003China

Si anode is of paramount importance for advanced energy-dense lithium-ion batteries(LIBs).However,the large volume change as well as stress generates during its lithiation-delithiation process poses a great challenge to the long-term cycling and hindering its *** this work,a composite binder is prepared with a soft component,guar gum(GG),and a rigid linear polymer,anionic polyacrylamide(APAM).Rich hydroxy,carboxyl,and amide groups on the polymer chains not only enable intermolecular crosslinking to form a web-like binder,A2G1,but also realize strong chemical binding as well as physical encapsulating to Si *** resultant electrode shows limited thickness change of merely 9%on lithiation and almost recovers its original thickness on *** demonstrates high reversible capacity of 2104.3 mAh g^(-1)after 100 cycles at a current density of 1800 mA g^(-1),and in constant capacity(1000 mAh g^(-1))test,it also shows a long life of 392 ***,this soft-hard combining web-like binder illustrates its great potential in the future applications.

关键词： anionic polyacrylamide lithium-ion batteries Si anode thickness change web-like binder

Observation and analysis of positive leader re-illumination in a 10 m ultra-high voltage transmission line gap under switching impulse voltages

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Plasma Science and Technology 2024年第10期26卷 93-100页

作者： Biao HUANG Xuan ZHOU She WANG Chijie ZHUANG Rong ZENG Le DENG Eliet Engineering School Changsha University of Science&TechnologyChangsha 410114People’s Republic of China State Key Laboratory of Disaster Prevention&Reduction for Power Grid Changsha University of Science&TechnologyChangsha 410114People’s Republic of China China International Engineering Consulting Co. Ltd.Beijing 100048People’s Republic of China Department of Electrical Engineering Tsinghua UniversityBeijing 100084People’s Republic of China

The leader propagation is one of the most important stages in long air gap *** mechanism behind leader re-illumination remains *** high humidity conditions(20.0–30.1 g/m^(3)),we have conducted experiments of long sparks in a 10 m ultra-high voltage(UHV)transmission line gap under switching impulse *** positive leaders predominantly propagate discontinuously,with almost no significantly continuous propagation *** leader channels are intensely luminous and each elongation segment is straight,with streamers resembling the“branch type”which differs from the“diffuse type”streamers at the front of continuous propagation *** distribution of the propagation velocities is highly random(3.7–18.4 cm/μs),and the average velocity(9.2 cm/μs)significantly exceeds that of continuous propagation(1.5–2.0 cm/μs).Analysis suggests that the current-velocity models suitable for continuous leader propagation do not align well with the experimental data in re-illumination *** on the discharge current waveforms and optical images,it is speculated that the newly elongated leader in re-illumination mode does not evolve gradually from the stem(about 1 cm)but rather evolves overall from a thermal channel much longer than stem.

关键词： long air gap discharge positive leader re-illumination discontinuous leader propagation

Millennial changes and cooling trends in land surface warm-season temperatures during the Holocene

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Science Bulletin 2024年第18期69卷 2930-2937页

作者： Yukun Zheng Hongyan Liu Hongya Wang Shucheng Xie Huan Yang Siwen Feng Zeyu Zhang Wenjie Zhao Boyi Liang College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes Peking UniversityBeijing 100871China State Key Laboratory of Biogeology and Environmental Geology School of Earth SciencesChina University of GeosciencesWuhan 430074China Hubei Key Laboratory of Critical Zone Evolution School of Geography and Information EngineeringChina University of GeosciencesWuhan 430074China College of Forestry Precision Forestry Key Laboratory of BeijingBeijing Forestry UniversityBeijing 100083China

The scarcity of proxies and calibration models for quantitatively reconstructing millennial timescale seasonal temperature tremendously constraints our understanding of the Holocene thermal variation and its driven ***,we established two global warm-season temperature models by applying deep learning neural network analysis to the branched tetraether membrane lipids originating from surface soil and lacustrine sediment *** utilized these optimal models in global well-dated lacustrine,peatland,and loess profiles covering the *** reconstructions of warm-season temperatures,consistent with climate model simulations,indicate cooling trends since the early Holocene,primarily induced by decreased solar radiation in the Northern Hemisphere due to the precession peak at the *** further demonstrated that the membrane lipids can effectively enhance the future millennial seasonal temperature research,including winter temperatures,without being restricted by geographical location and sedimentary carrier.

关键词： Warm-season temperature Branched tetraether membrane lipids Holocene Model simulations

Evolution of N=20,28,50 shell closures in the 20≤Z≤30 region in deformed relativistic Hartree-Bogoliubov theory in continuum

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Chinese Physics C 2024年第1期48卷 144-153页

作者：郑茹尤孙向向申国防耿立升 School of Physics Beihang UniversityBeijing102206China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Institut für Kernphysik Institute for Advanced Simulation and Jülich Center for Hadron PhysicsForschungszentrum JülichD-52425 JülichGermany CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Peng Huanwu Collaborative Center for research and Education Beihang UniversityBeijing 100191China beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang UniversityBeijing 102206China Southern Center for Nuclear-Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China

Magicity,or shell closure,plays an important role in our understanding of complex nuclear *** this work,we employ one of the state-of-the-art density functional theories,the deformed relativistic Hartree-Bogoliubov theory in continuum(DRHBc)with the density functional PC-PK1,to investigate the evolution of the N=20,28,50 shell closures in the 20≤Z≤30 *** show how these three conventional shell closures evolve from the proton drip line to the neutron drip line by studying the charge radii,two-neutron separation energies,two-neutron gaps,quadrupole deformations,and single-particle *** particular,we find that in the 21≤Z≤27 region,the N=50 shell closure disappears or becomes quenched,mainly due to the deformation ***,both experimental data and theoretical predictions indicate that the N=28 shell closure disappears in the Mn isotopic chain,mainly due to the deformation *** DRHBc theory predicts the existence of the N=20 shell closure in the Ca,Sc,and Ti isotopic chains,but the existing data for the Ti isotopes suggest the contrary,and therefore further research is needed.

关键词： shell evolution covariant density functional theories magic numbers

采用改进的元胞自动机方法对三元Al-Si-Mg合金凝固微观组织进行数值模拟

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Science China Materials 2024年第4期67卷 1150-1159页

作者：谭云骧赵海东许庆彦 Key Laboratory for Advanced Materials Processing Technology Ministry of EducationSchool of Materials Science and EngineeringTsinghua University Beijing 100084China National Engineering research Center of Near-Net-Shape for Metalic Materials South China University of TechnologyGuangzhou 510640China

铝硅合金具有轻量化、高强度和易成形等独特优点.这些特性使得在低压压铸下能够生产大型、薄壁、复杂的铸件,这对于车辆轻量化至关重要.然而,这些合金的铸造过程容易产生缺陷,它们的性能与微观结构密切相关.认识到工艺、结构和性能之间... 详细信息

铝硅合金具有轻量化、高强度和易成形等独特优点.这些特性使得在低压压铸下能够生产大型、薄壁、复杂的铸件,这对于车辆轻量化至关重要.然而,这些合金的铸造过程容易产生缺陷,它们的性能与微观结构密切相关.认识到工艺、结构和性能之间的深层联系具有巨大的学术和工程价值.在本工作中,我们通过整合热力学、动力学和多元相图数据库,建立了一个改进的元胞自动机(ICA)模型.基于在阶梯铸件不同位置的冷却曲线和凝固组织,我们建立了适用于Al-7SixMg合金低压铸造的等轴晶形核模型.随后对该合金进行了低压铸造实验,微观结构演变的3D模拟结果与实验观察相吻合.我们进行了阶梯件低压铸造的实验,ICA模型准确地描绘了α-Al树枝晶,以及冷却速率对三元Al-7Si-xMg合金中晶核密度和树枝晶尺寸均匀性的影响.我们的模拟结果与实验数据表现出显著的一致性.此外,我们对SDAS与冷却速率之间的关系进行了全面分析.通过将ICA模型与LGK分析模型进行对比,验证了在评估树枝晶生长速率时ICA模型的精确性.这项工作为集成计算材料工程建立凝固-组织-性能的定量关系提供了理论指导.

关键词：低压铸造冷却曲线凝固微观组织铝硅合金铸造过程尺寸均匀性冷却速率形核模型

Regulatory potential of soil available carbon,nitrogen,and functional genes on N_(2)O emissions in two upland plantation systems

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Journal of Integrative Agriculture 2024年第8期23卷 2792-2806页

作者： Peng Xu Mengdie Jiang Imran Khan Muhammad Shaaban Hongtao Wu Barthelemy Harerimana Ronggui Hu Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China College of Resources and Environment Huazhong Agricultural UniversityWuhan 430070China Hubei Collaborative Innovation centre for Grain Industry College of AgricultureYangtze UniversityJingzhou 434025China College of Agriculture Henan University of Science and TechnologyLuoyang 471000China College of Urban and Environmental Sciences Hubei Normal UniversityHuangshi 435002China University of Chinese Academy of Sciences Beijing 100049China

Dynamic nitrification and denitrification processes are affected by changes in soil redox conditions,and they play a vital role in regulating soil N_(2)O emissions in rice-based *** is imperative to understand the influences of different upland crop planting systems on soil N_(2)O *** this study,we focused on two representative rotation systems in Central China:rapeseed–rice(RR)and wheat–rice(WR).We examined the biotic and abiotic processes underlying the impacts of these upland plantings on soil N_(2)O *** results revealed that during the rapeseed-cultivated seasons in the RR rotation system,the average N_(2)O emissions were 1.24±0.20 and 0.81±0.11 kg N ha^(–1)for the first and second seasons,*** values were comparable to the N_(2)O emissions observed during the first and second wheat-cultivated seasons in the WR rotation system(0.98±0.25 and 0.70±0.04 kg N ha^(–1),respectively).This suggests that upland cultivation has minimal impacts on soil N_(2)O emissions in the two rotation *** positive correlations were found between N_(2)O fluxes and soil ammonium(NH_(4)^(+)),nitrate(NO_(3)^(–)),microbial biomass nitrogen(MBN),and the ratio of soil dissolved organic carbon(DOC)to NO_(3)^(–)in both RR and WR rotation ***,the presence of the AOA-amoA and nirK genes were positively associated with soil N_(2)O fluxes in the RR and WR systems,*** implies that these genes may have different potential roles in facilitating microbial N_(2)O production in various upland plantation *** using a structural equation model,we found that soil moisture,mineral N,MBN,and the AOA-amoA gene accounted for over 50%of the effects on N_(2)O emissions in the RR rotation *** the WR rotation system,soil moisture,mineral N,MBN,and the AOA-amoA and nirK genes had a combined impact of over 70%on N_(2)O *** findings demonstrate the interactive effects of functional genes and soil factors,including

关键词： upland-rice cultivation N_(2)O emission regulatory factors functional genes