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Molecular compositions and sources of organic aerosols at a rural site on the Guanzhong Plain,Northwest China:The importance of biomass burning

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Particuology 2024年第6期89卷 44-56页

作者： Yali Liu minxia Shen Haijiao Liu Wenting Dai Weining Qi Yifan zhang Lu Li Yue Cao Xin Wang Xiao Guo Yingkun Jiang Jianjun Li State Key Laboratory of Loess and Quaternary Geology Key Lab of Aerosol Chemistry and PhysicsInstitute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China Xi'an Institute for Innovative Earth Environment Research Xi'an 710061China National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain ShaanxiChina

The concentration of PM_(2.5)has considerably reduced in recent years,but remains relatively high in China.In particular,the increasing contribution of organic compounds to PM_(2.5)generates popular pressure for further reductions,resulting in an urgent need to study organic aerosol(OA).To investigate the molecular composition and source contribution of OA in the rural area of the Guanzhong Plain,Northwest China,PM_(2.5)samples were collected during 3–23 August 2016 and 5–20 January 2017 and studied for more than 100 organic tracer compounds.The mean concentration of total measured organic compounds is 662±296 ng/m^(3)in summer and 3258±1925 ng/m^(3)in winter.Levoglucosan is the most abundant single compound found throughout the sampling period,which is a crucial tracer for biomass burning emissions,preliminary suggesting that biomass burning is an essential source of OA.In summer,organic compounds such as lipid compounds,sugar compounds,and polycyclic aromatic hydrocarbons(PAHs),more come from higher plants,wood burning,vehicle exhausts,plastic waste,and other direct emission sources.Oxygenated PAHs(OPAHs),nitrophenols,and phthalic acids more come from the atmosphere through the oxidation reaction of aromatic precursors,especially photochemical oxidation.However,in winter,most of the increases in concentrations of organic compounds are attributed to biomass burning.The analysis of a haze event(14–19 January 2017)during the winter sampling period shows that the increases in the concentration of organic compounds are unaccompanied by strong secondary formation under lower relative humidity(49.1%±13.5%).The main reason for the growth of OA in this haze event is the accumulation of primary OA(POA).The source apportionment by the positive matrix factorization(PMF)model shows that biomass burning(37.1%)is the primary source of OA in the rural regions of the Guanzhong Plain,especially in winter(40.6%).The contribution of secondary formation decreases from 26.0%in summer to 16.9%in winter,and the contribution of fossil

关键词： Organic aerosol Molecular composition Seasonal variation Source apportionment Guanzhong Plain

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Growth of nitrate contribution to aerosol pollution during wintertime in Xi'an,northwest China:Formation mechanism and effects of NH_(3)

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Particuology 2024年第4期87卷 303-315页

作者： Hui Su Ting zhang Suixin Liu Yao Qu Huan Li Jiamao Zhou Zhuzi Zhao Qiyuan Wang Lu Li minxia Shen Shuoyuan Chen Steven Sai Hang Ho Junji Cao State Key Laboratory of Loess and Quaternary Geology.Key Laboratory ofAerosol Chemistry and Plhysics Institute of Earth EnvironmentChinese Acadery of SciencesXi'an 710061China Xi'an Institute for Innovative Earth Environment Research Xi'an 710061China National pbservation and Research Station of Regional Ecological Environment Change and Cornprehensive Management in the Guanzhong Plain Xi'an 710061China Shaanxi Key Laboratory of Atmospheric and Haze fog Pollution Prevention Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China University of Chinese Academy of Sciences Beijing 100049China School of Chemical and Environmental Engineering Jiangsu University of TechnologyChangzhou 213001China Division of Atmospheric Sciences Desert Research InstituteReno NV89512United States Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China

With the strengthened controls on SO2 emissions and extensive increases in motor vehicles'exhaust,aerosol pollution shifts from sulfate-rich to nitrate-rich in recent years in Xi'an,China.To further gain insights into the factors on nitrate formation and efficiently mitigate air pollution,highly time-resolved observations of water-soluble inorganic ions(WSIIs)in PM_(2.5) were measured in a suburban area of Xi'an,China during wintertime.Hourly concentration of total WSIIs is 39.8μg m-3 on average,accounting for 50.3%of PM_(2.5) mass.In contrast to a slight decrease in the mass fraction of SO_(4)^(2-),NO_(3)-shows a sig-nificant increase of the PM_(2.5) contribution with the aggravation of aerosol pollution.This suggests the importance of NO_(3)-formation to haze evolution.Furthermore,homogeneous reactions govern the formation of NO_(3)-,while alkali metals such as calcium and sodium play an additional role in retaining NO_(3)-in PM_(2.5) during clean periods.However,the heterogeneous hydrolysis reaction contributed more to NO_(3)-formation during the pollution periods under high relative humidity.Our investigation reveals that temperature,relative humidity,oxidant,and ammonia emissions facilitate rapid NO_(3)-formation.Using the random forest(RF)model,NO_(3)-concentrations were successfully simulated with measured variables for the training and testing datasets(R2>0.95).Among these variables,CO,NH_(3),and NO_(2) were found to be the main factors affecting the NO_(3)-concentrations.Compared with the period without vehicle re-striction,the contributions of NO_(3)-and NH4+to PM_(2.5) mass decreased by 5.3%and 3.4%in traffic re-striction periods,respectively.The vehicle restriction leads to the decreases of precursor gases of NO_(2),SO_(2),and NH_(3) by 12.8%,5.9%,and 27.6%,respectively.The results demonstrate collaborative emission reduction of NO_(x) and NH_(3) by vehicle restrictions,and using new energy vehicles(or electric vehicles)can effectively alleviate particulate matter pollution in northwest China.

关键词： PM_(2.5) Water-soluble inorganic ions Nitrate formation Excess ammonium Vehicle restrictions

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Using radium isotopes to evaluate the uncertainty of submarine groundwater discharge in the northeast and entirety of Daya Bay

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海洋学报:英文版 2023年第8期42卷 24-31页

作者： Hequan Gu Feng Zhao Zhixin Ni Meigui Wu Li Zhao Aicui Dang Dongmei Li minxia zhang Qin Hu South China Sea Environment Monitoring Center State Oceanic AdministrationGuangzhou 510300China Nansha Islands Coral Reef Ecosystem National Observation and Research Station Guangzhou 510300China Key Laboratory of Marine Environmental Survey Technology and Application Ministry of Natural ResourcesGuangzhou 510300China CNOOC Research Institute Co. Ltd.Beijing 100028China

Submarine groundwater discharge(SGD),which can be traced using naturally occurring radium isotopes,has been recognized as a significant nutrient source and land-ocean interaction passage for the coastal waters of the Daya Bay,China.However,uncertainties in assessing SGD fluxes must still be discussed in detail.In this study,we attempted to utilize the Monte Carlo method to evaluate the uncertainties of radium-derived SGD flux in the northeast and entirety of the Daya Bay.The results show that the uncertainties of the SGD estimate in the northeast bay are very sensitive to variations in excess radium inventories as well as radium inputs from bottom sediments,while the uncertainties of the SGD estimate for the entire bay are strongly affected by fluctuations in radium inputs from bottom sediments and radium end-members of SGD.This study will help to distinguish the key factors controlling the accuracy of SGD estimates in similar coastal waters.

关键词： submarine groundwater discharge(SGD) radium isotopes Monte-Carlo method Daya Bay uncertainty analysis

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Bearing behavior and failure mechanism of squeezed branch piles

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第5期10卷 935-946页

作者： minxia zhang Ping Xu Wenjie Cui Youbin Gao School of Civil Engineering Henan Polytechnic University School of Water Conservancy and Environmental Engineering Zhengzhou University

The current practice for the design of squeezed branch piles is mainly based on the calculated bearing capacity of circular piles. Insufficient considerations of the load-transfer mechanism, branch effect and failure mechanism, as well as overreliance on pile load tests, have led to conservative designs and limited application. This study performs full-scale field load tests on instrumented squeezed branch piles and shows that the shaft force curves have obvious drop steps at the branch position, indicating that the branches can effectively share the pile top load. The effects of branch position, spacing, number and diameter on the pile bearing capacity are analyzed numerically. The numerical results indicate that the squeezed branch piles have two types of failure mechanisms, i.e. individual branch failure mechanism and cylindrical failure mechanism. Further research should focus on the development of the calculation method to determine the bearing capacities of squeezed branch piles considering these two failure mechanisms.

关键词： Squeezed branch piles Field test Bearing behavior Failure mechanism Numerical simulation

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Road map for, and technical challenges of, carbon-nanotube integrated circuit technology

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National Science Review 2024年第3期11卷 14-16页

作者： Jia Si Panpan zhang Zhiyong zhang Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics School of Electronics Peking University State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

The past decade has witnessed an explosion of research on carbon-nanotube(CNT) electronics due to their outstanding properties, including an ultrathin body, a high carrier mobility and a high saturation velocity.

关键词： TRANSISTORS

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New structure transistors for advanced technology node CMOS ICs

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National Science Review 2024年第3期11卷 24-41页

作者： Qingzhu zhang Yongkui zhang Yanna Luo Huaxiang Yin Integrated Circuit Advanced Process R&D Center Institute of Microelectronics of Chinese Academy of Sciences(IMECAS) State key Lab of Fabrication Technologies for Integrated Circuits Institute of Microelectronics of Chinese Academy of Sciences School of Integrated Circuits University of Chinese Academy of Sciences

Over recent decades, advancements in complementary metal-oxide-semiconductor integrated circuits(ICs)have mainly relied on structural innovations in transistors. From planar transistors to the fin field-effect transistor(FinFET) and gate-all-around FET(GAAFET), more gate electrodes have been added to three-dimensional(3D) channels with enhanced control and carrier conductance to provide higher electrostatic integrity and higher operating currents within the same device footprint. Beyond the 1-nm node, Moore's law scaling is no longer expected to be applicable to geometrical shrinkage. Vertical transistor stacking, e.g. in complementary FETs(CFET), 3D stack(3DS) FETs and vertical-channel transistors(VFET), for enhanced density and variable circuit or system design represents a revolutionary scaling approach for sustained IC development. Herein, innovative works on specific structures, key process breakthroughs, shrinking cell sizes and design methodologies for transistor structure research and development are reviewed. Perspectives on future innovations in advanced transistors with new channel materials and operating theories are also discussed.

关键词： transistor CMOS GAAFET CFET 3DS FET

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Advances in methane emissions from agricultural sources:Part I.Accounting and mitigation

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Journal of Environmental Sciences 2024年第6期140卷 279-291页

作者： Xiaokun Wu Ying zhang Yinghui Han Yagang zhang Yuhang zhang Xiaodan Cheng Pei Zhong Xue Yuan Yuanxun zhang Zhengqiang Li State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071003China College of Resources and Environment University of Chinese Academy of SciencesBeijing 101408China Interdisciplinary Mathematics Institute University of South CarolinaColumbiaSC 29208United States Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China

Methane is one of the major greenhouse gases(GHGs)and agriculture is recognized as its primary emitter.Methane accounting is a prerequisite for developing effective agriculture mitigation strategies.In this review,methane accounting methods and research status for various agricultural emission source including rice fields,animal enteric fermentation and livestock and poultry manure management were overview,and the influencing factors of each emission source were analyzed and discussed.At the same time,it analyzes the different research efforts involving agricultural methane accounting and makes recommendations based on the actual situation.Finally,mitigation strategies based on accounting results and actual situation are proposed.This review aims to provide basic data and reference for agriculture-oriented countries and regions to actively participate in climate action and carry out effective methane emission mitigation.

关键词： Methane emission Agricultural sources Accounting methodology Mitigation Emission influencing factors

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Interface Engineering of Titanium Nitride Nanotube Composites for Excellent Microwave Absorption at Elevated Temperature

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Nano-Micro Letters 2024年第9期16卷 147-160页

作者： Cuiping Li Dan Li Shuai zhang Long Ma Lei zhang* Jingwei zhang Chunhong Gong College of Chemistry and Molecular Sciences Henan UniversityKaifeng 475004People’s Republic of China National and Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials Henan UniversityKaifeng 475004People’s Republic of China

Currently,the microwave absorbers usually suffer dreadful electromagnetic wave absorption(EMWA)performance damping at elevated temperature due to impedance mismatching induced by increased conduction loss.Consequently,the development of high-performance EMWA materials with good impedance matching and strong loss ability in wide temperature spectrum has emerged as a top priority.Herein,due to the high melting point,good electrical conductivity,excellent environmental stability,EM coupling effect,and abundant interfaces of titanium nitride(TiN)nanotubes,they were designed based on the controlling kinetic diffusion procedure and Ostwald ripening process.Benefiting from boosted heterogeneous interfaces between TiN nanotubes and polydimethylsiloxane(PDMS),enhanced polarization loss relaxations were created,which could not only improve the depletion efficiency of EMWA,but also contribute to the optimized impedance matching at elevated temperature.Therefore,the TiN nanotubes/PDMS composite showed excellent EMWA performances at varied temperature(298-573 K),while achieved an effective absorption bandwidth(EAB)value of 3.23 GHz and a minimum reflection loss(RLmin)value of−44.15 dB at 423 K.This study not only clarifies the relationship between dielectric loss capacity(conduction loss and polarization loss)and temperature,but also breaks new ground for EM absorbers in wide temperature spectrum based on interface engineering.

关键词： TiN nanotubes Interface engineering Polarization loss Impedance matching Electromagnetic wave absorption performance

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Environmental arsenic(As)and its potential relationship with endemic disease in southwestern China

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Journal of Environmental Sciences 2024年第5期139卷 46-59页

作者： Donglin Li Hucai zhang Fengqin Chang Lizeng Duan Yang zhang Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environmental ScienceYunnan UniversityKunming 650500China Southwest United Graduate School Kunming 650500China

Many cases of an unknown disease exhibiting the clinical features of limb gangrene,blisters,ulceration,and exfoliation have been reported in Daping village(DV)in southwestern China.However,the pathogenesis is unknown and has puzzled doctors for many years.A preliminary study on heavy metals and symptoms indicated that arsenic might pose the greatest threat to the health of local residents.Here,to explore the sources of and factors influencing arsenic enrichment in DV,whose residents exhibit signs of arsenic poisoning,the As contents in soil,water,and plants were systematically measured.The results indicated high As contents in plant and soil samples obtained from the area,and the source of As may be linked to the weathering of black shale rock.Ingestion of soil and consumption of plants were the two main As exposure pathways among children and adults,respectively,and children exhibited a higher health risk than adults.We presume and emphasize that when extreme drought events occur,humans might face unusual risks resulting from exposure to toxic elements and the direct consumption of highly polluted water.Our study provides a new perspective and sheds light on the environmental geochemistry and health links of this disease.

关键词： Endemic disease Arsenic(As) Risk assessment Black shale Climate change

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N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 165-178页

作者： Jingshu Yuan Yao zhang Xiaoyan zhang Junjie zhang Shen’gen zhang Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Xi’an Fanyi University Xi’an 710105China Shunde Graduate School of University of Science and Technology Beijing Foshan 528399China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao SAR 820000China

Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.

关键词： N-doped TiO_(2) N-doped graphene quantum dots P-doped g-C_(3)N_(4) porous hollow nanotube heterojunction photocatalysis

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