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Characteristics of bioaerosols under high-ozone periods,haze episodes,dust storms,and normal days in Xi'an,China

Particuology 2024年第7期90卷 140-148页

作者： Yiming Yang Liu Yang Xiaoyan Hu Zhenxing Shen Department of environmental Science and Engineering Xi’an Jiaotong UniversityXi’an710049China Key Lab of Aerosol Chemistry&physics SKLLQGInstitute of Earth EnvironmentChinese Academy of SciencesXi’an710049China

The characteristics of bioaerosols and their effects on human beings'health have become a major public concern in the recent *** study compared the characteristics of bioaerosols under different types of pollution(high-ozone[HO]episodes,haze episodes,and dust storms[DSs]),with those of bioaerosols on normal days(NDs)in Xi'an,*** concentrations,diurnal variations,and size distribution of bacteria,fungi,and total airborne microbes(TAMs)were *** results showed that the bacterial and fungal concentrations were the highest during DSs and on NDs,reaching 425.2 and 956.9 colony-forming units/m^(3),*** concentration of TAMs was the highest during HO episodes,reaching 10.7×10^(6)cells/m^(3),which was significantly higher than that during the other *** maximum concentrations of bacteria and fungi during HO episodes were observed in the morning,while they appeared separately in the morning and evening during haze *** and TAMs during DSs reached peak concentrations in the morning and evening,which is opposite to the particulate matter(PM)distribution *** NDs,temperature and relative humidity had significant effects on *** size distributions of airborne bacteria exhibited bimodal patterns,whereas unimodal distributions were observed for *** mainly attached in fine particles(<2.1μm)with proportions of 67.4%and 60.5%during haze episodes and DSs,respectively,which means that fungi were easily penetrated into the human respiratory *** evaluation of influence factors revealed that PM_(2.5) and PM10 had negative effects on fungal concentration during DSs,and ozone concentration and temperature were inversely correlated with fungal concentration during HO *** results provide valuable reference data for elucidating the formation and evolution of bioaerosols under different types of pollution.

关键词： Bacteria Fungi Total airborne microbe Different air pollution types Influence factors

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A CNN-SVR model for NO_(2)profile prediction based on MAX-DOAS observations:The influence of Chinese New Year overlapping the 2020 COVID-19 lockdown on vertical distributions of tropospheric NO_(2)in Nanjing,China

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Journal of environmental Sciences 2024年第7期141卷 151-165页

作者： Xin Tian Zijie Wang Pinhua Xie Jin Xu Ang Li Yifeng Pan Feng Hu Zhaokun Hu Mingsheng Chen Jiangyi Zheng Information Materials and Intelligent sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Key laboratory of environmental Optical and Technology Anhui Institute of optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China School of environmental Science and Optoelectronic Technology University of Science and Technology of ChinaHefei 230026China

In this study,a hybrid model,the convolutional neural network-support vector regression model,was adopted to achieve prediction of the NO_(2)profile in Nanjing from January 2019to March *** the sudden decline in NO_(2)in February 2020,the contribution of the Coronavirus Disease-19(COVID-19)lockdown,Chinese New Year(CNY),and meteorologi cal conditions to the reduction of NO_(2)was ***_(2)vertical column densities(VCDs) from January to March 2020 decreased by 59.05%and 32.81%,relative to the same period in 2019 and 2021,*** the period of 2020 COVID-19,the average NO_(2)VCDs were 50.50%and 29.96%lower than those during the pre-lockdown and post-lockdown pe riods,*** NO_(2)volume mixing ratios(VMRs)during the 2020 COVID-19 lock down significantly decreased below 400 *** NO_(2)VMRs under the different wind fields were significantly lower during the lockdown period than during the pre-lockdown period This phenomenon could be attributed to the 2020 COVID-19 *** NO_(2)VMRs be fore and after the CNY were significantly lower in 2020 than in 2019 and 2021 in the same period,which further proves that the decrease in NO_(2)in February 2020 was attributed to the COVID-19 *** source analysis of an NO_(2)pollution episode during the lockdown period showed that the polluted air mass in the Beijing-Tianjin-Hebei was trans ported southwards under the action of the north wind,and the subsequent unfavorable meteorological conditions(local wind speed of<2.0 m/sec)resulted in the accumulation o pollutants.

关键词： MAX-DOAS CNN-SVR Nitrogen dioxide COVID-19 Chinese New Year Regional transport

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environmentally persistent free radicals in PM_(2.5)from a typical Chinese industrial city during COVID-19 lockdown:The unexpected contamination level variation

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Journal of environmental Sciences 2024年第1期135卷 424-432页

作者： Lingyun Wang Wuduo Zhao Peiru Luo Qingyun He Wenfen Zhang Chuan Dong Yanhao Zhang College of Chemistry Zhengzhou UniversityZhengzhou 450001China Center of Advanced Analysis and Gene Sequencing Key Laboratory of Molecular Sensing and Harmful Substances Detection TechnologyZhengzhou UniversityZhengzhou 450001China State Key Laboratory of environmental and Biological Analysis Department of ChemistryHong Kong Baptist UniversityHong Kong 999077China institute of environmental Science Shanxi UniversityTaiyuan 030006China

The outbreak of COVID-19 has caused concerns *** reduce the rapid transmission of the virus,strict city lockdown measures were conducted in different *** is the country that takes the earliest home-based quarantine for *** normal industrial and social activities were suspended,the spread of virus was efficiently ***,another merit of the city lockdown measure was noticed,which is the improvement of the air *** levels of multiple atmospheric pollutants were ***,in this work,24 and 14 air fine particulate matter(PM_(2.5))samples were continuously collected before and during COVID-19 city lockdown in Linfen(a typical heavy industrial city in China),and intriguingly,the unreduced concentration was found for environmentally persistent free radicals(EPFRs)in PM_(2.5)after normal life *** primary non-stopped coal combustion source and secondary Cu-related atmospheric reaction may have impacts on this *** cigarette-based assessment model also indicated possible exposure risks of PM_(2.5)-bound EPFRs during lockdown of *** study revealed not all the contaminants in the atmosphere had an apparent concentration decrease during city lockdown,suggesting the pollutants with complicated sources and formation mechanisms,like EPFRs in PM_(2.5),still should not be ignored.

关键词： PM_(2.5) EPFRs COVID-19 City lockdown Health risks

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Short-term displacement prediction for newly established monitoring slopes based on transfer learning

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China Geology 2024年第2期7卷 351-364页

作者： Yuan Tian Yang-landuo Deng Ming-zhi Zhang Xiao Pang Rui-ping Ma Jian-xue Zhang institute of remote sensing and Geographical Information Systems Peking UniversityBeijing 100871China Beijing Key Laboratory of Spatial Information Integration and Its Applications Beijing 100871China institute of Public Safety Research Department of Engineering PhysicsTsinghua UniversityBeijing 100084China China institute of Geo-Environment Monitoring Beijing 100081China Technology Innovation Center for Geohazard Monitoring and Risk Early Warning Ministry of Natural ResourcesBeijing 100081China

This study makes a significant progress in addressing the challenges of short-term slope displacement prediction in the Universal Landslide Monitoring Program,an unprecedented disaster mitigation program in China,where lots of newly established monitoring slopes lack sufficient historical deformation data,making it difficult to extract deformation patterns and provide effective predictions which plays a crucial role in the early warning and forecasting of landslide hazards.A slope displacement prediction method based on transfer learning is therefore ***,the method transfers the deformation patterns learned from slopes with relatively rich deformation data by a pre-trained model based on a multi-slope integrated dataset to newly established monitoring slopes with limited or even no useful data,thus enabling rapid and efficient predictions for these ***,as time goes on and monitoring data accumulates,fine-tuning of the pre-trained model for individual slopes can further improve prediction accuracy,enabling continuous optimization of prediction results.A case study indicates that,after being trained on a multi-slope integrated dataset,the TCN-Transformer model can efficiently serve as a pretrained model for displacement prediction at newly established monitoring *** three-day average RMSE is significantly reduced by 34.6%compared to models trained only on individual slope data,and it also successfully predicts the majority of deformation *** fine-tuned model based on accumulated data on the target newly established monitoring slope further reduced the three-day RMSE by 37.2%,demonstrating a considerable predictive *** conclusion,taking advantage of transfer learning,the proposed slope displacement prediction method effectively utilizes the available data,which enables the rapid deployment and continual refinement of displacement predictions on newly established monitoring slopes.

关键词： Landslide Slope displacement prediction Transfer learning Integrated dataset Transformer Pre-trained model Universal Landslide Monitoring Program(ULMP) Geological hazards survey engineering

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remote sensing of air pollution incorporating integrated-path differential-absorption and coherent-Doppler lidar

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Defence Technology（防务技术） 2024年第1期31卷 594-601页

作者： Ze-hou Yang Yong Chen Chun-li Chen Yong-ke Zhang Ji-hui Dong Tao Peng Xiao-feng Li Ding-fu Zhou School of physics Beijing Institute of TechnologyBeijing 100081China Southwest institute of Technical physics Chengdu 610041SichuanChina School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China

An innovative complex lidar system deployed on an airborne rotorcraft platform for remote sensing of atmospheric pollution is proposed and *** system incorporates integrated-path differential absorption lidar(DIAL) and coherent-doppler lidar(CDL) techniques using a dual tunable TEA CO_(2)laser in the 9—11 μm band and a 1.55 μm fiber *** combining the principles of differential absorption detection and pulsed coherent detection,the system enables agile and remote sensing of atmospheric *** static tests validate the system’s real-time detection capabilities,including the measurement of concentration-path-length product(CL),front distance,and path wind speed of air pollution plumes over long distances exceeding 4 *** experiments is conducted with the *** of the pollutant concentration and the wind field is carried out in an approximately 1 km slant range over scanning angle ranges from 45°to 65°,with a radial resolution of 30 m and10 *** test results demonstrate the system’s ability to spatially map atmospheric pollution plumes and predict their motion and dispersion patterns,thereby ensuring the protection of public safety.

关键词： Differential absorption LIDAR Coherent Doppler lidar Remoting sensing Atmospheric pollution

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Pluggable multitask diffractive neural networks based on cascaded metasurfaces

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Opto-Electronic Advances 2024年第2期7卷 23-31页

作者： Cong He Dan Zhao Fei Fan Hongqiang Zhou Xin Li Yao Li Junjie Li Fei Dong Yin-Xiao Miao Yongtian Wang Lingling Huang Beijing Engineering Research Center of Mixed Reality and Advanced Display Key Laboratory of Photoelectronic Imaging Technology and System of Ministry of Education of ChinaSchool of Optics and PhotonicsBeijing Institute of TechnologyBeijing 100081China institute of Modern Optics Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network TechnologyNankai UniversityTianjin 300350China Department of physics and Optoelectronics Faculty of ScienceBeijing University of TechnologyBeijing 100124China Beijing National Laboratory for Condensed Matter physics Institute of PhysicsChinese Academy of SciencesBeijing 100191China Beijing Aerospace institute for Metrology and Measurement Technology Beijing 100076China

Optical neural networks have significant advantages in terms of power consumption,parallelism,and high computing speed,which has intrigued extensive attention in both academic and engineering *** has been considered as one of the powerful tools in promoting the fields of imaging processing and object ***,the existing optical system architecture cannot be reconstructed to the realization of multi-functional artificial intelligence systems *** push the development of this issue,we propose the pluggable diffractive neural networks(P-DNN),a general paradigm resorting to the cascaded metasurfaces,which can be applied to recognize various tasks by switching internal *** the proof-of-principle,the recognition functions of six types of handwritten digits and six types of fashions are numerical simulated and experimental demonstrated at near-infrared ***,the proposed paradigm not only improves the flexibility of the optical neural networks but paves the new route for achieving high-speed,low-power and versatile artificial intelligence systems.

关键词： optical neural networks diffractive deep neural networks cascaded metasurfaces

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High-Quality and Wafer-Scale Cubic Silicon Carbide Single Crystals

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Energy & environmental Materials 2024年第4期7卷 442-449页

作者： Guobin Wang Da Sheng Yunfan Yang Hui Li Congcong Chai Zhenkai Xie Wenjun Wang Jiangang Guo Xiaolong Chen Beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

Cubic silicon carbide (3C-SiC) has superior mobility and thermal conduction over that of widely applied hexagonal ***,much lower concentration of interfacial traps between insulating oxide gate and3C-SiC helps fabrica... 详细信息

关键词： cubic SiC high-temperature solution growth high-temperature surface tension solid–liquid interfacial energy wide band gap semiconductor

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Wireless Positioning:Technologies,Applications,Challenges,and Future Development Trends

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1135-1166页

作者： Xingwang Li Hua Pang Geng Li Junjie Jiang Hui Zhang Changfei Gu Dong Yuan School of physics and Electronic Information Engineering University of Henan PolytechnicJiaozuo454000China Jiaozuo Key Laboratory of Crow-sensing Network Jiaozuo454000China institute of Mining Engineering Guizhou Institute of TechnologyGuiyang550003China Coal Supervision Department Panzhou Energy BureauPanzhou553599China

The development of the fifth-generation(5G)mobile communication systems has entered the commercialization stage.5G has a high data rate,low latency,and high reliability that can meet the basic demands of most industries and daily life,such as the Internet of Things(IoT),intelligent transportation systems,positioning,and *** continuous progress and development of society have aroused wide *** accuracy is the core demand for the applications,especially in complex environments such as airports,warehouses,supermarkets,and ***,many factors also affect the accuracy of positioning in those environments,for example,multipath effects,non-line-of-sight,and clock synchronization *** paper provides a comprehensive review of the existing works about positioning for the future wireless network and discusses its key techniques and algorithms,as well as the current development and future *** first outline the current traditional positioning technologies and algorithms,which are discussed and analyzed with the relevant *** addition,we also discuss application scenarios for wireless *** comparing different positioning systems,the challenges and future development directions of existing wireless positioning systems are prospected.

关键词： 5G wireless positioning reconfigurable intelligent surface Internet of Vehicles

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Identi?cation and Analysis of the Intermediates from Photodegradation of 3,3′-diamino-4,4′-azoxyfurazan (DAAF)by SERS and HPLC–MS/MS

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Journal of Analysis and Testing 2024年第03期8卷 351-360页

作者： Qi Wu Zhenqi Zhang Wenxu Zheng Juan Li Nan Ma Rui Li Bo Yang Weimiao Wang Xiaodong Li Meikun Fan Faculty of Geosciences and environmental Engineering Southwest Jiaotong University institute of Chemical Materials China Academy of Engineering Physics College of Materials and Energy South China Agricultural University Southwest University of Science and Technology

Understanding the structural changes and degradation mechanisms of organic pollutants is critical in environmental *** this work, a xenon lamp was used as an analog light source to simulate the eff ect of sunlight on 3,3′-diamino-4,4′-azoxyfurazan (DAAF) in aqueous solution. Combining high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC–MS/MS), surface-enhanced Raman spectroscopy (SERS) with density functional theory (DFT), the degradation intermediates and mechanisms of DAAF were investigated. The sequential breakdown of the–NH 2and–O–N=bonds, followed by the removal of atomic O from–N=N(O)–, was emphasized and investigated using two-dimensional correlation spectroscopy (2D-COS) and SERS spectra. Three intermediates with mass-to-charge ratios (m/z) 181, 251 and180 were identifi ed and characterized by integrating experimental SERS data with DFT-calculated Raman spectra based on structures hypothesized from MS spectra. The fi ndings from HPLC–MS and SERS not only corroborate each other but also provide a foundation for a detailed examination of the DAAF degradation process.

关键词： DAAF High-performance liquid chromatography coupled with tandem mass spectrometry (HPLC–MS/MS) Photodegradation products Reaction pathways Surface-enhanced Raman spectroscopy (SERS)

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Phosphate-Bismuthate Glass and Fiber with Heavy Doping of Silver Nanoparticles(Invited)

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激光与光电子学进展 2024年第3期61卷 168-177页

作者： Chen Fuguang Jiang Bofan Chen Zhi Ma Siyuan Huang Yupeng Zhang Hang Ma Zhijun Research Center for Humanoid sensing Zhejiang LabHangzhou 311121ZhejiangChina State Key Laboratory of Luminescent Materials and Devices School of Materials Science and EngineeringSouth China University of TechnologyGuangzhou 510641GuangdongChina Laboratory for Shock Wave and Detonation physics Research Institute of Fluid PhysicsChina Academy of Engineering PhysicsMianyang 621900SichuanChina

Glass with heavy doping of noble metal nanoparticles is expected to exhibit high optical *** this study,the effects of glass composition,structure,and heat treatment on the formation of silver nanoparticles(Ag NPs)in phosphate-bismuthate(PB)glass are *** optimizing the chemical composition and preparation parameters,strong localized surface plasmon resonance is achieved in the PB glass with a silver mass fraction of more than 13%,which is 20 and 6 times higher than that in bismuthate and phosphate glasses reported previously,*** high solubility of the phosphate component and the self-reduction effect of the bismuthate component jointly contributed to the stability and high content of Ag NPs in the PB glass.Z-scan measurements show that such heavy doping PB glass has a reverse saturable absorption coefficient of-14×10^(-12)m·W^(-1)and a saturable absorption coefficient of 4.94×10^(-12)m·W^(-1)at 800 ***,the heavy doping PB glass exhibits excellent thermal stability,making it promising for the fabrication of nonlinear optical *** addition,with a heavily silver-doped PB glass rod as the core and a commercial silicate glass tube as the cladding,a composite glass fiber with high Ag-NP doping is successfully fabricated using a“molten-core”fiber drawing method.

关键词： phosphate-bismuthate glass silver nanoparticle optical nonlinearity molten-core fiber drawing

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