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Dynamic emission characteristics and control strategies of air pollutants from motor vehicles in downtown Beijing,China

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Journal of Environmental Sciences 2024年第2期136卷 637-646页

作者： Yan Shen Tongran wu Aiping Lian Jie Gao Fei Peng Guohua Song xuefang wu Yangyang Cui Xinyu Liu Yunfei Wan Jing Yan Yifeng xue National Engineering Research Center of Urban Environmental Pollution Control Beijing Municipal Research Institute of Eco-Environmental ProtectionBeijing 100037China Beijing Municipal Ecology and Environment Bureau Beijing 100048China Beijing Jiaotong University Beijing 100091China

This study combined the real-time monitoring and investigation of traffic flows to comprehensively analyze the road traffic flow and vehicle structure in downtown Beijing.A dynamic emission inventory of motor vehicle air pollutants in downtown Beijing in 2021 was established,and the impact of these emissions on air quality was simulated and quantified,and different emission reduction control scenarios were proposed to evaluate their environmental improvement effects and explore measures to mitigate the impact of pollution *** results show that the high traffic flow and the structure of the motor vehicle emissions in downtown Beijing are the main causes of severe motor vehicle *** data shows that traffic flow in central Beijing is dominated by small passenger vehicles,while the vehicle mix is better than in other regions,with 72.0%of vehicles meeting"National V"or higher emission ***,to achieve higher air quality goals,further reducing vehicle emissions is *** on dynamic traffic flow,the average daily emissions of nitrogen oxides(NOX),particulate matters(PM_(2.5))and volatile organic compounds(VOC)from motor vehicles in central Beijing are 17.7 tons,0.6 tons and 14.0 tons,respectively,accounting for 23.0%of the city’s average daily motor vehicle *** a zero-emission zone for motor vehicles were implemented in central Beijing,the annual average emission level of pollutants will be reduced by 10.4%to 21.0%.The designation of ultra-low emission zones for motor vehicles could be effective in improving the air quality in the center of Beijing.

关键词： Motor vehicle Air pollutant Emission characteristics Control strategy Beijing

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Will the 2022 compound heatwaveedrought extreme over the Yangtze River Basin become Grey Rhino in the future?

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Advances in Climate Change Research 2024年第3期15卷 547-556页

作者： Ai-Qing FENG Qing-Chen CHAO Lu-Lu LIU ge GAO Guo-Fu WANG xue-Jun ZHANG Qi-Guang WANG China Meteorological Administration Key Laboratory for Climate Prediction Studies National Climate CentreBeijing 100081China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China China Institute of Water Resources and Hydropower Research Beijing 100038China China Meteorological Administration Training Centre China Meteorological AdministrationBeijing 100081China

The increasingly frequent and severe regional-scale compound heatwave-drought extreme events(CHDEs),driven by global warming,present formidable challenges to ecosystems,residential livelihoods,and economic ***,uncertainty persists regarding the future trend of CHDEs and their insights into regional spatiotemporal *** integrating daily meteorological data from observations in 1961-2022 and global climate models(GCMs)based on the Shared Socioeconomic Pathways,the evolution patterns of CHDEs were compared and examined among three sub-catchments of the Yangtze River Basin,and the return periods of CHDE in 2050s and 210Os were *** findings indicate that the climate during the 2022 CHDE period was the warmest and driest recorded in 1961-2022,with precipitation less than 154.5 mm and a mean daily maximum temperature 3.4°C higher than the average of 1981-2010,whereas the char-acteristics in the sub-catchments exhibited temporal and spatial *** July-August 2022,the most notable feature of CHDE was its extremeness since 1961,with return periods of~200-year in upstream,80-year in midstream,and 40-year in downstream,*** 2050,the return periods witnessed 2022 CHDE would likely be reduced by *** towards 2100,under the highest emission scenario of SSP585,it was projected to substantially increase the frequency of CHDEs,with return periods reduced to one-third in the upstream and downstream,as well as halved in the *** findings provide valuable insights into the changing risks associated with forthcoming climate extremes,emphasizing the urgency of addressing these challenges in regional management and sustainable development.

关键词： Compound extreme event Joint return period Drought Heatwave Climate change Yangtze River Basin

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Highly efficient through-space charge transfer TADF molecule employed in TADF-and TADF-sensitized organic light-emitting diodes

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Science China Chemistry 2024年第4期67卷 1270-1276页

作者： Jiasen Zhang Deli Li Wei Li Yujie wu Xilin Mu Chunyu Liu Kaibo Fang Ziyi ge Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices South China University of TechnologyGuangzhou 510640China

The inception and harnessing of excitons are paramount for the electroluminescence performance of organic light-emitting devices(OLEDs).Through-space charge transfer(TSCT)via intramolecular interaction has proved to be one of the most potent techniques employed to achieve 100% internal quantum ***,molecular strategies utilized to comprehensively enhance the electroluminescent performance of TSCT emitters regarding improving the photoluminescence quantum yield(PLQY)and elevating the light out-coupling efficiency remain *** surmount this challenge,we deliberately designed and synthesized a proof-of-concept TSCT emitter called CzO-TRZ by incorporating an extra carbazole donor into spiroheterocyclic *** introduction of rigid spiral fragments can immensely boost the horizontal orientation dipole ratio and establish an extra through-bond charge transfer(TBCT)radiative decay *** a result,a very high PLQY of 98.7%,fast kRISCof 2.2×10^(5)s^(-1)and high k_(r)^(s) of 2.2×10^(7)s^(-1),and an ultrahigh horizontal dipolar ratio of 90%were concurrently achieved for Cz O-TRZ blended ***,corresponding thermally activated delayed fluorescence(TADF)-and TADF-sensitized fluorescence(TSF)-OLEDs based on CzO-TRZ demonstrated external quantum efficiencies(EQEs)of 33.4% and 30.3%,respectively,highlighting its versatile applications as both an emitter and sensitized host.

关键词： organic electronics organic light-emitting diodes polycyclic aromatic hydrocarbons multiple-resonance

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Cryo-EM combined with image deconvolution to determine ZIF-8 crystal structure

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Chinese Physics B 2024年第7期33卷 44-49页

作者：吴抗杨柏松薛文华孙大鹏葛炳辉王玉梅 Information Materials and Intelligent Sensing Laboratory of Anhui Province Leibniz International Joint Research Center of Materials Sciences of Anhui ProvinceInstitutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Beijing Branch of Songshan Lake Materials Laboratory Dongguan 523808China

Metal–organic frameworks(MOFs) are crystalline porous materials with tunable properties, exhibiting great potential in gas adsorption, separation and catalysis.[1,2]It is challenging to visualize MOFs with transmission electron microscopy(TEM) due to their inherent instability under electron beam irradiation. Here, we employ cryo-electron microscopy(cryoEM) to capture images of MOF ZIF-8, revealing inverted-space structural information at a resolution of up to about 1.7A and enhancing its critical electron dose to around 20 e^(-)/A^(2). In addition, it is confirmed by electron-beam irradiation experiments that the high voltage could effectively mitigate the radiolysis, and the structure of ZIF-8 is more stable along the [100] direction under electron beam irradiation. Meanwhile, since the high-resolution electron microscope images are modulated by contrast transfer function(CTF) and it is difficult to determine the positions corresponding to the atomic columns directly from the images. We employ image deconvolution to eliminate the impact of CTF and obtain the structural images of ZIF-8. As a result, the heavy atom Zn and the organic imidazole ring within the organic framework can be distinguished from structural images.

关键词： cryo-electron microscopy(cryo-EM) ZIF-8 image deconvolution crystal structure determination

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Lignin-reinforced PVDF electrolyte for dendrite-free quasi-solid-state Li metal battery

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Rare Metals 2024年第3期43卷 1006-1016页

作者： Xin-Yang Chen xue-Jie Gao Han-Yan wu Yu-Long Liu Xiao-Fei Yang Run-Cang Sun Center for Lignocellulosic Chemistry and Biomaterials College of Light Industry and Chemical EngineeringDalian Polytechnic UniversityDalian116034China Division of Energy Storage Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023China School of Chemistry Northeast Normal UniversityChangchun130024China

Quasi-solid-state lithium metal batteries(QSSLMBs)assembled with polyvinylidene fluoride(PVDF)are a promising class of next-generation rechargeable batteries due to their safety,high energy density,and superior interfacial ***,PVDF has a series of inherent drawbacks such as low ionic conductivity,ease of crystallization,and hydrophobic character that leading to poor cell *** tackle these issues,a lignin-reinforced PVDF electrolyte is proposed in this work to solve these drawbacks of PVDF and enhance the comprehensive performance of *** lithophilic polar groups of lignin can promote uniform deposition of Li on the *** with the improved mechanical properties can efficiently prevent Li dendrites penetration through the *** addition,more active sites provided by lignin can also enhance Li^(+)transport and lead to a faster electrochemical reaction *** from the ingenious design,Li symmetric cells with 5%lignin-PVDF quasi-solid-state electrolyte can operate for 900 h at a high current density/capacity of 5 mA·cm^(-2)/5 mAh·cm^(-2),while shortcircuiting occurs after 56 h for the counterpart(pure PVDF).Moreover,a full cell of Li/5%lignin-PVDF/LFP cell demonstrates a high capacity of 96.2 mAh·g^(-1)after 2000 cycles at 10 *** work is expected to open up promising opportunities to develop other high-energy/power-density QSSLMBs.

关键词： Quasi-solid-state electrolyte Lignin PVDF Dendrite-free Li metal battery

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Pure-high-even-order dispersion bound solitons complexes in ultra-fast fiber lasers

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Light(Science & Applications) 2024年第5期13卷 957-972页

作者： Ying Han Bo Gao Honglin Wen Chunyang Ma Jiayu Huo Yingying Li Luyao Zhou Qi Li ge wu Lie Liu College of Communication Engineering Jilin UniversityChangchun 130012China. Research Center of Circuits and Systems Peng Cheng LaboratoryShenzhen 518055China. International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China. College of Electronic Science and Engineering Jilin UniversityChangchun 130012China

Temporal solitons have been the focus of much research due to their fascinating physical *** solitons can form bound states,which are fundamentally crucial modes in fiber laser and present striking analogies with their matter molecules counterparts,which means they have potential applications in large-capacity transmission and alloptical information *** traditionally,second-order dispersion has been the dominant dispersion for conventional solitons,recent experimental and theoretical research has shown that pure-high-even-order dispersion(PHEOD)solitons with energy-width scaling can arise from the interaction of arbitrary negative-even-order dispersion and Kerr *** these advancements,research on the bound states of PHEOD solitons is currently *** this study,we obtained PHEOD bound solitons in a fiber laser using an intra-cavity spectral pulse shaper for high-order dispersion ***,we experimentally demonstrate the existence of PHEOD solitons and PHEOD bound solitons with pure-quartic,-sextic,-octic,and-decic *** simulations corroborate these experimental ***,vibrating phase PHEOD bound soliton pairs,sliding phase PHEOD bound soliton pairs,and hybrid phase PHEOD bound tri-soliton are discovered and *** results broaden the fundamental understanding of solitons and show the universality of multi-soliton patterns.

关键词： dispersion solitons soliton

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Comparing short-term outcomes of robot-assisted and conventional laparoscopic total mesorectal excision surgery for rectal cancer in elderly patients

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World Journal of Gastrointestinal Surgery 2024年第5期16卷 1271-1279页

作者： Hao Yang Gang Yang Wen-Ya wu Fang Wang xue-Quan Yao Xiao-Yu wu The Affiliated Hospital of Nanjing University of Chinese Medicine Nanjing University of Chinese MedicineNanjing 210029Jiangsu ProvinceChina Department of Surgical Oncology The Affiliated Hospital of Nanjing University of Chinese MedicineNanjing 210029Jiangsu ProvinceChina

BACKGROUND Da Vinci Robotics-assisted total mesorectal excision(TME)surgery for rectal cancer is becoming more widely *** is no strong evidence that roboticassisted surgery and laparoscopic surgery have similar outcomes in elderly patients with TME for rectal *** To determine the improved oncological outcomes and short-term efficacy of robot-assisted surgery in elderly patients undergoing TME *** A retrospective study of the clinical pathology and follow-up of elderly patients who underwent TME surgery at the Department of Gastrointestinal Oncology at the Affiliated Hospital of Nanjing University of Chinese Medicine was conducted from March 2020 through September *** patients were divided into a robotassisted group(the R-TME group)and a laparoscopic group(the L-TME group),and the short-term efficacy of the two groups was *** There were 45 elderly patients(≥60 years)in the R-TME group and 50 elderly patients(≥60 years)in the L-TME *** were no differences in demographics,conversion rates,or postoperative complication *** L-TME group had a longer surgical time than the R-TME group[145(125,187.5)vs 180(148.75,206.25)min,P=0.005),and the first postoperative meal time in the L-TME group was longer than that in the R-TME(4 vs 3 d,P=0.048).Among the sex and body mass index(BMI)subgroups,the R-TME group had better out-comes than did the L-TME group in terms of operation time(P=0.042)and intraoperative assessment of bleeding(P=0.042).In the high BMI group,catheter removal occurred earlier in the R-TME group than in the L-TME group(3 vs 4 d,P=0.001),and autonomous voiding function was *** The curative effect and short-term efficacy of robot-assisted TME surgery for elderly patients with rectal cancer are similar to those of laparoscopic TME surgery;however,robotic-assisted surgery has better short-term outcomes for individuals with risk factors such as obesity and pelvic *** the learning

关键词： Robotic surgery Laparoscopy Rectal cancer Total mesorectal excision Elderly

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Design optimization and testing of a morphing leading-edge with a variable-thickness compliant skin and a closed-chain mechanism

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Chinese Journal of Aeronautics 2024年第7期37卷 285-300页

作者： Zhigang WANG Xiasheng SUN Yu YANG Wenjie ge Daochun LI Jinwu XIANG Panpan BAO Qi wu Andrea DA RONCH School of Aeronautical Science and Engineering Beihang UniversityBeijing 100191China National Key Laboratory of Strength and Structural Integrity Aircraft Strength Research Institute of ChinaXi’an 710065China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Faculty of Engineering and Physical Sciences University of SouthamptonSouthampton SO171JBUK

Climate warming and the increased demand in air travels motivate the aviation industry to urgently produce technological *** of the most promising innovations is based on the smoothly continuous morphing leading-edge *** study proposes a two-step process for the design of a morphing leading-edge,including the optimization of the outer variable-thickness composite compliant skin and the optimization of the inner kinematic *** the compliant skin design,an optimization of the variable thickness composite skin is proposed based on a laminate continuity model,with laminate continuity constraint and other manufacturing *** laminate continuity model utilizes a guiding sequence and a ply-drop sequence to describe the overall stacking sequence of plies in different thickness regions of the complaint *** the inner kinematic mechanism design,a coupled four-bar linkage system is proposed and optimized to produce specific trajectories at the actuation points on the stringer hats of the compliant skin,which ensures that the compliant skin can be deflected into the aerodynamically optimal ***,a morphing leading-edge is manufactured and *** results are compared with numerical predictions,confirming the feasibility of the morphing leading-edge concept and the overall proposed design approach.

关键词： Optimization Design Morphing wing Compliant skin Kinematics Leading-edge Control surfaces

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Multicolor emission from lanthanide ions doped lead-free Cs_(3)Sb_(2)Cl_(9) perovskite nanocrystals

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Journal of Rare Earths 2024年第5期42卷 940-946,I0005页

作者： He Shao Lifang Li Xiufeng wu Lin Xu Biao Dong Donglei Zhou xue Bai Hongwei Song State Key Laboratory of Organic Electronics and Information Displays&Institute of Advanced Materials College of Materials Science and EngineeringNanjing University of Posts&TelecommunicationsNanjing210023China State Key Laboratory of Integrated Optoelectronics College of Electronic Science and Engineering Jilin UniversityChangchun130012China

The toxicity of lead ions has become the severe challenge for the all-inorganic lead halide p erovskite materials,although some works have rep orted the lead-free perovskite nanocrystals(NCs),the photoluminescence quantum yield(PLQY)of these materials is still ***,because the halogen ions can be easily exchanged,the controllable multicolor emission in perovskite NCs is difficult to realize in current *** this work,we introduced lanthanide ions into lead-free Cs_(3)Sb_(2)Cl_(9) perovskite *** from the energy transfer between Cs_(3)Sb_(2)Cl_(9) perovskite NC host and lanthanide ions,the multicolor emission was *** on controlling the doping concentration of Tb^(3+)and Eu^(3+)ions,the white light emission under UV excitation would be turned easily in the Tb^(3+)/Eu^(3+)codoped *** addition,efficient energy transfer from perovskite NCs to Tb^(3+)or Eu^(3+)ions is beneficial to improving the optical properties of lead-free perovskite NCs,resulting in maximum PLQYs of red,green and white light emission of 22.6%,19.7%and 28.5%,***,a white light emitting device(WLED)was fabricated with a power efficiency of 18.5 lm/W,which presents the Commission Internationale de l'Eclairage(CIE)of(0.33,0.35).

关键词： Perovskite nanocrystals Lead free Lanthanide ions Energy transfer White light emitting device Rare earths

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Mixed D-vine copula-based conditional quantile model for stochastic monthly streamflow simulation

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Water Science and Engineering 2024年第1期17卷 13-20页

作者： Wen-zhuo Wang Zeng-chuan Dong Tian-yan Zhang Li Ren Lian-qing xue Teng wu College of Water Resources and Hydrology Hohai UniversityNanjing 210098China Yellow River Research Center Hohai UniversityNanjing 210098China

Copula functions have been widely used in stochastic simulation and prediction of ***,existing models are usually limited to single two-dimensional or three-dimensional copulas with the same bivariate block for all *** address this limitation,this study developed a mixed D-vine copula-based conditional quantile model that can capture temporal *** model can generate streamflow by selecting different historical streamflow variables as the conditions for different months and by exploiting the conditional quantile functions of streamflows in different months with mixed D-vine *** up-to-down sequential method,which couples the maximum weight approach with the Akaike information criteria and the maximum likelihood approach,was used to determine the structures of multivariate Dvine *** developed model was used in a case study to synthesize the monthly streamflow at the Tangnaihai hydrological station,the inflow control station of the Longyangxia Reservoir in the Yellow River *** results showed that the developed model outperformed the commonly used bivariate copula model in terms of the performance in simulating the seasonality and interannual variability of *** model provides useful information for water-related natural hazard risk assessment and integrated water resources management and utilization.

关键词： Stochastic monthly streamflow simulation Mixed D-vine copula Conditional quantile model Up-to-down sequential method Tangnaihai hydrological station

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