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Spatiotemporal variations of ambient air pollutants and meteorological influences over typical urban agglomerations in China during the COVID-19 lockdown

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Journal of Environmental Sciences 2021年第8期33卷 26-38页

作者： Linping Fan Shuang Fu Xin Wang Qingyan Fu haohao jia hao Xu Guimei Qin Xue hu Jinping Cheng School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China China National Environmental Monitoring Center Beijing 100012China Shanghai Environmental Monitor Center Shanghai 200235China

To investigate the air quality change during the COVID-19 pandemic,we analyzed spatiotemporal variations of six criteria pollutants in nine typical urban agglomerations in China using ground-based data and examined meteorological influences through correlation analysis and backward trajectory analysis under different *** of PM2.5,PM10,NO2,SO2 and CO in urban agglomerations respectively decreased by 18%–45%(30%–62%),17%–53%(22%–39%),47%-64%(14%–41%),9%–34%(0%–53%)and 16%-52%(23%–56%)during Lockdown(Post-lockdown)period relative to Pre-lockdown ***2.5 pollution events occurred during Lockdown in Beijing-Tianjin-Hebe(BTH)and Middle and South Liaoning(MSL),and daily O3 concentration rose to gradeⅡstandard in Post-lockdown *** from the nationwide slump of NO2 during Lockdown period,a rebound(~40%)in Post-lockdown period was observed in Cheng-Yu(CY),Yangtze River Middle-Reach(YRMR),Yangtze River Delta(YRD)and Pearl River Delta(PRD).With slightly higher wind speed compared with 2019,the reduction of PM2.5(51%–62%)in Post-lockdown period is more than2019(15%–46%)in HC(Harbin-Changchun),MSL,BTH,CP(Central Plain)and SP(ShandongPeninsula),suggesting lockdown measures are effective to PM2.5 *** O3 concentrations generally increased during the lockdown,its increment rate declined compared with 2019 under similar sunlight duration and ***,unlike HC,MSL and BTH,which suffered from additional(>30%)air masses from surrounding areas after the lockdown,the polluted air masses reaching YRD and PRD mostly originated from the long-distance transport,highlighting the importance of joint regional governance.

关键词： COVID-19 Air pollutants Spatial and temporal variations Urban agglomeration Meteorological condition China

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Effect of the number of irradiation holes on rock breaking under constant laser energy

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Petroleum Science 2022年第6期19卷 2969-2980页

作者： Hai-Zeng Pan Yi hu Yong Kang Ze-Feng Wang jia-Wei Liu hao Chen Meng-Da Zhang hubei Key Laboratory of Waterjet Theory and New Technology Wuhan UniversityWuhan430072HubeiChina School of Power and Mechanical Engineering Wuhan UniversityWuhan430072HubeiChina The Institute of Technological Sciences Wuhan UniversityWuhan430072HubeiChina School of Urban Construction Wuhan University of Science and TechnologyWuhan430081HubeiChina jianghan Machinery Research Institute Limited Company of CNPC Wuhan430000HubeiChina

The use of mechanical drilling in accessing energy resources stored in deep and hard rock formations is becoming increasingly ***,laser irradiation has emerged as a novel drilling method with considerable in this *** study examines the variation of rock fracture length,fracture tortuosity,hole size,and rock breaking efficiency for a different number of holes and laser power,based on the constant total energy of laser *** indicated by the results,increasing the laser power increases the laser intensity,which helps increase the hole diameter and ***,for the same laser power,increasing the number of irradiated holes reduces the laser energy absorbed by each hole,which is not conducive to increasing the hole *** the number of holes increases,the mass loss of the rock also increases,while both specific energy(SE)and modified specific energy(MSE)*** the number of holes remains the same,the mass of the shale removed by low power is less than that removed by high power,while SE and MSE have an inverse relation with ***,high laser power and multiple-hole irradiation are more conducive to rock ***,the fracture length and fracture tortuosity of the rock irradiated by the low laser power will increase first and then decrease with the increase in the number of holes,and reach the peak value when the irradiation takes place through three *** a high-power laser irradiates the rock,the fracture length and tortuosity will increase with the increase in the number of irradiation *** is because a rock irradiated by low power dissipates more energy,with the result that the energy absorbed by the sample with four irradiation holes is not enough to break the rock *** study is expected to provide some guidance to break rock for drilling deep reservoirs and hard rock formations using laser irradiation.

关键词： Number of irradiation holes Rock breaking Fracture tortuosity Macrofracture

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Molecule functionalization to facilitate electrocatalytic oxygen reduction on graphdiyne

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Journal of Energy Chemistry 2022年第2期31卷 141-148页

作者： huiying Yao Yasong Zhao Nailiang Yang Wei hao hu Zhao Shuzhou Li jia Zhu Lin Shen Weihai Fang College of Chemistry Key Laboratory of Theoretical&Computational Photochemistry of Ministry of EducationBeijing Normal UniversityBeijing 100875China State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Materials Science and Engineering Nanyang Technological University50 Nanyang Avenue639798Singapore Department of Physics Beijing Normal UniversityBeijing 100875China Laboratory of Theoretical and Computational Nanoscience CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyChinese Academy of SciencesBeijing 100190China

Chemical doping is verified to be a promising strategy to regulate local electron distribution and further promote the poor intrinsic catalytic activity of ***,the current doping approach still faces problems such as precise doping for creating active sites and the destruction of graphdiyne skeleton calling for high ***,we achieved charge redistribution on graphdiyne surface through molecule functionalization.A p-type molecule–F4 TCNQ(2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodime thane)was introduced and the site-defined functionalization was *** calculations showed that the charge transfer ability is improved and graphdiyne becomes positively *** oxygen reduction electrocatalysis was conducted as a proof of principle,where the electronic states of sp hybridized C active site was tuned toward favorable reaction intermediates’*** work from both theoretical prediction and experimental validation,found that molecule functionalization is effective to promote the electrocatalytic oxygen reduction,which creates new possibilities for graphdiyne’s applications in different electrochemical reactions.

关键词： Graphdiyne F4TCNQ Density functional calculations Electronic structure Oxygen reduction reaction

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Topological superconductivity in a Bi2Te3/NbSe2 heterostructure:A review

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Chinese Physics B 2019年第6期28卷 5-15页

作者： hao Zheng Jin-Feng jia School of Physics and Astronomy Shanghai Jiao Tong University

Topological superconductors carry globally protected gapless boundary excitations, which are robust under local perturbations, and thus exhibit both fundamental and applicational importance. An unconventional pairing with p-wave symmetry, such as a nontrivial topology in the superconductor’s wavefunction, is required to generate a non-zero Berry phase. Until now, the Bi2 Te3/2 H–NbSe2 heterostructure has proven to be a practical way to realize a topological superconductor in real materials. This complex system, where odd numbers of spin-momentum locked Dirac cone surface states on the topological insulator Bi2 Te3 become superconducting, induced by the proximate effect from the underlying s-wave superconductor 2 H–NbSe2, realizes an effective two-dimensional(2 D) spinless px + i py topological superconductor. In this review article, we summarize the recent experimental progress of the successful synthesis of Bi2 Te3/2 H–NbSe2 heterostructures using molecular beam epitaxy, determining the thickness limit of the heterostructure, detecting the long thought Majorana quasiparticle inside a magnetic vortex core state by means of scanning tunneling microscopy and demonstration of the unique spatial and spin properties of a Majorana zero mode.

关键词： topological insulator topological superconductor Majorana zero mode scanning tunneling microscopy molecular beam epitaxy

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A universal and ultrafast method for fabricating a library of nanocellulose-supported metal nanoparticles

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Progress in Natural Science:Materials International 2024年第2期34卷 389-395页

作者： Ziyi Luo Xiaoyang Wang Baihua Cui hao Luo Tao Zhang jia Ding Yanan Chen Yida Deng Wenbin hu School of Materials Science and Engineering Tianjin University Department of Chemistry National University of Singapore State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and Engineering Hainan University

Using nanocatalysts to catalyze water electrolysis for hydrogen production is an ideal solution to address the energy *** most well-adopted fabrication methods for nanocatalysts are tube furnace annealing,Hydrothermal method,etc.,hardly satisfying the trade-off among coarsening,dispersity,and particle size due to mutual ***,a universal,ultrafast and facile cellulose nanometer whiskers-high temperature shock（CNWHTS） method was reported for fabricating a library of ultrafine metal nanoparticles with uniform dispersion and narrow size *** metal-anchor functional groups in CNW（i.e.,-OH and-COOH） and the characteristics of the HTS method for ultrafast heating and powerful quenching synergistically contribute to the successful synthesis of metal *** an initial demonstration,the as-prepared Pt nanocatalyst(η10 mA cm-2=51.8 mV) shows more excellent catalytic hydrogen evolution reaction（HER） performance than the Pt catalyst prepared in the tubular furnace(η10 mA cm-2=169.4 mV).This rapid and universal CNW-HTS method can pave the way for nanomanufacturing to produce high-quality metal nanoparticles,thereby expanding applications of energy conversion and electrocatalysis.

关键词： Nanoparticles High-temperature shock Nanocellulose Nanomanufacturing Hydrogen evolution reaction (HER) Electrocatalysis

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Einstein Probe discovery of EP240408a: A peculiar X-ray transient with an intermediate timescale

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 222-240页

作者： Wenda Zhang Weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai huaqing Cheng Francesco Coti Zelati Lixin Dai Jingwei hu Shumei jia Chichuan Jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong Li Bifang Liu Mingjun Liu Xing Liu Yuan Liu Zhu Liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo hu Maohai huang jia huo Zhenqing jia Bowen jiang Ge Jin Chengkui Li Junfei Li Longhui Li Maoshun Li Wei Li Zhengda Li Tianying Lian Congzhan Liu Heyang Liu huaqiu Liu Fangjun Lu Laidan Luo jia Ma Xuan Mao Haiwu Pan Xin Pan Liming Song hui Sun Yunyin Tan Qingjun Tang Yihan Tao hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and Space Sciences University of Chinese Academy of Sciences Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Institute of Space Sciences (ICE) CSIC Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck Institute for Extraterrestrial Physics Innovation Academy for Microsatellites Chinese Academy of Sciences Department of Physics University of Hong Kong School of Physics and Astronomy University of Leicester School of Physics and Astronomy Sun Yat-sen University Department of Physics Anhui Normal University Shanghai Institute of Technical Physics Chinese Academy of Sciences Physics Department Tsinghua University Nevada Center for Astrophysics University of Nevada Las Vegas Department of Physics and Astronomy University of Nevada Las Vegas South African Astronomical Observatory Department of Astronomy University of Cape Town Department of Physics University of the Free State Université Paris Cité CNRS Astroparticule et Cosmologie Université Paris Cité CEA Paris-Saclay IRFU/DAp-AIM Department of Astronomy Guangzhou University Cosmic Dawn Center (DAWN) Niels Bohr Institute University of Copenhagen Department of Physics and Astronomy Rutgers the State University of New Jersey Institute for Cosmic Ray Research The University of Tokyo ESA/ESTEC Department of Astronomy School of Physics huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney Institute for Astronomy School of Physics The University of Sydney Department of Astronomy Xiamen University Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Department of Astronomy University of Science and Technology School of Astronomy and Space Sciences University of Science and Technology of China Institute of Deep Space Sciences Deep Space Exploration Laboratory Department of Astronomy School of Physics and Astronomy Yunnan University Shanghai Astronomical Observatory Chi

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 ke V,～300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 ke V,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for ～4 d,followed by a steep decay till becoming undetectable ～10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of～10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients ${\bm~{Einstein~~Probe}}$

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Functional characterization of MdMYB73 reveals its involvement in cold stress response in apple calli and Arabidopsis

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Journal of Integrative Agriculture 2017年第10期16卷 2215-2221页

作者： ZHANG Quan-yan YU jian-qiang WANG jia-hui hu Da-gang hao Yu-jin State Key Laboratory of Crop Biology National Research Center for Apple Engineering and Technology Shandong Agricultural University Tai'an 271018 P.R.China

Recent studies have shown that the R2R3-MYB transcription factor MdMYB73 is involved in salt stress response in apple. However, no research was done whether MdMYB73 mediated cold tolerance in apple or not. In this study, we found that the expression of MdMYB73 was obviously induced by cold stress. Functional analysis showed that MdMYB73 significantly increased cold tolerance in transgenic apple calli and Arabidopsis. Quantitative real-time PCR （qRT-PCR） assay indicated that the expression levels of cold-responsive genes including MdCBF2, MdCBF3, MdCBF4, and MdCBF5 were obviously enhanced in MdMYB73 transgenic calli, suggesting that MdMYB73 increased cold tolerance via C-repeat binding factor （CBF） cold response pathway. Finally, we found that soluble sugar, which provides an osmoticum for cells, was increased in MdMYB73 transgenic calli compared to that in the wild type control. These findings provide a new insights into how MdMYB73 is involved in cold stress response.

关键词： apple MdMYB73 cold stress CBF soluble sugar

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拉伸条件下聚二甲基硅氧烷表面粗糙度对骨髓间充质干细胞成骨分化的影响

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中国组织工程研究 2025年第10期29卷 1981-1989页

作者：胡泽遵杨反磊徐浩罗宗平苏州大学附属第一医院骨科研究所江苏省苏州市215000

背景:研究表明,机械刺激对骨髓间充质干细胞的谱系特异性分化至关重要。然而,机械拉伸条件下不同粗糙度表面的骨髓间充质干细胞成骨分化情况尚不清楚。目的:探讨拉伸条件下聚二甲基硅氧烷(polydimethylsiloxane,PDMS)表面粗糙度对骨髓... 详细信息

背景:研究表明,机械刺激对骨髓间充质干细胞的谱系特异性分化至关重要。然而,机械拉伸条件下不同粗糙度表面的骨髓间充质干细胞成骨分化情况尚不清楚。目的:探讨拉伸条件下聚二甲基硅氧烷(polydimethylsiloxane,PDMS)表面粗糙度对骨髓间充质干细胞成骨分化的影响及作用机制。方法:通过不同目砂纸(120目、1 000目和10 000目)在PDMS表面构建3种不同粗糙度的形貌(PDMS-120M、PDMS-1000M和PDMS-10000M),与空气接触的PDMS表面作为对照组。采用RT-q PCR检测静态条件下和拉伸条件下(0%,2%,4%,6%拉伸幅度)不同粗糙度PDMS表面的骨髓间充质干细胞中成骨相关基因表达。采用RT-q PCR、Western blot检测2%拉伸条件下不同粗糙度表面骨髓间充质干细胞中SIRT1、成骨相关基因和蛋白表达,采用碱性磷酸酶染色、茜素红染色观察2%拉伸条件下不同粗糙度PDMS表面骨髓间充质干细胞的成骨分化能力。结果与结论:(1)静态条件下粗糙度为(13.51±2.11)μmPDMS-1000M表面的骨髓间充质干细胞成骨基因表达最高;(2)相对光滑PDMS表面的骨髓间充质干细胞在4%拉伸幅度条件下有更好的成骨分化效果,而PDMS-1000M表面的骨髓间充质干细胞在2%拉伸幅度条件下有更好的成骨分化效果;(3)在2%拉伸幅度条件下,粗糙度为(13.51±2.11)μm PDMS-1000M表面的骨髓间充质干细胞有更好的成骨分化效果,可能与激活SIRT1信号通路有关。

关键词：骨髓间充质干细胞成骨分化机械刺激机械拉伸粗糙度信号通路 SIRT1

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Identifying and Quantifying Pixel-Level Uncertainty among Major Satellite Derived Global Land Cover Products

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Journal of Meteorological Research 2020年第4期34卷 806-821页

作者： hao GAO Gensuo jia Yu FU National Satellite Meteorological Center China Meteorological AdministrationBeijing 100081 Key Laboratory of Regional Climate–Environment for Temperate East Asia(RCE-TEA) Chinese Academy of SciencesBeijing 100029 Climate Change Research Center Chinese Academy of SciencesBeijing 100029

Accurate global land cover(GLC), as a key input for scientific communities, is important for a wide variety of applications. In order to understand the current suitability and limitation of GLC products, the discrepancy and pixellevel uncertainty in major GLC products in three epochs are assessed in this study by using an integrated uncertainty index(IUI) that combines the thematic uncertainty and local classification accuracy uncertainty. The results show that the overall spatial agreements(Ao values) between GLC products are lower than 58%, and the total areas of forests are very consistent in major GLC products, but significant differences are found in different forest *** misclassification among different forest classes and mosaic types can account for about 20% of the total disagreements. The mean IUI almost reaches 0.5, and high uncertainty mostly occurs in transition zones and heterogeneous areas across the world. Further efforts are needed to make in the land cover classifications in areas with high uncertainty. Designing a classification scheme for climate models, with explicit definitions of land cover classes in the threshold of common attributes, is urgently needed. Information of the pixel-level uncertainty in major GLC products not only give important implications for the specific application, but also provide a quite important basis for land cover fusion.

关键词： global land cover(GLC) discrepancies thematic similarity local accuracy pixel-level uncertainty

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Cyclic-Auto-Correlation Based Timing Estimation Algorithm for Time-Frequency Overlapping Multi-Carrier Signals

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Journal of Electronic Science and Technology 2020年第3期18卷 223-233页

作者： Xing Zhang jian-hao hu National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengdu 610054

In recent years,the time-frequency overlapping multi-carrier signal has been a novel and valuable topic in blind signal processing,especially in the non-cooperative receiving *** there is little related research in public published *** paper proposes two timing estimation algorithms,which are non-data-aided and based on the cyclic auto-correlation *** order to evaluate the performance of the proposed algorithms,the theoretical bound of the timing estimation is *** to the analyses and simulation results,the effectiveness of the proposed algorithms has been *** shows that MethodⅠhas better performance than MethodⅡ.However,MethodⅡdoes not need prior information,so it has a wider range of applications.

关键词： Cyclic auto-correlation orthogonal frequency division multiplexing(OFDM) time-frequency overlapping signal timing estimation

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