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Persistent greening against drying in northeast Asian semiarid grasslands:Asymmetrical responses of direct and legacy effects to intensified drought

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Advances in Climate Change Research 2024年第1期15卷 9-20页

作者： Yu-Tong MA Hai-shan CHEN Yao-Ming SONG Bo-Tao ZHOU shan-lei SUN Xin-Guan DU Yue SUN Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing 210044China

Despite experiencing a decadal shift towards drought conditions at the end of the 2Oth century,semiarid grasslands in northeast Asia(NEA)exhibited an evident greening trend from 1982 to ***,the mechanism behind this phenomenon remains ***,we analysed the interdecadal changes in vegetation response to drought on the basis of the standardised precipitation evapotranspiration index(SPEI)and Global Inventory Modelling and Mapping Studies LAI4g datasets,with an emphasis on the differences between direct and legacy effects(as measured by resilience),to explore the mechanism of persistent grassland *** revealed that during the post-drought shift period(2000-2020),the sudden decrease in the water content of the intermediate soil layer triggered an intensified vegetation response to ***,although direct effects and resilience were amplified,they exhibited asymmetric *** was stronger than direct effects,and this difference increased with increasing drought(drought recovery)*** combined effects may account for persistent greening against intensified drying in the semiarid grasslands in *** the projected exacerbation of future droughts,this study holds notable importance for comprehending the long-term change dynamics of dryland ecosystems.

关键词： Semiarid grassland Drought decadal shift Direct effect Legacy effect(resilience) Northeast Asia

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A FRET-Based Ratiometric H_(2)S Sensor for Sensitive Optical Molecular Imaging in Second Near-Infrared Window

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Research 2024年第3期2023卷 671-684页

作者： shan lei Kejia Jiang Chenqing Zhang Wei Sun Yuantao Pan Dong Wang Peng Huang Jing Lin Marshall Laboratory of Biomedical Engineering International Cancer CenterShenzhen Key Laboratory of Tumor Visualization Molecular MedicineLaboratory of Evolutionary Theranostics(LET)School of Biomedical EngineeringShenzhen University Medical SchoolShenzhen UniversityShenzhen 518055China. Center for AIE Research College of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China.

Second near-infrared(NIR-II)window optical molecular imaging kicks off a new revolution in high-quality imaging in vivo,but always suffers from the hurdles of inevitable tissue autofluorescence background and NIR-II probe ***,we prepare a Förster resonance energy transfer-based ratiometric NIR-II window hydrogen sulfide(H_(2)S)sensor through the combination of an H_(2)S-responsive NIR-II cyanine dye(acceptor,LET-1055)and an H_(2)S-inert rhodamine hybrid polymethine dye(donor,Rh930).This sensor not only exhibits high sensitivity and selectivity,but also shows rapid reaction kinetics(~20 min)and relatively low limit of detection(~96 nM)toward H_(2)S,allowing in vivo ratiometric NIR-II fluorescence imaging of orthotopic liver and colon tumors and visualization of the drug-induced hepatic H_(2)S *** findings provide the potential for advancing the feasibility of NIR-II activity-based sensing for in vivo clinical diagnosis.

关键词： H_ Infrared kinetics

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Preparation and Structure-Property Regulation Mechanism of Reversible Thermochromic Polydiacetylene

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Chinese Journal of Polymer Science 2024年第8期42卷 1111-1121页

作者： Zhi-Qing Ge Shuo Yan Zu-Xiong Pan shan lei Xuan-Zhi Mao Chu Zhao Mo-Zhen Wang Xue-Wu Ge Key Laboratory of Precision and Intelligent Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China Marshall Laboratory of Biomedical Engineering International Cancer CenterLaboratory of Evolutionary Theranostics(LET)School of Biomedical EngineeringShenzhen University Medical SchoolShenzhen UniversityShenzhen 518055China shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

The thermochromic mechanism and the structure-property regulation principle of reversible thermochromic polydiacetylene(PDA)materials have always been a challenging *** this work,a series of diacetylene monomers(m-PCDA)containing phenyl and amide or carboxyl groups were synthesized from 10,12-pentacosadiynoic acid(PCDA)through the esterification or amidation *** effects of the number and the distribution of the functional groups in m-PCDA molecules on their solid-state polymerization capability,and the thermochromic mechanism of their corresponding polymers(m-PDA)were investigated and discussed in *** results show that the m-PCDA monomers containing both benzene ring and groups that can form hydrogen bonding interactions have strong intermolecular interaction,and are easy to carry out the solid phase polymerization under 254-nm UV irradiation to obtain the corresponding new thermochromic m-PDA *** thermochromic behavior of m-PDA depends on its melting *** initial color-change temperature(blue to red)is determined by the onset melting tem perature,and the temperature range in which reversible color recovery can be achieved by repeat heating-cooling treatment is determined by its melting *** to the proposed thermochromic mechanism of PDA,various new PDA materials with precise thermochromic temperatu res and reversible thermochromic temperature ra nges can be designed and synthesized through the appropriate introduction of benzene ring and groups that can form hydrogen bonding interactions into the molecular structure of linear diacetylene *** work provides a perspective to the precise molecular structure design and the property regulation of the reversible thermochromic PDA materials.

关键词： Polydiacetylene Thermochromism Hydrogen bonding Chemical modification

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Removal Effect of Precipitation on Atmospheric Particulate Matter (PM_(2.5) ) in Bengbu City

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Meteorological and Environmental Research 2024年第1期15卷 12-15,26页

作者： lei TIAN lei shan Jingyang CHEN Bengbu Meteorological Bureau Bengbu 233000China

Based on the monitoring data of PM_(2.5) concentration in Bengbu Environmental Monitoring Station and precipitation observation data of Bengbu National Meteorological Observation Station from 2016 to 2019, the influence of precipitation on PM_(2.5) mass concentration in Bengbu City was analyzed. The results show that precipitation had a washing and removal effect on PM_(2.5) in the air, and the removal effect was related to precipitation level, precipitation intensity, precipitation duration and PM_(2.5) concentration. The removal effect of precipitation on PM_(2.5) increased with the increase of precipitation level, and the seasonal difference was obvious. Precipitation intensity was positively correlated with the removal effect of PM_(2.5) , but the average removal rate began to decline when precipitation intensity exceeded 10 mm. With the increase of precipitation intensity, the proportion of positive removal showed an overall upward trend, but there was a low-value area as precipitation intensity was 3-10 mm. Precipitation duration was also positively correlated with the removal effect of PM_(2.5) , and there was a low-value area when precipitation duration was 10-15 h. When PM_(2.5) concentration was low before the precipitation process began, the removal effect was not good, and the average removal rate was negative. As PM_(2.5) concentration was high before the precipitation process started, the removal effect was obvious.

关键词： Precipitation PM_(2.5) Removal efficiency Bengbu

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Changing Characteristics of Comfort Index of Human Body in Bengbu City in the Past 40 Years under the Background of Climate Change

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Meteorological and Environmental Research 2024年第2期15卷 40-43页

作者： lei shan Xian ZHANG lei TIAN Ranran HE Jingyang CHEN Bengbu Meteorological Bureau Bengbu 233000China Anhui University of Finance and Economics Bengbu 233000China

Based on the daily meteorological data of Bengbu City during 1981-2020,the changing characteristics of three elements needed for the calculation of the comfort index of human body(CIHB)were discussed,and daily CIHB was classified and *** results show that from 1981 to 2020,annual average temperature tended to increase *** average wind speed and relative humidity showed a decreasing trend before 2011 but an increasing trend after *** duration of the four seasons in Bengbu City mainly rose in spring,reduced in winter,declined first and then increased in summer,and rose first and then decreased in *** CIHB was at grades 1 and 9(the most uncomfortable),the three factors had different effects on *** cold weather,the influence of relative humidity and wind speed on CIHB can not be ignored besides *** hot weather,the influence of temperature was dominant,and the change of annual average temperature could well correspond to the change in the number of very hot *** the context of climate warming,the number of cold days tended to decline generally,but it was larger in the years with fewer very cold *** the background of climate warming,there was no obvious change in the number of days of the overall comfort of human *** number of hot days was closely related to the duration of summer,and the number of days of grade 8 rose significantly in the years with an increase in the duration of summer.

关键词： Climate change Human comfort Comfort index of human body(CIHB)

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Imaging momentum-space Cooper pair formation and its competition with the charge density wave gap in a kagome superconductor

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 142-150页

作者： Yiming Sun Yubing Tu Yang Luo Shuikang Yu Hongyu Li Yunmei Zhang Ping Wu Zhuying Wang Fan Zhang Wanru Ma Zuowei Liang Jianjun Ying Tao Wu Ziji Xiang Junfeng He lei shan Zhenyu Wang Xianhui Chen Department of Physics CAS Key Laboratory of Strongly Coupled Quantum Matter Physicsand Hefei National LaboratoryUniversity of Science and Technology of ChinaHefei 230026China Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

The superconducting ground state of kagome metals AV_(3)Sb_(5)(where A stands for K,Rb,or Cs)emerges from an exotic charge density wave(CDW)state that potentially breaks both rotational and time reversal ***,the specifics of the Cooper pairing mechanism,and the nature of the interplay between these two states remain elusive,largely due to the lack of momentum-space(k-space)superconducting energy gap *** implementing Bogoliubov quasiparticle interference(B QPI)imaging,we obtain k-space information on the multiband superconducting gap structureΔ_(SC)^(i)(k)in pristine CsV_(3)Sb_(5).We show that the estimated energy gap on the vanadium d_(xy/x^(2)-y^(2))orbital is anisotropic but nodeless,with a minimal value located near the M ***,a comparison ofΔ_(SC)^(i)(k)with the CDW gapΔ_(CDW)^(i)(k)obtained by angle-re solved photoemission spectro scopy(ARPES)reveals direct k-space competition between the se two order parameters,i.e.,the opening of a large(small)CDW gap at a given momentum corresponds to a small(large)superconducting *** the long-range CDW order is suppressed by replacing vanadium with titanium,we find a nearly isotropic energy gap on both the V and Sb *** information will be critical for identifying the microscopic pairing mechanism and its interplay with intertwined electro nic orders in this kagome superconductor family.

关键词： kagome lattice charge density wave superconducting energy gap scanning tunneling microscopy

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Revisit of the anisotropic vortex states of 2H-NbSe_(2) towards the zero-field limit

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Chinese Physics B 2024年第6期33卷 80-86页

作者：张凡侯兴元姜宇轩张宗源涂玉兵朱相德陈根富单磊 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Center of Free Electron Laser and High Magnetic Field Anhui UniversityHefei 230601China Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Key Laboratory of Structure and Functional Regulation of Hybrid Materials in Anhui University Ministry of EducationHefei 230601China School of Physics and Materials Science Anhui UniversityHefei 230601China Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field LaboratoryHFIPSAnhuiChinese Academy of Sciencesand University of Science and Technology of ChinaHefei 230031China Hefei National Laboratory Hefei 230088China

We revisited the vortex states of 2H-NbSe_(2) towards zero fields by a low-temperature scanning tunneling *** structures of the anisotropic vortex states were distinguished, one is a spatially non-splitting zero bias peak, and the other is an in-gap conductance anomaly resembling evolved crossing features around the center of the three nearest *** of them distribute solely along the next nearest neighboring direction of the vortex lattice and become unresolved in much higher magnetic fields, implying an important role played by the vortex–vortex interactions. To clarify these issues,we have studied the intrinsic vortex states of the isolated trapped vortex in zero fields at 0.45 K. It is concluded that the anisotropic zero bias peak is attributed to the superconducting gap anisotropy, and the spatially evolved crossing features are related to the vortex–vortex interaction. The vortex core size under the zero-field limit is determined. These results provide a paradigm for studying the inherent vortex states of type-II superconductors especially based on an isolated vortex.

关键词： vortex states zero-bias conductance peak scanning tunneling microscopy

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基于连通性阈值分割的煤岩裂隙识别方法

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工矿自动化 2024年第8期50卷 127-134页

作者：肖福坤刘欢欢单磊黑龙江科技大学矿业工程学院黑龙江哈尔滨150022 黑龙江科技大学黑龙江省煤矿深部开采地压控制与瓦斯治理重点实验室黑龙江哈尔滨150022

煤岩裂隙发育形态是影响煤岩渗透性、决定煤岩体力学特征的重要因素。针对煤岩裂隙识别过程中存在的复杂结构处理不当、裂隙边界特征保留不足、噪声干扰等问题,提出了一种基于连通性阈值分割的煤岩裂隙识别方法。首先,采用直方图均衡化... 详细信息

煤岩裂隙发育形态是影响煤岩渗透性、决定煤岩体力学特征的重要因素。针对煤岩裂隙识别过程中存在的复杂结构处理不当、裂隙边界特征保留不足、噪声干扰等问题,提出了一种基于连通性阈值分割的煤岩裂隙识别方法。首先,采用直方图均衡化增强算法和非局部均值滤波去噪算法对图像进行预处理,其次,利用自适应Otsu阈值分割确定预处理后图像的阈值,识别出可能的裂隙区域,应用形态学运算对这些区域进行精细化处理,进一步突出裂隙的边界特征。然后,通过Canny边缘计算提取种子点,以识别图像中的关键特征。最后,基于这些种子点进行区域生长操作,从而有效抑制噪声,并在平滑图像裂隙的同时更加清晰地突出裂隙信息。实验结果表明:①连通性阈值分割的均方误差较自适应Otsu阈值分割和自适应阈值分割分别平均减少了7.20,7.10 dB,连通性阈值分割的峰值信噪比较自适应Otsu阈值分割和自适应阈值分割分别平均提高了0.60,0.59 dB。②连通性阈值分割不仅有效解决了裂隙提取不明显、末端提取效果差及连接处特征消失的问题,而且显著减少了噪声的干扰,使裂隙特征变得更加突出,从而极大地提高了裂隙识别的准确性和完整性。③连通性阈值分割在自适应Otsu阈值分割的基础上,强化了裂隙特征并有效消除了噪声点,平均准确率较自适应阈值分割算法和自适应Otsu阈值分割分别提高了8%和0.8%,达98.9%。

关键词：煤岩裂隙识别连通性阈值分割自适应Otsu阈值分割形态学运算 Canny边缘计算区域生长

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Superconducting state in Ba_((1-x)) Sr_(x)Ni_(2)As_(2) near the quantum critical point

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Chinese Physics B 2024年第6期33卷 488-493页

作者：余承峰张宗源宋林兴吴彦玮袁小秋侯杰涂玉兵侯兴元李世亮单磊 Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Key Laboratory of Structure and Functional Regulation of Hybrid Materials(Anhui University) Ministry of EducationHefei 230601China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

In the phase diagram of the nickel-based superconductor Ba_(1-x)Sr_(x)Ni_(2)As_(2),T_(C) has been found to be enhanced sixfold near the quantum critical point(QCP) x=0.71 compared with the parent ***,the mechanism is still under ***,we report a detailed investigation of the superconducting properties near the QCP(x≈0.7) by utilizing scanning tunneling microscopy and *** temperature-dependent superconducting gap and magnetic vortex state were obtained and analyzed in the framework of the Bardeen-Cooper-Schrieffer *** ideal isotropic s-wave superconducting gap excludes the long-speculated nematic fluctuations while preferring strong electron-phonon coupling as the mechanism for T_(C) enhancement near the *** lower than expected gap ratio of Δ/(k_(B) T_(C)) is rooted in the fact that Ba_(1-x)Sr_(x)Ni_(2)As_(2) falls into the dirty limit with a serious pair breaking effect similar to the parent compound.

关键词： nickel-based superconductor electron–phonon coupling dirty limit scanning tunneling microscopy/spectroscopy

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媒体融合背景下广播电视技术的发展

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数字通信世界 2024年第5期 139-141页

作者：冯庆单磊济南市章丘区融媒体中心山东济南250200

在信息技术快速发展的背景下,媒体领域正经历着较大的变革。传统的广播电视技术逐渐融入了互联网和移动通信技术,形成了新的媒体融合模式。这种媒体融合既是技术的突破,也是媒体产业的转型和创新。在媒体融合的大潮中,广播电视技术领域... 详细信息

在信息技术快速发展的背景下,媒体领域正经历着较大的变革。传统的广播电视技术逐渐融入了互联网和移动通信技术,形成了新的媒体融合模式。这种媒体融合既是技术的突破,也是媒体产业的转型和创新。在媒体融合的大潮中,广播电视技术领域也面临着巨大的挑战和机遇。作为一种传统的媒体形式,广播电视需要不断适应新的市场需求和技术趋势,与新兴媒体进行融合创新,以实现持续发展和长远竞争力。文章主要探讨分析了其在新媒体融合背景下面临的问题、发展策略及未来发展趋势,以供参考。

关键词：媒体融合广播电视技术创新发展应用

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