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A phenology-based vegetation index for improving ratoon rice mapping using harmonized Landsat and Sentinel-2 data

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Journal of Integrative Agriculture 2024年第4期23卷 1164-1178页

作者： Yunping Chen Jie Hu Zhiwen Cai Jingya Yang Wei Zhou Qiong Hu Cong Wang Liangzhi You Baodong Xu Macro Agriculture Research institute College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan 430070China College of Resources and Environment Huazhong Agricultural UniversityWuhan 430070China Key Laboratory of Agricultural remote sensing Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Key Laboratory for Geographical Process Analysis&Simulation of Hubei Province/College of Urban and environmental Sciences Central China Normal UniversityWuhan 430079China International Food Policy Research institute NWWashingtonD.C.20005USA

Ratoon rice,which refers to a second harvest of rice obtained from the regenerated tillers originating from the stubble of the first harvested crop,plays an important role in both food security and agroecology while requiring minimal agricultural ***,accurately identifying ratoon rice crops is challenging due to the similarity of its spectral features with other rice cropping systems(e.g.,double rice).Moreover,images with a high spatiotemporal resolution are essential since ratoon rice is generally cultivated in fragmented croplands within regions that frequently exhibit cloudy and rainy *** this study,taking Qichun County in Hubei Province,China as an example,we developed a new phenology-based ratoon rice vegetation index(PRVI)for the purpose of ratoon rice mapping at a 30 m spatial resolution using a robust time series generated from Harmonized Landsat and Sentinel-2(HLS)*** PRVI that incorporated the red,near-infrared,and shortwave infrared 1 bands was developed based on the analysis of spectro-phenological separability and feature *** on actual field samples,the performance of the PRVI for ratoon rice mapping was carefully evaluated by comparing it to several vegetation indices,including normalized difference vegetation index(NDVI),enhanced vegetation index(EVI)and land surface water index(LSWI).The results suggested that the PRVI could sufficiently capture the specific characteristics of ratoon rice,leading to a favorable separability between ratoon rice and other land cover ***,the PRVI showed the best performance for identifying ratoon rice in the phenological phases characterized by grain filling and harvesting to tillering of the ratoon crop(GHS-TS2),indicating that only several images are required to obtain an accurate ratoon rice ***,the PRVI performed better than NDVI,EVI,LSWI and their combination at the GHS-TS2 stages,with producer's accuracy and user's accuracy of 92.22 and 89.30%,respectively

关键词： ratoon rice phenology-based ratoon rice vegetation index(PRVI) phenological phase feature selection Harmonized Landsat Sentinel-2 data

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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Highly efficient tunable photodetector with a bipolar response in van der Waals heterojunctions

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Science China(Technological Sciences) 2024年第2期67卷 639-646页

作者： SHI ChaoFan ZHANG Shi XIAO KeNing ZHANG LiBo HAN Li ZHU YuLin TANG WeiWei LIU ChangLong LI GuanHai CHEN XiaoShuang College of physics and Optoelectronic Engineering Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences Hangzhou310024China State Key Laboratory of Infrared physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China

The heterojunction integration of two-dimensional(2D)materials via van der Waals(vdW)forces,unencumbered by lattice and processing constraints,constitutes an efficacious approach to enhance the overall optoelectronic performance of photodetectors,due to an assortment of distinctive light-matter ***,vdW heterojunction photodetectors based on transition metal dichalcogenides(TMDs)face an inevitable trade-off between low dark currents and high responsivity,curtailing the application potential of myriad novel optoelectronic components in sensing,spectral,and communication *** this study,we present the successful actualization of a highly sensitive,self-powered,and gate-tunable bipolar response *** mechanisms underlying photocurrent generation were scrutinized via bias-,power-,and position-dependent mapping photoresponse measurements,identifying the photovoltaic effect,which is attributable to the Schottky junction’s built-in electric field,as the predominant *** prototype Au-WS2-graphene photodetector exhibits a remarkable light on/off ratio of 1.2×10^(6),a specific detectivity of 6.12×10^(11)cm H^(z1/2)W^(-1)with 20μs response time at 638 *** wide gate-tunable responsivity provides an adjustability scope,ranging from 0.9 to 3.1 A W^(-1).Notably,the device demonstrates an exceptional linear photocurrent response,with a linear dynamic range(LDR)value approximating 130 dB,which significantly surpasses that of other photodetectors based on TMDs.

关键词： WS2/graphene van der Waals heterojunction gate-tunable bipolar response

One-step hydrothermal synthesis of few-layered metallic phase MoS2 for high-performance supercapacitors

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Progress in Natural Science:Materials International 2024年第2期34卷 429-436页

作者： Jing Xu Xulong Yuan Yujie Zhao Shaoqi Rui Qingling Jia Han Li Shun Lu Bing Li Yongxing Zhang Xuebin Zhu Anhui Province Key Laboratory of Pollutant Sensitive Materials and environmental Remediation Anhui Province Key Laboratory of Intelligent Computing and Applications Anhui Province Industrial Generic Technology Research Center for Alumics Materials Huaibei Normal University Chongqing institute of Green and Intelligent Technology Chinese Academy of Sciences Key Laboratory of Materials physics Institute of Solid State Physics HFIPS Chinese Academy of Sciences

In recent years,molybdenum disulfide（MoS2） has gained significant attention in the scientific *** MoS2demonstrates unique properties and potential ***,the synthesis of few-layered and high-purity 1T-MoS2is still a *** this study,we successfully employed a hydrothermal method to synthesize few-layered and high-purity *** purity of the material is controlled by a combination of sodium borohydride and ***,the few-layered 1T-MoS2exhibits exceptional performance as a supercapacitor,including the high specific capacitance(250.3 F g-1at a current density of 1 A g-1) and excellent long-trem cycling stability（90.7 % after 5000 cycles）.Meanwhile,the asymmetric device assembled by 6-FL-1TMoS2and active carbon on carbon cloths exhibits excellent flexibility and high energy and power density(23.1μWh cm-2at 600 μW cm-2,55 μWh cm-2at 12000 μW cm-2).This work provides valuable insights into the synthesis of few-layered and high-purity 1T-MoS2,opening up new avenues for further research and applications.

关键词： 1T-MoS2 Few-layered High-purity One-pot hydrothermal method Supercapacitor

Modified NiFe-MOF with defects induced by-NH_(2)and-SH for enhanced adsorption and photocatalytic reduction of CO_(2)

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Journal of Materials Science & Technology 2024年第3期170卷 167-176页

作者： Ruting Huang Yeyin Zhang Wenqiang Li Wanxia Zhang Yong Fang Wenrui Zhang Anqi Cui Yu Ying Xianyang Shi Information Materials and Intelligent sensing Laboratory of Anhui Province Anhui Province Key Laboratory of Wetland Ecosystem Protection and RestorationSchool of Resource and Environmental EngineeringAnhui UniversityHefei230601China Key Laboratory of Nutrient Cycling Resources and Environment of Anhui Institute of Soil and FertilizerAnhui Academy of Agricultural SciencesHefei230001China

In this study,a Ni-Fe metal-organic framework modified by-NH_(2)and-SH was synthesized using a sim-ple hydrothermal process for enhancing photocatalytic CO_(2)*** expected,the N2S-NiFe(NH_(2)-BDC/H_(4)DSBDC,2:1)displayed excellent photocatalytic CO_(2)reduction activity and high CO selectivity(12,412.23μmol g^(−1)h^(−1))under visible light irradiation(λ≥420 nm),which is 5 times that of ***,the excellent photocatalytic performance of N2S-NiFe can benefit from the rich defect trap site caused by the introduction of amino and sulfhydryl groups,accelerating charge transfer and promoting space charge separation,as supported by the photo-electrochemical *** better understand the CO_(2)adsorption mechanism,density functional theory calculations were performed,which revealed that the Niov site has more negative adsorption energy compared with the Feov *** study provides a simple strategy to establish efficient photocatalysts for CO_(2)reduction through the modification of organic ligands.

关键词： NiFe-MOF CO_(2)reduction Defect structure Photocatalytic

Electric tuning of plasmonic resonances in ultrathin gold nanoribbon arrays

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Photonics Research 2024年第08期12卷 1750-1759页

作者： ZHENXIN WANG ALEXEY V.KRASAVIN CHENXINYU PAN JUNSHENG ZHENG ZHIYONG LI XIN GUO ANATOLY V.ZAYATS LIMIN TONG PAN WANG State Key Laboratory of Extreme Photonics and Instrumentation College of Optical Science and Engineering Zhejiang University Department of physics and London Centre for Nanotechnology King's College London Jiaxing Key Laboratory of Photonic sensing & Intelligent Imaging Intelligent Optics & Photonics Research Center Jiaxing Research Institute Zhejiang University

Ultrathin plasmonic nanostructures offer an unparalleled opportunity for the study of light–matter interactions at the nanoscale and realization of compact nanophotonic devices. In this study, we introduce an ultrathin gold nanoribbon array and demonstrate an electric approach to actively tuning its plasmonic resonance, which leveraging the extreme light confinement capability in the ultrathin plasmonic nanostructure and a robust nanoscale electro-optical effect in indium tin oxide. Optimizing the design(to a total thickness as small as 12 nm for a 2-nmthick gold nanoribbon array), we numerically demonstrate a spectral shift in the plasmonic resonance up to 36 nm along with an approximately 16% change in the transmission at a gate voltage below 1.7 V at the wavelength of1.47 μm. This work presents progress towards electric tuning of plasmonic resonances in ultrathin metallic nanostructures for various applications including surface-enhanced spectroscopy, spontaneous emission enhancement,and optical modulation.

关键词： Chemical sensors Diffraction limit Electrooptical effects Indium tin oxide Light matter interactions Nanostructures

A vectorial model for the nonlinear gradient force exerted on metallic Rayleigh nanoparticles

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Chinese Optics Letters 2024年第2期22卷 207-213页

作者：朱政张聿全闵长俊 Aurèle J.LAdam H.Paul Urbach 袁小聪 Research Center for Humanoid sensing Research Institute of Intelligent SensingZhejiang LabHangzhou 311100China Nanophotonics Research Center Institute of Microscale Optoelectronics&State Key Laboratory of Radio Frequency Heterogeneous IntegrationShenzhen UniversityShenzhen 518060China Optics Research Group ImPhys DepartmentFaculty of Applied SciencesDelft University of TechnologyDelft 2628 CJThe Netherlands

Optical tweezers have proved to be a powerful tool with a wide range of *** gradient force plays a vital role in the stable optical trapping of *** scalar method is convenient and effective for analyzing the gradient force in traditional optical ***,when the third-order nonlinear effect of the nano-object is stimulated,the scalar method cannot adequately present the optical response of the metal nanoparticle to the external optical ***,we propose a theoretical model to interpret the nonlinear gradient force using the vector *** combining the optical Kerr effect,the polarizability vector of the metallic nanoparticle is derived.A quantitative analysis is obtained for the gradient force as well as for the optical potential *** vector method yields better agreement with reported experimental *** suggest that this method could lead to a deeper understanding of the physics relevant to nonlinear optical trapping and binding phenomena.

关键词： gradient forces nonlinear effect metallic nanoparticles

Long-wave infrared emission properties of strain-balanced InAs/In_(x)Ga_(1-x)As_(y)Sb_(1-y)type-Ⅱsuperlattice on different substrates

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Rare Metals 2024年第7期43卷 3194-3204页

作者： Chao Shi Xuan Fang Hong-Bin Zhao Deng-Kui Wang Xi Chen Dan Fang Dong-Bo Wang Xiao-Hua Wang Jin-Hua Li State Key Laboratory of High Power Semiconductor Lasers School of PhysicsChangchun University of Science and TechnologyChangchun 130022China State Key Laboratory of Advanced Materials for Smart sensing China General Research Institute for Nonferrous MetalsBeijing 100088China Department of Opto-Electronic Information Science School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

High-performance type-Ⅱsuperlattices ofⅢ-Ⅴsemiconductor materials play an important role in the development and application of infrared optoelectronic *** the quality of epitaxial materials and clarifying the luminescent mechanism are of great significance for practic al applic *** this work,strain-balanced and high-quality In As/In_(x)Ga_(1-x)As_(y)Sb_(1-y)superlattices without lattice mismatch were achieved on InAs and GaSb substrates *** grown on In As substrate could exhibit higher crystal quality and surface flatness based on high-resolution X-ray diffraction(HRXRD)and atomic force microscopy(AFM)measurements'***,the strain distribution phenomenon from geometric phase analysis indicates that fluctuations of alloy compositions in superlattices on GaSb substrate are more *** addition,the optical properties of superlattices grown on different substrates are discussed *** of the difference in fluctuations of element composition and interface roughness of superlattices on different substrates,the superlattices grown on In As substrate would have higher integral intensity and narrower full-width at half maximum of long-wave infrared ***,the thermal quenching of emission intensity indicates that the superlattices grown on the In As substrate have better recombination ability,which is beneficial for increasing the operating temperature of infrared optoelectronic devices based on this type of superlattices.

关键词： Photoluminescence Alloy compositions fluctuations InAs(Sb)/In_(x)Ga_(1-x)As_(y)Sb_(1-y) Type-Ⅱsuperlattice Substrate

Revealing the atomic mechanism of diamond–iron interfacial reaction

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Carbon Energy 2024年第3期6卷 255-263页

作者： Yalun Ku Kun Xu Longbin Yan Kuikui Zhang Dongsheng Song Xing Li Shunfang Li Shaobo Cheng Chongxin Shan Henan Key Laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Material PhysicsMinistry of EducationSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhouChina Department of Mechanical Engineering Stanford UniversityStanfordCaliforniaUSA Information Materials and Intelligent sensing Laboratory of Anhui Province Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationInstitutes of Physical Science and Information TechnologyAnhui UniversityHefeiChina institute of Quantum Materials and physics Henan Academy of SciencesZhengzhouChina

Diamond,with ultrahigh hardness,high wear resistance,high thermal conductivity,and so forth,has attracted worldwide ***,researchers found emergent reactions at the interfaces between diamond and ferrous materials,which significantly affects the performance of diamond-based ***,combing experiments and theoretical calculations,taking diamond–iron(Fe)interface as a prototype,the counter-diffusion mechanism of Fe/carbon atoms has been ***,it is identified that Fe and diamond first form a coherent interface,and then Fe atoms diffuse into diamond and prefer the carbon vacancies ***,the relaxed carbon atoms diffuse into the Fe lattice,forming Fe_(3)***,graphite is observed at the Fe_(3)C surface when Fe_(3)C is over-saturated by carbon *** present findings are expected to offer new insights into the atomic mechanism for diamondferrous material's interfacial reactions,benefiting diamond-based device applications.

关键词： coherent interface counter-diffusion diamond iron phase transition