检索结果-南通市图书馆

Reconstructing forest and grassland cover changes in China over the past millennium

Science China Earth Sciences 2025年第1期68卷 94-110页

作者： Fanneng HE Fan yang Yafei WANG Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Key Research Institute of Yellow River Civilization and Sustainable Development Henan University University of Chinese Academy of Sciences

Historical forest and grassland cover changes not only are critical indicators for quantifying ecological and environmental change processes but also serve as fundamental data for long-term climate change simulations and terrestrial ecosystem carbon emission assessments. However, because of limitations in historical data, quantitative estimations and spatially gridded reconstructions of these changes remain challenging, necessitating further methodological exploration. This study focused on China's present-day land area over the past millennium, objectively capturing the characteristics and drivers of forest and grassland cover changes. On this basis, using the forest transition theory and the space-for-time substitution method, we depicted the historical deforestation process as an inverted “S” curve and developed a model to reconstruct historical forest area changes based on the functional relationship between the forest area and population size dynamics. Subsequently, a gridded forest allocation model was established on the basis of deforestation tendencies. For the grassland cover, we implemented regionspecific methods, such as the cropland area deduction method and the habitat constraint method, to quantitatively reconstruct historical changes. Consequently, we obtained provincial forest and grassland area changes over the past millennium and mapped 10-km-resolution gridded data of forest and grassland cover. The results indicated the following.(1) The methods developed using population data as a proxy objectively reproduced the spatiotemporal evolution of forest and grassland cover in China over the past millennium. These feasible methods offer a novel pathway for the quantitative reconstruction of historical forest and grassland cover changes.(2) The data indicated that China's forest area generally decreased over the past millennium, characterized by a “decrease-then-increase” pattern. The forest area experienced three distinct phases: a slow decline(AD 1000

关键词： Land use and land cover change Forest Grassland Quantitative reconstruction Gridded reconstruction China historical period

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Distribution and mapping of temperate savanna in the sandy lands of eastern China

引用

Science China Earth Sciences 2025年第1期68卷 128-141页

作者： Xiaoya LI Feng WANG Tao DUAN Kaijie yang Bin yang Chunmei WANG Xin TIAN Qi LU Institute of Ecological Conservation and Restoration Institute of Desertification Studies Chinese Academy of Forestry Institute of Desertification Institute of Desertification Studies Chinese Academy of Forestry Institute of Great Green Wall Satellite Application Centre for Ecology and Environment MEE Institute of Microelectronics Chinese Academy of Sciences Aerospace Information Research Institute Chinese Academy of Sciences Institute of Forest Resource Information Techniques Chinese Academy of Forestry

Savannas are distributed globally across various *** perform a significant socioeconomic role in regulating net primary productivity and the terrestrial carbon *** to the high spatial heterogeneity induced by the mixed distribution of trees and grasses,current global land-cover classification maps often classify savannas as forests or grasslands Temperate savannas in China cover a vast area,yet their spatial patterns and extent remain poorly *** study developed a novel remote sensing temperate savannas mapping method by integrating very high-resolution （VHR） unmanned aerial vehicle （UAV） and GF-6 satellite imagery based on the vegetation structure characteristics of temperate savannas using the FAO definition of *** and validation datasets were collected from VHR UAV imagery covering the main temperate savannah types with a ground area of 1818 *** fractional woody vegetation cover （FWVC） and fractional herbaceous vegetation cover （FHVC） in temperate savannas were estimated by integrating Classification and Regression Tree and Random Forest *** current distribution of temperate savannas in the Horqin and Otindag Sandy Lands of Eastern China was mapped to a unit area of 0.5 *** root-mean-square error （RMSE） values for the FWVC and FHVC models were 10.69% and 11.67%,and the R2values were 0.66 and 0.63,*** assessment indicated that the new temperate savanna map had high identification accuracy,with a Kappa coefficient of 0.70,overall accuracy of 0.88,and average accuracy of *** savannas in the sandy lands of eastern China were primarily distributed in the northern Horqin Sandy Land the central and eastern regions of the Otindag Sandy Land,and the transition zone from the southern slopes of the Greater Khingan Mountains to the plains,covering a total area of 3.27×10～6 *** main savannah types were elm,oak/maple,and shrub *** savannas were widely distributed in the Otindag Sandy

关键词： Temperate savanna UAV imagery GF-6 Fractional woody vegetation cover Fractional herbaceous vegetation cover Machine learning

来源：

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Positive-Controllability,Positive-Near-Controllability,and Canonical Forms of Driftless Discrete-Time Bilinear Systems

引用

Journal of Systems Science & Complexity 2022年第4期35卷 1225-1243页

作者： tie lin School of Automation Science and Electrical Engineering Beihang UniversityBeijing100083China

Controllable canonical forms play important roles in the analysis and design of control *** this paper,a fundamental class of discrete-time bilinear systems are *** systems are of interest since,on one hand,they have the most complete controllability *** the other hand,they can be nearly-controllable even if controllability ***,controllability of the systems with positive control inputs is studied and necessary and sufficient algebraic criteria for positive-controllability and positive-near-controllability are ***,controllable canonical forms and nearly-controllable canonical forms of the systems are presented,respectively,where the corresponding transformation matrices are also explicitly *** are given to demonstrate the effectiveness of the derived controllability criteria and controllable canonical forms.

关键词： Canonical forms controllability discrete-time bilinear systems near-controllability positive control inputs

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Engineering N3C vacancies in hierarchical porous carbon nitride nanosheets for room temperature ultradeep photocatalytic aerobic oxidative desulfurization

引用

Science China Chemistry 2025年

作者： Yina Nie Weijie yang Xin Wang Xiang Li Lele Wei Xiaolin Bai lin Liu Feng Fu Jun Wan College of Chemistry & Chemical Engineering Research Institute of Comprehensive Energy Industrial Technology Shaanxi Key Laboratory of Chemical Reaction Engineering Yan'an University Anhui Engineering Research Center of Carbon Neutrality College of Chemistry and Materials Science Anhui Normal University

The production of ultra-low sulfur clean fuels holds global significance for improving energy efficiency and reducing environmental pollution. Photocatalytic aerobic oxidative desulfurization（PODS） offers an attractive approach to efficiently remove refractory heterocyclic aromatic sulfur compounds under mild conditions. However, the sluggish charge dynamics,insufficient molecule activation, and slow mass transfer within photocatalysts restrict the overall desulfurization efficiency,hindering the widespread application of this technology. Herein, we developed a defective g-C3N4（M1U3CN） photocatalyst with bridged N3Cvacancies and hierarchical porous structures to address these limitations. This catalyst not only demonstrates outstanding dibenzothiophene（DBT） removal efficiency of 99.6% for model oil with high conversion and selectivity but also achieves complete sulfur removal from gasoline as well as 96.7% sulfur removal for distilled diesel at room temperature,successfully achieving ultradeep aerobic oxidative desulfurization. The introduction of rich N3Cvacancies and abundant micromeso-macroporous distribution in M1U3CN enhances kinetic efficiencies by promoting charge carrier separation, mass transfer,and molecular activation simultaneously; resulting in exceptional PODS performance. This work provides a collaborative strategy to overcome kinetic challenges in aerobic oxidative desulfurization via defect and structural engineering of the catalyst.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Insights from untargeted metabolomics: revealing potential marker compounds into the maturation of fermented chili

引用

Food Science and Human Wellness 2025年

作者： Shiyu Liu Mingyuan yang Jianhua Zhao Meijuan Lei Jinlin Han Min Xu Ping Liu Jie Tang Hongbin lin School of Food and Bio-engineering， Xihua University China Agricultural University-Sichuan Advanced Agricultural & Industrial Institute Chongqing Key Laboratory of Speciality Food Co-Built by Sichuan and Chongqing Food Microbiology Key Laboratory of Sichuan Province

Chili fermentation is one of the most important processes in the production of Pixian Douban (PXDB)， which determines the flavor and product quality of PXDB. However， the maturity of fermented chili mainly depends on empirical judgment， which can not satisfy the need for standardized production of PXDB. Therefore， this study aimed to investigate volatile and non-volatile substances during the maturation process and to find markers related to the maturity of fermented chili. GC×GC-MS combined with multivariate statistical analysis revealed that 2-methoxy-3-isobutyl pyrazine， linalool， 3-(methylthio)propionaldehyde， myrcene， and decanal (ROAV ≥ 1， VIP > 1， P linalool， and decanal) along with fructose and adenosine could serve as markers for evaluating the maturity of chili. This study is expected to establish a standard for the determination of maturity the fermented chili and lay the foundation for intelligent production of PXDB.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Late Paleozoic to early Mesozoic volcanic-sedimentary history of the southeastern margin of the Central Asian Orogenic Belt: Timing of uplift of the Inner Mongolia paleo-uplift

引用

Science China Earth Sciences 2025年第1期68卷 297-309页

作者： Wenxing HAO Jin-Hui yang Guang ZHU State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences School of Resource and Environmental Engineering Hefei University of Technology

The Kulun region is located in the eastern Bainaimiao arc belt on the southeastern margin of the Central Asian Orogenic Belt(CAOB), adjacent to the North China Craton(NCC) to the south. This region records the closure of the PaleoAsian Ocean during the Paleozoic to early Mesozoic and is key to study the tectonic evolution of the northern margin of the *** conducted zircon U-Pb geochronology and Hf isotope analysis of volcanic-sedimentary and intrusive rocks in the Kulun region. The volcanic-sedimentary rocks were previously assigned an early Carboniferous age, but include volcanic rocks with ages of 267–266 Ma and sedimentary rocks with youngest detrital zircon age peaks of 265–244 Ma, which were intruded by a granite with an age of 242 Ma. This indicates that these rocks are actually middle Permian to Middle Triassic in age(267–242Ma) and correspond to the Qingfengshan and Liujiagou formations. Moreover, two volcanic rock samples have high εHf(t) values(+1.6 to +16.1) and relatively young two-stage Hf model ages(1095–327 Ma), indicating their sources associated with the CAOB. The age spectra and Hf isotopic characteristics of detrital zircons from the sedimentary rocks suggest that, during the middle Permian to Middle Triassic, the sedimentary provenance in the Kulun region was mainly the CAOB. However, by the Early Jurassic, the provenance changed to the NCC(i.e., the Inner Mongolia Paleo-uplift, IMPU). This result, combined with the development of a series of conglomerates on the northern margin of the NCC in the Late Triassic(i.e., Xingshikou, Xiaoyingzi,and Xiaohekou formations), indicates the Kulun region experienced an abrupt change in paleogeography during the Late Triassic, with the IMPU undergoing significant uplift and thus becoming the main sediment source in the Kulun region. Based on the Late Triassic alkaline igneous belt(235–215 Ma) in the IMPU, we speculate that this uplift was caused by detachment of the southward-subducting Paleo-Asian oceanic

关键词： Central Asian Orogenic Belt the North China Craton Zircon geochronology Hf isotopes Inner Mongolia Paleo-uplift

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Turbulent Agglomeration of Microparticles in a Cylinder Wake Flow Using LES-DEM:Focusing on the Effect of the Reynolds Number

引用

Journal of Thermal Science 2025年第1期34卷 34-49页

作者： WANG Shuang MU lin LI Xue XIE Jun DONG Ming School of Energy and Power Engineering Dalian University of Technology School of Optical Information and Energy Engineering Wuhan Institute of Technology School of Energy and Environment Shenyang Aerospace University

Turbulent agglomeration is viewed as a promising technology for enhancing fine particle removal *** better understand particle transport,agglomeration behaviors,and fluid-particle interactions,we numerically explored these phenomena under cylindrical vortex wake influence using a coupled large eddy simulation and discrete element method（LES-DEM） *** validity of the LES approach was verified by comparison with available direct numerical simulation（DNS） *** adopted the Johnson-Kendall-Roberts（JKR） contact model for particle-particle *** particle dispersion and agglomeration characteristics of particles with different diameters（dp=2-20 μm） in the laminar and transition of shear layer（TrSL） flow regimes were *** particles were concentrated at the vortex centers,while larger particles accumulated around the *** agglomeration efficiency exhibited an M-shaped profile spanwise（y-direction）.With increasing Reynolds number,the agglomeration efficiency and turbulence intensity *** particle agglomeration efficiency peaks at a certain Reynolds ***,at higher Reynolds numbers,reducing the residence time of particles in the flow field decreases the agglomeration efficiency.

关键词： discrete element method large eddy simulation microparticle particle agglomeration

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Prussian Blue Analogue‑Templated Nanocomposites for Alkali‑Ion Batteries:Progress and Perspective

引用

Nano-Micro Letters 2025年第1期17卷 216-261页

作者： Jian‑En Zhou Yilin Li Xiaoming lin Jiaye Ye Key Laboratory of Theoretical Chemistry of Environment Ministry of EducationSchool of ChemistrySouth China Normal UniversityGuangzhou 510006People’s Republic of China School of Chemistry and Physics Faculty of ScienceQueensland University of Technology2 George StreetBrisbaneQLD 4000Australia Centre for Materials Science Queensland University of Technology2 George StreetBrisbaneQLD 4000Australia

Lithium-ion batteries(LIBs)have dominated the portable electronic and electrochemical energy markets since their commercialisation,whose high cost and lithium scarcity have prompted the development of other alkali-ion batteries(AIBs)including sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).Owing to larger ion sizes of Na^(+)and K^(+)compared with Li^(+),nanocomposites with excellent crystallinity orientation and well-developed porosity show unprecedented potential for advanced lithium/sodium/potassium *** enticing open rigid framework structures,Prussian blue analogues(PBAs)remain promising self-sacrificial templates for the preparation of various nanocomposites,whose appeal originates from the well-retained porous structures and exceptional electrochemical activities after thermal *** review focuses on the recent progress of PBA-derived nanocomposites from their fabrication,lithium/sodium/potassium storage mechanism,and applications in AIBs(LIBs,SIBs,and PIBs).To distinguish various PBA derivatives,the working mechanism and applications of PBA-templated metal oxides,metal chalcogenides,metal phosphides,and other nanocomposites are systematically evaluated,facilitating the establishment of a structure–activity correlation for these *** on the fruitful achievements of PBA-derived nanocomposites,perspectives for their future development are envisioned,aiming to narrow down the gap between laboratory study and industrial reality.

关键词： Prussian blue analogues Self-sacrificial template Lithium-ion batteries Sodium-ion batteries Potassium-ion batteries

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

High-temperature-tolerant flexible supercapacitors: Gel polymer electrolytes and electrode materials

引用

Journal of Energy Chemistry 2025年第1期100卷 426-457页

作者： Chong Peng Xinyi Huang Mingwei Zhao Shuling Liao Quanhong yang Nianjun yang Siyu Yu School of Chemistry & Chemical Engineering Southwest University Nanoyang Group Tianjin Key Laboratory of Advanced Carbon and Electrochemical Energy Storage School of Chemical Engineering and Technology and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin University Department of Chemistry & IMO-IMOMEC Hasselt University

The development of flexible supercapacitors(FSCs) capable of operating at high temperatures is crucial for expanding the application areas and operating conditions of supercapacitors. Gel polymer electrolytes and electrode materials stand as two key components that significantly impact the efficacy of hightemperature-tolerant FSCs(HT-FSCs). They should not only exhibit high electrochemical performance and excellent flexibility, but also withstand intense thermal stress. Considerable efforts have been devoted to enhancing their thermal stability while maintaining high electrochemical and mechanical performance. In this review, the fundamentals of HT-FSCs are outlined. A comprehensive overview of state-of-the-art progress and achievements in HT-FSCs, with a focus on thermally stable gel polymer electrolytes and electrode materials is provided. Finally, challenges and future perspectives regarding HT-FSCs are discussed, alongside strategies for elevating operational temperatures and *** review offers both theoretical foundations and practical guidelines for designing and manufacturing HT-FSCs, further promoting their widespread adoption across diverse fields.

关键词： Polymer membrane electrodes

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

ON NEARLY-CONTROLLABLE SUBSPACES OF A CLASS OF DISCRETE-TIME BIlinEAR SYSTEMS

引用

Journal of Systems Science & Complexity 2013年第4期26卷 512-526页

作者： tie lin School of Automation Science and Electrical Engineering Beihang University

If a linear time-invariant system is uncontrollable,then the state space can be decomposed as a direct sum of a controllable subspace and an uncontrollable *** this paper,for a class of discrete-time bilinear systems which are uncontrollable but can be nearly controllable,by studying the nearly-controllable subspaces and defining the near-controllability index,the controllability properties of the systems are fully *** are provided to illustrate the conceptions and results of the paper.

关键词： Bilinear systems discrete-time systems near-controllability near-controllability index,nearly-controllable subspaces.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：