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Challenges and opportunities in Quaternary palynology

Science China Earth Sciences 2024年第7期67卷 2148-2161页

作者： qinghai xu Houyuan LU Zhuo ZHENG College of Geographical Sciences Hebei Key Laboratory of Environmental Change and Ecological ConstructionHebei Normal UniversityShijiazhuang 050024China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China School of Earth Sciences and Engineering Sun Yat-sen UniversityZhuhai 519082China

Quaternary palynology plays a pivotal role in investigating global climate change and various other research fields,serving as an essential tool for the quantitative analysis of paleoenvironment ***,due to the vast diversity of terrestrial ecosystems and intricate interactions between vegetation,climate,and human activities,further advancements are required in the following aspects within this discipline.(1)The accuracy of classification in pollen morphology and fossil pollen identification needs improvement,particularly at the species *** represents a significant challenge in present Quaternary ***-aided intelligent recognition holds promise as a solution for species identification based on more detail pollen morphology.(2)Most pollen-based vegetation and climate reconstructions overlook the significance of bare *** bare ground can lead to substantial inaccuracies when quantitatively reconstructing past vegetation and climate.(3)While pollen records provide reliable information on paleoclimate changes,current quantitative climate reconstruction models heavily rely on modern pollen datasets derived from present-day vegetation disturbed more or less by human *** introduces bias and uncertainties into paleoclimate reconstruction.(4)Although pollen can serve as an indicator of human activities,accurately quantifying the intensity of human influence remains *** accurate identification of crop pollen,reconstructing reliable land cover/use data,and integrating multidisciplinary data may enhance the identification and quantification of signals related to human activity in pollen records.

关键词： Quaternary palynology Paleoclimate Paleovegetation Human activity

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从艺术家形象到中世纪秩序论乔伊斯对但丁的重写

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上海文化 2024年第5期 109-120页

作者：许清海南京师范大学文学院

乔伊斯和意大利有着不解之缘,的里雅斯特是他流亡生涯的重要一站。他的小说创作也离不开意大利先驱们的影响,托马斯·阿奎那、乔丹尔诺·布鲁诺、乔瓦尼·巴蒂斯塔·维柯等人的形象或思想在他的作品中反复出现。作为意大利历史上最重要... 详细信息

乔伊斯和意大利有着不解之缘,的里雅斯特是他流亡生涯的重要一站。他的小说创作也离不开意大利先驱们的影响,托马斯·阿奎那、乔丹尔诺·布鲁诺、乔瓦尼·巴蒂斯塔·维柯等人的形象或思想在他的作品中反复出现。作为意大利历史上最重要的作家,但丁也成为乔伊斯推崇、学习和书写的对象。根据理查德·艾尔曼的记载,在大学期间,乔伊斯就开始阅读、研究但丁的作品,他的意大利语教师查尔斯·盖齐(Charles Ghezzi)神父教授了他关于但丁的基础知识,在当时,他就在盖齐面前表现出对但丁推崇备至。到了意大利之后,乔伊斯有了更充足的条件去研究但丁。

关键词：意大利语托马斯·阿奎那乔伊斯布鲁诺推崇备至人的形象的里雅斯特但丁

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A Cool-Arid Climate with Large Temperature Seasonality Implied by Arboreal Pollen in the Early Holocene,North-Central China

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地球科学学刊:英文版 2023年第5期34卷 1629-1631页

作者： Fang Tian Meijiao Chen qinghai xu Xianyong Cao College of Resource Environment and Tourism Capital Normal UniversityBeijing 100048China College of Geography Sciences Hebei Normal UniversityShijiazhuang 050024China Group of Alpine Paleoecology and Human Adaptation(ALPHA) State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

The climate of the North-Central China during the Early Holocene is still debated,particularly with regard to precipitation,despite various paleoclimate records based on multi proxies and models(Chen et al.,2015;Liu J B et al.,2015;Liu Z Y et al.,2014).The temperature pattern is also uncertain because of a lack of temperature records for north-central *** sequences are still the most abundant paleo-environmental record particularly for north-central China and have the potential to explore the past precipitation and temperature changes,because both precipitation and temperature are essential for plant growth,and the sensitivity to climatic variables varies among different plants(Liang et al.,2020).Quantitative climate reconstructions based on the modern pollen-climate relationship have been widely generated for east Asia,and the results used to explore the spatial-temporal patterns and mechanisms of past climate changes(Chen et al.,2020,2015;Herzschuh et al.,2019).

关键词： China Holocene climate

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Analysis of the Sedimentary Characteristics of a Modern Distributive Fluvial System:A Case Study of the Great Halten River in the Sugan Lake Basin,qinghai,China

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Journal of Earth Science 2023年第4期34卷 1249-1262页

作者： Xianghui Zhang Changmin Zhang Adrian Hartley qinghai xu Wenjie Feng Taiju Yin Rui Zhu School of Geosciences Yangtze UniversityWuhan 430100China Department of Geology and Petroleum Geology School of GeosciencesUniversity of AberdeenAberdeen AB243UEUK

Understanding controls on river planform changes can help to build predictive models for distributive fluvial systems,and then guide the oil and gas *** do this we have undertaken a detailed investigation of the modern Great Halten River distributive fluvial system from the Sugan Lake Basin,qinghai,*** aerial vehicle(UAV) photography,satellite remote sensing data and elemental analysis were used to determine differences in the sedimentary characteristics of the distributive fluvial *** the apex to the toe,the changes in the slope,river morphology,sedimentary characteristics and element content in different regions were determined and three facies belts:“proximal”,“medial” and “distal” were *** found that the sedimentary structure and elemental content characteristics of each facies differ *** compare the large-scale evolution of rivers from braided to meandering rivers,and the fine description of sedimentary characteristics in combination with each observation,we strengthen our overall understanding of the modern DFS from macro to micro *** the same time,we summarize the sedimentation model of the Great Halten River DFS,and our study provides a reference for establishing the sedimentary model in continental petroliferous basins.

关键词： Sugan Lake Basin distributive fluvial system river morphology sedimentary model sedimentary structure sedimentology.

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中国现代孢粉数据库的质量评估、整合及其应用

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第四纪研究 2024年第3期44卷 605-622页

作者：崔安宁范保硕徐德克郑卓许清海罗运利黄康有李月丛沈才明曹现勇吕厚远中国科学院地质与地球物理研究所中国科学院新生代地质与环境重点实验室北京100029 河北师范大学地理科学学院河北石家庄050024 中国科学院地球科学研究院北京100029 中山大学地球科学与工程学院广东省地球动力作用与地质灾害重点实验室广东珠海519082 中国科学院植物研究所北京100093 云南师范大学地理学部云南昆明650050 中国科学院青藏高原研究所古生态与人类适应团队北京100101 中国科学院青藏高原研究所青藏高原地球系统与资源环境重点实验室北京100101 中国科学院大学地球与行星科学学院北京100049

高质量的现代孢粉数据库及其准确的气象插值数据是古气候定量重建的基础。目前我国已公开发表的覆盖全国范围的多个现代孢粉数据库,极大地推进了我国孢粉学在古气候、古环境方面的研究。但是由于不同的数据库是在不同时间、由不同学者... 详细信息

高质量的现代孢粉数据库及其准确的气象插值数据是古气候定量重建的基础。目前我国已公开发表的覆盖全国范围的多个现代孢粉数据库,极大地推进了我国孢粉学在古气候、古环境方面的研究。但是由于不同的数据库是在不同时间、由不同学者相继建立的,在数据库使用中目前存在三类问题:1)孢粉属种分类标准不统一,未统计蕨类孢子和水生植物花粉类群;2)现代孢粉点的气候参数插值不准确,经常利用网格经纬度取值,缺少垂直带海拔高度的校正;3)现代孢粉点空间分布不均匀,缺少高寒旱区和东部平原区的数据。本研究通过对新增加的青藏高原寒区、旱区等1791个现代孢粉组合数据和公开发表的现代孢粉数据,进行质量评估和整合,规范了孢粉类型,删除了重复的、质量差的样点;对比了网格法和反距离法插值年均温和年降水量的优劣。整理成为包含555个科/属的9484个样点的现代孢粉数据库(MPD_IGG.A),其中包含蕨类孢子和水生植物花粉的5107样点另外组成MPD_IGG.B数据库,将不包含蕨类孢子和水生植物花粉的4377样点组成MPD_IGG.C数据库。质量评估表明,利用具有蕨类孢子和水生植物花粉的数据库(MPD_IGG.B)以及采用反距离方法获取的年均温、年降水量的数据集建立的转换函数,其预测误差相对更小,重建值与观测值间相关系数更高。新整合的这3套数据库将会为我国古气候、古环境、古生态等定量重建研究提供重要支撑。

关键词： IGG现代孢粉数据库气候插值古气候定量重建

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分支河流体系河网形态演变规律——以格尔木河流扇为例

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地质论评 2024年第3期70卷 1047-1060页

作者：王浩楠张昌民孙家惠张祥辉徐清海刘洪平 Adrian John HARTLEY 长江大学地球科学学院中国武汉430100 阿伯丁大学地球科学学院英国阿伯丁AB243UE

为了探索分支河流体系河网分布规律,为创建储层建模训练图像提供知识库信息。利用Google Earth、Global Mapper、91卫图助手等现代地理信息软件,系统测量了现代格尔木河流扇表面河道分叉特征,应用Horton定律和分形方法建立了河流扇的河... 详细信息

为了探索分支河流体系河网分布规律,为创建储层建模训练图像提供知识库信息。利用Google Earth、Global Mapper、91卫图助手等现代地理信息软件,系统测量了现代格尔木河流扇表面河道分叉特征,应用Horton定律和分形方法建立了河流扇的河网形态模型。结果表明:①格尔木河流扇从顶点到入湖段共识别出26级河道,882个节点和2162个河道段,泉线上、下的河道表现出不同的河网形态;②泉线上部共发育64个节点,每级河道数目增长是上一级河道的R_(B)=1.8900倍,每级河道平均长度是下一级河道的R_(L)=1.0095倍,即河网形态特征参数R_(B)=1.8900和R_(L)=1.0095;泉线下部共发育818个节点,每级河道数目增长是上一级河道的R_(B)=1.0279倍,每级河道平均长度是下一级河道的R_(L)=0.9899倍,即河网形态特征参数是R_(B)=1.0279和R_(L)=0.9899;③河网形态特征参数受坡度影响变化较大,坡度较大则河网形态特征参数较大,坡度较小则河网形态特征参数较小。河网形态特征参数定量表征促进了分支河流体系沉积学发展,为开展陆相盆地储层建模和砂体预测提供了新的知识库信息.

关键词：分支河流体系河网形态河网模型 Horton定律格尔木河流扇

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High-responsivity on-chip waveguide coupled germanium photodetector for 2 μm waveband

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Photonics Research 2024年第1期12卷 115-122页

作者： JIANING WANG XI WANG YIHANG LI YANFU YANG qinghai SONG KE xu Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic Systems Harbin Institute of TechnologyShenzhen 518055China Department of Electronic&Information Engineering Harbin Institute of TechnologyShenzhen 518055China Department of Science Harbin Institute of TechnologyShenzhen 518055China

Recently,the emerging 2μm waveband has gained increasing interest due to its great potential for a wide scope of *** with the existing optical communication windows at shorter wavelengths,it also offers distinct advantages of lower nonlinear absorption,better fabrication tolerance,and larger free carrier plasma effects for silicon photonics,which has been a proven device *** much progress has been witnessed for silicon photonics at the 2μm waveband,the primary challenge still exists for on-chip *** the maturity and compatibility of the waveguide coupled photodetectors made of germanium,the 2μm regime is far beyond its cutoff *** this work,we demonstrate an efficient and high-speed on-chip waveguidecoupled germanium photodetector operating at the 2μm *** weak sub-bandgap absorption of epitaxial germanium is greatly enhanced by a lateral separation absorption charge multiplication *** detector is fabricated by the standard process offered by a commercial *** device has a benchmark performance with responsivity of 1.05 A/W and 3 dB bandwidth of 7.12 GHz,which is able to receive high-speed signals with up to 20 Gbit/s data *** availability of such an efficient and fast on-chip detector circumvents the barriers between silicon photonic integrated circuits and the potential applications at the 2μm waveband.

关键词： waveguide responsivity wave

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鄂尔多斯盆地志靖—安塞地区延长组7段致密砂岩微观孔隙结构评价

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吉林大学学报（地球科学版） 2024年第1期54卷 83-95页

作者：余光展王健吴楠徐清海刘显凤付清萌长江大学地球科学学院武汉430100 构造与油气资源教育部重点实验室(中国地质大学) 武汉430074

储层微观孔隙结构的研究对油气勘探开发具有重要意义。本文采用氮气吸附、铸体薄片观察、扫描电子显微镜(SEM)观察、X射线衍射(XRD)和核磁共振等实验手段研究志靖—安塞地区延长组7段致密砂岩的微观孔隙结构,计算孔隙结构参数,观察微孔... 详细信息

储层微观孔隙结构的研究对油气勘探开发具有重要意义。本文采用氮气吸附、铸体薄片观察、扫描电子显微镜(SEM)观察、X射线衍射(XRD)和核磁共振等实验手段研究志靖—安塞地区延长组7段致密砂岩的微观孔隙结构,计算孔隙结构参数,观察微孔分布,分析微孔隙类型,探讨并分析影响微孔发育的矿物成分、粒度及分选等相关参数。结果表明:研究区长7段的岩性主要为长石砂岩;致密砂岩微孔隙结构复杂,主要以黏土粒间溶孔、长石溶孔等形式存在;长7段主要发育小孔喉,微孔体积平均值为6.19×10^(-3)mL/g,孔隙发育差;长7油层组砂岩样品中,长7段的BET(Brunauer-Emmett-Teller)比表面积平均值为4.252 m^(2)/g,总孔体积平均值为0.0183 mL/g,最大孔径平均值为185.9 nm;砂岩孔隙以介孔为主,宏孔和微孔次之。

关键词：鄂尔多斯盆地长7段致密砂岩氮气吸附微观孔隙研究

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Highly responsive broadband Si-based MoS2 phototransistor on high-k dielectric

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Science China(Information Sciences) 2024年第6期67卷 180-189页

作者： Ali IMRAN Xin HE Jiwei LIU qinghai ZHU Muhammad SULAMAN Fei xuE Mingsheng xu Deren YANG College of Integrated Circuits State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University ZJU-Hangzhou Global Scientific and Technological Innovation Centre School of Materials Science and Engineering State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of Technology

The demand for photodetectors and image sensors has grown exponentially in the past decade in biomedical, security surveillance, robotics, automotive, quality control, image recognition, and military applications, due to their superior quality, broadband detection, lower noise, and economic viability. Here,we report a MoS2channel-based phototransistor over an HfO2/n-Si substrate isolated by an h BN layer. The high photoresponse is achieved through the integration of the photoconduction, photogating, and mobility enhancement process by utilizing excellent features of MoS2, HfO2/Si, and h BN. The capacitive coupling of the photogenerated carriers by high-k dielectric HfO2leads to modulation of MoS2Fermi level due to electrostatic doping. Furthermore, the MoS2also contributes to the photogeneration of carriers due to its semiconducting nature, leading to additional photocurrent. Ultimately, the combination of photogating,photoconduction, and swift carrier extraction with remarkable mobility of 11.65 cm2· V-1· s-1results in high responsivity, external quantum efficiency, and detectivity of 4.5 × 10～8A · W-1, 0.72 × 10～6, and 6.20× 1016Jones at 266 nm illumination, respectively. The device also demonstrates broadband photoresponse from 266–1000 nm wavelengths. The high responsivity distinguishes the potential of our device for the future of optoelectronics and broadband image sensing applications.

关键词： photogating photoconduction two-dimensional materials high $~k$ dielectric carrier scattering phototransistor

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Spatial patterns of vegetation and climate in the North China Plain during the Last Glacial Maximum and Holocene climatic optimum

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Science China Earth Sciences 2019年第8期62卷 1279-1287页

作者： Manyue LI Shengrui ZHANG qinghai xu Jule XIAO Ruilin WEN Institute of Nihewan Archaeology Hebei Normal UniversityShijiazhuang050024China College of Resources and Environment Hebei Key Laboratory of Environmental Change and Ecological ConstructionHebei Normal UniversityShijiazhuang050024China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China CAS Center for Excellence in Life and Paleoenvironment Beijing100044China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China

Reconstructing the spatial patterns of regional climate and vegetation during specific intervals in the past is important for assessing the possible responses of the ecological environment under future global warming scenarios. In this study, we reconstructed the history of regional vegetation and climate based on six radiocarbon-dated pollen records from the North China Plain. Combining the results with existing pollen records, we reconstruct the paleoenvironment of the North China Plain during the Last Glacial Maximum(LGM) and the Holocene Climatic Optimum(HCO). The results show that changes in the regional vegetation since the LGM were primarily determined by climatic conditions, the geomorphic landscape and by human *** the LGM, the climate was cold and dry;mixed broadleaf-coniferous forest and deciduous-evergreen broadleaf forest developed in the southern mountains, and cold-resistant coniferous forest and mixed broadleaf-coniferous forest were present in the northern mountains. The forest cover was relatively low, with mesophytic and hygrophilous meadow occupying the southern part of the plain, and temperate grassland and desert steppe were distributed in the north;Chenopodiaceae-dominated halophytes grew on the exposed continental shelf of the Bohai Sea and Yellow Sea. During the HCO, the climate was warm and wet;deciduous broadleaf forest and deciduous-evergreen broadleaf forest, with subtropical species, developed in the southern mountains, and deciduous broadleaf forest with thermophilic species was present in northern mountains. Although the degree of forest cover was greater than during the LGM, the vegetation of the plain area was still dominated by herbs, while halophytes had migrated inland due to sea level rise. In addition, the expansion of human activities, especially the intensification of cultivation,had a significant influence on the natural vegetation. Our results provide data and a scientific basis for paleoclimate modelling and re

关键词： North China Plain Last Glacial Maximum Holocene Climatic Optimum Pollen Vegetation Paleoenvironment

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