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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 China.Pollen 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

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 exploration.To do this we have undertaken a detailed investigation of the modern Great Halten River distributive fluvial system from the Sugan Lake Basin,qinghai,China.Unmanned aerial vehicle(UAV) photography,satellite remote sensing data and elemental analysis were used to determine differences in the sedimentary characteristics of the distributive fluvial system.From 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 identified.We found that the sedimentary structure and elemental content characteristics of each facies differ greatly.We 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 scale.At 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.

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 activity.During 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 regional carbon cycle assessment in north China, w

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

Gate-tunable high-performance broadband phototransistor array of two-dimensional PtSe_(2) on SOI

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Nano Research 2023年第5期16卷 7559-7567页

作者： Yexin Chen qinghai Zhu Xiaodong Zhu Yijun Sun Zhiyuan Cheng Jing xu Mingsheng xu School of Micro-Nano Electronics State Key Laboratory of Silicon MaterialsZhejiang UniversityHangzhou 310027China State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China College of Information Science&Electronic Engineering Zhejiang UniversityHangzhou 310027China Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province Ocean CollegeZhejiang UniversityZhoushan 316021China

Two-dimensional(2D)layered materials have attracted extensive research interest in the field of high-performance photodetection due to their high carrier mobility,tunable bandgap,stability,other excellent properties.Herein,we propose a gate-tunable,high-performance,self-driving,wide detection range phototransistor based on a 2D PtSe_(2)on silicon-oninsulator(SOI).Benefiting from the strong built-in electric field of the PtSe_(2)/Si heterostructure,the phototransistor has a fast response time(rise/fall time)of 36.7/32.6μs.The PtSe_(2)/Si phototransistor exhibits excellent photodetection performance over a broad spectral range from ultraviolet to near-infrared,including a responsivity of 1.07 A/W and a specific detectivity of 6.60×10^(9)Jones under 808 nm illumination at zero gate voltage.The responsivity and specific detectivity of PtSe_(2)/Si phototransistor at 5 V gate voltage are increased to 13.85 A/W and 1.90×10^(10) Jones under 808 nm illumination.Furthermore,the fabricated PtSe_(2)/Si phototransistor array shows excellent uniformity,reproducibility,long-term stability in terms of photoresponse performance with negligible variation between pixel cells.The architecture of present PtSe_(2)/Si on SOI platform paves a new way of a general strategy to realize high-performance photodetectors by combining the advantages of both 2D materials and conventional semiconductors which is compatible with current Si-complementary metal oxide semiconductor(CMOS)process.

关键词： two-dimensional PtSe_(2) silicon-on-insulator(SOI) heterojunction phototransistor gate voltage modulation

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 applications.Compared 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 technology.While much progress has been witnessed for silicon photonics at the 2μm waveband,the primary challenge still exists for on-chip detectors.Despite the maturity and compatibility of the waveguide coupled photodetectors made of germanium,the 2μm regime is far beyond its cutoff wavelength.In this work,we demonstrate an efficient and high-speed on-chip waveguidecoupled germanium photodetector operating at the 2μm waveband.The weak sub-bandgap absorption of epitaxial germanium is greatly enhanced by a lateral separation absorption charge multiplication structure.The detector is fabricated by the standard process offered by a commercial foundry.The 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 rate.The 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

High performance IEICO-4F/WSe_(2)heterojunction photodetector based on photoluminescence quenching behavior

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Nano Research 2022年第9期15卷 8595-8602页

作者： qinghai Zhu Yexin Chen Tianyi Chen Lijian Zuo Yijun Sun Rong Wang Mingsheng xu School of Micro-Nano Electronics State Key Laboratory of Silicon MaterialsZhejiang UniversityHangzhou 310027China Department of Polymer Science and Engineering State Key Laboratory of Silicon MaterialsZhejiang UniversityHangzhou 310027China College of Information Science&Electronic Engineering Zhejiang University38 Zheda RoadHangzhou 310027China ZJU Hangzhou Global Sci&Technol Innovation Centre Adv Semiconductor Research InstituteHangzhou 311215China

Heterostructure is the basic building block for functional optoelectronic devices.Heterostructures consisting of two-dimensional(2D)transition metal dichalcogenides(TMDs)and organic semiconductors are currently attracting great interest for highperformance optoelectronics.However,how to design heterostructure for highly efficient optoelectronic devices remains a big challenge.Here we design high-performance organic semiconductor/WSe_(2)heterostructure photodetectors by tailoring the charge transfer effect between 2,2ʹ-((2Z,2ʹZ)-(((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydros-indaceno[1,2-b:5,6-bʹ]dithiophene-2,7-diyl)bis(4-((2-ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(IEICO-4F)organic semiconductors with various thicknesses and monolayer WSe_(2).With the increase of IEICO-4F layer thickness,the photoluminescence(PL)characteristics of WSe_(2)could be completely quenched due to the charge transfer from the lowest unoccupied molecular orbital(LUMO)level of IEICO-4F to the conduction band minimum(CBM)of WSe_(2).Benefiting from the exquisite charge transfer behavior,the IEICO-4F/WSe_(2)heterojunction photodetector with optimized 6.0-nm thick IEICO-4F shows high performance including the responsivity of 8.32 A/W and specific detectivity of 4.65×10^(11)Jones at incident light of 808 nm.This work demonstrates a simple approach based on PL characteristics to design high-performance IEICO-4F/WSe_(2)heterojunction,thus paving the way for the development of excellent optoelectronic devices based on organic/TMD heterostructures.

关键词： tungsten diselenide organic semiconductor type-II heterojunction photoluminescence quenching photodetector

Spatial homogenization of soil-surface pollen assemblages improves the reliability of pollen-climate calibration-set

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Science China Earth Sciences 2020年第11期63卷 1758-1766页

作者： Fang TIAN Xianyong CAO Ran ZHANG Qinghai xu Wei DING Xingqi LIU Baolin PAN Jianhui CHEN College of Resource Environment and Tourism Capital Normal UniversityBeijing 100048China Alpine Paleoecology and Human Adaptation Group(ALPHA) Key Laboratory of Alpine EcologyInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China College of Resources and Environment Sciences Hebei Normal UniversityShijiazhuang 050024China Institute of Geological Sciences PalaeontologyFree University of BerlinBerlin 12249Germany Key Laboratory of Western China's Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China

To make a reliable reconstruction of past climate from soil-surface modern pollen,it is necessary to reduce the sources of error.In this paper,pollen percentages of the sub-continental scale modern pollen-climate dataset from China and Mongolia(with 68%soil-surface samples)are homogenized at various spatial scales.A tailored calibration-set is then applied to lake sediment-surface pollen assemblages from north-central China to evaluate their predictive power.Results indicate that spatial homogenization of modern pollen percentages can increase the proportion of inertia explained by climatic variables in CCA and improve the model performance of leave-one-out cross-validation using WA-PLS.Soil-surface pollen assemblages can thus be employed into a calibration-set for reliable climate estimation and they perform better when the calibration-set has been locally homogenized.Small-scale(e.g.,radii 2,5,or 10 km)homogenization reduces the local noise in soil-surface pollen assemblages and improves the cross-validated performance,while broader scale homogenization(more than 20 km radius)blurs the pollen-climate relationship.Lake sediment-surface pollen assemblages from close to the shore could contain pollen grains transported by rivers or from the shore vegetation and thus fail to represent regional climate well like the assemblages from the central part and deep-water area of lake.

关键词： North-central China Soil-surface pollen Climate reconstruction WA-PLS

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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论乔伊斯的宗教之维

外国文学 2022年第4期 161-171页

作者：许清海南京师范大学文学院江苏南京210097

乔伊斯与宗教之间的关系十分复杂,他在年轻时宣称脱离教会,但宗教传统却从未从他的作品中退场。乔伊斯称自己是一个自由思想的典型,他在小说创作中对宗教传统的运用也基于这一身份和艺术家身份的结合。他推崇托马斯·阿奎那,后者的神学... 详细信息

乔伊斯与宗教之间的关系十分复杂,他在年轻时宣称脱离教会,但宗教传统却从未从他的作品中退场。乔伊斯称自己是一个自由思想的典型,他在小说创作中对宗教传统的运用也基于这一身份和艺术家身份的结合。他推崇托马斯·阿奎那,后者的神学体系为他带来了美学上的启示,在有意或无意的误解中,他剥离了阿奎那美学思想的神学性,创造出强调审美主体的“领悟”的美学体系。在乔伊斯的小说中,在人类身上重演神明的故事是宗教传统的又一重要呈现形式,通过类比、反讽等方法,一些宗教人物和典故也成为塑造人、表现人性的武器。

关键词：乔伊斯自由思想宗教传统阿奎那类比反讽

Quantitative indicative significance of pollen assemblages on vegetation coverage in deciduous Quercus forest in the central Loess Plateau, China

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Science China Earth Sciences 2019年第6期62卷 992-1001页

作者： Yuanhao SUN Shengrui ZHANG Qinghai xu Yiwen LI Wei SHEN Tao WANG Zhongze ZHOU Ruchun ZHANG College of Resources and Environment Sciences Hebei Key Laboratory of Environmental Change and Ecological ConstructionHebei Normal University Institute of Nihewan Archaeology Hebei Normal University College of Resources and Environment Anhui University Institute of Geographical Science Hebei Academy of Sciences

We compared the pollen assemblages of surface moss samples and corresponding vegetation inventory data from 34 sites in the Huangling region of the central Loess Plateau. Our aims were to determine the characteristics of the pollen assemblages from the deciduous broadleaved forest climax community and its significance in terms of vegetation type and species composition. The pollen assemblages are dominated by woody plants such as Quercus(42% of total terrestrial pollen),Betula(16%) and Pinus(12%), with minor differences between different plant communities. The pollen assemblages of individual sampling sites differed from the vegetation composition within the 0–100 m scope and were more similar to the vegetation coverage within the 0–1000 m scope. This indicates that the surface pollen assemblages mainly reflect the comprehensive information from the vegetation composition of a large area, rather than the vegetation composition close to the sampling site. The contents of Quercus, Betula and Pinus pollen are high, and close to their vegetation coverage; whereas the contents of deciduous broadleaved arbor taxa(such as Malus and Acer) are lower, but their corresponding regional vegetation cover is higher. This suggests that the vegetation information conveyed by poorly-represented pollen taxa should be considered when interpreting stratigraphic pollen assemblages. Using the observed quantitative relationships between pollen and vegetation of the main taxa, we reconstructed the regional vegetation composition in the Gonghai Lake area of the northeastern Loess Plateau during the middle Holocene(7300–5000 yr BP). The results indicated that Quercus-dominated deciduous broadleaved forest climax community developed in the mountains surrounding the lake.

关键词： Loess Plateau Deciduous broadleaved forest Climax community Pollen assemblage Absolute vegetation coverage