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Electronic structure and effective mass of pristine and Cl-doped CsPbBr_(3)

Chinese Physics B 2024年第5期33卷 167-171页

作者：魏志远魏愉昊徐申东彭舒婷 Makoto Hashimoto 路东辉潘旭匡泯泉肖正国何俊峰 Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics University of Science and Technology of ChinaHefei 230026China Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics and School of Physical Science and TechnologySouthwest UniversityChongqing 400715China Key Laboratory of Photovoltaic and Energy Conservation Materials Institute of Applied TechnologyHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Stanford Synchrotron Radiation Lightsource and Stanford Institute for Materials and Energy Sciences SLAC National Accelerator LaboratoryMenlo ParkCalifornia 94025USA

Organic–inorganic lead halide perovskites(LHPs) have attracted great interest owing to their outstanding optoelectronic ***,the underlying electronic structure would determinate the physical properties of *** as for now,limited studies have been done to reveal the underlying electronic structure of this material system,comparing to the huge amount of investigations on the material *** effective mass of the valance band is one of the most important physical parameters which plays a dominant role in charge transport and photovoltaic *** pristine CsPbBr_(3),the Fr?hlich polarons associated with the Pb–Br stretching modes are proposed to be responsible for the effective mass *** this regard,it would be very interesting to explore the electronic structure in doped ***,we report high-resolution angle-resolved photoemission spectroscopy(ARPES) studies on both pristine and Cl-doped CsPbBr_(3).The experimental band dispersions are extracted from ARPES spectra along both ■ and ■ high symmetry *** calculations are performed and directly compared with the ARPES *** results have revealed the band structure of Cl-doped CsPbBr_(3) for the first time,which have also unveiled the effective mass renormalization in the Cl-doped CsPbBr_(3) *** dependent measurements indicate that the chlorine doping could moderately tune the renormalization *** results will help understand the physical properties of LHPs as a function of doping.

关键词： lead halide perovskites electronic structure effective mass

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Catchment environmental change over the 20th Century recorded by sedimentary leaf wax n-alkane δ^(13)C off the Pearl River estuary

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Science China Earth Sciences 2016年第5期59卷 975-980页

作者： xu shendong ZHANG Jie WANG Xianxu JIA GuoDong Key Laboratory of Marginal Sea Geology Guangzhou Institute of Geochemistry Chinese Academy of Sciences Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China State Key Laboratory of Marine Geology Tongji University

The compound-specific stable carbon isotope compositions(δ^(13)C) of leaf wax n-alkanes from two short sediment cores recovered off the Pearl River estuary(PRE) were analyzed to check for their capability of indicating decadal scale catchment environmental change. Sedimentary long-chain n-alkanes exhibited an odd-over-even predominance, with a maximum at n-C_(29) or n-C_(31), indicating their leaf wax origin was from vascular plants. The δ^(13)C values of C_(29) and C_(31) n-alkane in all the sediment samples were in the range of -28.8‰ to -31.2‰, consistent with the C_3 plant-dominated vegetation in the Pearl River catchments. The time series of δ^(13)C records from the two cores were comparable and displayed a decreasing trend from the early 20 th century to the end of the 1970s, followed by a reversal in that change leading to continued increase for ca. 15 years. After being corrected for the effect of atmospheric CO_2 rise and δ^(13)C_(atm) decline, the δ^(13)C_(29) records largely retained their raw changing pattern; the post-1980 increase being more conspicuous. The slightly decreasing trend in corrected δ^(13)C records before around 1980 may have been caused by an increase in precipitation, whereas the subsequent increase of δ^(13)C is likely associated with the observed dry climate and/or intensive anthropogenic deforestation. Our results thus demonstrate that leaf wax n-alkanes buried in the sediments off the PRE may well reflect change in the regional climate and/or human activity in the river catchments over the past century.

关键词： Leaf wax n-alkanes compound-specific δ^(13)C values environmental change Pearl River estuary

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长棘海星胃含物和幽门肠δ^(13)C对其食源的指示意义

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热带地理 2024年第10期44卷 1847-1853页

作者：马蕾许慎栋余克服黄学勇陈飚韦芬广西大学海洋学院广西南海珊瑚礁研究重点实验室南宁530004 中国科学院烟台海岸带研究所中国科学院海岸带环境过程与生态修复重点实验室山东烟台264003

长棘海星(Acanthaster spp.)是珊瑚的天敌,其周期性暴发是导致珊瑚礁退化的最重要原因之一。了解长棘海星的食物来源或有可能为应对长棘海星暴发提供科学依据,但迄今关于长棘海星食物来源的认识基本来自于野外,即认为长棘海星以珊瑚组... 详细信息

长棘海星(Acanthaster spp.)是珊瑚的天敌,其周期性暴发是导致珊瑚礁退化的最重要原因之一。了解长棘海星的食物来源或有可能为应对长棘海星暴发提供科学依据,但迄今关于长棘海星食物来源的认识基本来自于野外,即认为长棘海星以珊瑚组织为食,极少关于其同位素方面的信息。文章以2020年3月在南海西沙群岛采集的不同体长的长棘海星为材料,首次测定其胃含物稳定碳、氮同位素值(δ^(13)C、δ^(15)N)及幽门肠碳稳定同位素值,以探讨其食物来源。根据体长将所分析的长棘海星分为亚成体(体长10~200 mm)、成体(体长200~350 mm)、高龄成体(体长>350 mm)3个年龄段。结果显示:1)胃含物和幽门肠的δ^(13)C值范围分别为-15.03‰~-13.00‰和-15.21‰~-13.24‰,二者的变化趋势一致,表明其对食源的指示具有一致性;2)随着体长和年龄的增长,长棘海星的胃含物和幽门肠的碳同位素值均呈下降趋势,而胃含物的氮同位素值呈上升趋势,表明长棘海星的食源随年龄增加发生改变,且其营养级也呈增高趋势,在亚成体阶段的食物以相对低营养级的食物为食,而在成体后以相对高营养级的食物为食。

关键词：碳稳定同位素氮稳定同位素食性胃含物幽门肠长棘海星

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西沙群岛永乐环礁礁外坡沉积物中有机碳的含量与来源分析

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热带海洋学报 2024年第3期43卷 131-145页

作者：高洁余克服许慎栋黄学勇陈飚王永刚广西大学海洋学院广西南宁530004 广西大学珊瑚礁研究中心广西南宁530004 广西南海珊瑚礁研究重点实验室广西南宁530004 中国科学院烟台海岸带研究所山东烟台264003

有机碳埋藏作用是碳循环过程的重要环节,但迄今关于珊瑚礁沉积物中有机碳的研究却很少,影响着对珊瑚礁碳循环的准确评估。本文以南海西沙群岛永乐环礁礁外坡的现代表层沉积物为材料,分析其总有机碳(total organic carbon,TOC)含量、总氮... 详细信息

有机碳埋藏作用是碳循环过程的重要环节,但迄今关于珊瑚礁沉积物中有机碳的研究却很少,影响着对珊瑚礁碳循环的准确评估。本文以南海西沙群岛永乐环礁礁外坡的现代表层沉积物为材料,分析其总有机碳(total organic carbon,TOC)含量、总氮(total nitrogen,TN)含量、有机碳同位素(δ13C)值以及沉积物粒度、叶绿素含量等指标。永乐环礁礁外坡的生态状况相对较好,具有代表健康珊瑚礁生态系统沉积物中有机碳特征的潜力。结果表明:(1)永乐环礁礁外坡沉积物中的TOC含量在0.71~1.66mg·g^(−1)之间,平均为(1.23±0.3)1mg·g^(−1);TN含量在0.12~0.28mg·g^(−1)之间,平均为(0.20±0.05)mg·g^(−1);(2)C/N比值在6.16~7.59之间,平均为(6.75±0.34);δ13C值在−17.49‰~−15.85‰之间,平均为(−16.61±0.49)‰,表明沉积物中的有机碳以海洋自生来源为主,且主要来自底栖植物;(3)有机碳含量与水深负相关,与叶绿素a含量和脱镁叶绿素含量正相关,表明底栖植物控制的初级生产力是礁外坡有机碳含量的主要来源。结合全新世以来太平洋海域礁外坡沉积物沉积速率(2~5mm·a^(−1)),推测永乐环礁礁外坡有机碳埋藏通量约在3~8g·m^(−2)·a^(−1)之间。本研究为评估南海珊瑚礁对碳循环的贡献提供了新的信息。

关键词：珊瑚礁沉积物有机碳碳同位素永乐环礁西沙群岛

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Spatial variations in the trophic status of Favia palauensis corals in the South China Sea:Insights into their different adaptabilities under contrasting environmental conditions

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Science China Earth Sciences 2021年第6期64卷 839-852页

作者： shendong xu Zhinan ZHANG Kefu YU xueyong HUANG Hanji CHEN Zhenjun QIN Risheng LIANG Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Coral Reef Research Centre of ChinaSchool of Marine SciencesGuangxi UniversityNanning530004China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao266061China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519000China

Scleractinian corals exhibit a dual trophic pattern of autotrophic photosynthesis and heterotrophic ***,whether corals can adjust their trophic status under contrasting environmental conditions remains *** our study,70 scleractinian corals(Favia palauensis)were collected from Sanya and the Xisha and Nansha Islands in the South China *** measured the zooxanthellae density(ZD)andδ^(13)C of zooxanthellae(δ^(13)C_(z))and host tissue(δ^(13)C_(h))and analyzed the difference betweenδ^(13)C_(h) andδ^(13)C_(z)(i.e.,△^(h-z)^(13)C).The relatively high ZD andδ^(13)C_(z) values in the samples from Sanya indicate that these corals might have higher photosynthetic rates and autotrophic abilities than those from Xisha and *** contrast,the relatively lowδ^(13)C_(h) and△^(h-z)^(13)C values in the samples from Xisha and Nansha suggest that these corals might have a higher heterotrophic ability than those from *** addition,we tested the coral tissue biomass and skeletalδ^(13)C(δ^(13)C_(s))in the samples from Sanya and examined their correlations with△^(h-z)^(13)*** results showed a negative correlation,indicating that the more the organic material produced by the coral,the stronger its heterotrophic *** results show that corals can adjust their trophic status under different environmental and physiological conditions,which is essential for increasing their adaptability to different environmental conditions.

关键词： Scleractinian corals Symbiotic zooxanthellae density Stable carbon isotope Trophic status Spatial variation South China Sea

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Impacts of tropical cyclones and anthropogenic activities on marine vanadium: A unique perspective from high resolution Porites coral record

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Science China Earth Sciences 2022年第12期65卷 2285-2296页

作者： Wei JIANG Xingyuan WU Kefu YU Haodan YANG shendong xu Ning WANG Yangyang YONG Yinan SUN Chaoshuai WEI Yinghui WANG Guangxi Laboratory on the Study of Coral Reefs in the South China Sea/Coral Reef Research Center of China/School of Marine Sciences Guangxi UniversityNanning 530004China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China

As a typical contaminant in fossil fuels,vanadium has undergone dramatically increase due to the impacts from human *** excessive anthropogenic vanadium emissions have altered natural geochemical ***,research on vanadium geochemistry in the ocean,which is the major sink for vanadium mobilized on land,has lagged much behind relative to those of other *** we reconstruct historical patterns of vanadium in surface seawater utilizing a high-resolution temporal record(1984–2015 CE)of geochemical proxies(vanadium/calcium(V/Ca),δ^(18)O,δ^(13)C,etc.)in a Porites coral colony from an offshore non-estuarine island in the northern South China Sea(SCS).We find a close association between the surface winds and the temporal patterns of coral V/Ca ratios,revealing great potential for documenting prehistoric changes in tropical ***,the coral V/Ca record remarkably captured the temporal patterns of anthropogenic activities,offering a valuable and novel tool for testing the efficacy of specific legislation on pollution *** with the other reported coral vanadium data,we recovered the historical changes in vanadium emissions in the northern SCS and identified that changing industrial practices should be responsible for the differences in anthropogenic vanadium emissions at each *** results demonstrated that the coral V/Ca ratio at a high temporal resolution has great potential as a new and direct geochemical proxy for tropical cyclones after removing artificial disturbances in the ocean.

关键词： Vanadium Coral Tropical Cyclones Oil spill Weizhou Island Northern South China Sea

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宜荆荆恩森林城市群建设的总体布局研究

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中国城市林业 2024年第4期22卷 92-99页

作者：姜莎莎张昶赵莉徐慎东孙振凯金佳莉殷鲁秦王成中国林业科学研究院林业研究所国家林业和草原局城市森林研究中心北京100091 宜昌市林业和园林局湖北宜昌443000

宜昌市、荆州市、荆门市和恩施州构成的宜荆荆恩城市群是湖北省三大城市群之一,也是长江经济带上重要的生态安全屏障区,开展森林城市群建设对促进区域生态、经济、社会和文化协同发展具有重要意义。文章分析了宜荆荆恩城市群生态安全格... 详细信息

宜昌市、荆州市、荆门市和恩施州构成的宜荆荆恩城市群是湖北省三大城市群之一,也是长江经济带上重要的生态安全屏障区,开展森林城市群建设对促进区域生态、经济、社会和文化协同发展具有重要意义。文章分析了宜荆荆恩城市群生态安全格局、森林湿地资源、生态产业发展、生物多样性保护等现状,从城市群尺度指出存在的问题和发展需求;在此基础上,提出“山区强四库,平原织两网,城乡提三景,全域筑四链”的宜荆荆恩森林城市群总体建设布局,并阐述具体的建设内容。

关键词：宜荆荆恩城市群森林城市群协同发展建设布局

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西沙群岛琛航岛全新世珊瑚礁的起始发育时间及其海平面指示意义

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热带地理 2019年第3期39卷 319-328页

作者：覃业曼余克服王瑞姜伟许慎栋广西大学广西南海珊瑚礁研究重点实验室南宁530004 广西大学珊瑚礁研究中心南宁530004 广西大学海洋学院南宁530004 广西大学林学院南宁530004

以西沙群岛琛航岛珊瑚礁钻孔为材料,通过高精度铀系测年技术测定了全新世底界的年代;同时利用MAT-253同位素质谱仪和电感耦合等离子体质谱仪测定了0~20m层段δ^13C、δ^18O和锶元素的质量分数,以U-Th年龄为基础,结合δ^13C、δ^18O和锶... 详细信息

以西沙群岛琛航岛珊瑚礁钻孔为材料,通过高精度铀系测年技术测定了全新世底界的年代;同时利用MAT-253同位素质谱仪和电感耦合等离子体质谱仪测定了0~20m层段δ^13C、δ^18O和锶元素的质量分数,以U-Th年龄为基础,结合δ^13C、δ^18O和锶元素的质量分数均在16~17m之间明显降低这一特点,得到琛航岛全新世珊瑚礁的起始发育时间为距今7900a前,不整合于晚更新世的珊瑚礁体(年代老于110ka)之上,全新世礁体的厚度为16.7m。考虑研究区域新构造活动相对稳定,以及南海现代珊瑚礁的礁坪面与大潮低潮面基本一致,琛科2井的钻孔井位高于现代礁坪约2.9m,推测其起始发育时的位置在现代海平面大潮低潮面之下约13.8m,即西沙群岛海域7900a前的海平面在现代海平面以下约13.8m,近7900a以来海平面上升了至少13.8m。这一结果为理解全新世南海珊瑚礁的发育历史及海平面变化提供了新的信息。

关键词：全新世珊瑚礁起始发育时间海平面西沙群岛琛航岛

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稀土元素地球化学在珊瑚礁环境记录中的研究进展

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热带海洋学报 2016年第5期35卷 62-74页

作者：姜伟余克服王英辉许慎栋广西大学珊瑚礁研究中心广西南宁530004 广西大学海洋学院广西南宁530004 中国科学院南海海洋研究所广东广州510301

综述了稀土元素地球化学在珊瑚记录过去环境变化和珊瑚对环境变化响应等方面的研究进展。珊瑚骨骼中的稀土元素能够记录的环境信息主要包括海平面、污染、地下水、氧化还原环境等;而在珊瑚对环境变化的响应方面,主要体现在稀土元素的含... 详细信息

综述了稀土元素地球化学在珊瑚记录过去环境变化和珊瑚对环境变化响应等方面的研究进展。珊瑚骨骼中的稀土元素能够记录的环境信息主要包括海平面、污染、地下水、氧化还原环境等;而在珊瑚对环境变化的响应方面,主要体现在稀土元素的含量,配分型式以及Ce、Eu等元素的异常上。珊瑚骨骼中的稀土元素因为具有稳定性高、保存信息丰富以及记录环境准确等优势,显示出了极好的应用前景。未来的研究中,需要进一步探索珊瑚骨骼稀土元素含量的种间及空间差异性,探讨成岩作用对珊瑚骨骼稀土元素含量和配分型式的影响,这将有利于重建更准确、更长时间序列的珊瑚生长时期的环境信息记录。

关键词：稀土元素珊瑚礁环境记录海水碳酸盐岩

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Riverine sulfate sources and behaviors in arid environment,Northwest China:Constraints from sulfur and oxygen isotopes

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Journal of Environmental Sciences 2024年第3期137卷 716-731页

作者： Yifu xu Wenjing Liu Bing xu Zhifang xu Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

The fate of riverine sulfate ion (SO_(4)^(2-)) and its environmental effects in arid environment are difficult to evaluate due to its complicated sources and strongly coupled behaviors with water cycle which is significantly modified by *** understand the sulfur cycle in aquatic systems in arid environment,the chemical and sulfur and oxygen isotopic compositions (δ^(34)S_(SO4)and δ^(18)O_(SO4)) of major rivers around the Badain Jaran Desert,northwestern China,were *** rivers had averaged SO_(4)^(2-)content at 1336μmol/L,over 10times higher than the global *** δ^(34)S_(SO4)and δ^(18)O_(SO4)values ranged from-5.3‰to+11.8‰and+1.6‰to+12.8‰,*** end-member analysis and the inverse model showed that riverine sulfate was mainly derived from evaporites dissolution (0-87%),sulfide oxidation (13%-100%) and precipitation (0-33%),indicating heterogeneity in sulfur sources and behaviors along the river drainage with the lithology variations and climate *** isotopic tools combining with hydro-chemistry compositions could be applied to reveal sulfur cycle in arid *** on the calculation,sulfide oxidation plays the primary role in the headwater and upstream in the Qilian-Mountains area,where sulfide is widely *** the proportion of evaporites dissolution contributing to riverine sulfate is much higher in downstream in a drier ***,less precipitation and higher temperature can lead to more intensive evaporation,affecting the process of sulfide oxidation and enhancing the rates of evaporites dissolution and sulfate precipitation in the basin.

关键词： Sulfur and oxygen isotopes Source apportionment Inverse model Arid environment Inland rivers Northwestern China

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