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Molecular fossil and paleovegetation records of paleosol S4 and adjacent loess layers in the Luochuan loess section, NW China

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Science China Earth Sciences 2008年第3期51卷 321-330页

作者： zhang HuCai YANG MingSheng zhang wenxiang LEI GuoLiang CHANG FengQin PU Yang FAN HongFang Key Laboratory of Western China’s Environmental Systems Ministry of EducationCollege of Earth and Environment SciencesLanzhou UniversityLanzhou 730000China State Key Laboratory of Lake and Environment Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China

Using gas chromatography-mass spectrometry (GC-MS) technique, a series of biomarkers were identi- fied, including n-alkanes, n-alkane-2-ones, isoprenoid etc. from the loess-paleosol samples collected from the S4 and adjacent L5, L4 of the Luochuan loess section, Northwestern China. Based on these data, especially n-alkanes and high-resolution magnetic susceptibility and grain size data, the pa- leoenvironment and paleovegetation history during S4 was reconstructed. The CPI (Carbon Predomi- nance Index) and correlation between n-alkanes and magnetic susceptibility and grain size data dem- onstrated that the molecular fossils in paleosol and loess layers can reflect the vegetation condition during the loess-paleosol formation, if the allochthonous organic inputs could be excluded reasonably. The ACL (average chain length) index is correlated well with paleomagnetic susceptibility and grain size variations, displaying their good synchrony with warm and humid climate. However, it relatively lagged behind the paleomagnetic susceptibility and the grain size variations when the climate began to deteriorate. During the formation period of paleosol, the n-alkanes was dominated by C31 homologue, indicating that the primary organic input originated from herbs. Our study also demonstrated that the herbs were more flourish than wood plants in Loess Plateau, especially in the Luochuan area during the warm and humid phase, and there was no typical forest vegetation developed in the studied period.

关键词： paleoenvironment Paleosol S4 Luochuan loess section biomarker paleovegetation

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Ionic Covalent Organic Framework:What Does the Unique Ionic Site Bring to Us?

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Chemical Research in Chinese Universities 2022年第2期38卷 296-309页

作者： FU Yu LI Yinhui zhang wenxiang LUO Chen JIANG Lingchang MA Heping School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an 710049P.R.China Petrochemical Research Institute PetroChinaBeijing 102200P.R.China College of Biological Chemical Science and EngineeringJiaxing UniversityJiaxing 314001P.R.China

Ionic covalent organic frameworks featuring both crystallinity and charged sites have arose tremendous attention from scientific community. The adjustable textural structures, well-defined channels and abundant charged sites of ionic COFs facilitate great potential in diverse aspects, such as separation, ion conduction, sensing, catalysis and energy storage. In this review, we first introduced the design and construction of ionic covalent organic frameworks(COFs), and classified them according to the types of charged sites. We focused on the various applications of ionic COFs in diverse fields. The structure-function relationship was also explored in detail. Finally, the opportunities and challenges of ionic COFs were summarized to provide guidance for better design and application of ionic COFs.

关键词： Ionic covalent organic framework Design and construction Various application Structure-function relationship

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Geochemical fractionation of rare earth elements in lacustrine deposits from Qaidam Basin

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Science China Earth Sciences 2009年第11期52卷 1703-1713页

作者： zhang HuCai zhang wenxiang CHANG FengQin YANG LunQing LEI GuoLiang YANG MingSheng PU Yang LEI YangBin Key Laboratory of Western China’s Environments MOECollege of Earth Sciences and EnvironmentsLanzhou UniversityLanzhou 730000China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China Key Laboratory of Boyang Lake MOESchool of Environmental and Chemical EngineeringNanchang UniversityNanchang 330031China

Based on the concentration and distribution pattern analysis of the rare earth elements (REEs) at the Shell Bar section from Qaidam Basin, we studied the geochemical fractionations of REE in paleolake deposits and their paleo-environmental significance. Our results show that the REE concentration in AS (acid soluble) and AR (acid residual) fractions are 20.9 μg/g and 95.4 μg/g (except element Y) individually, showing a strong REE differentiation between AS and AR fractions. However, the two types of fractions (AS & AR) have similar REE distribution patterns, which are slightly rich in light earth rare elements (LREEs), with slightly right-tilting and negative Eu anomaly. The LREE of AR is richer than that of AS. There were no significant correlations between the REE in AS, AR and other proxies. It indicated that the lacustrine deposition had different material sources and experienced varying geochemical procedures. Correlation analysis between the REE and the content of fine grain-size (<4 μm) of the sediments, Rb/Sr ratio and Mn concentration showed high correlation coefficients. Our results demonstrated that the REE in acid soluble and residual fractions bear different environmental significances, which are strongly dependent on local environment. The REE of acid soluble fraction is closely related to the paleoclimatic changes in the lake catchment and the evolutionary processes of lake itself. Our results suggest that δCe and (La/Yb)n could be used as proxies of the reduction-oxidation conditions and furthermore the temperature change and the lake level fluctuations. Using these proxies, we reconstructed the paleoclimate and water level fluctuation history during the high lake level period lasting between 43.5 and 22.4 cal. ka BP.

关键词： Shell Bar section rare earth elements (REE) fractionation paleoclimate Qaidam Basin

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Study on Strength Reduction Law and Meso-Crack Evolution of Lower Layered Cemented Tailings Backfill

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Journal of Renewable Materials 2023年第3期11卷 1513-1529页

作者： Huazhe Jiao wenxiang zhang Yunfei Wang Xinming Chen Liuhua Yang Yangyang Rong State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization School of Civil EngineeringHenan Polytechnic UniversityJiaozuo454003China Provincial Key Laboratory of Underground Engineering and Disaster Prevention and Control School of Civil EngineeringHenan Polytechnic UniversityJiaozuo454003China School of Civil Engineering Henan Polytechnic UniversityJiaozuo454003China

The green disposal of tailings solid waste is a problem to be solved in mine *** tailings filling stoping method can realize the dual goals of solid waste resource utilization and mined-out area ***,the volume of the mined-out area of the open-pit method is larger than the filling capacity,resulting in the complex stratification of the underground backfill,and the strength of the backfill cannot meet the *** this paper,according to the delamination situation,the specimens of horizontal and inclination angle layered cemented tailings backfill(LCTB)is made for a uniaxial compression test,and the failure process of delamination backfill is reduced by *** results show that the corresponding reduction factorφof horizontal LCTB is 0.560–0.932,and the correspondingφvalue of inclination angle LCTB is 0.338–*** failure mode of backfill in different layers is mainly manifested as a tensile *** PFC numerical simulation results are consistent with laboratory test results,which verifies the correctness of backfill *** research results provide a reliable theoretical basis for the strength design of backfill in goaf,which is of great significance for solid waste utilization and environmental protection.

关键词： Solid wastes recycling LCTB uniaxial compression strength reduction granular flow

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通渭县常家河镇山楂产业助力水土流失综合治理成效浅析

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山西水土保持科技 2024年第1期 16-18页

作者：张文祥陈荣郭冰李媛媛定西市水土保持科学研究所甘肃定西743000

近年来通渭县常家河镇依托合作社资金、技术、人才优势,秉承着“发掘并弘扬历史文化,建设乡村景观,促进农村经济发展和乡村面貌提升”的理念,坚持“以旅游为先导,以产业为核心,以传统文化为灵魂,以乡村体验为价值,以乡村振兴为目标”的... 详细信息

近年来通渭县常家河镇依托合作社资金、技术、人才优势,秉承着“发掘并弘扬历史文化,建设乡村景观,促进农村经济发展和乡村面貌提升”的理念,坚持“以旅游为先导,以产业为核心,以传统文化为灵魂,以乡村体验为价值,以乡村振兴为目标”的水土流失综合治理,依托山地资源优势,通过引进山楂树种,大力实施“兴林兴草”战略,科学稳步推进水土保持建设,获得了可观的经济与生态双重收益。本篇文章旨在概括民间投资对于水土保持生态建设工程的关键经验与实施方式,为绿水青山转化为金山银山提供实践依据,并全力打造出富含本地文化特色的水土流失防治提供创新途径和发展模式。

关键词：小流域综合治理定西市

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台风对淤泥质潮滩冲淤影响研究——基于无人机测量与现场水动力观测

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华东师范大学学报（自然科学版） 2024年第4期 150-160页

作者：张新淼薛力铭史本伟张文祥李天佑彭彪彪李秀珍汪亚平华东师范大学河口海岸学国家重点实验室上海200241 自然资源部第一海洋研究所自然资源部海岸带科学与综合管理重点实验室山东青岛266061

台风等极端天气会使淤泥质潮滩发生数十厘米的冲淤变化.在全球变暖导致台风强度及频率增大的背景下,厘清台风影响下潮滩冲淤变化及其机制,对潮滩保护与生态系统完整性维持具有重要意义.本文借助基于运动恢复结构算法的无人机(unmanned a... 详细信息

台风等极端天气会使淤泥质潮滩发生数十厘米的冲淤变化.在全球变暖导致台风强度及频率增大的背景下,厘清台风影响下潮滩冲淤变化及其机制,对潮滩保护与生态系统完整性维持具有重要意义.本文借助基于运动恢复结构算法的无人机(unmanned aerial vehicle,UAV)摄影测量方法,于2021年7月“烟花”台风前后对崇明东滩典型样地进行滩面高程测量,并在盐沼-光滩过渡带现场采集水动力泥沙数据.结果表明:无人机摄影测量精度为4.1 cm;台风影响下光滩区域侵蚀、盐沼区域淤积,变幅达±32 cm.其原因是:台风影响下,光滩区域在天文大潮时波高及水深增大,达到波浪破碎条件后表层沉积物被侵蚀并被强潮流搬运;涨潮流携带悬浮泥沙进入盐沼后,因盐沼缓流消浪作用导致水体挟沙能力下降,泥沙在盐沼区域沉积.因此,盐沼-光滩过渡带呈现光滩区域侵蚀、盐沼区域沉积的冲淤分带性.本文将无人机摄影测量与同步水动力泥沙现场观测结合,为深刻认识台风事件对潮滩冲淤的影响提供了新视角.

关键词：台风无人机测量冲淤变化现场观测冲淤机制

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网络平台治理的理论探索与中美欧互鉴——全球视野下的平台治理学术研究全景扫描

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新闻春秋 2024年第3期 30-42页

作者：张文祥杨林陈力双方兴东浙大宁波理工学院传媒与法学院浙江大学网络空间安全学院浙大宁波理工学院网络空间治理与数字经济法治(长三角)研究基地宁波315100 中国科学技术大学公共事务学院合肥230002 暨南大学新闻与传播学院广州510632 浙江大学国际传播研究中心浙江大学乌镇数字文明研究院杭州310058

从平台的传媒属性到互联网成为社会基础设施,再到数据、算法成为网络平台的生产要素和工具,全球平台治理进入互联网革命的深水区。中美欧掀起的平台治理风暴出现明显分化,冷热不均,起伏不定。呈现在学术层面的诸多研究成果,成为深入分... 详细信息

从平台的传媒属性到互联网成为社会基础设施,再到数据、算法成为网络平台的生产要素和工具,全球平台治理进入互联网革命的深水区。中美欧掀起的平台治理风暴出现明显分化,冷热不均,起伏不定。呈现在学术层面的诸多研究成果,成为深入分析全球平台治理进程的最佳观察点。随着近年平台治理研究持续深入,开始形成概念和理论体系。围绕平台的基础理论、平台治理的制度构建、平台的社会化治理模式创新、平台治理的司法实践和中美欧不同区域的互鉴和比较,形成学术热点。除经济和技术上的持续发展和竞争外,平台治理制度创新是国家实力角逐的重要维度。互联网平台治理还缺乏一锤定音式的解决办法,未来还需政府、学界、业界共同寻求制度上的根本创新和突破。推进平台治理应当寻求监管必要性与互联网经济发展、技术创新之间的平衡。

关键词：平台治理社会化治理互联网革命互联网反垄断

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Experimental Study of Temperature Control Based on Composite Phase Change Materials during Charging and Discharging of Battery

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Journal of Thermal Science 2024年第2期33卷 578-590页

作者： LI Xiaolin WANG Jun CAO wenxiang zhang Xuesong School of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang212013China

This study is to utilize the heat-absorbing and releasing capabilities of phase change materials(PCM)to regulate the surface temperature fluctuations of batteries during charging and *** goal is to keep the battery within the optimal operating temperature *** impact of PCM thickness and phase change temperature on battery temperature is investigated by encircling a cylindrical battery with a PCM *** improve the thermal conductivity of PCM,expanded graphite(EG) is added to make a composite phase change material(CPCM),and the effects of various EG mass ratios on battery surface temperature and CPCM utilization level are *** findings indicate that increasing PCM thickness effectively extends temperature control time,but its impact is *** difference in phase change temperature of PCM controls the battery temperature in different temperature *** phase change temperatures are unsuitable for controlling battery temperature in high temperature *** addition of EG enhances the thermal conductivity of PCM,leading to further control of battery *** results show that the addition of 6%(mass ratio) EG to CPCM extends the effective temperature control time by 11 min and improves by 28% compared to a single *** CPCM utilization is also more satisfactory and achieved a balance between heat storage and thermal conductivity in a battery thermal management system(BTMS) based on PCM.

关键词： phase change material expanded graphite thermal management system effective control time

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Discovery of bacteriopheophytin-a in lacustrine deposits from Lake Zigetang on the central Tibetan Plateau and its paleoenvironmental significance

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Science China Earth Sciences 2017年第12期60卷 2171-2180页

作者： LI HuaYong zhang HuCai CHANG FengQin ZHENG Qian zhang wenxiang LEI GuoLiang LEI YanBin PU Yang JI JunFeng Key Laboratory of Plateau Lake Ecology and Global Change Yunnan Provincial Key Laboratory of Plateau Geography Process and Environment ChangesCollege of Tourism and Geography ScienceYunnan Normal UniversityKunming 650500China School of Resource Environment and Tourism Anyang Normal UniversityAnyang 455000China College of Urban and Environment Sciences Central China Normal UniversityWuhan 430079China Key Laboratory for Subtropical Mountain Ecology(Ministry of Science and Technology and Fujian Province Funded) Fujian Normal UniversityFuzhoa 350007China Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100085China School of Remote Sensing Nanjing University of Information Science&TechnologyNanjing 210044China Institute of Surface Geochemistry Department of Earth SciencesNanjing UniversityNanjing 210093China

Lake Zigetang is located on the central Tibetan Plateau(TP) and represents a rare but typical meromictic lake in *** lake's stable meromixis sustains microflora communities, and changes in these communities are relatively independent of climate. Therefore, these communities can be used as paleoclimate proxies. In this paper, the stratification properties and their relationships with the microflora of Lake Zigetang were analyzed. We found that water depth and climate conditions were two important factors for maintaining meromixis in Lake Zigetang. Generally, stratification was enhanced during warm periods, while temperature differences between the mixolimnion and monimolimnion were decreased during cold periods. The presence of anoxygenic phototrophic bacteria(APB) was demonstrated by the discovery of bacteriopheophytin-a(Bph-a) in the *** bacterial community is mainly concentrated at the bottom of the chemocline and the top of the monimolimnion, where it forms a thin APB layer. Moreover, total APB productivity is mainly affected by the light intensity penetrating to the APB layer,which exponentially increases as the thermocline becomes shallow. Therefore, high Bph-a values in the lake corresponded to a shallow thermocline and warm periods, low Bph-a values corresponded to cold periods, and zero changes indicated that the water was completely mixed and reflected an extreme cold climate or low lake level period. Thus, Bph-a can be used as a climate proxy to reconstruct the history of lake stratification and climate changes.

关键词： Lake Zigetang Tibetan Plateau Meromictic lakes Thermocline Anoxygenic phototrophic bacteria

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Removal of Low-concentration Ammonia from Ambient Air by Aluminophosphates

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Chemical Research in Chinese Universities 2018年第3期34卷 480-484页

作者： LI Chunyang WU Shujie YU Guiyang YANG Xuwei LIU Gang zhang wenxiang Key Laboratory of Surface and Interface Chemistry of Jilin Province College of Chemistry Jilin University Changchun 130021 P. R. China

A series of aluminumphosphate materials was prepared and used as adsorbents for the removal of ammonia at low concentrations. The influence of various preparation parameters, including the pH value of sol, calcination temperature and molar ratio of P/A1, on the structure and surface properties as well as adsorption capacity was investigated. The results showed that large amount of P-OH present on the surface of aluminophosphates was suitable for the removal of ammonia. They were the major source of weak Br6nsted acid sites and acted as the main active centers for capturing ammonia.

关键词： Ammonia adsorption Aluminophosphate Air purification Weak acid Porous material

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