检索结果-南通市图书馆

Methoxy n-fatty acids in surface soils from the Gongga and Kunlun Mountains:Ecological implications

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第21期55卷 2258-2267页

作者： BAI Yan FANG XiaoMin nie junsheng MENG QiangXiang CHI YunPing Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China Key Laboratory of Western China's Environmental Systems Ministry of Education of China and College of Resources and Environment Lanzhou University Lanzhou 730000 China Department of Geological Sciences Jackson School of Geosciences University of Texas Austin TX 78712 USA Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou 730000 China

GC-MS characteristics of surface soil samples from the eastern and northern Tibetan Plateau provide tentative identification of 8(-14)-Methoxy hexadecanoic acid(iME-16:0)and 9(-17)-methoxy octadecanoic acid(iME-18:0).Sixty surface soil samples were collected from the eastern slope of Gongga Mountain,at elevations ranging from～1230 to 4500 m(eastern Tibetan Plateau),and from the northern slope of West Kunlun Mountains,ranging from～1300 to 5500 m(northern Tibetan Plateau).This study also analyzed the methoxy n-fatty acids(MFAs)of Gongga Mountain tree leaves from six common living species,at the elevation of 2900-4200 *** dominate these samples,with more centrally located methoxy groups eluting earlier than those with methoxy groups located closer to the end of the main carbon *** occur prominently in most of the Gongga Mountain soil samples(and from six tree samples)from dominantly coniferous and deciduous broadleaved *** than in two narrow vegetation zones between 4000-4350 m and 2900-3300 m,no MFAs were found in 19 Kunlun Mountains soil samples from areas covered mainly with montane desert and alpine desert steppe *** on the inventory of plants and soils from which MFAs have been isolated,we conclude that the MFAs most probably originate from specific woody *** we can exclude some particular grasses as sources,MFAs may be specific woody plants-derived biomarkers;thus they would serve as an important additional proxy for comprehensive and precise ecological reconstructions.

关键词：表层土壤西昆仑山生态重建甲氧基脂肪酸欧米茄青藏高原东部土壤样品

Magnetic properties of surface soils across the southern Tarim Basin and their relationship with climate and source materials

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2011年第3期56卷 290-296页

作者： ZAN JinBo FANG XiaoMin nie junsheng YANG ShengLi SONG ChunHui DAI Shuang Center for Basin Resource and Environment Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China Key Laboratory of Western China's Environmental Systems Ministry of Education of China Lanzhou 730000 China College of Geography Science Nanjing Normal University Nanjing 210046 China

The magnetic susceptibility (χ) of surface soils on the Chinese Loess Plateau (CLP) has strong positive correlation with mean annual *** is widely accepted that ultrafine magnetite/maghemite grains produced during pedogenesis are responsible for the enhancement of χ,and loess χ on the CLP has been widely used as a proxy for the intensity of the East Asian summer ***,few works have investigated mechanisms for the enhancement of χ in the case of surface aeolian sediments in westerly-dominated inland China,north of the Tibetan *** detailed rock magnetism and grain size studies of 49 surface samples taken across the southern Tarim Basin for different rainfall/temperature/altitude conditions are *** results show that samples taken from desert have the lowest χ values and that χ of loessic sand and loess samples decreases with increasing *** addition,the rock magnetism studies suggest that the magnetic properties of surface soils across the southern Tarim Basin are mainly controlled by the concentration of coarse aeolian ferrimagnetic *** contribution of ultrafine pedogenically produced magnetic grains to χ is very limited.

关键词：塔里木盆地表层土壤磁学性质中国黄土高原材料气候青藏高原北部岩石磁学

Supra-orbital-timescale variations of goethite content in the Chinese Red Clay sequence

在线全文

学校读者我要写书评

暂无评论

Supra-orbital-timescale variations of goethite content in th...

2017中国地球科学联合学术年会

作者： Rui Zhang junsheng nie Key Laboratory of Western China’s Environmental Systems College of Earth and Environmental Sciences Lanzhou University

Goethite is a common magnetic mineral in soils and holds great potentials in understanding past climatic and environmental *** loess environmental magnetic studies on the Chinese Loess Plateau(CLP)reveal that high goethite content during interglacial periods at orbital timescales,providing framework for interpreting goethite

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

伊犁黄土的磁学性质及其与黄土高原对比

中国科学（D辑） 2010年第1期40卷 61-72页

作者：宋友桂史正涛方小敏 nie junsheng NAOTO Ishikawa 强小科王旭龙中国科学院地球环境研究所黄土与第四纪地质国家重点实验室西安710075 云南师范大学地理科学与旅游学院昆明650092 中国科学院青藏高原研究所北京100085 Jackson School of Geosciences University of Texas at Austin Graduate School of Human and Environmental Studies Kyoto University

近20多年来黄土高原的黄土磁学性质与古气候研究取得了重要进展,极大地推动了东亚古季风演化、亚洲内陆干旱化及过去全球变化的研究,但对亚洲内陆天山地区的黄土磁学性质知之甚少.选择天山伊犁盆地黄土剖面进行了系统的磁性测量,包括磁... 详细信息

近20多年来黄土高原的黄土磁学性质与古气候研究取得了重要进展,极大地推动了东亚古季风演化、亚洲内陆干旱化及过去全球变化的研究,但对亚洲内陆天山地区的黄土磁学性质知之甚少.选择天山伊犁盆地黄土剖面进行了系统的磁性测量,包括磁化率、无磁滞磁化率、高低温磁化率和磁滞参数等,并与黄土高原进行了对比,开展了伊犁黄土的X射线衍射矿物学分析,初步探讨了伊犁黄土磁化率增强的机制.结果表明,伊犁黄土磁性矿物的总含量要远远低于黄土高原,但磁性矿物类型与黄土高原黄土基本类似,以磁铁矿、磁赤铁矿和赤铁矿为主,部分样品还有钛铁矿等.在磁性矿物中磁赤铁矿占的比例总体上要比黄土高原黄土低,而磁铁矿和赤铁矿占的比例比黄土高原黄土要高.磁性矿物的粒度要比黄土高原粗,以准单畴(PSD)和多畴(MD)为主.成壤作用产生的细粒超顺磁体对磁化率的贡献非常有限,粒径为PSD和MD的磁铁矿和磁赤铁矿为伊犁黄土磁化率的主要贡献者.伊犁黄土磁化率增强既有风速论模式(阿拉斯加或西伯利亚黄土成土模式),又有黄土高原超细颗粒成壤模式,但以前一种模式为主导.伊犁黄土磁化率增强除与源区的原生磁性矿物有关以外,还与当地的地形气候环境和地质背景有关.伊犁黄土磁化率增强的机制十分复杂,将磁化率应用古气候的解释时要慎重.

关键词：黄土磁学性质磁化率伊犁盆地黄土高原

柴达木盆地晚中新世河湖相沉积物粒度组成及其古环境意义

在线全文

学校读者我要写书评

暂无评论

第四纪研究 2017年第5期37卷 1017-1026页

作者：聂军胜李曼兰州大学资源环境学院、西部环境教育部重点实验室兰州730000

本文应用沉积物粒度端元分析模型对柴达木盆地怀头他拉剖面开放湖相沉积物进行分离，得到4个具有现实环境意义的端元组分，分别代表4种动力过程。端元1为河流沉积，端元2、3都为湖相沉积，端元4为三角洲沉积。这些成分含量在晚中新世的... 详细信息

本文应用沉积物粒度端元分析模型对柴达木盆地怀头他拉剖面开放湖相沉积物进行分离，得到4个具有现实环境意义的端元组分，分别代表4种动力过程。端元1为河流沉积，端元2、3都为湖相沉积，端元4为三角洲沉积。这些成分含量在晚中新世的变化趋势不明显但变化幅度相对较大，表明柴达木盆地这套地层记录了沉积环境或气候的快速变化。尽管怀头他拉粒度变化趋势总体不明显，然而平均粒径在约8．3～7．0Ma期间有所降低，指示当时亚洲季风可能发生了增强，导致柴达木古湖面积扩大，到达研究站点沉积物的粒度变细。东亚和南亚地区古气候数据合成支持这一推论，由此我们推断亚洲大陆在约8．3～7．0Ma期间气候相对较湿润，是青藏高原隆升的一个直接反应；而7Ma以后气候变干可能反映了大气CO2含量下降的驱动。轨道尺度研究表明柴达木盆地气候在约8．3～7．1Ma期间发生了较大幅度的变化，支持青藏高原隆升是气候变化放大器的观点。

关键词：柴达木盆地端元分析粒度中新世亚洲季风

基于Pecube模型重建青藏高原东南缘临沧花岗岩地区新生代阶段性地貌演化

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

第四纪研究 2022年第3期42卷 637-649页

作者：刘方斌聂军胜兰州大学资源环境学院西部环境教育部重点实验室甘肃兰州730000

基于三维热-动力学数值模拟(Pecube),本研究分别采用稳定地形、高原-稳定地形以及高原-动态地形3种模型重建了青藏高原东南缘临沧花岗岩地区晚始新世以及中中新世时期的地貌演化过程。反演结果揭示了在新生代早期(晚始新世),只有高原-... 详细信息

基于三维热-动力学数值模拟(Pecube),本研究分别采用稳定地形、高原-稳定地形以及高原-动态地形3种模型重建了青藏高原东南缘临沧花岗岩地区晚始新世以及中中新世时期的地貌演化过程。反演结果揭示了在新生代早期(晚始新世),只有高原-稳定地形模拟的结果能够约束研究区冷却-剥露过程,并论证了该时期发生强烈构造抬升的事件,正是因为此次抬升事件,使得高原东南缘地区古高度接近或达到现今状态;中中新世时期,澜沧江侵蚀下切约1 km,对原有的高原地貌进行了进一步改造,从而形成现今的地貌格局。该模型结果验证了青藏高原东南部的构造隆升主要发生在新生代早期,这与侧向挤出模型的预测相一致。

关键词： Pecube 地貌演化晚始新世中中新世临沧地区

Simulation and evaluation study of atmospheric aerosol nonsphericity as a function of particle size

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第7期90卷 281-291页

作者： Qianjun Mao Xin nie School of Urban Construction Wuhan University of Science and TechnologyWuhan430065China College of New Energy and Materials Northeast Petroleum UniversityDaqing163318China

Aerosol nonsphericity causes great uncertainty in radiative forcing assessments and climate *** considerable studies have attempted to quantify this uncertainty,the relationship between aerosol nonsphericity and particle size is usually not considered,thus reducing the accuracy of the *** this study,a coupled inversion algorithm combining an improved stochastic particle swarm optimization algorithm and angular light scattering is used for the nonparametric estimation of aerosol nonsphericity variation with particle size,and the optimal sample selection method is employed to screen the *** on the verification of inversion accuracy,the variation of aerosol aspect ratio with particle size based on the ellipsoidal model in global regions has been obtained from Aerosol Robotic Network(AERONET)data,and the effect of nonsphericity on radiative forcing and dry deposition has been *** results show that the aspect ratio increases with particle size in all regions,with the maximum ranging from 1.4 to 1.8 in the desert,reflecting the differences in aerosol composition at different particle *** radiation calculations,considering aerosol nonsphericity makes the aerosol cooling effect weaker and surface radiative fluxes increase,but hardly changes the aerosol absorption,with maximum differences of 9.22%and 22.12%at the bottom and top of the atmosphere,***,the differences in radiative forcing between aspect ratios as a function of particle size and not varying with particle size are not significant,averaging less than 2%.Besides,the aspect ratio not varying with particle size underestimates the deposition velocity of small particles and overestimates that of large particles compared to that as a function of particle size,with maximum differences of 7%and 4%,respectively.

关键词： Aerosol nonsphericity Inversion Aspect ratio Radiative forcing Dry deposition velocity

A review of recent advances in red-clay environmental magnetism and paleoclimate history on the Chinese Loess Plateau

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A review of recent advances in red-clay environmental magnet...

Remanence unmixing reveals late Miocene-early Pleistocene paleoclimate history in the Zhada Basin, southwestern Tibet

2016中国地球科学联合学术年会

作者： junsheng nie Yougui Song John W.King Jinbo Zan Joel Saylor Key Laboratory of Western China’s Environment System (Ministry of Education) College of Earth and Environmental Sciences State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of Sciences Graduate School of Oceanography University of Rhode Island Institute of Tibetan Plateau Research Chinese Academy of Sciences Department of Earth and Atmospheric sciences University of Houston

＜正＞The late Miocene-Pliocene deposited red-clay sequence on the Chinese Loess Plateau is encoded with important information of past climate ***,in comparison to the overlying Pleistocene loesspaleosol sequence,it h...

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Remanence unmixing reveals late Miocene-early Pleistocene pa...