检索结果-南通市图书馆

Petrogenesis of early Yanshanian highly evolved granites in the Longyuanba area,southern Jiangxi Province:Evidence from zircon U-Pb dating,Hf-O isotope and whole-rock geochemistry

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2013年第5期56卷 922-939页

作者： TAO JiHua li WuXian li xianhua CEN Tao State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of Sciences Graduate University of Chinese Academy of Sciences State Key Laboratory of lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences

Early Yanshanian(Jurassic) granitoids are widespread in the Nanling Range,South *** large granitic batholiths commonly crop out in the center of the Nanling Range(corresponding geographically to the central and northern parts of Guangdong Province),many small stocks occur in the southern part of Jiangxi *** of the small stocks are associated closely with economically significant rare-metal deposits(W,Sn,Nb,Ta).Here we report the results for biotite granites and two-mica granites from three Yanshanian stocks of the Longyuanba ***-ICPMS U-Pb dating of zircon yields an age of 156.1±2.1 Ma for Xiaomubei biotite granite,and U-Pb zircon dating using SIMS yields an age of 156.7±1.2 Ma for Longyuanba-Chengjiang biotite granite and 156.4±1.3 Ma for Jiangtoudong two-mica *** granites are silica-rich(SiO 2 =70%-79%),potassic(K 2 O/Na 2 O>1.9),and peraluminous(ASI=1.05-1.33).Associated samples are invariably enriched in Rb,Th,Pb and LREE,yet depleted in Ba,Nb,Sr,P and Ti,and their REE pattern shows a large fractionation between LREE and HREE((La/Yb) N =10.7-13.5) and a pronounced Eu negative anomaly(δEu=0.28-0.41).Two-mica granite samples are also silica-rich(SiO 2 =75%-79%),potassic(K 2 O/Na 2 O>1.2),and peraluminous(ASI=1.09-1.17).However,in contrast to the biotite granites,they are more enriched in Rb,Th,Pb and extremely depleted in Ba,Nb,Sr,P and Ti,and exhibit nearly flat((La/Yb) N =0.75-1.08) chondrite-normalized REE patterns characterized by strong Eu depletion(δEu=0.02-0.04) and clear tetrad effect(TE 1.3 =1.10-1.14).Biotite granites and two-mica granties have comparable Nd isotopic signatures,and their εNd(t) are concentrated in the 13.0 to 9.6 and 11.5 to 7.7 *** zircon Hf-O isotopes of both also show similarity(biotite granites:εHf(t)= 10.8-7.9,δ 18 O=7.98‰-8.89‰ and εHf(t)= 13.8 to 9.1,δ 18 O=8.31‰-10.08‰;two-mica granites:εHf(t)= 11.3 to 8.0,δ 18 O=7.91‰-9.77‰).The results show that both biotite and two-mica gra

关键词： highly evolved tetrad effect granite early Yanshanian southern Jiangxi Province

同方期刊数据库

在线全文

学校读者我要写书评

暂无评论

可侧摆腱驱五指灵巧手的设计与仿真

佳木斯大学学报（自然科学版） 2024年第2期42卷 14-18,35页

作者：蔡钰李宪华杜鹏飞邱洵安徽理工大学人工智能学院安徽淮南232001

为了实现五指灵巧手对多种物体稳定抓取的目的,针对灵巧手结构复杂、成本高等问题,提出了一种基于蜗轮蜗杆驱动的手指侧摆方案,设计了一种以腱绳作为传动方案的仿人型五指灵巧手,具有驱动简单、质量轻、成本低等优点;利用D-H法建立了灵... 详细信息

为了实现五指灵巧手对多种物体稳定抓取的目的,针对灵巧手结构复杂、成本高等问题,提出了一种基于蜗轮蜗杆驱动的手指侧摆方案,设计了一种以腱绳作为传动方案的仿人型五指灵巧手,具有驱动简单、质量轻、成本低等优点;利用D-H法建立了灵巧手指的运动学模型;且利用MATLAB的机器人工具箱,分析了手指的工作空间;利用ADAMS软件创建五指灵巧手的虚拟模型,分析了此单腱欠驱动灵巧手设计的有效性和抓取可行性。

关键词：灵巧手结构设计运动学腱驱动工作空间 ADAMS仿真

Zircon Xenocrysts from the Shaka Ridge Record Ancient Continental Crust:New U-Pb Geochronological and Oxygen Isotopic Data

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2022年第1期33卷 5-16页

作者： Sergey G.Skublov Natalia A.Rumyantseva Qiuli li Boris G.Vanshtein Dmitriy I.Rezvukhin xianhua li Institute of Precambrian Geology and Geochronology of Russian Academy of Sciences St.Petersburg 199034Russia Saint Petersburg Mining University St.Petersburg 199106Russia Institute for Geology and Mineral Resources of the World Ocean(VNIIOkeangeologia) St.Petersburg 190121Russia State Key Laboratory of lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Sobolev Institute of Geology and Mineralogy Siberian Branch of the Russian Academy of SciencesNovosibirsk 630090Russia

Over the past two decades, a significant number of discoveries of ancient zircon xenocrysts in ocean-floor magmatic rocks have been reported. These findings provide compelling evidence for the presence of ancient continental crust within young oceanic lithosphere. Almost all finds of ancient zircon xenocrysts within oceanic crust are from the Mid-Atlantic Ridge. For other localities, however, similar data are very limited. This report presents the first age determinations(U-Pb, SHRIMPII) and isotope-geochemical data(oxygen, trace and rare earth elements) for zircon xenocrysts from gabbro-diorites of the Shaka Ridge, in the vicinity of the Shaka fracture zone, near the western end of the Southwest Indian Ridge. The work is based on a study of bottom rock material dredged during expeditionary research on the R/V"Akademik Fedorov"(Russia) in 2016. The U-Pb isotope system of the zircon xenocrysts recorded a crystallization age of ~2.8 Ga at an upper discordia intercept and an age of ~600 Ma interpreted as the timing of a superimposed thermal event at a lower discordia *** zircon xenocrysts show geochemical signatures of magmatic origin, i.e., fractionated REE distribution spectra with an increase in chondrite-normalized values from light to heavy REE, positive Ce anomalies and negative Eu anomalies, and high Th/U ratios(0.59-7.77). In discrimination diagrams based on a series of inter-element relationships, zircon compositions fall into the fields of zircons from rocks of continental crust, mostly granitoids. The li content of the zircons is high(1.8 ppm-50 ppm),adding further evidence to their derivation from rocks of continental crust. During their residence within young oceanic crust, the zircon xenocrysts experienced alterations under the influence of submarine high-temperature hydrothermal fluids, which selectively affected the distribution of trace elements in the zircons and reduced the δ;O values to 1.75‰-3.15‰. The presence of obviously older zircons

关键词： zircon U-Pb geochronology oxygen isotopes trace elements rare earth elements Shaka Ridge South Atlantic Southwest Indian Ridge

Dynamic simulation of the tractor HMCVT under typical working conditions based on AMESim

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2022年第2期15卷 102-110页

作者： Maohua Xiao Yuanfang Zhao xianhua li Ghulam Hussain Shengjie Wang Yejun Zhu College of Engineering Nanjing Agricultural UniversityNanjing 210031China Key Laboratory of Modern Manufacturing Technology Guizhou UniversityGuiyang 550025China Faculty of Mechanical Engineering Ghulam Ishaq Khan Institute of Engineering Sciences&TechnologyTopi23460Pakistan Jiangsu Yueda Intelligent Agricultural Equipment Co. Ltd.Yancheng 224004JiangsuChina

In order to study the dynamic characteristics of hydro-mechanical continuously variable transmission(HMCVT)under ploughing and sowing conditions,a complete simulation model of HMCVT is established based on AMESim software,including mechanical transmission model,pump controlled hydraulic motor speed control model and section changing hydraulic system *** addition,the dynamic model of tractor is *** order to verify the correctness of the simulation model,a test-bed is *** test of tractor running speed and the test of pump controlled hydraulic motor system were carried out on the *** test results show that the simulation model of pump control hydraulic system can correctly reflect the change of transmission ratio of pump controlled hydraulic motor,and the simulation model can reflect the actual working condition change of ***,the correctness of the previous simulation model based on AMESim is *** on the simulation model established by AMESim,the dynamic characteristics of HMCVT under ploughing and sowing conditions are *** results show that:Under ploughing condition,the planetary platoon will have strong impact at the moment of throttle opening and changing *** sowing condition,the HMCVT will have a great impact at the time of variable cross section,but the variation range of rodent force decreases and the changing trend tends to be stable.

关键词： tractor HMCVT AMESim dynamics simulation test

Shoshonitic intrusive suite in SE Guangxi: Petrology and geochemistry

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

Chinese Science Bulletin 2000年第7期45卷 653-659页

作者： li xianhua ZHOU Hanwen liU Ying LEE Chi-yu SUN Min CHEN Chenhong Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640China Department of Earth Sciences University of Hong KongPokfulam RoadHong KongChina Department of Geology Taiwan UniversityTaipei 106-17China

A NE-direction Mesozoic shoshonitic intrusive s黫te in SE Guangxi has been identified in terms of geological, petrological and geochemical investigations. The shoshonitic intrusives are characterized by enrichment of liLE, HFSE and LREE and no obvious Nb-Ta depletion, similar to those potassic rocks formed in within-plate and rifting environments. Unlike most shoshonitic rocks forming in arc settings, the SE Guangxi shoshonitic intrusives were likely generated during regional lithosphere extension induced by upwelling of asthenosphere mantle.

关键词： shoshonitic rocks petrology element geochemistry Guangxi.

Age of granulite from Huangtuling, Dabie Mountain:Pb-Pb dating of garnet by a stepwise dissolution technique

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第10期44卷 941-944页

作者： Hanwen Zhou xianhua li Ying liu Zhendong You Shutian Suo Zengqiu Zhong Chinese Acad Sci Guangzhou Inst Geochem Canton 510640 Peoples R China China Univ Geosci Dept Geol Wuhan 430074 Peoples R China

A new stepwise dissolution scheme, involving acids with different properties, enables the selective recovery of radiogenic and common Pb from a mineral, and makes single-mineral Pb-Pb dating possible. Garnet from a granulite sample from Huangtuling, northern Dabie Mountain yields a Pb-Pb isochron age of (1098 ± 35) Ma, which is interpreted as the timing of peak metamorphism of granulite facies.

关键词： garnet stepwise dissolution technique Pb-Pb isochron age dating of metamorphic rocks granulite Dabie Mountain.

In situ U-Pb dating of titanite by LA-ICPMS

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第20期57卷 2506-2516页

作者： SUN JinFeng YANG JinHui wu FuYuan XIE lieWen YANG YueHeng liU ZhiChao li xianhua State Key Laboratory of lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Graduate University of the Chinese Academy of Sciences Beijing 100049China

Titanite is an ideal mineral for U-Pb isotopic dating because of its relatively high U,Th and Pb ***,we developed a technique for U-Pb dating of titanite using the 193 nm ArF laser-ablation system and Agilent 7500a *** of titanite (BLR-1 and OLT-1) and zircon (91500 and GJ-1) were dated using single spot and line raster scan analytical *** check the matrix effect,titanite (BLR-1) and zircon (91500) standards were analyzed as the external *** weighted mean 206 Pb/238 U ages of OLT-1 titanite are 1015±5 Ma (2,n=24) and 1017±6 Ma (2,n=24) by single spot and line raster scan analyses,respectively,using BLR-1 titanite as the external *** ages are consistent with its reference age of about 1014 ***,using 91500 zircon as the external standard,the weighted mean 206 Pb/238 U ages are 917±4 Ma (2,n=24) and 927±5 Ma (2,n=24) for BLR-1 titanite,and 891±4 Ma (2,n=24) and 901±5 Ma (2,n=24) for OLT-1 titanite by single spot and line raster scan analyses,*** is evident that these ages are ～12% younger than their reference *** results reveal that significant matrix effect does exist between different kinds of minerals during LA-ICPMS U-Pb age determination,whereas it is insignificant between same ***,same mineral must be used as the external standard for fractionation corrections during in situ LA-ICPMS U-Pb age *** addition,we determined U-Pb ages for titanites from the Early Cretaceous Fangshan pluton,which indicates a rapid cooling history of this pluton.

关键词： LA-ICPMS U-Pb定年 U-Pb年龄测定原位榍石光栅扫描基体效应加权平均

Petrogenesis of the Neopro-terozoic bimodal volcanic rocks along the western margin of the Yangtze Block:New constraints from Hf isotopes and Fe/Mn ratios

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

Chinese Science Bulletin 2005年第21期50卷 2481-2486页

作者： li xianhua QI Changshi liU Ying liANG Xirong TU Xianglin XlE liewen YANG Yueheng Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China Graduate University of Chinese Academy of Sciences Beijing 100039 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

High-precision major element and Hf isotope data are reported for the Neoproterozoic Suxiong volcanic rocks along the western margin of the Yangtze Block. These volcanic rocks have variable εHf(T) values and Fe/Mn ratios. The relatively primitive basalts have high Fe/Mn ratios and high Hf-Nd isotopic compositions, indicating that they were generated by partial melting of garnet clinopyroxene in mantle plume at high pressure. Thus, the Suxiong basalts are genetically related to the proposed Neoproterozoic super-plume. On the contrary, a few differentiated basalts have low Fe/Mn ratios and low Hf-Nd isotopic compositions. They are likely to experience assimilation-fractional crystallization process. The Suxiong rhyolites have consistent Hf and Nd model ages of 1.3―1.4 Ga. They are likely generated by shallow dehydration melting of pre-existing young arc igne-ous rocks associated with the basaltic underplating/intrusion in a continental rift.

关键词：火山岩页岩同位素玄武岩岩石学

在线全文

学校读者我要写书评

暂无评论

柳树丛枝病感病植株内源激素含量变化研究

陕西农业科学 2024年第8期70卷 109-112页

作者：哈琦琦孙玉洁徐奕琳李鲜花榆林学院生命科学学院陕西榆林719000

为探究植原体诱发的柳树丛枝病病株内源激素含量的变化,为柳树丛枝病的致病机理及防治提供理论依据。本研究以垂柳和旱柳为试验材料,采用LC-MS/MS法检测丛枝病病株和健株叶片中四大类13种植物激素的含量变化情况。结果表明,两种柳树病... 详细信息

为探究植原体诱发的柳树丛枝病病株内源激素含量的变化,为柳树丛枝病的致病机理及防治提供理论依据。本研究以垂柳和旱柳为试验材料,采用LC-MS/MS法检测丛枝病病株和健株叶片中四大类13种植物激素的含量变化情况。结果表明,两种柳树病株与健株相比,ABA和CTK类激素DZ、6-BA显著增加,生长素类激素NAA、IPA和GA类激素GA-3、GA-4、GA-7显著减少。柳树被植原体侵染后其内源激素含量剧烈变化,从而导致柳树出现丛枝、腋芽丛生等症状。

关键词：柳树丛枝病内源激素液相色谱串联质谱法