检索结果-南通市图书馆

Mineralogy, geochemistry and age dating of shear zone-hosted Nb-Ta-, Zr-Hf-, Th-, U-bearing granitic rocks in the Ghadir and El-Sella areas, South Eastern Desert, Egypt

引用

Chinese Journal Of Geochemistry 2011年第4期30卷 453-478页

作者： Ali M.A. lentz D.R.2 Nuclear Materials Authority Depatment of geology University of New Brunswick

The rare metal minerals of mineralized altered granites within the Ghadir and El-Sella shear zones, are represented by betafite, U-minerals (uraninite and uranophane), zircon, monazite, xenotime, and rutile in the Ghadir shear zone. While they are columbite-tantalite minerals as ferrocolumbite, pyrochlore, and fergusonite, Th-minerals (cheralite, uranothorite, and huttonite monazite), Hf-zircon, monazite and xenotime in the El-Sella shear zone. Hf-zircon in the El-Sella and Ghadir shear zones (increasing from the core to the rim) contains high inclusions of U-Th, and REE minerals such as cheralite, uranothorite, huttonite monazite and xenotime especially in the El Sella shear zone. The rare-metal minerals, identified from peralkminous granites of the shear zones are associated with muscovite, quartz, chlorite, fluorite, magnetite, and biotite that are restricted to the two shear zones. Uraninite (low Th content) occurring in the Ghadir shear zone indicates the hydrothermal origin, but there are thorite, uranothorite, cheralite, and Hf-zircon in the El Sella shear zone, also indicating the hyrothermal proccess after magmatic origin. Compositional variations of Ta/(Ta+Nb) and Mn/(Mn+Fe) in columbite from 0.07-0.42 and 0.04-0.33, respectively, and Hf contents in zircon are so high as to be 12%, especially in the rim in the El Sella shear zone. This feature re-flects the extreme degree of magmatic fractionation. Four samples from the altered granites of the Ghadir shear zone also are very low in TiO2 (0.04 wt%-0.17 wt%), Sr [(82-121)×10-6], and Ba [(36-380)×10-6], but high in Fe2O3T (0.46 wt%-0.68 wt%), CaO (0.64 wt%-1.23 wt%), alkalis (8.59 wt%-8.88 wt%), Rb [(11-203)×10-6], Zr [(98-121)×10-6], Nb [(9-276)×10-6], Ta [(2-139)×10-6], U [(14-63)×10-6], Th [(16-105)×10-6], Pb [(13-32)×10-6], Zn [(7-8)×10-6], Y [(15-138)×10-6], Hf [(3-9)×10-6], and ∑REE [(81-395)×10-6, especially LREE [(70-322)×10-6]. They are very high in Zr/Hf (15.07-85.96) and Nb/Ta (7.17-21.48), and low

关键词：剪切带矿物学花岗岩钽矿物锆石钽铌地球化学蝶

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mineralogy and geochemistry of Nb-,Ta-,Sn-,U-,Th-,and Zr-bearing granitic rocks from Abu Rusheid shear zones,South Eastern Desert,Egypt

引用

Chinese Journal Of Geochemistry 2011年第2期30卷 226-247页

作者： Ali M.A. lentz D.R. Hall D.C. Nuclear Materials Authority P.O.530.El MaadiCairoEgypt Department of Geology New Brunswick UniversityUNBCanada Microscopy and Microanalysis Facility New Brunswick UniversityUNBCanada

Granite-hosted,Nb-,Ta-,Sn-,U-,Th-,and Zr(Hf)-bearing mineralization from the Abu Rusheid shear zones occurs about 97 km southwest of the town of Marsa Alam,South Eastern Desert,*** SSE-trending brittle-ductile Abu Rusheid shear zones crosscut the peralkalic granitic gneisses and cataclastic to mylonitic rocks(mylonite,protomlyonite,and ultramylonite).The northern shear zone varies in width from 1 to 3 m with a strike length of >500 m,and the southern shear zone is 0.5 to 8 m wide and >1 km *** shear zones locally host less altered lamprophyre and locally sheared granitic aplite-pegmatite *** rare-metal minerals,identified from the peralkalic granitic gneisses and cataclastic to mylonitic rocks are associated with muscovite,chlorite,quartz,fluorite,pyrite,magnetite,and rare biotite that are restricted to the Abu Rusheid shear zones;these are columbite-tantalite and pyrochlore(***) in the northern shear zone and ferrocolumbite in the southern shear *** occurs as inclusions in the columbite-tantalite minerals.U-and Th-minerals(uraninite,thorite,uranothorite,ishikawaite,and cheralite) and Hf-rich zircon ***(?) zircon contains numerous inclusions of rutile,fluorite,U-Th and REE minerals,such as uranothorite,cheralite,monazite,and *** variations in Ta/(Ta+Nb) and Mn/(Mn+Fe) in columbite range from 0.07-0.42 and 0.04-0.33,respectively,and Hf contents in zircon from 1.92-6.46 of the two mineralized shear zones reflect the extreme degree of magmatic *** samples of peralkalic granitic gneisses and cataclastic to mylonitic rocks from the southern shear zone have very low TiO2(0.02 wt%-0.04 wt%),Sr [(15-20)×10-6],and Ba [(47-78)×10-6],with high Fe2O3T(0.94 wt%-1.99 wt%),CaO(0.14 wt%-1.16 wt%),alkalis(9.2 wt%-10.1 wt%),Rb [(369-805)×10-6],Zr [(1033-2261)×10-6],Nb [(371-913)×10-6],U [(51-108)×10-6],Th [(36-110)×10-6],Ta [(38-108)×10-6],Pb [(39-364)×10-6],Zn [(21-424)×10-6],Y [(8-304)×10-6],Hf

关键词： uranium thorium zircon columbite-tantalite fluorite monazite xenotime age dating granitic gneisses South Eastern Desert Egypt

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Emissions and noise mitigation through use of electric motorcycles

引用

Transportation Safety and Environment 2019年第2期1卷 164-175页

作者： Michael Hernandez Kara M.Kockelman James O.lentz Jooyong Lee Department of Civil Architecturaland Environmental EngineeringThe University of Texas at Austin301 E Dean KeetonECJSuite 6.9AustinTX 78712-1076USA

Gasoline-powered motorcycles contribute disproportionately to traffic noise and emissions,so motorcycle electrification merits *** advances in battery efficiency allow electric motorcycles(EMCs)to join electric cars and bicycles as a viable consumer *** study quantifies noise and emissions using both simulations and experimental data,examines the factors that make motorcycles big offender and uses popular EMC makes and models to estimate the costs and benefits of electrification in the *** produce more CO,CH4,NOx,HC and particulate matter per vehicle-mile travelled than passenger *** to limited regulation of motorcycles and weak enforcement,the perceived noise level of motorcycles exceeds that of most other vehicles,being roughly double those of automobiles at speeds of over 30 mph and surpassing even those of medium trucks and buses at speeds of over 50 mph,at which point motorcycles exceeds the 80 dBA US standard *** can resolve such issues,although range limitations and high prices are presently a barrier to widespread *** order to realize these environmental benefits,it is important that electrification occurs with a corresponding shift away from coal as an energy *** emission regulations and stronger enforcement of existing prohibitions on certain forms of customization could also reduce the outlier status of gasoline-powered motorcycles.

关键词： motorcycles electric motorcycles motorcycle emissions motorcycle sound emissions electrification

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

New Insights into Neoproterozoic–Cretaceous Events in the Mamfe Basin(SW Cameroon,Central Africa):Evidence from Textural Analyses,U-Th Composition,and U-Pb Zircon Geochronology from Granitic Basement

引用

Journal of Earth Science 2021年第6期32卷 1472-1484页

作者： Nguo S.Kanouo Arnaud P.Kouské David R.lentz Rose F.Yongué Mineral Exploration and Ore Genesis Unit Department of Mining Engineering and Mineral ProcessingFaculty of Mines and Petroleum IndustriesUniversity of MarouaMaroua Kangola 46Cameroon Department of Civil Engineering the University Institute of TechnologyUniversity of DoualaDouala 8698Cameroon Department of Earth Sciences University of New BrunswickNew BrunswickE3B 5A3Canada Department of Earth Sciences University of YaoundéYaoundé812Cameroon

Backscattered electron BSE-CL images,U-Th abundance,and U-Pb ages were obtained for zircons from the Nkogho granitic basement rocks cropping out in the Mamfe Basin(SW Cameroon).These data are used to characterize and classify each zircon,elucidate their geochemical *** were also used to formulate a model of their host composition to ascertain the source,and document any preserved postemplacement *** zircons mainly form long to short prisms that are pyramidal to dipyramidal in *** typically exhibit complex oscillatory growth zoning,as well as exhibit sector *** features are mainly compatible with igneous zircons,although a few examples have metamorphic *** U(30 ppm–6380 ppm),Th(4 ppm–1280 ppm),and Pb(12 ppm–648 ppm)contents show core to rim variations with most values fall within the range of crustal granitic *** Th/U ratios(0.08–1.23),with core to rim differences mainly encompass values typical of magmatic zircons with a few values characterizing metamorphic zircons that grew in equilibrium with an anatectic *** U-Pb ages(108.4±1.7 to 988.4±19.0 Ma)with some core and rim age differences date Early Neoproterozoic,Cryogenian–Ediacarian,Early Cambrian–Ordovician,Devonian–Carboniferous,and Aptian–Albian *** arc-like Nkogho I-type granitoid crystallized from granitic magma during Cryogenian to Ediacarian times and was later affected by post-Ediacarian Cambrian to Albian magmatic ***–Albian ages probably reflect opening of the Mamfe Basin.

关键词： Cameroon Mamfe Basin granitoid zircon U-Pb age U/Th

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Geochemical and Nd-Sr Isotopic Compositions of Hypabyssal Adakites in the Torud-Ahmad Abad Magmatic Belt,Northern Central Iran Zone:Analysis of Petrogenesis and Geodynamic Implications

引用

Journal of Earth Science 2021年第6期32卷 1428-1444页

作者： Fazilat Yousefi Ryan D.Mills Mahmoud Sadeghian David R.lentz Christina Wanhainen Habibollah Ghasemi Laicheng Miao Department of Earth Sciences University of New BrunswickFrederictonCanada Department of Geological Sciences University of North Carolina at Chapel HillChapel HillUSA Faculty of Earth Sciences Shahrood University of TechnologyShahroodIran Department of Civil Environmental and Natural Resources EngineeringLulea University of TechnologyLuleaSweden Institute of Geology and Geophysics Chinese Academy of SciencesBeijing100029China

Eocene intermediate to felsic subvolcanic rocks of the Torud-Ahmad Abad magmatic belt(TAMB),in the northern part of the Central Iran zone,are exposed between the Torud and Ahmad Abad regions in South-Southeast *** igneous rocks include hypabyssal dacite,trachyte,andesite,trachy-andesite,and basaltic andesite;they are mainly composed of phenocrysts and microcrystalline groundmass of pyroxene,amphibole,and plagioclase,with minor biotite and titanomagnetite;they form domal structures(plugs and stocks),dikes,and sills that intruded into Neoproterozoic to cogenetic Eocene volcano-sedimentary *** on isotopic analysis of these intermediate to acidic rocks,initial ratios of^(143)Nd/^(144)Nd range from 0.512775 to 0.512893 and initial ratios of^(87)Sr/^(86)Sr range from 0.703746 to 0.705314,with quite positiveε_(Nd(i))values of+3.69 to+*** are enriched in light rare earth elements and large ion lithophile elements and depleted in heavy rare earth elements and high-field strength elements,the SiO_(2) content is(52-62)wt.%,and Na_(2)O content>3 wt.%,Al_(2)O_(3) content>16 wt.%,Yb<1.8 ppm,and Y<18 *** geological,geochemical,and Sr and Nd isotopic data are consistent with adakitic signatures originating by partial melting of the subducted Neo-Tethys oceanic slab(Sabzevar branch)and lithospheric suprasubduction zone *** mantle signatures typifying the rapidly emplaced adakitic rocks(slab(high-silica adakite)and suprasubduction zone(low-silica adakite)melts)together with their locally voluminous extent are evidences that support a locally extensional geodynamic setting;and the evidence is consistent with an evolution to local transpression in the Late Eocene in this convergent margin are environment to rifting(basalts to adakites)towards submarine conditions in the Neogene.

关键词： isotope geochemistry adakite rocks Central Iran zone Shahrood Iran

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

压汞法测量玻璃毛细孔中的水和正癸烷

引用

物理化学学报 1992年第1期8卷 109-112页

作者：周亚平 lentz H. 天津大学化学系天津300072 西德Siegen大学化学系

水在固体表面或在毛细孔玻璃中的性质,一直是人们感兴趣的问题。而靠近固体表面的水,其性质不同于体相(Bulk)水,也是为人所知的事实。已经知道,邻近水的热容、密度、粘度、电导及结构等都不同于体相水。但邻近水的厚度究竟为多少,或者说... 详细信息

水在固体表面或在毛细孔玻璃中的性质,一直是人们感兴趣的问题。而靠近固体表面的水,其性质不同于体相(Bulk)水,也是为人所知的事实。已经知道,邻近水的热容、密度、粘度、电导及结构等都不同于体相水。但邻近水的厚度究竟为多少,或者说,这种固体表面对水的性质影响究竟是长程的还是短程的,目前还没有统一的结论。用压汞法测量多孔物质的孔体积,是人们已熟知的方法,但还没有人将其用于测量液体在毛细孔中的体积、密度等行为。我们尝试了用压汞法,测量具有确定孔径的毛细孔玻璃(CPG),在吸附了不同量水后孔体积的变化,进而计算了不同吸附层的水在CPG中的体积、密度。此外还测定了载有不同量正癸烷后,CPG孔体积的变化。

关键词：毛细孔玻璃水正癸烷压汞法

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Methods for the development and assessment of atrial fibrillation and heart failure dog models

引用

Journal of Geriatric Cardiology 2011年第3期8卷 133-140页

作者： Jon F Urban Renee L Gerhart Jason R Krzeszak Corey R Leet Linnea R lentz Carolyn B McClay Medtronic Inc. 710 Medtronic Parkway MS C200 Minneapolis MN 55432-5604 USA

Objective To report Medtronic experiences with the development of animal models for atrial fibrillation （AF） and chronic heart failure （CHF） using high-rate pacing for AF and microemboli for CHF. Methods For the AF model, an atrial lead was attached to a Medtronic SynergyTM neurostimulator, which was programmed to stimulate at 50 Hz in an on-off duty cycle. Atrial natfiuretic peptide （ANP）, brain natriuretic peptide （BNP） and N-terminal pro brain nalriuretic peptide （NT-proBNP） were assayed at select time points. For CHF model, a serial injection of 90 μm polystyrene microspheres at 62,400 beads/mL （Polybead, Polysciences, Inc.） was performed to induce global ischemia, either with weekly monitoring and embolization schedule （group 1, n = 25） or with biweekly monitoring and emboliation schedule （group 2, n = 36 ）. Echocardiograms were used along with ventriculograms and magnetic resonance imaging scans weekly to assess cardiac function and ANP, BNP and NT-proBNP were monitored. Results For the AF model, the days to sustained AF for four animals following surgery were 7, 25, 21 and 19, respectively; For the CHF model, the days to meet CHF endpoints were 116 in group 1 and 89 in group 2. For both AF and CHF models, NT-proBNP correlated well with the development of disease states. Conclusion Our experience for the development and assessment of AF and CHF dog models may help researchers who are in search for animal model for assessing the safety and efficacy of a device-based therapy.

关键词： atrial fibrillation congestive heart failure biological markers dog models microembolism

来源：

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 STUDY OF DETERMINING MICROPORE VOLUME OF ACTIVATED CARBON BY MERCURY POROSIMETRY

引用

Transactions of Tianjin University 1997年第1期3卷 40-44页

作者：周亚平 H.lentz 天津大学化学系德国Siegen大学

The Micro pore volume in porous materials usually interests many researchers. However, there has been few, if not, direct method to determine it. A strategy of combining mercury porosimetry with pre adsorption is proposed in the present paper. The total pore volume in activated carbon is determined through direct measurements for the first time. The application scope of mercury porosimetry is also enlarged. Besides, the present experiments also confirmed the preference of adsorption to the smaller pores even in the range of meso and macro pores.

关键词： mercury porosimeter distribution of pore sizes micro pore volume activated carbon

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

如何使移动学习内容适用于多种设备

引用

中国远程教育 2012年第20期 97-98页

作者： Michelle lentz&Brandon Carson 殷蕾(译) 不详北京开放大学

在改计移动学习内容时，应多追问几个为什么：为什么要开发移动课程？这个课程是否有必要在移动设备上展开？为什么需要在特定的设备上运行？用户在使用你设计的产品时的心态与所期待的体验是什么？当他们访问内容时会想些什么？

关键词：学习内容移动设备课程

来源：

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

Molecular Integrators of Neuropathy and Pain in Diabetes Mellitus

引用

生物化学与生物物理进展 2014年第9期41卷 851-859页

作者： STOYANOV Stoyan B. lentz Soren L. VALDES-HERRERA Jose P. KRASTEV Nikolai S. KRASTEV Dimo S. Pathophysiology of Dementia German Centre for Neurodegenerative Diseases Magdeburg 39120 Germany Molecular Neuroplasticity German Centre for Neurodegenerative Diseases Magdeburg 39120 Germany Department of Anatomy Medical Academy of Sofia Sofia 1000 Bulgaria

Glycation of nucleotides, proteins and phospholipids contributes to the development of late diabetic complications,including the most debilitating one——diabetic neuropathy. Reactive intermediates of AGE formation such as glyoxal, methylglyoxal(MG) and other dicarbonyls are detoxified by the glyoxalase-system. However little is known about the regulation and nature of the mechanisms underlying neuropathology. Therefore we decided to focus on the role of MG-glyoxalase 1(GLO-1) system in modulation of painful diabetic neuropathy.

关键词：摘要编辑部编辑工作读者

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：