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The Rise of Asian Defense Diplomacy:Convergence or Divergence in Sino-Australian Security Relations? 被引量:2
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作者 Brendan Taylor 《Contemporary International Relations》 2011年第3期169-185,共17页
The rise of multilateral defense diplomacy in Asia is an important new phenomenon.In addition to the newly established ADMM+ process and the Shangri-La Dialogue(SLD) ,ASEAN defense ministers,ASEAN chiefs of defense an... The rise of multilateral defense diplomacy in Asia is an important new phenomenon.In addition to the newly established ADMM+ process and the Shangri-La Dialogue(SLD) ,ASEAN defense ministers,ASEAN chiefs of defense and ASEAN chiefs of intelligence are now all meeting on a regular basis.Such gatherings were almost unthinkable as recently as a decade ago.This paper seeks to interpret these developments and their implications for the Sino-Australian security relationship.It argues that while these recent developments appear to reflect a deepening of Asian security cooperation,they are actually a manifestation of an intensifying institutional competition,namely between the ASEAN-centered ADMM and the Western-backed SLD.This,in turn,is symptomatic of a broader institutional contestation——reflecting underlying strategic competition——which is becoming a distinctive feature of Asia's emerging security ‘architecture.’ The paper goes on to argue that China and Australia find themselves on opposite sides of this competition and,particularly in the area of defense diplomacy,are likely to become increasingly important players in fuelling it.The paper concludes by observing why such a dynamic is potentially problematic and offers a modest set of policy recommendations designed to assist Beijing and Canberra in addressing and alleviating their competitive tendencies. 展开更多
关键词 安全 亚洲 防务 分歧 收敛 香格里拉 体系结构 澳大利亚
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The current status of nitrogen fertiliser use efficiency and future research directions for the Australian cotton industry 被引量:7
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作者 MACDONALD Ben C.T. LATIMER James O. +2 位作者 SCHWENKE Graeme D. NACHIMUTHU Gunasekhar BAIRD Jonathan C. 《Journal of Cotton Research》 2018年第3期41-50,共10页
Fifty years of sustained investment in research and development has left the Australian cotton industry well placed to manage nitrogen(N) fertiliser. The average production in the Australian cotton industry today is... Fifty years of sustained investment in research and development has left the Australian cotton industry well placed to manage nitrogen(N) fertiliser. The average production in the Australian cotton industry today is greater than two tonnes of lint per hectare due to improved plant genetics and crop management. However, this average yield is well below the yield that would be expected from the amount of N fertiliser used. It is clear from the recent studies that across all growing regions, conversion of fertiliser N into lint is not uniformly occurring at application rates greater than 200-240 kg·hm;of N. This indicates that factors other than N availability are limiting yield, and that the observed nitrogen fertiliser use efficiency(NFUE) values may be caused by subsoil constraints such as sodicity and compaction. There is a need to investigate the impact of subsoil constraints on yield and NFUE.Gains in NFUE will be made through improved N fertiliser application timing, better targeting the amount of fertiliser applied for the expected yield, and improved soil N management. There is also a need to improve the ability and confidence of growers to estimate the contribution of soil N mineralisation to the crop N budget. Many Australian studies including data that could theoretically be collated in a meta-analysis suggest relative NFUE values as a function of irrigation technique; however, with the extensive list of uncontrolled variables and few studies using non-furrow irrigation, this would be a poor substitute for a single field-based study directly measuring their efficacies. In irrigated cotton, a re-examination of optimal NFUE is due because of the availability of new varieties and the potential management and long-term soil resilience implications of the continued removal of mineralised soil N suggested by high NFUE values. NFUE critical limits still need to be derived for dryland systems. 展开更多
关键词 Nitrogen fertiliser Nitrogen use efficiency DRYLAND IRRIGATED
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Donald V.Helmberger,the master mentor:Testimonials from former international students
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作者 Xiaodong Song Sidao Ni +6 位作者 Ying Tan Alex Song Risheng Chu Daoyuan Sun Shengji Wei Semechah Lui Voon Hui Lai 《Earthquake Science》 2022年第1期67-70,共4页
Don trained many Ph.D.students over the〜5 decades of his career,at least 45 were advised or co-advised according to a Caltech account.A large number were international students including a high percentage of Chinese s... Don trained many Ph.D.students over the〜5 decades of his career,at least 45 were advised or co-advised according to a Caltech account.A large number were international students including a high percentage of Chinese students.The contributors to this article graduated over a time span of 26 years,and we are now distributed in 6 countries across 14 time zones,yet we represent only a small fraction of his former students and postdocs. 展开更多
关键词 Donald CAREER trained
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Ultrasensitive Indium Phosphide Nanomembrane Wearable Gas Sensors
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作者 Shiyu Wei Tuomas Haggren +4 位作者 Zhe Li Hark Hoe Tan Chennupati Jagadish Antonio Tricoli Lan Fu 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第6期209-217,共9页
Air quality is deteriorating due to continuing urbanization and industrialization.In particular,nitrogen dioxide(NO_(2))is a biologically and environmentally hazardous byproduct from fuel combustion that is ubiquitous... Air quality is deteriorating due to continuing urbanization and industrialization.In particular,nitrogen dioxide(NO_(2))is a biologically and environmentally hazardous byproduct from fuel combustion that is ubiquitous in urban life.To address this issue,we report a high-performance flexible indium phosphide nanomembrane NO_(2)sensor for real-time air quality monitoring.An ultralow limit of detection of~200 ppt and a fast response have been achieved with this device by optimizing the film thickness and doping concentration during indium phosphide epitaxy.By varying the film thickness,a dynamic range of values for NO_(2)detection from parts per trillion(ppt)to parts per million(ppm)level have also been demonstrated under low bias voltage and at room temperature without additional light activation.Flexibility measurements show an adequately stable response after repeated bending.On-site testing of the sensor in a residential kitchen shows that NO_(2)concentration from the gas stove emission could exceed the NO_(2)Time Weighted Average limit,i.e.,200 ppb,highlighting the significance of real-time monitoring.Critically,the indium phosphide nanomembrane sensor element cost is estimated at<0.1 US$due to the miniatured size,nanoscale thickness,and ease of fabrication.With these superior performance characteristics,low cost,and real-world applicability,our indium phosphide nanomembrane sensors offer a promising solution for a variety of air quality monitoring applications. 展开更多
关键词 air quality monitoring FLEXIBLE III-V semiconductors NANOFILM ULTRATHIN
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Telecom-band multiwavelength vertical emitting quantum well nanowire laser arrays
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作者 Xutao Zhang Fanlu Zhang +13 位作者 Ruixuan Yi Naiyin Wang Zhicheng Su Mingwen Zhang Bijun Zhao Ziyuan Li Jiangtao Qu Julie MCairney Yuerui Lu Jianlin Zhao Xuetao Gan Hark Hoe Tan Chennupati Jagadish Lan Fu 《Light(Science & Applications)》 SCIE EI CSCD 2024年第10期2405-2413,共9页
Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies,which require compact,multiwavelength laser sources at the tele... Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies,which require compact,multiwavelength laser sources at the telecom band.Here,we report on-substrate vertical emitting lasing from ordered InGaAs/InP multi-quantum well core–shell nanowire array epitaxially grown on InP substrate by selective area epitaxy.To reduce optical loss and tailor the cavity mode,a new nanowire facet engineering approach has been developed to achieve controlled quantum well nanowire dimensions with uniform morphology and high crystal quality.Owing to the strong quantum confinement effect of InGaAs quantum wells and the successful formation of a vertical Fabry–Pérot cavity between the top nanowire facet and bottom nanowire/SiO_(2) mask interface,stimulated emissions of the EH11a/b mode from single vertical nanowires from an on-substrate nanowire array have been demonstrated with a lasing threshold of~28.2μJ cm^(−2) per pulse and a high characteristic temperature of~128 K.By fine-tuning the In composition of the quantum wells,room temperature,single-mode lasing is achieved in the vertical direction across a broad near-infrared spectral range,spanning from 940 nm to the telecommunication O and C bands.Our research indicates that through a carefully designed facet engineering strategy,highly ordered,uniform nanowire arrays with precise dimension control can be achieved to simultaneously deliver thousands of nanolasers with multiple wavelengths on the same substrate,paving a promising and scalable pathway towards future advanced optoelectronic and photonic systems. 展开更多
关键词 ARRAYS tuning quantum
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Archean-Paleoproterozoic Lithospheric Mantle at the Northern Margin of the North China Craton Represented by Tectonically Exhumed Peridotites 被引量:5
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作者 TIAN Wei WANG Shuangyue +4 位作者 LIU Fenglin CHU Zhuyin WANG Bin CHEN Mimi Jennifer PRICHARD 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第6期2041-2057,共17页
Tectonically emplaced peridotites from North Hebei Province, North China Craton, have retained an original harzburgite mineral assemblage of olivine (54%-58%) + orthopyroxene (40%-46%) +minor clinopyroxene (〈1... Tectonically emplaced peridotites from North Hebei Province, North China Craton, have retained an original harzburgite mineral assemblage of olivine (54%-58%) + orthopyroxene (40%-46%) +minor clinopyroxene (〈1%)+spinel. Samples with honinite-like chemical compositions also coexist with these peridotites. The spinels within the peridotites have high-A1 end-members with A1203 content of 30 wt%-50 wt%, typical of mantle spinels. When compared with experimentally determined melt extraction trajectories, the harzburgites display a high degree of melting and enrichment of SiO2, which is typical of cratonic mantle peridotites. The peridotites display variably enriched light rare earth elements (REEs), relatively depleted middle REEs and weakly fractionated heavy REEs, which suggest a melt extraction of over 25% in the spinel stability field. The occurrence of are- and SSZ-type chromian spinels in the peridotites suggests that melt extraction and metasomatism occurred mostly in a subduction-related setting. This is also supported by the geochemical data of the coexisting boninite-like samples. The peridotites have lS7Os/lSSOs ratios ranging from 0.113-0.122, which is typical of cratonic iithospheric mantle. These lSTOs/ISSOs ratios yield model melt extraction ages (TRD) ranging from 981 Ma to 2054 Ma, which may represent the minimum estimation of the melt extraction age. The Ai203- lSTOs/lSSOs-proxy isochron ages of 2.4 Ga-2.7 Ga suggest a mantle melt depletion age between the Late Achaean and Early Paleoproterozoic. Both the peridotites and boninite-like rocks are therefore interpreted as tectonically exhumed continental lithospheric mantle of the North China Craton, which has experienced mantle melt depletion and subduction-related mantle metasomatism during the Neoarchean- Paleoproterozoic. 展开更多
关键词 HARZBURGITE BONINITE Re-Os isotopes lithospheric mantle PALEOPROTEROZOIC North China Craton
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Adakitic rocks associated with the Shilu copper–molybdenum deposit in the Yangchun Basin,South China,and their tectonic implications 被引量:12
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作者 Lipeng Zhang Yongbin Hu +5 位作者 Jinlong Liang Trevor Ireland Youliang Chen Rongqing Zhang Saijun Sun Weidong Sun 《Acta Geochimica》 EI CAS CSCD 2017年第2期132-150,共19页
South China is famous for the extensive magmatism and polymetallic mineralization that took place there in the Mesozoic. Shilu is a large porphyry–skarn Cu–Mo deposit in the Yangchun Basin, South China. The litholog... South China is famous for the extensive magmatism and polymetallic mineralization that took place there in the Mesozoic. Shilu is a large porphyry–skarn Cu–Mo deposit in the Yangchun Basin, South China. The lithology of the Shilu intrusion is granodiorite and quartz diorite, both of which are high-K calc-alkaline series, with high Sr([400 ppm) content along with low Y and Yb contents. Most of the samples have characteristics of adakite except for a few samples that have slightly higher Y and Yb contents, which may be plausibly explained by crustal contamination. Laser Ablation Inductively Coupled Plasma Mass Spectrometry zircon U–Pb dating revealed ages between 106.6 ± 1.3 and 103.9 ± 0.5 Ma, with multiple magmatic pulses. Molybdenite Re–Os isochron age of 102.2 ± 2.9 Ma(MSWD = 9.4) was determined, which is identical to the youngest zircon U–Pb age(103.9 ± 0.5 Ma) within error.The Shilu intrusion has high oxygen fugacity as indicated by high zircon Ce^(4+)/Ce^(3+) and Eu_N/Eu_N* ratios. Considering the geochemical characteristics(high Sr, and low Y and Yb contents), high oxygen fugacity, and copper mineralization of the Shilu intrusion, it was most likely formed by partial melting of a subducted young oceanic slab. Whole-rock Sr–Nd isotope-, zircon Hf isotope-, and whole-rock trace element analyses show that Shilu adakitic magmas may have interacted with type II enriched mantle and/or crustal materials during ascent. South China was affected by the Pacific tectonic regime to the east and the Neo-Tethys tectonic regime to the south in the Cretaceous. Based on the Pacific Plate drifting and rotation history, it is hard to explain how the Pacific Plate would have subducted and melted, forming adakitic rocks in the Shilu region. Considering the tectonic history of Southeast Asia and the South China Sea, the Neo-Tethys trench should have been much closer to the South China Block in the Cretaceous, and thus have had a greater impact on the South China Block. Based on the subduction direction, time of subduction,and distance between the Neo-Tethys subduction zone and the Shilu deposit, subduction of the Neo-Tethys ridge is the best mechanism for explaining the Shilu adakitic rocks and Cu–Mo mineralization. 展开更多
关键词 Shilu deposit Adakitic rocks CRETACEOUS NEO-TETHYS South China
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Long-term stabilization of stage 4 colon cancer using sodium dichloroacetate therapy 被引量:4
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作者 Akbar Khan Douglas Andrews Anneke C Blackburn 《World Journal of Clinical Cases》 SCIE 2016年第10期336-343,共8页
Oral dichloroacetate sodium(DCA) has been investigated as a novel metabolic therapy for various cancers since 2007, based on data from Bonnet et al that DCA can trigger apoptosis of human lung, breast and brain cancer... Oral dichloroacetate sodium(DCA) has been investigated as a novel metabolic therapy for various cancers since 2007, based on data from Bonnet et al that DCA can trigger apoptosis of human lung, breast and brain cancer cells. Response to therapy in human studies is measured by standard response evaluation criteria for solid tumours definitions, which define "response" by the degree of tumour reduction, or tumour disappearance on imaging. However, Blackburn et al have demonstrated that DCA can also act as a cytostatic agent in vitro and in vivo, without causing apoptosis(programmed cell death). A case is presented in which oral DCA therapy resulted in tumour stabilization of stage 4 colon cancer in a 57 years old female for a period of nearly 4 years, with no serious toxicity. Since the natural history of stage 4 colon cancer consists of steady progression leading to disability and death, this case highlights a novel use of DCA as a cytostatic agent with a potential to maintain long-term stability of advanced-stage cancer. 展开更多
关键词 DICHLOROACETATE Cancer COLON Colorectal CYTOSTATIC STABILIZATION Growth inhibition INTRAVENOUS
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The Relative Contribution of Non-Foliar Organs of Cotton to Yield and Related Physiological Characteristics Under Water Defi cit 被引量:4
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作者 HU Yuan-yuan ZHANG Ya-li +4 位作者 YI Xiao-ping ZHAN Dong-xia LUO Hong-hai Chow Wah Soon ZHANG Wang-feng 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第5期975-989,共15页
Water deficit is one of the most important causes of decreased yield in cultivated plants. Non-foliar green organs in cotton play an important role in yield formation at the late growth stage. Although better photosyn... Water deficit is one of the most important causes of decreased yield in cultivated plants. Non-foliar green organs in cotton play an important role in yield formation at the late growth stage. Although better photosynthetic performance was observed in a non-foliar organ (bract) compared with leaves under water deficit. However, the physiological response of each organ in cotton to water deficit has not been comprehensively studied in relation to the water status and photosynthesis characteristics. We studied the maintenance of water status of each organ in cotton by measuring their relative water content, proline content and stomatal characteristics. Water deficit significantly decreased the surface area of each organ, but to a lesser extent in non-foliar organs. Our results showed that the relative contribution of biomass accumulation of non-foliar organs increased under water deficit. Non-foliar organs (bracts and capsule wall) showed less ontogenetic decrease in O2 evolution capacity and in RuBPC activity (per dry weight) as well as better antioxidant systems than leaves at various days after anthesis. We conclude that the photosynthesis from non-foliar organs is important for increasing cotton yield especially under water deficit conditions. 展开更多
关键词 non-foliar organ water deficit water status antioxidant systems biomass accumulation COTTON
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The Early-Middle Pleistocene Transition: characterization and proposed guide for the defining boundary 被引量:6
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作者 Martin J. Head Brad Pillans Sarah A. Farquhar 《Episodes》 SCIE 2008年第2期255-259,共5页
The mid-Pleistocene transition (MPT, c. 1.2 to 0.5 Ma) records fundamental changes in Earth's climate state, where low-amplitude 41-kyr obliquity-dominated cycles gave way progressively to the high-amplitude, quasi... The mid-Pleistocene transition (MPT, c. 1.2 to 0.5 Ma) records fundamental changes in Earth's climate state, where low-amplitude 41-kyr obliquity-dominated cycles gave way progressively to the high-amplitude, quasiperiodic (c. 100-kyr) fluctuations that characterize the later Pleistocene and Holocene. We use wavelet analysis on the LR04 δ^l8O benthic foraminiferal stack to confirm low-frequency power as early as 1.25-1.20 Ma, determine the persistence of obliquity-dominated cyclicity through and beyond the MPT, and reveal new levels of complexity in climate evolution. 展开更多
关键词 地球 气候状态 洪积世 振幅
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Climate Change and Security at the Third Pole 被引量:5
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作者 Katherine Morton 《Contemporary International Relations》 2011年第3期34-55,共22页
The consequences of global climate change present a serious strategic challenge in one of the most remote parts of the world.The Tibetan Plateau is the largest high-altitude landmass on earth,with more than 45,000 gla... The consequences of global climate change present a serious strategic challenge in one of the most remote parts of the world.The Tibetan Plateau is the largest high-altitude landmass on earth,with more than 45,000 glaciers that feed the major river systems in Asia,which,in turn,support 40 per cent of the world's population.Temperatures in the region are rising twice as fast as the global average,posing serious risks to hydrological systems,agriculture,and critical infrastructure.Looking at regional cooperation through the lens of ecological security raises important questions about the extent to which the threat of large-scale climate-related disaster could trigger new forms of cooperative action.The sobering reality is that current responses fall far short of ensuring a mutually secure future. 展开更多
关键词 全球气候变化 生态安全 三极 世界人口 区域合作 青藏高原 河流系统 平均速度
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A mathematical model of cortical bone remodeling at cellular level under mechanical stimulus 被引量:2
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作者 Qing-Hua Qin Ya-Nan Wang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2012年第6期1678-1692,共15页
A bone cell population dynamics model for cor- tical bone remodeling under mechanical stimulus is devel- oped in this paper. The external experiments extracted from the literature which have not been used in the creat... A bone cell population dynamics model for cor- tical bone remodeling under mechanical stimulus is devel- oped in this paper. The external experiments extracted from the literature which have not been used in the creation of the model are used to test the validity of the model. Not only can the model compare reasonably well with these ex- perimental results such as the increase percentage of final values of bone mineral content (BMC) and bone fracture en- ergy (BFE) among different loading schemes (which proves the validity of the model), but also predict the realtime devel- opment pattern of BMC and BFE, as well as the dynamics of osteoblasts (OBA), osteoclasts (OCA), nitric oxide (NO) and prostaglandin E2 (PGE2) for each loading scheme, which can hardly be monitored through experiment. In conclusion, the model is the first of its kind that is able to provide an in- sight into the quantitative mechanism of bone remodeling at cellular level by which bone cells are activated by mechan- ical stimulus in order to start resorption/formation of bone mass. More importantly, this model has laid a solid foun- dation based on which future work such as systemic control theory analysis of bone remodeling under mechanical stimu- lus can be investigated. The to-be identified control mecha- nism will help to develop effective drugs and combined non- pharmacological therapies to combat bone loss pathologies. Also this deeper understanding of how mechanical forces quantitatively interact with skeletal tissue is essential for the generation of bone tissue for tissue replacement purposes in tissue engineering. 展开更多
关键词 Cortical bone remodeling Cell population dy-namics MECHANOTRANSDUCTION MECHANOSENSITIVITY Bonefracture energy - Bone mineral content
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Cambro-Silurian magmatisms at the northern Gondwana margin(Penninic basement of the Ligurian Alps) 被引量:2
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作者 Matteo Maino Laura Gaggero +2 位作者 Antonio Langone Silvio Seno Mark Fanning 《Geoscience Frontiers》 SCIE CAS CSCD 2019年第1期315-330,共16页
The Early Paleozoic evolution of the northern margin of Gondwana is characterized by several episodes of bimodal magmatism intruded or outpoured within thick sedimentary basins. These processes are well recorded in th... The Early Paleozoic evolution of the northern margin of Gondwana is characterized by several episodes of bimodal magmatism intruded or outpoured within thick sedimentary basins. These processes are well recorded in the Variscan blocks incorporated in the Ligurian Alps because they experienced low temperature Alpine metamorphism. During the Paleozoic, these blocks, together with the other Alpine basements, were placed between the Corsica-Sardinia and the Bohemian Massif along the northern margin of Gondwana. In this framework, they host several a variegated lithostratigraphy forming two main complexes(Complexs I and II) that can be distinguished by both the protoliths and their crosscutting relationships, which indicate that the acidic and mafic intrusives of Complex II cut an already folded sequence made of sediments, basalts and granitoids of Complex I. Both complexes were involved in the Variscan orogenic phases as highlighted by the pervasive eclogite-amphibolite facies schistosity(foliation II). However, rare relicts of a metamorphic foliation at amphibolite facies conditions(foliation I)is locally preserved only in the rocks of Complex I. It is debatable if this schistosity was produced during the early folding event e occurred between the emplacement of Complex I and II e rather than during an early stage of the Variscan metamorphic cycle.New SHRIMP and LA ICP-MS Ue Pb zircon dating integrated with literature data, provide emplacement ages of the several volcanic or intrusive bodies of both complexes. The igneous activity of Complex I is dated between 507 ± 15 Ma and 494 ± 5 Ma, while Complex II between 467 ± 12 Ma and 445.5 ± 12 Ma.The folding event recorded only by the Complex I should therefore have occurred between 494 ± 5 Ma and 467 ± 12 Ma. The Variscan eclogite-amphibolite facies metamorphism is instead constrained between ~420 Ma and ~300 Ma. These ages and the geochemical signature of these rocks allow constraining the Early Paleozoic tectono-magmatic evolution of the Ligurian blocks, from a middleeupper Cambrian rifting stage, through the formation of an Early Ordovician volcanic arc during the Rheic Ocean subduction, until a Late Ordovician extension related to the arc collapse and subsequent rifting of the PaleoThetys. Furthermore, the ~420-350 Ma ages from zircon rims testify to thermal perturbations that may be associated with the Silurian rifting-related magmatism, followed by the subduction-collisional phases of the Variscan orogeny. 展开更多
关键词 U-Pb zircon dating Early PALEOZOIC MAGMATISM Pre-Alpine BASEMENTS GONDWANA margin Ligurian ALPS
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A new cache of Eoarchaean detrital zircons from the Singhbhum craton,eastern India and constraints on early Earth geodynamics 被引量:2
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作者 Bulusu Sreenivas Sukanta Dey +3 位作者 Y.J. Bhaskar Rao T. Vijaya Kumar E.V.S.S.K. Babu Ian S. Williams 《Geoscience Frontiers》 SCIE CAS CSCD 2019年第4期1359-1370,共12页
The dominant geodynamic processes that underpin the formation and evolution of Earth’s early crust remain enigmatic calling for new information from less studied ancient cratonic nuclei.Here,we present U-Pb ages and ... The dominant geodynamic processes that underpin the formation and evolution of Earth’s early crust remain enigmatic calling for new information from less studied ancient cratonic nuclei.Here,we present U-Pb ages and Hf isotopic compositions of detrital zircon grains from^2.9 Ga old quartzites and magmatic zircon from a 3.505 Ga old dacite from the Iron Ore Group of the Singhbhum craton,eastern India.The detrital zircon grains range in age between 3.95 Ga and 2.91 Ga.Together with the recently reported Hadean,Eoarchean xenocrystic(up to 4.24 Ga)and modem detritus zircon grains from the Singhbhum craton,our results suggest that the Eoarchean detrital zircons represent crust generated by recycling of Hadean felsic crust formed at^4.3-4.2 Ga and^3.95 Ga.We observe a prominent shift in Hf isotope compositions at^3.6-3.5 Ga towards super-chondritic values,which signify an increased role for depleted mantle and the relevance of plate tectonics.The Paleo-,Mesoarchean zircon Hf isotopic record in the craton indicates crust generation involving the role of both depleted and enriched mantle sources.We infer a short-lived suprasubduction setting around^3.6-3.5 Ga followed by mantle plume activity during the Paleo-,Mesoarchean crust formation in the Singhbhum craton.The Singhbhum craton provides an additional repository for Earth’s oldest materials. 展开更多
关键词 U-PB ZIRCON ages Hf isotopes SINGHBHUM CRATON HADEAN Eoarchean GEODYNAMICS
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2D organic semiconductors, the future of green nanotechnology 被引量:3
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作者 Guru Prakash Neupane Wendi Ma +3 位作者 Tanju Yildirim Yilin Tang Linglong Zhang Yuerui Lu 《Nano Materials Science》 CAS 2019年第4期246-259,共14页
The discovery of 2D organic semiconductors of atomically thin structures has attracted great attention due to their emerging optical, electronic, optoelectronic and mechatronic properties. Recent progress in such orga... The discovery of 2D organic semiconductors of atomically thin structures has attracted great attention due to their emerging optical, electronic, optoelectronic and mechatronic properties. Recent progress in such organic nanostructures has opened new opportunities for engineering material properties in many ways, such as, 0D/1D/2D nanoparticles hybridization, strain engineering, atomic doping etc. Moreover, 2D organic nanostructures exhibit a unique feature of bio–functionality and are highly sensitive to bio-analytes. Such peculiar behavior in 2D organics can be utilized to design highly-efficient bio-sensors. Also, a bio-molecular integrated electronic/optoelectronic device with enhanced performance can be attained. Furthermore, the bio-degradable, biocompatible, biometabolizable, non-toxic behaviour and natural origin of organic nanomaterials can address the current ecological concerns of increasing inorganic material based electronic waste. This review highlights the benefits of 2D organic semiconductors. Considering the importance of strategic techniques for growing thin 2D organic layers,this review summarizes progress towards this direction. The possible challenges for long-time stability and future research directions in 2D organic nano electronics/optoelectronics are also discussed. We believe that this review article provides immense research interests in organic 2D nanotechnology for exploiting green technologies in the future. 展开更多
关键词 2D organic semiconductor Green nanotechnology OTFTs OLEDS Photo-diodes Organic solar cell Optical wave guide
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Modulation Instability and Non-Degenerate Akhmediev Breathers of Manakov Equations 被引量:5
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作者 Chong Liu Shao-Chun Chen +1 位作者 Xiankun Yao Nail Akhmediev 《Chinese Physics Letters》 SCIE EI CAS CSCD 2022年第9期28-32,共5页
We reveal a special subset of non-degenerate Akhmediev breather(AB)solutions of Manakov equations that only exist in the focusing case.Based on exact solutions,we present the existence diagram of such excitations on t... We reveal a special subset of non-degenerate Akhmediev breather(AB)solutions of Manakov equations that only exist in the focusing case.Based on exact solutions,we present the existence diagram of such excitations on the frequency-wavenumber plane.Conventional single-frequency modulation instability leads to simultaneous excitation of three ABs with two of them being non-degenerate. 展开更多
关键词 EXCITATION DEGENERATE SUBSET
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Major Miocene geological events in southern Tibet and eastern Asia induced by the subduction of the Ninetyeast Ridge 被引量:4
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作者 Xinlei Sun Wei-dong Sun +8 位作者 Yong-bin Hu Wei Ding Trevor Ireland Mei-zhen Zhan Ji-qiang Liu Ming-xing Ling Xing Ding Zhao-feng Zhang Wei-ming Fan 《Acta Geochimica》 EI CAS CSCD 2018年第3期395-401,共7页
Cenozoic adakitic rocks in the Gangdese changed from barren continental melts to ore-forming slab melts at * 23 Ma. The distribution and chemical characteristics of the ore-forming adakites point to an association wit... Cenozoic adakitic rocks in the Gangdese changed from barren continental melts to ore-forming slab melts at * 23 Ma. The distribution and chemical characteristics of the ore-forming adakites point to an association with the Ninetyeast Ridge. The subduction of the thick,rigid Ninetyeast Ridge changed the geometry and rheology of the eastern Tibetan Plateau lithosphere and asthenosphere, restrained the eastward escape of asthenospheric mantle as well as continental fragments, and promoted the uplift and building of the Tibetan Plateau, which consequently changed the tectonic and climatic regimes in eastern Asia. 展开更多
关键词 RIDGE SUBDUCTION Eastern Tibetan Plateau CENOZOIC MINERALIZATION Seismic anomaly
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From granulite fluids to quartz-carbonate megashear zones:The gold rush 被引量:9
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作者 Bin Fu Jacques L.R.Touret 《Geoscience Frontiers》 SCIE CAS CSCD 2014年第5期747-758,共12页
At peak granulite-facies metamorphic conditions, lower continental crust is arguably fluxed by large amounts of two key low water activity fluids: (i) high-density CO2 and/or (ii) concentrated saline so- lutions.... At peak granulite-facies metamorphic conditions, lower continental crust is arguably fluxed by large amounts of two key low water activity fluids: (i) high-density CO2 and/or (ii) concentrated saline so- lutions. These fluids are either internally-derived, generated by mineral reactions or dehydration melting or, notably for CO2, externally-derived, issued from the underlying mantle. Postmetamorphic evolution results in complete disappearance of these fluids, except for minute remnants preserved in minerals as fluid inclusions. Two major processes are involved: (i) at peak conditions, granitoid magmas form, migrate upward, and crystallize as shallow intrusions in the upper crust (mineralized porphyry types or reduced intrusions); (ii) during the rapid decompression which almost systematically follows a period of post-peak isobaric cooling, especially for ultrahigh-temperature granulites (anticlockwise P-T paths), quartz-carbonate megashear zones are formed by repeated periods of seismic activity. Seismic activity may continue until all free fluids have disappeared, resulting in the ultramylonites and pseudotachylites that are found in many granulite domes. A great majority of vein-type Au deposits worldwide occur in the above-mentioned settings or nearby. We suggest that the Au has been scavenged by the granulite fluids, then redistributed and concentrated during the formation of veins and related phenomena. 展开更多
关键词 Granulite CO2 BrinesMegashear zonesAu mineralization
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Late syn-to post-collisional magmatism in Madagascar:The genesis of the Ambalavao and Maevarano Suites 被引量:2
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作者 Donnelly B.Archibald Alan S.Collins +3 位作者 John D.Foden Justin L.Payne Peter Holden Théodore Razakamanana 《Geoscience Frontiers》 SCIE CAS CSCD 2019年第6期2063-2084,共22页
The East African Orogen involves a collage of Proterozoic microcontinents and arc terranes that became wedged between older cratonic blocks during the assembly of Gondwana.The Ediacaran-Cambrian Ambalavao and Maevaran... The East African Orogen involves a collage of Proterozoic microcontinents and arc terranes that became wedged between older cratonic blocks during the assembly of Gondwana.The Ediacaran-Cambrian Ambalavao and Maevarano Suites in Madagascar were emplaced during the waning orogenic stages and consist of weakly deformed to undeformed plutonic rocks and dykes of mainly porphyritic granite but also gabbro,diorite and charnockite.U-Pb geochronological data date emplacement of the Ambalavao Suite to between ca.580 Ma and 540 Ma and the Maevarano Suite to between ca.537 Ma and522 Ma.Major and trace element concentrations are consistent with emplacement in a syn-to postcollisional tectonic setting as A-type(anorogenic) suites.Oxygen(δ^(18)O of 5.27‰-7.45‰) and hafnium(ε(Hf)(t) of-27.8 to-12.3) isotopic data from plutons in the Itremo and Antananarivo Domains are consistent with incorporation of an ancient crustal source.More primitive δ^(18)O(5.27‰-5.32‰) andε(Hf)(t)(+0.0 to+0.2) isotopic values recorded in samples collected from the Ikalamavony Domain demonstrate the isotopic variation of basement sources present in the Malagasy crust.The Hf isotopic composition of Malagasy zircon are unlike more juvenile Ediacaran-Cambrian zircon sou rces elsewhere in the East African Orogen and,as such,Madagascar represents a distinct and identifiable detrital zircon source region in Phanerozoic sedimentary provenance studies.Taken together,these data indicate that high-T crustal anatexis,crustal assimilation and interaction of crustal material with mantle-derived melts were the processes operating during magma emplacement.This magmatism was coeval with polyphase deformation throughout Madagascar during the amalgamation of Gondwana and magmatism is interpreted to reflect lithospheric delamination of an extensive orogenic plateau. 展开更多
关键词 Madagascar geology East African OROGEN ZIRCON geochronology ZIRCON oxygen and HAFNIUM isotopes POST-COLLISIONAL MAGMATISM
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A history of Proterozoic terranes in southern South America:From Rodinia to Gondwana 被引量:2
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作者 C.Casquet C.W.Rapela +5 位作者 R.J.Pankhurst E.G.Baldo C.Galindo C.M.Fanning J.A.Dahlquist J.Saavedra 《Geoscience Frontiers》 SCIE CAS 2012年第2期137-145,共9页
The role played by Paleoproterozoic cratons in southern South America from the Mesopro- terozoic to the Early Cambrian is reconsidered here. This period involved protracted continental amal- gamation that led to forma... The role played by Paleoproterozoic cratons in southern South America from the Mesopro- terozoic to the Early Cambrian is reconsidered here. This period involved protracted continental amal- gamation that led to formation of the supercontinent Rodinia, followed by Neoproterozoic continental break-up, with the consequent opening of Clymene and Iapetus oceans, and finally continental re-assembly as Gondwana through complex oblique collisions in the Late Neoproterozoic to Early Cambrian. The evidence for this is based mainly on a combination of precise U-Pb SHRMP dating and radiogenic isotope data for igneous and metamorphic rocks from a large area extending from the Rio de la Plata craton in the east to the Argentine Precordillera in the west and as far north as Arequipa in Peru. Our interpretation of the paleogeographical and geodynamic evolution invokes a hypothetical Paleoproterozoic block (MARA) embracing basement ultimately older than 1.7 Ga in the Western Sierras Pampeanas (Argentina), the Arequipa block (Peru), the Rio Apa block (Brazil), and probably also the Paraguaia block (Bolivia). 展开更多
关键词 Paleoproterozoic CRATONS GRENVILLIAN Neoproterozoic rifting SW Gondwana assembly
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