检索结果-南通市图书馆

Copper Isotope Fractionation during Basalt Leaching at 25℃ and pH=0.3,2

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 82-91页

作者： Dandan Li Sheng-ao liu State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesBeijing 100083China

The geochemical cycling of copper in the hydrosphere and soil environments primarily involves the transport of Cu from rocks to rivers via *** the factors controlling Cu isotope fractionation during weathering is crucial for the purpose of using Cu isotopes as a tracer of geochemical ***,we performed acid-leaching experiments on natural basalts (BHVO-2 and GBW07105) and chalcopyrite in Erlenmeyer flasks at T=25℃ and different pH values (0.3 and 2).Our results reveal substantial Cu isotope fractionations (△^(65)Cu_(solution-initial)) between leachates (Cu_(solution)) and starting materials (Cu_(initial)).The leachates released from GBW07105 and chalcopyrite are consistently enriched in heavier Cu isotopes relative to the starting materials at pH=***,the δ^(65)Cu_(solution)values decrease to about-0.6‰first,then increase to>0 for BHVO-2 at pH=2 and GBW07105 at pH=*** results indicate that leaching of natural rocks by acidic liquids can produce both positive and negative Cu isotope fractionation,depending on pH values and the types of minerals in starting materials.X-ray power diffraction analysis (XRD) patterns reveal similar mineral assemblages between starting basalts and residues after each reaction *** most likely mechanisms responsible for such Cu isotope fractionation are the relative rates of Cu oxidation at the surface and Cu release into solution,and the sequence of mineral *** study represents an important step for future studies to use Cu isotopes to explain Cu isotopic variations in natural rocks and waters.

关键词： Cu isotopes isotope fractionation basalt chalcopyrite leaching

An Inverse Power Generation Mechanism Based Fruit Fly Algorithm for Function Optimization

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2019年第2期32卷 634-656页

作者： liu ao DENG Xudong REN Liang liu Ying liu Bo School of Management Wuhan University of Science and Technology Center for Service Science and Engineering Wuhan University of Science and Technology Hubei Province Key Laboratory of Intelligent Information Processing and Real-time Industrial System School of Economics and Management Beihang University Academy of Mathematics and Systems Science Chinese Academy of Sciences

As a novel population-based optimization algorithm, fruit fly optimization(FFO) algorithm is inspired by the foraging behavior of fruit flies and possesses the advantages of simple search operations and easy implementation. Just like most population-based evolutionary algorithms, the basic FFO also suffers from being trapped in local optima for function optimization due to premature *** this paper, an improved FFO, named IPGS-FFO, is proposed in which two novel strategies are incorporated into the conventional FFO. Specifically, a smell sensitivity parameter together with an inverse power generation mechanism(IPGS) is introduced to enhance local exploitation. Moreover,a dynamic shrinking search radius strategy is incorporated so as to enhance the global exploration over search space by adaptively adjusting the searching area in the problem domain. The statistical performance of FFO, the proposed IPGS-FFO, three state-of-the-art FFO variants, and six metaheuristics are tested on twenty-six well-known unimodal and multimodal benchmark functions with dimension 30, respectively. Experimental results and comparisons show that the proposed IPGS-FFO achieves better performance than three FFO variants and competitive performance against six other meta-heuristics in terms of the solution accuracy and convergence rate.

关键词： Evolutionary algorithms fruit fly optimization function optimization meta-heuristics

Copper isotope constraints on the origins of basaltic and andesitic magmas in the Tengchong volcanic field,SE Tibet

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2024年第4期15卷 290-303页

作者： Yuan-Ru Qu Sheng-ao liu State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesBeijing 100083China

The Tengchong volcano field(TVF),situated at the southeastern margin of the Tibetan Plateau,holds crucial information regarding Cenozoic volcanic activities and geotectonic evolution of the SE *** provide new constraints on petrogenesis and evolution of the Tengchong volcanism,here we conducted copper(Cu)elemental and isotopic analyses on a suite of samples that document the evolution from basalts to andesites in the *** basalts are Cu-depleted(29.7-36.9 ppm)and have higherδ65Cu val-ues(0.19‰-0.40‰,mean=0.31‰±0.05‰;n=11)than those of mid-ocean ridge basalts(MORBs,~0.09‰)and the mantle(~0.06‰)as well as the majority of island arc *** with the low Cu/Zr ratios,these characteristics are interpreted to reflect the fractionation of isotopically light sulfides in the S-saturated systems during magma ascent,rather than source heterogeneity induced by recycled materials and redox *** with the basalts,the andesites have slightly lower Cu contents(14.4-29.4 ppm)and lighter Cu isotopic compositions(mean=-0.14‰±0.06‰;n=13).These differences cannot be attributed to progressive sulfide fractionation of basaltic magmas but require the assimilation of lower crustal materials with lowδ65Cu values during evolution of the andesitic *** results collectively suggest that Cu isotopes can provide valuable insights into magma origin and evolution.

关键词： Copper isotopes Sulfide segregation Magmatic differentiation Tengchong volcanic field

Linking deep CO2 outgassing to cratonic destruction

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

National Science Review 2022年第6期9卷 12-22页

作者： Zhao-Xue Wang Sheng-ao liu Shuguang Li Di liu Jingao liu State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences

Outgassing of carbon dioxide from the Earth's interior regulates the surface climate through deep *** we examine the role of cratonic destruction in mantle CO2outgassing via collating and presenting new data for Paleozoic kimberlites, Mesozoic basaltic rocks and their mantle xenoliths from the eastern North China Craton（NCC）, which underwent extensive destruction in the early Cretaceous. High Ca/Al and low Ti/Eu and δ26Mg are widely observed in lamprophyres and mantle xenoliths, which demonstrates that the cratonic lithospheric mantle（CLM） was pervasively metasomatized by recycled *** analysis of bubble-bearing melt inclusions shows that redox melting of the C-rich CLM produced carbonated silicate melts with high CO2content. The enormous quantities of CO2in these magmas,together with substantial CO2degassing from the carbonated melt–CLM reaction and crustal heating,indicate that destruction of the eastern NCC resulted in rapid and extensive mantle CO2emission, which partly contributed to the early Cretaceous greenhouse climate episode.

关键词： carbonate metasomatism lithospheric mantle CO_2 outgassing deep carbon cycling cratonic destruction North China Craton

Tracing the Deep Carbon Cycle Using Metal Stable Isotopes: Opportunities and Challenges

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Engineering 2019年第3期5卷 448-457页

作者： Sheng-ao liu Shu-Guang Li State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China

The subduction of marine carbonates and carbonated oceanic crust to the Earth’s interior and the return of recycled carbon to the surface via volcanism may play a pivotal role in governing Earth’s atmosphere, climate, and biosphere over geologic time. Identifying recycled marine carbonates and evaluating their fluxes in Earth’s mantle are essential in order to obtain a complete understanding of the global deep carbon cycle (DCC). Here, we review recent advances in tracing the DCC using stable isotopes of divalent metals such as calcium (Ca), magnesium (Mg), and zinc (Zn). The three isotope systematics show great capability as tracers due to appreciable isotope differences between marine carbonate and the terrestrial mantle. Recent studies have observed anomalies of Ca, Mg, and Zn isotopes in basalts worldwide, which have been interpreted as evidence for the recycling of carbonates into the mantle, even into the mantle transition zone (410–660 km). Nevertheless, considerable challenges in determining the DCC remain because other processes can potentially fractionate isotopes in the same direction as expected for carbonate recycling;these processes include partial melting, recycling of carbonated eclogite, separation of metals and carbon, and diffusion. Discriminating between these effects has become a key issue in the study of the DCC and must be considered when interpreting any isotope anomaly of mantle-derived rocks. An ongoing evaluation on the plausibility of potential mechanisms and possible solutions for these challenges is discussed in detail in this work. Based on a comprehensive evaluation, we conclude that the large-scale Mg and Zn isotope anomalies of the Eastern China basalts were produced by recycling of Mg- and Zn-rich carbonates into their mantle source.

关键词： Deep carbon cycle Calcium isotopes Magnesium Zinc

Simulation and experimental investigation on a dynamic lateral flow mode in trepanning electrochemical machining

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 Journal of Aeronautics 2017年第4期30卷 1624-1630页

作者： Dong ZHU Zhouzhi GU Tingyu XUE ao liu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

An appropriate flow mode of electrolyte has a positive effect on process efficiency, surface roughness, and machining accuracy in the electrochemical machining（ECM） process. In this study, a new dynamic lateral flow mode, in which the electrolyte flows from the leading edge to the trailing edge, was proposed in trepanning ECM of a diffuser. Then a numerical model of the channel was set up and simulated by using computational fluid dynamics software. The result showed that the distribution of the flow field was comparatively uniform in the inter-electrode gap. Furthermore, a fixture was designed to realize this new flow mode and then corresponding experiments were carried out. The experimental results illustrated that the feeding rate of the cathode reached 2 mm/min, the best taper angle was about 0.4°, and the best surface roughness was up to Ra= 0.115 lm. It reflects that this flow mode is suitable and effective, and can also be applied to machining other complex structures in trepanning ECM.

关键词： Diffuser Electrochemical machining Electrolyte Experiment Flow

Zinc isotopic behavior of mafic rocks during continental deep subduction

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2021年第5期12卷 182-191页

作者： Li-Juan Xu Sheng-ao liu Shuguang Li State Key Laboratory of Geological Processes and Mineral Resources School of Scientific ResearchChina University of GeosciencesBeijing 100083China

Zinc isotopes may act as a new tool of tracking recycling of crustal materials that causes compositional heterogeneity of the *** application relies on an investigation of Zn isotopic behaviors during slab *** this study,we report Zn isotopic compositions for a suite of metabasalts(greenschists,amphibolites,and coesitebearing eclogites)from the Dabie Orogen(China),which were formed via the subduction of mafic rocks into different depths and up to>200 *** out of eight greenschists are characterized by lighterδ^(66)ZnJMC-Lyon(0.10‰-0.16‰)than those of global basalts(0.28‰±0.05‰),which may be caused by crustal assimilation of the protoliths by sedimentary rocks due to their extremely high ^(87)Sr/^(86)Sr(up to 0.7130)and lowεNd values(down to−12.3).The remaining greenschists have relatively low ^(87)Sr/^(86)Sr and theirδ66Zn values(0.21‰-0.38‰)overlap the ranges of amphibolites(0.18‰-0.32‰)and coesite-bearing eclogites(0.18‰-0.36‰).There is no correlation betweenδ^(66)Zn and sensitive indicators of dehydration(Rb/TiO_(2),Ba/Yb,and H_(2)O+),suggesting that no detectable Zn isotope fractionation has occurred during the deep subduction of mafic rocks even into>200 km,which is attributed to the limited loss of Zn during prograde metamorphism and ***,Zn isotopic compositions of the deeply subducted mafic rocks are inherited from their *** that these metamorphosed rocks have higherδ66Zn than that of the mantle value by up to 0.2‰,the recycled/subducted mafic crust can incorporate isotopically heavy Zn into the *** subducted slabs may partially melt and generate a metasomatized mantle,resulting in changes of Zn isotopic composition of the hybridized mantle as have been observed in some mantle xenoliths and basaltic lavas.

关键词： Zn isotopes Metamorphosed rocks Dehydration Crustal deep subduction

Highly bonded T-Nb2O5/rGO nanohybrids for 4 V quasisolid state asymmetric supercapacitors with improved electrochemical performance

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第9期11卷 4673-4685页

作者： Yuzhi Jiao Haitao Zhang Hailang Zhang ao liu Yanxia liu Suojiang Zhang Beijing Key Laboratory of Ionic Liquids Clean Process Institute of Process Engineering Chinese Academy of Sciences Beijing I O0190 China School of Chemical and Material Engineering Jiangnan University Wuxi 214122 China Department of Chemical and Material Engineering Hefei University Hefei 230601 China Zhengzhou Key Laboratory of Energy Storage Science and Technology Zhengzhou Institute of Emerging Industrial Technology Zhengzhou 450000 China

Orthorhombic niobium pentoxide （T-Nb2O5）/reduced graphene oxide nanohybrids were fabricated via the hydrothermal attachment of Nb2Os nanowires to dispersed graphene oxide nanosheets followed by a high-temperature phase transformation. Electrochemical measurements showed that the nanohybrid anodes possessed enhanced reversible capacity and superior cycling stability compared to those of a pristine T-Nb205 nanowire electrode. Owing to the strong bonds between graphene nanosheets and T-Nb2O5 nanowires, the nanohybrids achieved an initial capacity of 227 mAh·g^-1. Additionally, non-aqueous asymmetric supercapacitors （ASCs） were fabricated with the synthesized nanohybrids as the anode and activated carbon as the cathode. The 3 V Li-ion ASC with a LiPF6-based organic electrolyte achieved an energy density of 45.1 Wh·kg^-1 at 715.2 W·kg^-1. The working potential could be further enhanced to 4 V when a polymer ionogel separator （PVDF-HFP/LiTFSI/EMIMBF4） and formulated ionic liquid electrolyte were employed. Such a quasi-solid state ASC could operate at 60℃ and delivered a maximum energy density of 70 Wh·kg^-1 at 1 kW·kg^-1.

关键词： solid-state supercapacitor nanohybrid electrode ionogel polymer electrolyte electrochemicalperformance

Online scheduling of two identical machines under a grade of service provision 36

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

Online scheduling of two identical machines under a grade of...