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Mantle geochemistry: Insights from ocean island basalts

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Science China Earth Sciences 2017年第11期60卷 1976-2000页

作者： HUANG shichun ZHENG YongFei Department of Geoscience University of Nevada CAS Key Laboratory of Crust-Mantle Material and Environment School of Earth and Space Sciences University of Science and Technology of China

The geochemical study of the Earth's mantle provides important constraints on our understanding of the formation and evolution of Earth, its internal structure, and the mantle dynamics. The bulk Earth composition is inferred by comparing terrestrial mantle rocks with chondrites, which leads to the chondritic Earth model. That is, Earth has the same relative proportions of refractory elements as that in chondrites, but it is depleted in volatiles. Ocean island basalts(OIB) may be produced by mantle plumes with possible deep origins; consequently, they provide unique opportunity to study the deep Earth. Isotopic variations within OIB can be described using a limited number of mantle endmembers, such as EM1, EM2 and HIMU, and they have been used to decipher important mantle processes. Introduction of crustal material into the deep mantle via subduction and delamination is important in generating mantle heterogeneity; however, there is active debate on how they were sampled by mantle melting, i.e.,the role of olivine-poor lithologies in the OIB petrogenesis. The origin and location of high 3He/4He mantle remain controversial,ranging from unprocessed(or less processed) primitive material in the lower mantle to highly processed materials with shallow origins, including ancient melting residues, mafic cumulates under arcs, and recycled hydrous minerals. Possible core-mantle interaction was hypothesized to introduce distinctive geochemical signatures such as radiogenic 186 Os and Fe and Ni enrichment in the OIB. Small but important variations in some short-lived nuclides, including 142 Nd, 182 W and several Xe isotopes, have been reported in ancient and modern terrestrial rocks, implying that the Earth's mantle must have been differentiated within the first 100 Myr of its formation, and the mantle is not efficiently homogenized by mantle convection.

关键词： Mantle structure Mantle composition Crustal components Crust-mantle interaction Crustal recycling

APPLICATION OF ARTIFICIAL NEURAL NETWORK IN COMPLEX SYSTEMS OF REGIONAL SUSTAINABLE DEVELOPMENT

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Chinese Geographical Science 2004年第1期14卷 1-8页

作者： shichun PhilipJAMES GUOZhong-yang DepartmentofGeography SchoolofResourcesandEnvironmentalSciencel／KeyLaboratoryofGeographicalInformationScienceEastChinaNormalUniversityShanghai200062P.R.China TelfordInstituteofEnvironmentalSystems SchoolofEnvironmentandLifeSciencesUniversityofAlfordSalfordM66PUUK

Meeting the challenge of sustainable development requires substantial advances in understanding the interaction of natural and human systems. The dynamics of regional sustainable development could be addressed in the context of complex system thinking. Three features of complex systems are that they are uncertain, non-linear and self-organizing. Modeling regional development requires a consideration of these features. This paper discusses the feasibility of using the artificial neural networt(ANN) to establish an adjustment prediction model for the complex systems of sustainable development (CSSD). Shanghai Municipality was selected as the research area to set up the model, from which reliable prediction data were produced in order to help regional development planning. A new approach, which could help to manage regional sustainable development, is then explored.

关键词： complex systems sustainable development artificial neural network regional development

Calcium isotope compositions as a means to trace carbonate recycling

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National Science Review 2022年第6期9卷 8-10页

作者： shichun Huang Stein B.Jacobsen Department of Geoscience University of Nevada Department of Earth and Planetary Sciences Harvard University

Marine carbonates, such as sedimentary carbonates and secondary carbonates formed during marine alteration processes, are returned to the mantle at subduction zones, and their fates regulate the global carbon cycle. S... 详细信息

关键词： Carbonates

DEVELOPMENT OF THE CONTROL METHODOLOGY OF THE GIANT MAGNETOSTRICTIVE ACTUATOR BASED ON MAGNETIC FLUX DENSITY

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Chinese Journal of Mechanical Engineering 2003年第4期16卷 359-362页

作者： JiaZhenyuan YangXing shichun GuoOongming SchoolofMechanicalEngineering DalianUniversityofTechnologyDalian116024China DepartmentofPrecisionInstrumentsandMechnology TsinghuaUniversityBeijing100084China SchoolofMechanicalEngineenng DalianUniversityofTechnologyDalian116024China

According to the principle of the magnetostriction generating mechanism, thecontrol model of giant magnetostriction material based on magnetic field and the control method withmagnetic flux density are developed. Furthermore, this control method is used to develop a giantmagnetostrictive micro-displacement actuator (GMA) and its driving system. Two control methods whosecontrol variables are current intensity and magnetic flux density are compared with each other byexperimental studies. Finally, effective methods on improving the linearity and control precision ofmicro-displacement actuator and reducing the hysteresis based on the controlling magnetic fluxdensity are obtained.

关键词： Giant magnetostriction Magnetic flux density Control method Micro-displacement actuator

High mixing effectiveness lobed nozzles and mixing mechanisms

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Science China(Technological Sciences) 2015年第7期58卷 1218-1233页

作者： SHENG ZhiQiang CHEN shichun WU Zhe HUANG PeiLin School of Aeronautic Science and Engineering Beijing University of Aeronautics and Astronautics

For a circular lobed nozzle with the exit plane displaced from the center body,adding a central plug at exit or replacing the nozzle with an alternating-lobe nozzle can improve the mixing *** this study,numerical investigations of jet mixing in the lobed nozzles with a central plug and alternating-lobe nozzles in pumping operation were *** effects of the central plugs with the wake ranging from attached to separated flow on the mixing were analyzed,along with the mechanism of improving the mixing performance in a"sword"alternating-lobe *** simulation results reveal that the large-scale mixing rate,which is dominated by streamwise vortices,is related to the intensity of the attainable heat and mass transfer in the streamwise *** effects of the streamwise vortices on the normal vortex ring are virtually a manifestation of the heat and mass transfer/mixing process of the streamwise *** simulation results also show that the central plug with the attached rear-flow performs better in improving the mixing effectiveness and pumping performance;on the contrary,if the rear-flow is separated,more pressure loss will be *** particular,a completely separated flow over the rear of the central plug will severely degrade the attainable heat and mass transfer in the streamwise *** the sword alternating-lobe nozzle,wider sword deep troughs help to increase the flux of the secondary stream around the core region and delay the confluence of the primary stream in the region between the deep and shallow ***,the mixing is improved in the middle and posterior *** to the lobed nozzle with a central plug,the improved sword alternating-lobe nozzle can achieve a higher mixing effectiveness with much less pressure loss,which is preferred in situations when the power loss of the engine is restricted.

关键词： jet mixing lobed nozzle mixing effectiveness streamwise vortices heat and mass transfer

Design Engineering,Synthesis Protocols,and Energy Applications of MOF-Derived Electrocatalysts

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Nano-Micro Letters 2021年第9期13卷 16-47页

作者： Amr Radwan Huihui Jin Daping He shichun Mu School of Science Wuhan University of TechnologyWuhan 430070People’s Republic of China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Xianhu Hydrogen ValleyFoshan 528200People’s Republic of China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070People’s Republic of China

The core reactions for fuel cells,rechargeable metal-air batteries,and hydrogen fuel production are the oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen evolution reaction(HER),which are heavily dependent on the efficiency of *** attempts have previously been devoted in non-noble electrocatalysts born out of metal-organic frameworks(MOFs)for ORR,OER,and HER applications,due to the following advantageous reasons:(i)The significant porosity eases the electrolyte diffusion;(ii)the supreme catalyst-electrolyte contact area enhances the diffusion efficiency;and(iii)the electronic conductivity can be extensively increased owing to the unique construction block subunits for MOFs-derived ***,the recent progress of MOFs-derived electrocatalysts including synthesis protocols,design engineering,DFT calculations roles,and energy applications is discussed and *** can be concluded that the elevated ORR,OER,and HER performances are attributed to an advantageously well-designed high-porosity structure,significant surface area,and plentiful active ***,the perspectives of MOF-derived electrocatalysts for the ORR,OER,and HER are presented.

关键词： MOF-derived electrocatalysis Oxygen reduction reaction Oxygen evolution reaction Hydrogen evolution reaction

Brain network markers of abnormal cerebral glucose metabolism and blood flow in Parkinson's disease

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Neuroscience Bulletin 2014年第5期30卷 823-837页

作者： shichun Peng David Eidelberg Yilong Ma Center for Neurosciences The Feinstein Institute for Medical ResearchNorth Shore-Long Island Jewish Health System

Neuroimaging of cerebral glucose metabolism and blood flow is ideally suited to assay widely-distributed brain circuits as a result of local molecular events and behavioral modulation in the central nervous system. With the progress in novel analytical methodology, this endeavor has succeeded in unraveling the mechanisms underlying a wide spectrum of neurodegenerative diseases. In particular, statistical brain mapping studies have made significant strides in describing the pathophysiology of Parkinson＇s disease （PD） and related disorders by providing signature biomarkers to determine the systemic abnormalities in brain function and evaluate disease progression, therapeutic responses, and clinical correlates in patients. In this article, we review the relevant clinical applications in patients in relation to healthy volunteers with a focus on the generation of unique spatial covariance patterns associated with the motor and cognitive symptoms underlying PD. These characteristic biomarkers can be potentially used not only to improve patient recruitment but also to predict outcomes in clinical trials.

关键词： Parkinson's disease metabolism blood flow PET SPECT movement disorder network analysis imaging biomarkers

Revitalizing osmium-based catalysts for energy conversion

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Energy Reviews 2023年第4期2卷 81-88页

作者： Ding Chen shichun Mu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China

Designing high cost-effective catalysts has been one of the core topics in energy conversion and *** to unique electronic structure and excellent comprehensive properties,Pt-group metal(PGM)based-materials occupy the top region of numerous volcanic curves and are currently difficult to be replaced by abundant tran-sition metal ***,we pay attention to the osmium(Os),as the cheapest and the least noticed PGM in the field of electrocatalysis,with promising application ***,the three main modification strategies(anion modulation,heterostructure construction,substrate engineering)of Os-based catalysts in hydrogen evolution reaction(HER),the structural advantages provided in oxygen evolution reaction(OER),and other energy-related electrocatalysis applications are discussed one by *** addition,we discuss the key problems and countermeasures faced in their further breakthroughs,and look forward to future development trends and ***,the insights in this work will promote the understanding and designation of Os-based catalysts.

关键词： Energy conversion Electrocatalysis Pt-group metals Os-based catalysts

Effects of Al_2O_3 Nano-additive on Performance of Micro-arc Oxidation Coatings Formed on AZ91D Mg Alloy

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Journal of Materials Science & Technology 2014年第10期30卷 984-990页

作者： Yan Wang Dongbo Wei Jie Yu shichun Di School of Mechatronics Engineering Harbin Institute of Technology

Ceramic coatings were prepared on AZ91 D Mg alloy by micro-arc oxidation （MAO） in aluminate electrolytes, with Al2O3 nano-additive suspending at different concentrations. Effects of nano-additive concentration on the structure, phase composition, hardness and anti-corrosion property of the MAO coatings were analyzed by scanning electron microscopy, X-ray diffraction, micro-hardness test and electrochemical method, respectively. The results revealed that Al2O3 nano-particles were mostly incorporated into ceramic coating chemically, transferred into MgAl2O4, rather than being trapped mechanically during MAO process. With the increase of Al2O3 concentration, the voltage-time response, content of MgAl2O4, hardness and anti-corrosion property increased. However, when the concentration varied from 10 g/L to 15 g/L, these behaviors and properties changed only a little. This result indicated that, after the concentration of Al2O3 nano-additive reaching 10 g/L, the incorporation of Al2O3 nano-particles turned into a saturation state, due to the complex process during MAO treatment. Therefore, 10 g/L might be a proper concentration for MAO coating to incorporate Al2O3 nano-particles,

关键词： Micro-arc oxidation Al2O3 nano-additive Mg alloy Corrosion Hardness