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Theory and classification of mass extinction causation

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National Science Review 2024年第1期11卷 16-36页

作者： Thomas J.Algeo jun shen State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences—Wuhan State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences—Wuhan Department of Geosciences University of Cincinnati

Theory regarding the causation of mass extinctions is in need of systematization, which is the focus of this contribution. Every mass extinction has both an ultimate cause, i.e. the trigger that leads to various climato-environmental changes, and one or more proximate cause(s), i.e. the specific climato-environmental changes that result in elevated biotic mortality. With regard to ultimate causes, strong cases can be made that bolide(i.e. meteor) impacts, large igneous province(LIP) eruptions and bioevolutionary events have each triggered one or more of the Phanerozoic Big Five mass extinctions, and that tectono-oceanic changes have triggered some second-order extinction events. Apart from bolide impacts, other astronomical triggers(*** flares, gamma bursts and supernova explosions) remain entirely in the realm of speculation. With regard to proximate mechanisms, most extinctions are related to either carbon-release or carbon-burial processes, the former being associated with climatic warming, ocean acidification, reduced marine productivity and lower carbonate δ13C values, and the latter with climatic cooling, increased marine productivity and higher carbonate δ13C values. Environmental parameters such as marine redox conditions and terrestrial weathering intensity do not show consistent relationships with carbon-cycle *** this context, mass extinction causation can be usefully classified using a matrix of ultimate and proximate factors. Among the Big Five mass extinctions, the end-Cretaceous biocrisis is an example of a bolide-triggered carbon-release event, the end-Permian and end-Triassic biocrises are examples of LIP-triggered carbon-release events, and the Late Ordovician and Late Devonian biocrises are examples of bioevolution-triggered carbon-burial events. Whereas the bolide-impact and LIP-eruption mechanisms appear to invariably cause carbon release, bioevolutionary triggers can result in variable carbon-cycle changes, e.g. carbon burial durin

关键词： biocrisis ultimate cause proximate cause bolide large igneous province bioevolutionary event

Large reversible magnetocaloric effect in antiferromagnetic Er_(3)Si_(2)C_(2) compound

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Journal of Rare Earths 2024年第8期42卷 1555-1559,I0005页

作者： Hao Sun Lu Tian Xinqiang Gao Zhaojun Mo jun shen Baogen shen School of Rare Earths University of Science and Technology of ChinaHefei230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou341000China Department of Energy and Power Engineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing100081China

The magnetic properties,magnetic phase transition and magnetocaloric effects(MCE) of Er_(3)Si_(2)C_(2) compound were investigated based on theoretical calculations and experimental *** on the first principles calculations,the antiferromagnetic(AFM) ground state type in Er_(3)Si_(2)C_(2) compound was predicted and its electronic structure was *** experimental results show that Ei_(3)Si_(2)C_(2) compound is an AFM compound with the Neel temperature(T_(N) of 7 K and undergoes a field-induced firstorder magnetic phase transition from AFM to ferromagnetic(FM) under magnetic fields exceeding 0.6 T at 2 *** magnetic transition process of Er_(3)Si_(2)C_(2) compound was investigated and *** values of the maximum magnetic entropy change(-ΔS_(M)^(max)) and the refrigeration capacity(RC) are 17 J/(kg·K)and 193 J/kg under changing magnetic fields of 0-5 T,*** a potential cryogenic magnetic refrigerant,the Er_(3)Si_(2)C_(2) compound also provides an interesting research medium to study the magnetic phase transition process.

关键词： Magnetic materials Magnetocaloric Metamagnetic transitions Magnetic phase transition Rare earths

Progress on the glassy-crystal laminates:From design,microstructure to deformation and future solutions

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Journal of Materials Science & Technology 2024年第5期172卷 113-144页

作者： Yu Chen Ronggao Cui jun shen Gang Wang College of Mechatronics and Control Engineering Shenzhen UniversityShenzhen 518060China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Department of Motor Design Business Weichai New Energy Technology Co.Ltd.Weifang 261061China Guangdong Key Laboratory of Electromagnetic Control and Intelligent Robots Shenzhen UniversityShenzhen 518060China Laboratory for Microstructures Institute of MaterialsShanghai UniversityShanghai 200444China

The development of new design strategies to create innovative structural materials,refine existing ones,and achieves compatible combinations of strength and plasticity remains a worldwide *** alloys,such as shape memory alloys(SMAs),bulk metallic glasses(BMGs),high entropy alloys(HEAs),and heterogeneous pure metals such as Cu,have excellent mechanical responses,but they still fall short of meeting all the requirements of structural materials due to specific flaws,such as lack of tensile de-formation for BMGs and low yielding strength for *** address these shortcomings,proposals such as integrating glassy matrices and crystallized alloys,such as HEAs/SMAs,have been ***,these solutions have unresolved issues,such as the challenging control of B2 phase formation in BMG ***,glass-crystal(A/C)laminated alloys with alternating layers have been reported to exhibit improved mechanical properties and activated work-hardening behaviors,but they still face press-ing issues such as bonding interfaces and unknown deformation *** review focuses on design routes such as the selection of alloy components and processing techniques,exploration of micro-structural evolution and deformation modes with an increase in strain,and future solutions to address pressing and unsolved *** prominent advantages include diversified deformation mechanisms,such as deformation twinning,martensitic phase transformation,and precipitation hardening,as well as tuned interactive reactions of shear bands(SBs)near the A/C ***,this review provides a promising pathway to design and develop structural materials in the materials field community.

关键词： Glassy-crystal laminates Bulk metallic glasses High entropy alloys Shape memory alloys Microstructure Deformation mechanisms Future solutions

Derivatives of Intersection Local Time for Two Independent Symmetricα-stable Processes

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1273-1292页

作者： Huan ZHOU Guang jun shen Qian YU Department of Mathematics Anhui Normal UniversityWuhu 241002P.R.China Department of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 211106P.R.China Key Laboratory of Mathematical Modelling and High Performance Computing of Air Vehicles(NUAA) MIITNanjing 211106P.R.China

In this paper,we consider the derivatives of intersection local time for two independent d-dimensional symmetricα-stable processes X^(α) and X^(α)with respective indices α and α.We first study the sufficient condition for the existence of the derivatives,which makes us obtain the exponential integrability and H?lder *** we show that this condition is also necessary for the existence of derivatives of intersection local time at the ***,we also study the power variation of the derivatives.

关键词： Symmetric stable processes intersection local time exponential integrability power variation

Large low-field reversible magnetocaloric effect in K_(3)Gd(PO_(4))_(2) at sub-Kelvin temperature

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Journal of Rare Earths 2024年第6期42卷 1087-1092,I0003页

作者： Haojie Wang Zhaojun Mo Jianjian Gong Heng Tu Guochun Zhang jun shen School of Rare Earths University of Science and Technology of ChinaHefei230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou341119China Center for Crystal Research and Development Key Laboratory of Functional Crystals and Laser TechnologyKey Laboratory of CryogenicsTechnical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China Department of Energy and PowerEngineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing100081China

We synthesized a potassium gadolinium phosphate K3Gd(PO_(4))_(2)with monoclinic structure(P2_(1/m))by the high-temperature solid-state reaction *** lattice constants obtained by Rietveld refinements of XRD curve are a=0.7411 nm,b=0.5624 nm,and c=0.9433 *** and magnetocaloric properties of K_(3)Gd(PO_(4))_(2)were investigated in *** magnetic phase transition temperature of K3Gd(PO_(4))2 was determined by ultra-low temperature testing to be 0.58 K.K_(3)Gd(PO_(4))2 exhibits large magnetic entropy changes(-ΔSM).The maximum-ΔSM are 20.2 and 29.4 J/(kg·K)in the magnetic field variation(ΔH)of 1 and 2 T,respectively,which are larger than that of the commercial Gd_(3)Ga_(5)O_(12)(GGG).The maximum adiabatic temperature change(ΔT_(ad))reaches 5.91 K under a magnetic field change(ΔH)of 1 T.K_(3)Gd(PO_(4))_(2)is a potential magnetic refrigeration material for obtaining sub-Kelvin temperatures.

关键词： Ultra-low temperature Magnetocaloric effect Magnetic entropy change Magnetic refrigeration Rare earths

Theoretical study on the effect of H_(2)O on the formation mechanism of NO_(x) precursors during indole pyrolysis

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Frontiers of Chemical Science and Engineering 2024年第6期18卷 99-112页

作者： Ziqi Wang jun shen Xuesong Liu Sha Wang shengxiang Deng Hai Zhang Yun Guo School of Mechanical and Automotive Engineering Shanghai University of Engineering ScienceShanghai 201620China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The incineration technology of kitchen waste is one of the effective technologies to achieve the resource utilization of municipal solid *** is an important stage of *** is a rich initial product in the pyrolysis process of kitchen waste,and the presence of H_(2)O has a significant impact on the decomposition of indole to form NO_(x) ***,this study uses density functional theory method to study the effect of H_(2)O on the thermal decomposition of indole to produce NH_(3),HNCO,and *** H_(2)O participates in the reaction,it can provide oxidative groups to generate a new product HNCO,which is different from the previous findings by indole pyrolysis without the presence of H_(2)***,this study theoretically proves that NH_(3) is easier to form than *** is consistent with the phenomenon that NH_(3) release is higher than HCN release in pyrolysis *** addition,compared with the individual pyrolysis of indole,the participation of H_(2)O reduces the energy barriers for the formation of NH_(3) and HCN during indole pyrolysis,thereby promoting the formation of NH_(3) and HCN.

关键词： indole pyrolysis H_(2)O NO_(x)precursors DFT

Review on current development of polybenzimidazole membrane for lithium battery

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Journal of Energy Chemistry 2024年第4期91卷 579-608页

作者： Yonggui Deng Arshad Hussain Waseem Raza Xingke Cai Dongqing Liu jun shen College of Mechatronics and Control Engineering Shenzhen UniversityShenzhen 518060GuangdongChina Interdisciplinary Research Center for Hydrogen Technologies and Carbon Management(IRC-HTCM) King Fahd University of Petroleum&MineralsKFUPM Box 504031261 DhahranSaudi Arabia Institute for Advanced Study Shenzhen UniversityShenzhen 518060GuangdongChina

With the rapid development of portable technology,lithium batteries have emerged as potential candidates for high-performance energy storage systems owing to their high energy density and cycling *** the key components of a lithium battery system,the separator plays a critical role as it directly influences the battery performance benchmark(cycling performance and safety).However,traditional polyolefin separators(polypropylene/polyethylene)are unable to meet the demands of highperformance and safer battery systems due to their poor electrolyte compatibility,thermal runaways,and ultimate growth of *** contrast,membranes fabricated using polybenzimidazole(PBI)exhibit excellent electrolyte wettability and outstanding thermal dimensional stability,thus holding great potential as separators for high-performance and high-safety *** this paper,we present a comprehensive review of the general requirements for separators,synthesis technology for separators,and research trends focusing PBI membranes in lithium batteries to alleviate the current commercial challenges faced by conventional polyolefin *** addition,we discuss the future development direction for PBI battery separators by considering various factors such as production cost,ecological footprint,preparation technology,and battery component *** exploring these perspectives,we aim to promote the continued application and exploration of PBI-based materials to advance lithium battery technology.

关键词： Lithium batteries Separators Porous separators Polybenzimidazole Membrane

SmartEagleEye:A Cloud-Oriented Webshell Detection System Based on Dynamic Gray-Box and Deep Learning

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Tsinghua Science and Technology 2024年第3期29卷 766-783页

作者： Xin Liu Yingli Zhang Qingchen Yu Jiajun Min jun shen Rui Zhou Qingguo Zhou School of Information Science and Engineering Lanzhou UniversityLanzhou 730000China College of Computer Science and Technology Zhejiang UniversityHangzhou 310058China School of Computing and Information Technology University of WollongongWollongong 2500Australia

Compared with traditional environments,the cloud environment exposes online services to additional vulnerabilities and threats of cyber attacks,and the cyber security of cloud platforms is becoming increasingly prominent.A piece of code,known as a Webshell,is usually uploaded to the target servers to achieve multiple *** Webshell attacks has become a hot spot in current ***,the traditional Webshell detectors are not built for the cloud,making it highly difficult to play a defensive role in the cloud ***,a Webshell detection system based on deep learning that is successfully applied in various scenarios,is proposed in this *** system contains two important components:gray-box and neural network *** gray-box analyzer defines a series of rules and algorithms for extracting static and dynamic behaviors from the code to make the decision *** neural network analyzer transforms suspicious code into Operation Code(OPCODE)sequences,turning the detection task into a classification *** experiment results show that SmartEagleEye achieves an encouraging high detection rate and an acceptable false-positive rate,which indicate its capability to provide good protection for the cloud environment.

关键词： Webshell detection cloud web security deep learning

Synergistic CO_(2) mineralization using coal fly ash and red mud as a composite system

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International Journal of Coal Science & Technology 2024年第3期11卷 149-158页

作者： Zhenchao Yao Yugao Wang jun shen Yanxia Niu Jiang Feng Yang Xianyong Wei School of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuanShanxi030024China Key Laboratory of Coal Processing and Efficient Utilization Ministry of EducationUniversity of Mining&Technology221116XuzhouJiangsuChina

CO_(2) mineralization plays a critical role in the storage and utilization of CO_(2).Coal fly ash(CFA)and red mud(RM)are widely utilized as CO_(2) ***,the inert calcium species in CFA limit its carbonation capacity,meanwhile the substantial Ca^(2+)releasing of RM is hindered by a covering layer of calcium *** this study,CO_(2) mineralization in a composite system of CFA and RM was investigated to enhance the carbonation *** analyzers were employed to characterize the raw materials and resulting mineralization *** results demonstrated that a synergistic effect existed in the composite system of CFA and RM,resulting in improving CO_(2) mineralization rate and *** produced calcium carbonate was ectopically attached the surface of CFA in the composite system,thus slowing down its coverage on the surface of *** phenomenon facilitated further releasing Ca^(2+)from the internal RM,thereby enhancing CO_(2) mineralization ***,the inclusion of RM significantly improved the alkalinity of the composite system,which not only promoted the dissolution of Ca^(2+)of the inert CaSO_(4)(H_(2)O)_(2) in CFA,but also accelerated CO_(2) mineralization *** investigation would be beneficial to CO_(2) mineralization using industrial solid wastes.

关键词： CO_(2)mineralization Coal fly ash Red mud Synergistic effect