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Impacts of land surface darkening on frozen ground and ecosystems over the Tibetan Plateau

Science China Earth Sciences 2024年第10期67卷 3213-3225页

作者： Shuchang TANG Tao WANG Dan LIU Tandong yao Shilong PIAO Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking UniversityBeijing 100101China State Key Laboratory of Tibetan Plateau Earth System Resources and EnvironmentInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

Tibetan Plateau(TP) is known as the “Third Pole” of the Earth. Any changes in land surface processes on the TP can have an unneglectable impact on regional and global climate. With the warming and wetting climate, the land surface of the TP saw a darkening trend featured by decreasing surface albedo over the past decades, primarily due to the melting of glaciers, snow,and greening vegetation. Recent studies have investigated the effects of the TP land surface darkening on the field of climate, but these assessments only address one aspect of the feedback loop. How do these darkening-induced climate changes affect the frozen ground and ecosystems on the TP? In this study, we investigated the impact of TP land surface darkening on regional frozen ground and ecosystems using the state-of-the-art land surface model ORCHIDEE-MICT. Our model results show that darkening-induced climate changes on the TP will lead to a reduction in the area of regional frozen ground by 1.1×10~4±0.019×10~4km~2, a deepening of the regional permafrost active layer by 0.06±0.0004 m, and a decrease in the maximum freezing depth of regional seasonal frozen ground by 0.06±0.0016 m compared to the scenario without TP land surface ***, the darkening-induced climate change on the TP will result in an increase in the regional leaf area index and an enhancement in the regional gross primary productivity, ultimately leading to an increase in regional terrestrial carbon stock by0.81±0.001 PgC. This study addresses the remaining piece of the puzzle in the feedback loop of TP land surface darkening, and improves our understanding of interactions across multiple spheres on the TP. The exacerbated regional permafrost degradation and increasing regional terrestrial carbon stock induced by TP land surface darkening should be considered in the development of national ecological security barrier.

关键词： Tibetan Plateau Albedo Land surface darkening Frozen ground Ecosystem

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Exploring luminescence quenching on lanthanide-doped nanoparticles through changing the spatial distribution of sensitizer and activator

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Nano Research 2024年第5期17卷 4517-4524页

作者： Jiwei Li yao Xie Renrui Sun Junxun Zhou Lining Sun Department of Chemistry College of SciencesShanghai UniversityShanghai 200444China Department of Physics College of SciencesShanghai UniversityShanghai 200444China School of Medicine Shanghai UniversityShanghai 200444China

Luminescence quench is common in overdoped upconversion *** methods have been proposed to counteract the adverse effects of concentration quenching on luminescence,but in upconversion nanoparticles that are highly doped with both sensitizers and activators,the factors that contribute to the diminishing of the emission cannot be summarized by a single ***,a core-shell design is used to spatially separate the sensitizer(Yb^(3+))and activator(Er^(3+))and to modulate the emission by changes in the distribution position as well as the concentration of the dopant ions in order to probe the factors affecting the *** the sensitizer ions are located in the core,the luminescence intensity of the nanoparticles is significantly weaker than that of the other distribution,which implies that the effect of sensitizer and activator on luminescence in the highly doped state has a different and more complex *** intensity of the emission is more affected by Yb^(3+)than Er^(3+),which includes not only the self-quenching of Yb^(3+),but also the dominance in the Yb^(3+)-Er^(3+)*** this finding may provide new ideas for revealing the reasons for the diminished luminescence of highly doped upconversion nanoparticles and thus for enhancing luminescence.

关键词： upconversion luminescence lanthanide ion core-shell nanoparticles concentration quenching cross-relaxation

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Legacy and emerging per-and polyfluoroalkyl substances(PFAS) in the atmosphere: A comprehensive review

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Science China Technological Sciences 2024年第10期67卷 3032-3050页

作者： QIAO BiTing SONG DongBao CHEN Hao yao YiMing SUN HongWen MOE Key Laboratory of Pollution Processes and Environmental Criteria College of Environmental Science and EngineeringNankai University

With long-term production and widespread application, per-and polyfluoroalkyl substances(PFAS) have been detected in various media worldwide, including the atmosphere. Since the gradual restriction and phase-out of C8perfluoroalkyl acids(PFAAs), environmental contamination by emerging PFAS substitutes such as short-chain PFAA homologues, perfluoroether carboxylic, and sulfonic acids has been reported. Although there has been extensive monitoring of emerging PFAS substitutes in the aquatic environment, few studies have conducted target analysis and nontarget screening(NTS) of emerging unknown PFAS in the atmosphere over the past decade. To fill the gap, this review focused on emerging PFAS in the atmosphere in addition to legacy PFAS. The reported sampling, pretreatment, and instrumental analysis methods for target analysis and NTS of both neutral and ionic PFAS in the atmosphere are summarized, along with the advantages and current limitations of different sampling and NTS methods for PFAS in the atmosphere. The global levels, composition, and spatiotemporal distribution characteristics of legacy and emerging PFAS in the atmosphere are summarized and their transport, transformation, and dry/wet deposition are elucidated. The review highlights the importance of developing and applying the all-in-one strategy integrating target, suspect screening, and NTS to gain insights into emerging PFAS in the atmosphere and provide a reference for future research.

关键词： emerging PFAS atmosphere nontarget screening spatiotemporal distribution fate

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Synergistic asymmetric diarylation of tethered alkenes via C–H functionalization of simple(hetero)arenes

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Science China Chemistry 2024年第8期67卷 2710-2718页

作者： Jian yao Can Zhao Lili Shao Xiaohong Huo Xiaoming Wang Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs Frontiers Science Center for Transformative MoleculesSchool of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China

By virtue of the atom-and step-economy, utilization of simple arenes as a supplant of pre-prepared aryl metal species or aryl halides for the synthesis of arylated chiral molecules has attracted great attention from the synthetic community. While transition-metal-catalyzed enantioselective diarylation of tethered alkenes has been employed to prepare important chiral cyclic compounds, the direct use of simple arenes as aryl precursors is still underdeveloped, probably due to the difficulties in the effective control of the reactivity, site-selectivity and/or enantioselectivity. Herein we report an asymmetric Pd/Ag dual metal catalytic system for the non-directed, site-and enantioselective domino Heck/intermolecular C–H functionalization of *** studies showed that Pd and Ag act in cooperation in the catalysis and the chiral bisphosphine ligand plays a bifunctional role, i.e., assisting the silver species in the cleavage of the aryl C–H bond, while inducing the enantioselectivity on direct complexation with palladium. This method provides an efficient approach to the corresponding chiral oxindoles with good enantiomeric excesses from a broad scope of arenes, including fluoroarenes, heteroarenes and several complex products derived from medicines or natural products.

关键词： asymmetric Pd/Ag dual metal catalytic system simple arenes C–H functionalization bifunctional role chiral oxindoles

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Low-permittivity LiLn(PO_(3))_(4)(Ln=La,Sm,Eu)dielectric ceramics for microwave/millimeter-wave communication

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Journal of Advanced Ceramics 2024年第5期13卷 602-620页

作者： Huanrong Tian Xiaohan Zhang Zidong Zhang yao Liu Haitao Wu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China School of Materials Science and Engineering Shandong UniversityJinan 250061China School of Environmental and Material Engineering Yantai UniversityYantai 264005China

The development of dielectric materials with low permittivity and low loss is a great challenge in wireless *** this study,LiLn(PO_(3))_(4)(Ln=La,Sm,Eu)ceramic systems were successfully prepared using the traditional solid-state method.X-ray diffraction analysis indicated that the LiLn(PO_(3))_(4)ceramics crystallized in a monoclinic structure when sintered at 850–940℃.The characteristic peak shifted to higher angles with variations in the Ln element,which was ascribed to a reduction in the cell *** analysis by structure refinement revealed that the reduction in the cell volume resulted from the decrease in chemical bond lengths and the compression of[LiO_(4)]and[PO_(4)]***,the LiLn(PO_(3))_(4)ceramic system displayed exceptional performance at low sintering temperatures(910–925℃),including a high quality factor(Q·f)of 41,607–75,968 GHz,low temperature coefficient of resonant frequency(τ_(f))ranging from−19.64 to−47.49 ppm/℃,low permittivity(ε_(r))between 5.04 and 5.26,and low density(3.04–3.26 g/cm^(3)).The application of Phillips–van Vechten–Levine(P–V–L)theory revealed that the increased Q·f value of the LiLn(PO_(3))_(4)systems can be attributed to the enhanced packing fraction,bond covalency,and lattice energy,and the stability of τ_(f) was associated with the increase in the bond ***,a prototype microstrip patch antenna using LiEu(PO_(3))_(4) ceramics was *** measurement results demonstrated excellent antenna performance with a bandwidth of 360 MHz and a peak gain of 5.11 dB at a central frequency of 5.08 ***,low-εr LiLn(PO_(3))_(4)ceramic systems are promising candidates for microwave/millimeter-wave communication.

关键词： low permittivity LiLn(PO_(3))_(4) microwave dielectric properties Phillips-van Vechten-Levine(P-V-L)theory microstrip patch antenna

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Non-cooperative Game Based Optimal Dispatch Model for Integrated Energy Systems

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1195-1207页

作者： Jiandong Duan Qian Sun Chen Wu yao Yang Siyu Tu School of Electrical Engineering Xi’an University of TechnologyXi’an710056China IEEE CSEE

In order to improve the efficiency of energy utilization,the integrated energy system(IES)has *** IES typically acts as a whole system during operations,the subsystems are separated,and the interests of each system are *** this paper,considering the relationship between the various energy systems,non-cooperative game theory is used to establish the optimal dispatch *** proposed model mainly relies on the relationship between the cooperation and competition among various subsystems to obtain the maximum benefit they can ***,the basic definition is combined with the particle swarm optimization algorithm to solve the *** results show that the optimization strategy proposed in this paper can operate safely and reliably,and effectively distribute the benefits of each energy system.

关键词： Integrated energy system multi-energy complimentarily non-cooperative game theory

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Research on mass loss and nose shape evolution of kinetic energy projectiles penetrating concrete at high velocity

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Acta Mechanica Sinica 2024年第7期40卷 92-108页

作者： Zhiyan yao Fenglei Huang Jinzhu Li State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

The high-speed penetration of concrete targets by kinetic energy projectiles results in apparent mass loss,which blunts the nose of the projectile and decrease its penetration *** friction work between the projectile and the concrete target,the plastic deformation of the projectile,and the cutting of aggregates to the projectile significantly affect the mass loss of the *** address these effects,a discrete iterative model is developed for the mass loss and nose shape evolution of the projectile by coupling three mechanisms based on the effect of temperature on *** the model,both friction work and plastic work increase the temperature of the projectile's surface layer,thereby weakening the strength of this part and rendering it easier for mass loss to occur due to aggregate *** model discretizes the projectile and penetration process with respect to the space and time dimensions,*** mass loss and nose shape evolution of the projectile are obtained by iteratively calculating a point-by-point *** predicted depth of penetration(DOP),mass loss,and residual projectile profile are compared with experimental data to validate the *** comparison shows satisfactory agreement between the calculated results and experimental ***,the deceleration,velocity,DOP,and mass loss during penetration are analyzed with respect to ***,based on the model,the effects of projectile strength,caliber-radius-head(CRH),and concrete target strength on penetration are discussed.

关键词： Kinetic energy projectile High-velocity penetration Coupled model Mass loss Nose shape evolution

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Superexchange and charge transfer in the nickelate superconductor La_(3)Ni_(2)O_(7) under pressure

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 1-8页

作者： Wéi Wú Zhihui Luo Dao-Xin yao Meng Wang Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of PhysicsSun Yat-sen UniversityGuangzhou 510275China

Recently, a bulk nickelate superconductor La_(3)Ni_(2)O_(7) is discovered at pressures with a remarkable high transition temperature T_(c)~ 80 K. Here, we study a Hubbard model with tight-binding parameters derived from ab initio calculations of La_(3)Ni_(2)O_(7),by employing large scale determinant quantum Monte Carlo and cellular dynamical mean-field theory. Our result suggests that the superexchange couplings in this system are comparable to that of cuprates. The system is a charge transfer insulator as the hole concentration becomes four per site at large Hubbard U. Upon hole doping, two low-energy spin-singlet bands emerge in the system exhibiting distinct correlation properties: while the one composed of the out-of-plane Ni-d_(3z^(2)-r^(2)) and O-p_(z) orbitals demonstrates strong antiferromagnetic correlations and narrow effective bandwidth, the in-plane singlet band consisting of the Ni-d_(x^(2)-y^(2)) and O-p_(x)/p_(y) orbitals is in general more itinerant. Over a broad range of hole doping, the doped holes occupy primarily the d_(x^(2)-y^(2)) and p_(x)/p_(y) orbitals, whereas the d_(3z^(2)-r^(2)) and p_(z) orbitals retain underdoped. We propose an effective t-J model to capture the relevant physics and discuss the implications of our result for comprehending the La_(3)Ni_(2)O_(7) superconductivity.

关键词： superconductivity nickelate superconductors Hubbard model superexchange charge transfer insulator quantum Monte Carlo

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Exploring a balance between strength and ductility of hexagonal BN nanoplatelet reinforced ZK61 magnesium composite

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Journal of Magnesium and Alloys 2024年第5期12卷 1899-1910页

作者： Kewei Zhang Xiaolong Lu Yufeng Sun Shaokang Guan yao Chen School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Key Laboratory of Advanced Magnesium Alloys in Henan Province Zhengzhou UniversityZhengzhou 450002China Key Laboratory of Advanced Materials Processing&Mold Ministry of EducationZhengzhou 450002China School of Mechanical and Electrical Engineering Soochow UniversitySuzhou 215021China

The practical applications of magnesium(Mg)alloys are usually beset by their relatively low strength and limited *** we attempt to fabricate hexagonal BN nanoplatelet(BNNP)reinforced ZK61 magnesium composites using a combination of spark plasma sintering and friction stir *** resulting composites exhibit microstructural characteristics of homogeneous dispersion of BNNP in Mg matrix with refined equiaxed grains and(0002)basal texture roughly surrounding the pin column *** electron microscopy observation illustrates that trace amounts of Mg_(3)N_(2)and MgB_(2)form at BNNP-Mg interface,in which Mg_(3)N_(2)locates at the basal plane of a BNNP and MgB_(2)grows at its open *** spatial distribution of Mg_(3)N_(2)and MgB_(2)facilitates interfacial wetting and stronger BNNP-Mg interface in such a way that interfacial products act as anchors bonding between *** comparison with monolithic ZK61 alloy,the BNNP/ZK61 composites display simultaneous improvements in yield strength,hardness and ductility,achieving good strength-ductility *** research is expected to shed some light on BNNP potentials for designing and producing magnesium composites with high strength and good ductility.

关键词： BN nanoplatelet Magnesium composite Strength Ductility Spark plasma sintering Friction stir processing

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Approaching high oxygen evolution reaction performance by synergetic dual-ion leaching

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Nano Research 2024年第9期17卷 7975-7983页

作者： Hancheng Ma yao Ding Jianqi Li Wei Peng Liqiang Mai School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Self-reconstruction of catalysts during oxygen evolution reaction(OER)is crucial for the development of energy conversion ***,the relationship between the specific atomic structure of pre-catalysts and their electrocatalytic behavior after reconstruction via dual-ion leaching has not been extensively *** this work,we design a highly effective non-noble metal OER catalyst with heterointerface through continuous self-reconstruction of Co_(2)(OH)_(3)Cl@NiMoO_(4)as pre-catalyst by a straightforward dual-ion(***_(4)^(2-)and Cl^(-))***-situ Raman and in-situ Fourier transform infrared(FT-IR)spectroscopy have precisely identified the progressive phase transformation of the pre-catalyst during self-reconstruction,which results in a stable heterojunction of CoOOH and NiOOH(CoOOH@NiOOH).Further calculations based on density functional theory(DFT)of CoOOH@NiOOH evident that more electrons will be aggregated in the Fermi level of ***,Gibbs free energy(ΔG)for different OER steps of CoOOH@NiOOH exhibit lower energy costs of all intermediates,implying the well catalytic ***,the catalyst derived from dual-ion leaching displays outstanding OER performance,characterized by an overpotential of 275 mV at a current density of 10 mA·cm^(-2)and exceptional stability over 12 h *** work successfully paves a way of finding high-performance OER catalysts based on non-noble metal through dual-ion leaching during self-reconstruction.

关键词： dual-ion leaching oxygen evolution reaction chemical reconstruction NiMoO_(4) Co_(2)(OH)_(3)Cl

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