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Ion and electron motions in the outer electron diffusion region of collisionless magnetic reconnection

earth and Planetary Physics 2024年第3期8卷 472-478页

作者： Cong Chang QuanMing Lu San Lu Kai Huang RongSheng Wang Deep space Exploration Laboratory School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Chinese Academy of sciences(CAS)center for Excellence in Comparative Planetology CAS Key Laboratory of Geospace EnvironmentHefei 230026China collaborative innovation center of Astronautical science and Technology Harbin 150001China

Two-dimensional particle-in-cell simulations are performed to study the coupling between ion and electron motions in collisionless magnetic *** electron diffusion region(EDR),where the electron motions are demagnetized,is found to have a two-layer structure:an inner EDR near the reconnection site and an outer EDR that is elongated to nearly 10 ion inertial lengths in the outflow *** the inner EDR,the speed of the electron outflow increases when the electrons move away from the X *** the outer EDR,the speed of the electron outflow first increases and then decreases until the electrons reach the boundary of the outer *** the boundary of the outer EDR,the magnetic field piles up and forms a depolarization *** the perspective of the fluid,a force analysis on the formation of electron and ion outflows has also been *** the X line,the electrons are accelerated by the reconnection electric field in the out-of-plane *** the electrons move away from the X line,we find that the Lorentz force converts the direction of the accelerated electrons to the x direction,forming an electron *** electric field forces and electron gradient forces tend to drag the electron *** acceleration along the x direction is caused by the Lorentz force,whereas the pressure gradient force tends to decelerate the ion *** these two terms are important,their effects on ions are almost *** Hall electric field force does positive work on ions and is not *** ions are continuously accelerated,and the ion and electron outflow velocities are almost the same near the depolarization front.

关键词： collisionless magnetic reconnection electron diffusion region force analysis particle-in-cell simulation

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C_(60) as a metal-free catalyst for lithium-oxygen batteries

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Nano Research 2024年第5期17卷 3982-3987页

作者： Xinxin Zhang Jiaming Tian Yu Wang Shaohua Guo Yafei Li Jiangsu collaborative innovation Centre of Biomedical Functional Materials School of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023China College of Engineering and Applied sciences Jiangsu Key Laboratory of Artificial Functional MaterialsNational Laboratory of Solid State MicrostructuresCollaborative Innovation Center of Advanced MicrostructuresFrontiers Science Center for Critical Earth Material CyclingNanjing UniversityNanjing 210023China

Carbon materials have shown significant potential as catalysts for lithium-oxygen batteries(LOBs).However,the intrinsic carbon sites are typically inert,necessitating extensive modifications and resulting in a limited density of active *** we present C_(60) as a metal-free cathode catalyst for LOBs,using density functional theory calculations and experimental *** lithiation reactions on the pristine carbon sites of C_(60) are energetically favorable due to its curvedπ-conjugation over the pentagon-hexagon *** kinetic analysis specifically reveals low energy barriers for Li_(2)O_(2) decomposition and Li diffusion on C_(60).Consequently,C_(60) exhibits significantly higher catalytic activity than typical carbon materials such as graphene and carbon *** electrochemical measurements validate the predictions,notably demonstrating that the intrinsic activity of C_(60) is comparable to that of noble metals.

关键词： lithium-oxygen batteries C_(60) density functional theory(DFT)calculations metal-free cathode

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Global hybrid simulations of soft X-ray emissions in the earth’s magnetosheath

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earth and Planetary Physics 2024年第1期8卷 47-58页

作者： Jin Guo TianRan Sun San Lu QuanMing Lu Yu Lin XueYi Wang Chi Wang RongSheng Wang Kai Huang School of earth and space sciences University of Science and Technology of ChinaHefei 230026China CAS center for Excellence in Comparative Planetology/CAS Key Lab of Geospace Environment University of Science and Technology of ChinaHefei 230026China collaborative innovation center of Astronautical science and Technology Harbin 150001China National space science center Chinese Academy of SciencesBeijing 100190China Physics Department Auburn UniversityAuburnALUSA

earth’s magnetopause is a thin boundary separating the shocked solar wind plasma from the magnetospheric plasmas,and it is also the boundary of the solar wind energy transport to the *** X-ray imaging allows investigation of the large-scale magnetopause by providing a two-dimensional(2-D)global view from a *** performing 3-D global hybrid-particle-in-cell(hybrid-PIC)simulations,we obtain soft X-ray images of earth’s magnetopause under different solar wind conditions,such as different plasma densities and directions of the southward interplanetary magnetic *** all cases,magnetic reconnection occurs at low latitude *** soft X-ray images observed by a hypothetical satellite are shown,with all of the following identified:the boundary of the magnetopause,the cusps,and the *** X-ray emissivity in the magnetosheath is characterized by large amplitude fluctuations(up to 160%);however,the maximum line-of-sight-integrated X-ray intensity matches the tangent directions of the magnetopause well,indicating that these fluctuations have limited impact on identifying the magnetopause boundary in the X-ray ***,the magnetopause boundary can be identified using multiple viewing *** also find that solar wind conditions have little effect on the magnetopause *** Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will provide X-ray images of the magnetopause for the first time,and our global hybrid-PIC simulation results can help better understand the 2-D X-ray images of the magnetopause from a 3-D perspective,with particle kinetic effects considered.

关键词： magnetopause X-ray emissivity X-ray imaging SMILE global hybrid-PIC simulation

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Iso-propagation vortices with OAM-independent size and divergence toward future faster optical communications

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Advanced Photonics 2024年第3期6卷 51-59页

作者： Wenxiang Yan Zhaozhong Chen Xian Long Yuan Gao Zheng Yuan Zhi-Cheng Ren Xi-Lin Wang Jianping Ding Hui-Tian Wang Nanjing University School of Physics National Laboratory of Solid State Microstructures Nanjing University Collaborative Innovation Center of Advanced Microstructures University of Glasgow James Watt School of Engineering Nanjing University Collaborative Innovation Center of Solid-State Lighting and Energy-Saving Electronics

Recognized in the 1990s, vortex beams' ability to carry orbital angular momentum(OAM) has significantly contributed to applications in optical manipulation and high-dimensional classical and quantum information communication. However, inherent diffraction in free space results in the inevitable expansion of beam size and divergence contingent upon the OAM, limiting vortex beams' applicability in areas such as spatial mode multiplexing communication, fiber-optic data transmission, and particle manipulation. These domains necessitate vortex beams with OAM-independent propagation *** introduce iso-propagation vortices(IPVs), vortex beams characterized by OAM-independent propagation behavior, achieved through precise radial index configuration of Laguerre–Gaussian beams. IPVs display notable transmission dynamics, including a reduced quality factor, resilience post-damage, and decreased and uniform modal scattering under atmospheric turbulence. Their distinctive attributes render IPVs valuable for potential applications in imaging, microscopy, optical communication, metrology, quantum information processing, and light–matter interactions. Notably, within optical communication, the case study suggests that the IPV basis, due to its OAM-independent propagation behavior, provides access to a more extensive spectrum of data channels compared with conventional spatial multiplexing techniques, consequently augmenting information capacity.

关键词： orbital angular momentum optical communication structured light optical vortices

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CO_(2) hydrogenation to methanol over the copper promoted In_(2)O_(3) catalyst

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Journal of Energy Chemistry 2024年第6期93卷 135-145,I0004页

作者： Rui Zou Chenyang Shen Kaihang Sun Xinbin Ma Zhuoshi Li Maoshuai Li Chang-Jun Liu School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China collaborative innovation center of Chemical science&Engineering Tianjin UniversityTianjin 300072China

The metal promoted In_(2)O_(3) catalysts for CO_(2) hydrogenation to methanol have attracted wide attention because of their high activity with high methanol ***,there was still no experimental confirmation if copper could be a good promoter for In_(2)O_(3).Herein,the Cu promoted In_(2)O_(3) catalyst was prepared using a deposition-precipitation *** prepared Cu/In_(2)O_(3) catalyst shows significantly higher CO_(2) conversion and space time yield(STY)of methanol,compared to the un-promoted In_(2)O_(3) *** loading of Cu facilitates the activation of both H_(2) and CO_(2) with the interface between the Cu cluster and defective In_(2)O_(3) as the active *** Cu/In_(2)O_(3) catalyst takes the CO hydrogenation pathway for methanol synthesis from CO_(2) *** exhibits a unique size effect on the CO *** temperatures below 250℃,CO adsorption on Cu/In_(2)O_(3) is stronger than that on In_(2)O_(3),causing higher methanol *** increasing temperatu res,the Cu catalyst aggregates,which leads to the formation of weak CO adsorption site and causes a decrease in the methanol *** with other metal promoted In_(2)O_(3) catalysts,it can be concluded that the catalyst with stronger CO adsorption possesses higher methanol selectivity.

关键词： CO_(2)hydrogenation Methanol Cu In_(2)O_(3) CO Selectivity DFT

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Supported Atomically Dispersed Pd Catalyzed Direct Alkoxylation and Allylic Alkylation

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Chinese Journal of Chemistry 2024年第7期42卷 719-724页

作者： Ruixuan Qin Ziwen Chen Qingyuan Wu Nanfeng Zheng Pengxin Liu New Cornerstone science Laboratory State Key Laboratory for Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy Materialsand National&Local Joint Engineering Research Center of Preparation Technology of NanomaterialsCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamenFujian 361005China innovation Laboratry for Scences and Technoogies of Energy Materials of Fujan Province(IKKM) Xiamen Fujian 361102China School of Physical science and Technology Shanghai Tech UniversityShanghai 201210China Fujian Key Laboratory of Rare-earth Functional Materials Fujian Shanhai Collaborative Innovation Center of Rare-earth Functional MaterialsLongyanFujian 366300China

A new approach to allylic alkylation is realized using an atomically dispersed palladium catalyst(Pd1/TiO2-EG).Unlike conventional methods that require derivation of substrates and utilization of additives,this method allows for direct allylic alkylation from allylic alcohols,producing H2O as the sole *** catalyst's high efficiency is attributed to the local hydrogen bonding at the or-ganic-inorganic interface(Pd-EG interface),facilitating hydroxyl group activation forη3π-allyl complex *** system demonstrates successful direct C—O and C—C coupling reactions with high selectivity,requiring no *** study highlights the potential of supported atomically dispersed catalysts for greener and more efficient catalysis,meanwhile,offers unique insights into the distinct behavior of atomically dispersed catalysts in comparison to homogeneous or nanoparticle-based catalysts.

关键词： Atomically dispersed catalyst Alkylation C—C coupling Organic-inorganic Interface Hydrogen bond Tsuji-Trost reaction Green catalysis

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Azocalixarenes: a scaffold of universal excipients with high efficiency

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science China Chemistry 2024年第5期67卷 1697-1706页

作者： Yu-Xin Yue Yi-Lin Lin Meng-Meng Chen Han-Wen Tian Rong Ma Ze-Han Wang Fang-Yuan Chen Yu-Chen Pan Dong-Sheng Guo College of Chemistry State Key Laboratory of Elemento-Organic ChemistryKey Laboratory of Functional Polymer Materials(Ministry of Education)Frontiers Science Center for New Organic MatterCollaborative Innovation Center of Chemical Science and Engineering(Tianjin)Nankai UniversityTianjin 300071China

Excipients are important components of pharmaceutical preparations that affect their quality, safety, and efficacy. Macrocyclic receptors are a family of supramolecular excipients with several advantages, including molecular-level protection, small sizes,fast kinetics of host-guest recognition, and modular construction. With the continuous advances in the medical field, personalized and precision medicine requires the development of excipients with low dosages, integrated modifying effects, universality,and controlled release. To meet these requirements, we have developed a new family of macrocyclic excipients based on calixarenes by integrating their covalent(broad chemical design space) and noncovalent(wide range of substrates) ***, azocalixarenes(Azo CAs) were designed, showing high binding affinities to a broad spectrum of active pharmaceutical ingredients(APIs), selectivity to interferents, and responsiveness to hypoxic microenvironments. Due to their highly efficient and controllable recognition, Azo CAs serve as low-dose excipients for 30 APIs. Molecular encapsulation by Azo CAs results in the integrated modification of the physicochemical properties of APIs, including solubility, stability, bioavailability,and biocompatibility. Moreover, Azo CAs can be reduced by azoreductases overexpressed in hypoxic microenvironments,leading to the controlled release of APIs. Collectively, Azo CA excipients have broad application prospects for a series of diseases such as enteritis, arthritis, stroke, cancer, bacterial infection and kidney injury, with diverse therapeutic modalities,including chemotherapy, photodynamic therapy, photothermal therapy, immunotherapy, boron neutron capture therapy, radiotherapy, fluorescence imaging, and their combinations.

关键词： supramolecular chemistry host-guest systems excipient calixarene molecular recognition

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Effects of water molecules on luminescence in europium and terbium coordination polymers with p-fluorobenzoic acid as ligand

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Journal of Rare earths 2024年第7期42卷 1258-1264,I0003页

作者： Xiaoqi Zhao Puyan Hao Yami Ling Mengzhen Jia Rui Zhu Jiawen Liu Qiang Xu Jianhong Zhou collaborative innovation center of Rare-earth Optical Functional Materials and Devices Development Baoji Key Laboratory of Micro-Nano Optoelectronics and Terahertz TechnologySchool of Physics and Opto-Electronic TechnologyBaoji University of Arts and SciencesBaoji721016China

Our previous experimental observations show that the crystal structure of lanthanide luminescent complexes synthesized in aqueous solution usually contains a large number of coordination water molecules or free water *** order to probe the influence of water molecules on luminescent processes of lanthanide complexes,the photoluminescence properties of Ln-FBA(Ln=Eu and Tb,FBA=p-fluorobenzoic acid)coordination polymers at different ambient temperatures,in different solvents and aqueous DMSO solutions with different volume concentrations were systematically *** experiment results show that the presence of water molecules can promote the energy transfer from FBA ligand to Ln3+,at the same time,can cause luminescent non-radiation quenching of lanthanide *** addition,the variation of emission intensity ratio of 615 nm/591 nm peaks of Eu^(3+)with increasing the volume concentration of H_(2)O can be potentially used for the quantitatively detection of water traces in organic *** order to suppress the non-radiation quenching caused by the water molecules,Ln-FBA(Ln=Eu and Tb)coordination polymers were embedded into the PVP matrix to prepare Ln-FBA@PVP hybrid *** photoluminescence investigation indicates that PVP can not only block the quenching effect of water molecules on luminescence,but also effectively sensitize Eu^(3+)and Tb^(3+)*** experimental conclusions are useful for probing the influence of water molecules on luminescent processes of lanthanide complexes,quantitatively detecting water traces in organic solvents and enhancing the photoluminescence intensity in lanthanide complexes.

关键词： Lanthanide complexes Photoluminescence Luminescent quenching Rare earths

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Tropical cyclone genesis over the western north Pacific in La Ni?a decay summers: Comparison between 2018 and 2021

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science China earth sciences 2024年第10期67卷 3098-3109页

作者： Yunyun LIU Zhensong GONG China Meteorological Administration Key Laboratory for Climate Prediction Studies National Climate Centre collaborative innovation center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science &Technology

As the primary interannual signal of variability in the tropical ocean-atmosphere interaction, the El Ni?o-Southern Oscillation has a considerable impact on tropical cyclone(TC) activity over the western North Pacific(WNP). Both 2018 and2021 were La Ni?a decay years, but TC activity over the WNP during the two summers(June–August) showed notable differences. In 2018, summer TC activity was unusually high with a total of 18 TCs, and the region of TC genesis was mainly in the central and eastern WNP. In contrast, only 9 TCs were generated in summer 2021, and the region of TC genesis was primarily in the western WNP. By comparing the characteristics of the large-scale environmental conditions over the regions of TC genesis, the thermal factors of the tropical oceans, and the activity of the Madden-Julian Oscillation(MJO), this study revealed the possible causes for the marked differences in TC genesis over the WNP during the two summers, which both had a similar background of La Ni?a decay. The Indian Ocean Basin Mode(IOBM) transitioned of a cold anomaly in the winter of 2017/2018and persisted until summer 2018. At the same time, the Pacific Meridional Mode(PMM) maintained a positive phase, leading to eastward and northward displacement of the Western Pacific Subtropical High in summer, and eastward extension of the tropical monsoon trough, which presented conditions conducive to TC genesis over the Northwest Pacific. Moreover, the days when the MJO stagnated in phases 5 and 6 in the summer of 2018 increased by approximately 150% relative to climatological state,providing dynamic conditions favorable for TC formation. In 2021, the IOBM quickly turned to a warm anomaly in March and persisted until summer, whereas the PMM became a negative phase in January and remained so until summer. At the same time,the MJO stagnated in phases 2 and 3 for up to 47 days, with the center of convection located over the western Maritime Continent, producing conditions unconducive to TC ge

关键词： Tropical cyclone La Niña events Indian Ocean Basin Mode Pacific Meridional Mode Madden-Julian Oscillation Western Pacific Subtropical High Monsoon trough

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Giant low-field reversible magnetocaloric effect at liquid helium temperature of niobium and iron co-substituted EuTiO_(3) compounds

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Journal of Rare earths 2024年第4期42卷 710-715页

作者： Zhihong Hao Quanyi Liu Huicai Xie Yan Zhang Zhaojun Mo School of Rare earth and New Materials Engineering Ganzhou Innovation Center of Rare Earth Permanent Magnet Material Advanced Manufacturing and Intelligent Equipment TechnologyGannan University of Science and TechnologyGanzhou341000China Ganjiang innovation Academy Chinese Academy of SciencesGanzhou34119China School of Materials science and Engineering Taiyuan University of Science and TechnologyTaiyuan030024China

Giant magnetocaloric effect(MCE)materials in the liquid helium temperature region have attracted a lot of attention in the field of low-temperature magnetic refrigeration(MR).In this study,a series of niobium(Nb)and iron(Fe)co-substituted EuTiO_(3) perovskites with cubic structure(space group pm3m)was successfully fabricated,and their magnetic properties as well as cryogenic magnetocaloric effects were investigated in *** expected,the introduction of Nb and Fe can significantly modulate the magnetic phase transition and magnetocaloric effect of the EuTiO_(3) *** increasing Fe concentration,two local minima corresponding to the AFM-FM magnetic phase transition near 5.0 K and FM-PM transition near 10 K with no hysteresis in the thermomagnetic curves are observed,which is attributed to an enhancement of FM *** the same time,the gradually widened-ΔSM-T curves and the two peaks with a broad shoulder lead to considerable refrigeration capacity(RC).With the field change ofΔH=2 T,the calculated values of-ΔS_(M)^(max) for the EuTi_(0.9375-x)Nb_(0.0625)Fe_(x)O_(3)(x=0.075,0.1,0.125,0.15)compounds are 24.2,17.6,14.5 and 14.0 J/(kg·K),*** corresponding RC values were calculated to be 144.6,138.3,151.2 and 159 J/kg,***,the values of-ΔS_(M)^(max) for EuTi_(0.8625)Nb_(0.0625)Fe_(0.075)O_(3) are 8.6 and 15.1 J/(kg·K)under low field changes of 0.5 and 1 T,*** giant low-field reversible magnetocaloric effect makes them attractive candidates for magnetic refrigeration in the liquid helium temperature region.

关键词： Magnetocaloric effect Refrigeration capacity Magnetic entropy change Rareearths

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