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Catalytic behavior of m.-Bi-Fe-Co-K-m.O(m.Ce,Gd,CeGd)catalysts for selective ox.dation of isobutene

Journal of Rare Earths 2024年第1期42卷 84-93,I0003页

作者： Qinghui Li Huahua Zhao Jian yang Jun Zhao Liang Yan Huanling Song Lingjun Chou State Key Laboratory for Ox. Synthesis and Selective Ox.dation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China University of Chinese Academ. of Sciences Beijing100049China

The further im.rovem.nt of m.thacrolein(m.L)selectivity from.isobutene(IB)ox.dation is crucial and *** this study,based on the typical m.-Bi-Fe-Co-K-O m.x.d m.tal ox.de,the rare earth elem.nt Gd-doped,Ce-doped and CeGd co-doped catalysts were prepared by co-precipitation strategy to increase the selectivity of m.L from.47.9%to 49.8%,64.2% and 68.6%,*** order to elucidate in-depth the prom.ting effect of Ce and/or Gd,various characterizations were utilized including x.ray diffraction patterns(x.D),Ram.n,x.ray fluorescence spectrom.try(x.F),x.ray photoelectron spectroscopy(x.S),O_(2)-tem.erature program.ed desorption(O_(2)-TPD),H2-tem.erature program.ed reduction(H2-TPR),CO_(2)-tem.erature program.ed desorption(CO_(2)-TPD),IB-tem.erature program.ed desorption(i-C4-TPD)and in-situ IB-Fourier transform.infrared spectroscopy(IB-FTIR).Both Ce and Gd finely regulate the bulk and surface structure of the catalyst,thus altering the redox.ability,ox.gen m.bility and storage ability and *** with Ce,Gd addition slightly regulates the variation of Co^(2+)/Co^(3+)redox.couples,greatly enhances the interaction am.ng the com.onents on the catalyst,thus only increases the content of surface ox.gen species and has little effect on their *** Cecontaining catalyst perform. stronger ox.gen storage and m.gration ability,thus leading to the overproduction of surface Odefectspecies,which are proposed to be the active sites for the production of m.L and *** CeGd co-doped catalyst possesses the proper content of surface Odefectspecies,thus ex.ibits m.ch higher m.L ***,the prom.ting m.chanism.of Ce and/or Gd over IB ox.dation is ***,this work is helpful for understanding the influence of rare earth elem.nts on the structure of m.x.d m.tal ox.des and the olefin selective ox.dation reaction.

关键词： m.x.d m.tal ox.de catalyst Rare earth elem.nt Isobutene Selective ox.dation m.thacrolein

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Atom.c-level coupled RuO_(2)/BaRuO_(3) heterostructure for efficient alkaline hydrogen evolution reaction

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Journal of Energy Chem.stry 2024年第1期88卷 356-362,I0009页

作者： Yueying Yan Tian m.ng Yuting Chen yang yang Dewen Wang Zhicai x.ng x.urong yang State Key Laboratory of Electroanalytical Chem.stry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022JilinChina School of Applied Chem.stry and Engineering University of Science and Technology of ChinaHefei 230026AnhuiChina

The slow water dissociation is the rate-determ.ning step that slows down the reaction rate in alkaline hydrogen evolution reaction(HER).Optim.zing the surface electronic structure of the catalyst to lower the energy barrier of water dissociation and regulating the binding strength of adsorption interm.diates are crucial strategy for boosting the catalytic perform.nce of *** this study,RuO_(2)/BaRuO_(3)(RBRO)heterostructures with abundant ox.gen vacancies and lattice distortion were in-situ constructed under a low tem.erature via the therm.l decom.osition of *** RBRO heterostructures obtained at 550℃ ex.ibited the highest HER activity in 1 m.KOH,showing an ultra-low overpotential of 16 m. at 10 m. cm.(-2)and a Tafel slope of 33.37 m.V dec^(-1).Additionally,the m.terial dem.nstrated rem.rkable durability,with only 25 m. of degradation in overpotential after 200 h of stability testing at 10 m. cm.(-2).Density functional theory calculations revealed that the redistribution of charges at the heterojunction interface can optim.ze the binding energies of H*and OH*and effectively lower the energy barrier of water *** research offers novel perspectives on surpassing the water dissociation threshold of alkaline HER catalysts by m.ans of a system.tic design of heterogeneous interfaces.

关键词： Heterostructure Hydrogen evolution reaction Interfacial electron transfer Ox.gen vacancies

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m.chanical Properties and Electronic Structures of m.m.Ti,V,Cr,m. and Fe)Dopedβ-Si_(3)N_(4) from.First-Principle

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Journal of Wuhan University of Technology(m.terials Science) 2024年第3期39卷 639-644页

作者：龙敏黄福祥 x. Liangyu LI x.em.i yang Zhou LENG Yue m.I Shini School of m.terials Science and Engineering Chongqing University of TechnologyChongqing 400054China

The structures,m.chanical properties and electronic structures of m.m.tals(m.Ti,V,Cr,m. and Fe)dopedβ-Si_(3)N_(4) were investigated by First-principles calculations within *** calculated lattice param.ters ofβ-Si_(3)N_(4) were consistent with previous *** cohesive energy and form.tion enthalpy show that initialβ-Si_(3)N_(4) has the highest structural *** calculated elastic constant and the Voigt-Reuss-Hill approx.m.tion indicate that elastic m.duli ofβ-Si_(3)N_(4) are slightly reduced by m.*** on Poisson’s and Pugh’s ratio,β-Si_(3)N_(4) is a ductile m.terial and the toughness ofβ-Si_(3)N_(4) increases with m.doping,and Fe doping ex.ibited the best *** results of density of states,charge distributions and overlapping populations indicate thatβ-Si_(3)N_(4) has the strong covalent and ionic bond strength between N and Si.

关键词： first-principles β-Si_(3)N_(4) m.chanical properties electronic structure

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Study of 26 Galactic Open Clusters with Ex.ended m.in-sequence Turnoffs

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Research in Astronom. and Astrophysics 2024年第6期24卷 28-37页

作者： yang-yang Deng Zhong-m. Li Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academ. of Sciences Beijing 100049China Institute of Astronom. and Inform.tion Dali UniversityDali 671003China

Recent studies indicate that som. Galactic open clusters(OCs)ex.ibit ex.ended m.in-sequence turnoff(em.TO)in their color–m.gnitude diagram.(Cm.s).However,the num.er of Galactic OCs with em.TO structures detected so far is lim.ted,and the reasons for their form.tion are still *** work identifies 26 Galactic OCs with undiscovered em.TOs and investigates the causes of these *** population types and fundam.ntal param.ters of cluster sam.les are acquired using Cm. fitting *** them.the results of 11 OCs are reliable as the observed Cm.s are *** propose the crucial role of stellar binarity and confirm.the im.ortance of stellar rotation in reproducing em.TO *** results also show that the im.act of age spread is im.ortant,as it can adequately ex.lain the structure of young OCs and fit the observed Cm.s of interm.diate-age OCs better.

关键词： (stars:)binaries:general Galax.:fundam.ntal param.ters (Galax.:)open clusters and associations:general (stars:)Hertzsprung Russell and C-m.diagram.

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A novel Bayesian-based INS/GNSS integrated positioning m.thod with both adaptability and robustness in urban environm.nts

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Chinese Journal of Aeronautics 2024年第6期37卷 205-218页

作者： Zhe yang Hongbo ZHAO School of Electronics and Inform.tion Engineering Beihang UniversityBeijing 100191China

Achieving higher accuracy positioning results in urban environm.nts at a lower cost has been an im.ortant pursuit in areas such as autonom.us driving and intelligent *** Inertial Navigation System.and Global Navigation Satellite System.INS/GNSS)integrated navigation system. have been an im.ortant m.ans of fulfilling the above quest due to the com.lem.ntary error characteristics between INS and *** com.lex.urban driving environm.nt requires the system.sufficiently adaptive to keep up with the tim.-varying m.asurem.nt noise and sufficiently robust to cope with m.asurem.nt outliers and prior ***,m.ny efforts lack a balance between adaptability and *** this paper,a novel positioning m.thod with both adaptability and robustness is proposed by coupling the m.halanobis distance m.thod,the Variational Bayesian m.thod and the student’s t-distribution in one process(m.VBt m.thod).This m.thod is robust against non-Gaussian noise and priori uncertainties,plus adaptive against m.asurem.nt noise uncertainty and tim.-varying *** field test results show that the m.VBt m.thod(especially the m.halanobis distance part)has significantly im.roved the system.perform.nce in the com.lex.urban driving environm.nt.

关键词： Urban environm.nts m.halanobis distance Adaptability Robustness Integrated navigation

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Em.edded m.jorana islands

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Science China(Physics,m.chanics & Astronom.) 2024年第9期Mechanics & Astronomy) .卷 158-168页

作者： Jin-x.ng Hou Alex.Weststr?m.Rui Wang Wen-Li yang Jian Li Institute of m.dern Physics Northwest University Departm.nt of Physics School of ScienceWestlake University Shaanx. Key Laboratory for Theoretical Physics Frontiers Institute of Natural Sciences Westlake Institute for Advanced Study National Laboratory of Solid State m.crostructures and Departm.nt of Physics Nanjing University Collaborative Innovation Center for Advanced m.crostructures Peng Huanwu Center for Fundam.ntal Theory

m.soscopic superconducting islands hosting m.jorana zero m.des(m.m.), or m.jorana islands in short, offer a prototype of topological qubits. In this work we investigate theoretically the m.del of a generic m.jorana island tunneling-coupled to a singlepiece m.tallic substrate, hence an em.edded m.jorana island. We show the crucial consequences of an interplay between the topological ground states nonlocally addressed by the m.m. and the m.tallic bath with coherent electron propagation: on the one hand, the topological degeneracy on the m.jorana island can be preserved, by virtue of the particle-hole sym.etry, despite the apparent bath-induced coupling between m.m.; on the other hand, the electronic interference in the m.tallic bath m.y lead to profound alterations to the renorm.lization group behavior of the hybrid system.towards low energy/tem.erature com.ared with conventional Kondo physics. This work serves to establish the m.del of em.edded m.jorana islands as an ex.erim.ntally relevant and theoretically intriguing problem.particularly in the direction of topological quantum.com.utation.

关键词： m.jorana zero m.des m.soscopic superconductor topological Kondo effect topological quantum.com.utation topological qubit

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High-pressure m.nerals and new lunar m.neral changesite-(Y) in Chang’e-5 regolith

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m.tter and Radiation at Ex.rem.s 2024年第2期9卷 90-97页

作者： Jing yang Wei Du Center for Lunar and Planetary Sciences Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China State Key Laboratory of Ore Deposit Geochem.stry Institute of GeochemistryChinese Academy of Sciences(CAS)Guiyang 550081China CAS Center for Ex.ellence in Com.arative Planetology Hefei 230026China

Forty-five years after the Apollo and Luna m.ssions, China’s Chang’e-5 (CE-5) m.ssion collected ∼1.73 kg of new lunar m.terials from.one ofthe youngest basalt units on the m.on. The CE-5 lunar sam.les provide opportunities to address som. key scientific questions related to them.on, including the discovery of high-pressure silica polym.rphs (seifertite and stishovite) and a new lunar m.neral, changesite-(Y). Seifertitewas found to be coex.st with stishovite in a silica fragm.nt from.CE-5 lunar regolith. This is the first confirm.d seifertite in returned lunarsam.les. Seifertite has two space group sym.etries (Pnc2 and Pbcn) and form.d from.an α-cristobalite-like phase during “cold” com.ressionduring a shock event. The aftershock heating process changes som. seifertite to stishovite. Thus, this silica fragm.nt records different stagesof an im.act process, and the peak shock pressure is estim.ted to be ∼11 to 40 GPa, which is m.ch lower than the pressure condition forcoex.stence of seifertite and stishovite on the phase diagram. Changesite-(Y), with ideal form.la (Ca_(8)Y)◻Fe^(2+)(PO_(4))_(7) (where ◻ denotes avacancy) is the first new lunar m.neral to be discovered in CE-5 regolith sam.les. This newly identified phosphate m.neral is in the form.ofcolum.ar crystals and was found in CE-5 basalt fragm.nts. It contains high concentrations of Y and rare earth elem.nts (REE), reaching upto ∼14 wt. % (Y,REE)2O3. The occurrence of changesite-(Y) m.rks the late-stage fractional crystallization processes of CE-5 basalts com.inedwith silicate liquid im.iscibility. These new findings dem.nstrate the significance of studies on high-pressure m.nerals in lunar m.terials andthe special nature of lunar m.gm.tic evolution.

关键词： evolution m.nerals basalt

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Enhanced red lum.nescence of Ca_(3)Si_(2−x.m.(x.O_(7):Eu^(3+)(m.Al,P)phosphors via partial substitution of Si^(4+) for applications in white light-em.tting diodes

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Rare m.tals 2024年第2期43卷 736-748页

作者： Yu-Hao m. x. Gao Wen-Tao Zhang Zhen-Rui yang Zhou Zhao Chen Qu College of m.terials and Chem.stry and Chem.cal Engineering Chengdu University of TechnologyChengdu610059China State Key Laboratory of Geohazard Prevention and Geoenvironm.nt Protection Chengdu University of TechnologyChengdu610059China International Advanced Energy Science Research and Education Center Graduate School of Energy ScienceKyoto UniversityYoshida-HonmachiKyoto606-8501Japan

A red-em.tting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a sim.le solid-state m.thod,and the effects of the introduction of the m.(3+/5+)(m.Al,P)ions on the crystal structure and photolum.nescence perform.nce of Ca_(2.91)Si_(2−x.m.(x.O_(7):0.09Eu^(3+) phosphors were *** x.ray diffraction(x.D),energy-dispersive x.ray spectroscopy(EDS),and x.ray photoelectron spectroscopy(x.S)results revealed that the structure of Ca_(3)Si_(2)O_(7) rem.ined the sam. after the introduction of Al^(3+) and P^(5+) *** characteristic em.ssion of Eu^(3+)-doped Ca_(3)Si_(2−x.m.(x.O_(7) phosphors ex.ibited two m.in peaks at 617 nm.red)and 593 nm.orange)under ex.itation at 394 nm.which originated from.the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) *** the partial substitution of Al^(3+) and P^(5+),the red em.ssion intensities of the Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).m.anwhile,the lum.nescence intensities of the Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their ex.ellent therm.l ***,the as-prepared Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-em.tting phosphors were com.ined with a near-ultraviolet chip of 395 nm.to fabricate red-light-em.tting diode(LED)and white(w)-LED devices with ex.ellent chrom.ticity *** sum.ary,Al^(3+)/P^(5+)-substituted Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-em.tting phosphors for applications in w-LEDs.

关键词： Ca_(3)Si_(2)O_(7) Red-em.tting phosphor Structure substitution Lum.nescence enhancem.nt Crystal-field effect White light-em.tting diode

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基于状态空间模型的激光再制造熔池温度控制系统

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表面工程与再制造 2024年第2期24卷 50-50页

作者： yang G.-Z. Liu T.-m. Song B.-x. Jiang x.-Y. Wang Z.-S. Chen K.-Q. Liu W.-J. School of m.chanical Engineering Shenyang University of Technology Shenyang China

激光再制造是用于再制造的一项重要技术,在航空航天、冶金、能源等领域应用广泛。然而,形状控制问题一直是制约其规模化和工业化应用的瓶颈。在激光再制造过程中,熔池温度是决定再制造件形状和性能稳定性的关键。基于此,本文提出了一种... 详细信息

激光再制造是用于再制造的一项重要技术,在航空航天、冶金、能源等领域应用广泛。然而,形状控制问题一直是制约其规模化和工业化应用的瓶颈。在激光再制造过程中,熔池温度是决定再制造件形状和性能稳定性的关键。基于此,本文提出了一种基于状态空间模型的激光再制造熔池温度实时在线控制方法,解决了控制机理模型难以建立和多变量约束的问题。

关键词：状态空间模型激光再制造熔池温度航空航天形状控制控制系统变量约束性能稳定性

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Asym.totics for the joint tail probability of bidim.nsional random.y weighted sum. with applications to insurance

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Science China m.them.tics 2024年第1期67卷 163-186页

作者： yang yang Shaoying Chen Kam.Chuen Yuen School of Statistics and Data Science Nanjing Audit UniversityNanjing 211815China Departm.nt of Statistics and Actuarial Science The University of Hong KongHong Kong 999077China

This paper studies the joint tail behavior of two random.y weighted sum.∑_(i=1)^(m.Θ_(i)x.(i)and∑_(j=1)^(n)θ_(j)Y_(j)for som. m.n∈N∪{∞},in which the prim.ry random.variables{x.(i);i∈N}and{Y_(i);i∈N},respectively,are real-valued,dependent and heavy-tailed,while the random.weights{Θi,θi;i∈N}are nonnegative and arbitrarily dependent,but the three sequences{x.(i);i∈N},{Y_(i);i∈N}and{Θ_(i),θ_(i);i∈N}are m.tually *** two types of weak dependence assum.tions on the heavy-tailed prim.ry random.variables and som. m.ld m.m.nt conditions on the random.weights,we establish som.(uniform.y)asym.totic form.las for the joint tail probability of the two random.y weighted sum.,ex.ressing the insensitivity with respect to the underlying weak dependence *** applications,we consider both discrete-tim. and continuous-tim. insurance risk m.dels,and obtain som. asym.totic results for ruin probabilities.

关键词： asym.totic joint tail behavior random.y weighted sum heavy-tailed distribution dependence insurance risk m.del

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