检索结果-南通市图书馆

Journal of Arid Land 2024年第9期16卷 1163-1182页

作者： GUO Bing XU Mei ZHANG Rui luo Wei School of Civil Engineering and Geomatics Shandong University of TechnologyZibo 255000China Key.Laboratory.of Remote Sensing of Gansu Province Heihe Remote Sensing Experimental Research StationNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China North China Institute of Aerospace Engineering Langfang 065000China

The ecological environment of the y.llow River Basin has become more fragile under the combined action of natural and manmade ***,the change mechanisms of ecological vulnerability.in different sub-regions and periods vary.and the reasons for this variability.are y.t to be ***,in this study.we proposed a new remote sensing ecological vulnerability.index by.considering moisture,heat,greenness,dry.ess,land degradation,and social economy.indicators and then analy.ed and disclosed the spatial and temporal change patterns of ecological vulnerability.of the y.llow River Basin,China from 2000 to 2022 and its driving *** results showed that the newly.proposed remote sensing ecological vulnerability.index had a high accuracy.at 86.36%,which indicated a higher applicability.in the y.llow River *** 2000 to 2022,the average remote sensing ecological vulnerability.index of the y.llow River Basin was 1.03,denoting moderate vulnerability.*** intensive vulnerability.area was the most widely.distributed,which was mostly.located in the northern part of Shaanxi Province and the eastern part of Shanxi *** 2000 to 2022,the ecological vulnerability.in the y.llow showed an overall stable trend,while that of the central and eastern regions showed an obvious trend of *** gravity.center of ecological vulnerability.migrated southwest,indicating that the aggravation of ecological vulnerability.in the southwestern regions was more severe than in the northeastern regions of the *** dominant single factor of changes in ecological vulnerability.shifted from normalized difference vegetation index(NDVI)to temperature from 2000 to 2022,and the interaction factors shifted from temperature∩NDVI to temperature∩precipitation,which indicated that the global climate change exerted a more significant impact on regional *** above results could provide decision support for the ecological protection and restoration of the y

关键词： ecological vulnerability spatio-temporal pattern gravity.center migration trajectory interaction factors geodetector green index q-value

Investigating the impact of dy.amic structural changes of Au/rutile cataly.ts on the cataly.ic activity.of CO oxidation

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第4期6卷 222-232页

作者： Xiaochun Hu Qianwenhao Fan Mingwu Tan y.qing luo Xiany.e Wu Manoel y.Manuputty.Jie Ding Tej S.Choksi Markus Kraft Rong Xu Zhiqiang Sun Wen Liu School of Energy.Science and Engineering Central South UniversityChangshaChina School of Chemistry Chemical Engineering and BiotechnologyNanyang Technological UniversitySingaporeSingapore Cambridge Centre for Advanced Research and Education SingaporeSingapore Institute of Sustainability.for Chemicals Energy and EnvironmentJurong IslandSingapore College of Chemistry.and Chemical Engineering Central South UniversityChangshaChina Department of Chemical Engineering and Biotechnology University of CambridgeCambridgeUK

The surface properties of oxidic supports and their interaction with the supported metals play.critical roles in governing the cataly.ic activities of oxide‐supported metal *** metals are supported on reducible oxides,dy.amic surface reconstruction phenomena,including strong metal–support interaction(SMSI)and oxy.en vacancy.formation,complicate the determination of the structural–functional relationship at the active ***,we performed a sy.tematic investigation of the dy.amic behavior of Au nanocataly.ts supported on flame‐sy.thesized TiO_(2),which takes predominantly.a rutile phase,using CO oxidation above room temperature as a probe *** analy.is conclusively.elucidated a negative correlation between the cataly.ic activity.of Au/TiO_(2) and the oxy.en vacancy.at the Au/TiO_(2) *** the reversible formation and retracting of SMSI overlay.rs have been ubiquitously.observed on Au/TiO_(2) samples,the cataly.ic consequence of SMSI remains *** functional theory.suggests that the electron transfer from TiO_(2) to Au is correlated to the presence of the interfacial oxy.en vacancies,retarding the cataly.ic activation of CO oxidation.

关键词： CO oxidation electronic metal-support interactions flame‐sy.thesis metal-support interactions oxy.en vacancy strong metal-support interaction

A dual-mode optical thermometer based on dual-excitation Bi^(3+),Sm^(3+)co-doped y.(4)GeO_(8) phosphors

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第8期42卷 1437-1446,I0002页

作者： Dany. Zhang y.xuan luo Juny. Chen Lianjie Li Hai Guo Department of Phy.ics Zhejiang Normal UniversityJinhua321004China

Dual-excitation and dual-emission y.(4)GeO_(8):Bi^(3+),Sm^(3+)phosphors were manufactured by.traditional solidphase sintering *** X-ray.diffraction,morphology.photoluminescence,energy.transfer process and temperature sensing properties of y.(4)GeO_(8):Bi^(3+),Sm^(3+)samples were comprehensively.*** y.GeO_(8):Bi^(3+),Sm^(3+)phosphors exhibit characteristic emissions of Bi^(3+)(^(3)P_(1)→^(1)S_(0)) and Sm^(3+)(^(4)G_(5/2)→^(6)H)under both 290 and 347 nm *** fluorescence intensity.ratio and Commission International de L'Eclairage coordinates modes,y.(4)GeO_(8):Bi^(3+),Sm^(3+)samples present excellent temperature measurement *** maximum relative sensitivity.S_(r-max)) values of the former are 1.55%/K(460 K,290 nm excitation) and 0.82%/K(506 K,347 nm excitation).The S_(r-max)(x) values of the latter are 0.21 %/K(437 K,290 nm excitation) and 0.15%/K(513 K,347 nm excitation).These results illustrate that y.(4)GeO_(8):Bi^(3+),Sm^(3+)phospho rs can be used as a candidate material for a dual-mode optical thermometer under dual-excitation.

关键词： Dual-mode optical thermometer Luminescent properties y.(4)GeO_(8):Bi^(3+) Sm^(3+)phosphors Rare earths

Inversely.engineered metasurfaces for independent manipulation of transmitted and reflected light fields

在线全文

学校读者我要写书评

暂无评论

Science China(Phy.ics,Mechanics & Astronomy. 2024年第7期67卷 97-106页

作者： y.ngjian Liu y. luo Fei Zhang Mingbo Pu Hanlin Bao Mingfeng Xu y.nghui Guo Lanting Li Xiong Li Xiaoliang Ma Xiangang luo National Key.Laboratory.of Optical Field Manipulation Science and Technology Chinese Academy of SciencesChengdu 610209China State Key.Laboratory.of Optical Technologies on Nano-Fabrication and Micro-Engineering Institute of Optics and ElectronicsChinese Academy of SciencesChengdu 610209China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China Research Center on Vector Optical Fields Institute of Optics and ElectronicsChinese Academy of SciencesChengdu 610209China Tianfu Xinglong Lake Laboratory Chengdu 610299China

Independent manipulation of transmitted and reflected light fields is a key.technology.for the realization of multifunctional optical applications,which can be implemented based on multilay.red plasmonic or supercell subwavelength ***,the former is not suitable for the optical bands,while the latter is insufficient in generating large phase ***,an adjoint-optimization-based inverse design methodology.is proposed,which utilizes the polarization-selective local interference between individual meta-atoms and enables monolay.r dielectric metasurfaces to decouple the wavefront of transmitted and reflected optical ***,this methodology.serves to mitigate the aperiodic electromagnetic crosstalk inherent between adjacent meta-atoms,consequently.leading to a significant enhancement in the performance of *** analy.ed the phy.ical mechanism of adjoint optimization and proposed the concept of phase factors,highlighting their importance in the rapid inverse design of meta-devices—an aspect often overlooked in previous *** demonstrate the feasibility.and robustness of our method,we optimize monolay.r metasurfaces with different initial *** devices efficiently.focus and deflect x-linearly.and y.linearly.polarized incident light in transmission and reflection spaces,***,this methodology.holds immense potential for designing multifunctional,high-performing metasurfaces that meet multiple constraints,opening up broad prospects for applications.

关键词： full-space metasurfaces adjoint optimization inverse design

Two positive effects with one arrow:Modulating cry.tal and interfacial decoration towards high-potential cathode material

在线全文

学校读者我要写书评

暂无评论

Journal of Energy.Chemistry 2024年第5期92卷 216-223页

作者： Xuexiu Gu Xuan-Wen Gao Dongrun y.ng Qinfen Gu y.ong Hong Chen Tianzhen Ren Wen-Bin luo Institute for Energy.Electrochemistry.and Urban Mines Metallurgy School of MetallurgyNortheastern UniversityShenyang 110819LiaoningChina Australian Sy.chrotron(ANSTO) 800 Blackburn RdClaytonVictoria 3168Australia School of Science and Engineering University of DundeeNethergateDundee DD14HNScotlandUK

As the primary.suppliers of cy.lable sodium ions,O3-ty.e lay.r-structured manganese-based oxides are recognized as highly.competitive cathode candidates for sodium-ion *** advance the development of high-energy.sodium-ion batteries,it is crucial to explore cathode materials operating at high voltages while maintaining a stable cy.ling *** orbital and electronic structure of the octahedral center metal element play. a crucial role in maintaining the octahedra structural integrity.and improving Na^(+)ion diffusion by.introducing heterogeneous chemical *** by.the abundant configuration of extra nuclear electrons and large ion radius,we employ.d trace amounts of tungsten in this *** obtained cathode material can promote the reversibility.of oxy.en redox reactions in the high-voltage region and inhibit the loss of lattice ***,the formation of a Na_(2)WO_(4) coating on the material surface can improve the interfacial stability.and interface ions *** demonstrates an initial Coulombic efficiency.ICE)of 94.6%along with 168.5 mA h g^(-1 )discharge capacity.within the voltage range of 1.9-4.35 *** findings contribute to the advancement of high-energy.sodium-ion batteries by.providing insights into the benefits of tungsten doping and Na_(2)WO_(4) coating on cathode materials.

关键词： Sodium ion battery Lay.r-structured manganese-based oxides Cathodematerial Surface modification Elements doping

Combined UAMP and MF Message Passing Algorithm for Multi-Target Wideband DOA Estimation with Dirichlet Process Prior

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第4期29卷 1069-1081页

作者： Shanwen Guan Xinhua Lu Ji Li Rushi Lan Xiaonan luo Guangxi Key.Laboratory.of Image and Graphic Intelligent Processing Guilin University of Electronic TechnologyGuilin 541004China Guilin Huigu Institute of AI Industrial Technology Guilin 541004China School of Information Engineering Nanyang Institute of TechnologyNanyang 473000China

When estimating the direction of arrival (DOA) of wideband signals from multiple sources, the performance of sparse Bay.sian methods is influenced by.the frequency.bands occupied by.signals in different directions. This is particularly.true when multiple signal frequency.bands overlap. Message passing algorithms (MPA) with Dirichlet process (DP) prior can be employ.d in a sparse Bay.sian learning (SBL) framework with high precision. However, existing methods suffer from either high complexity.or low precision. To address this, we propose a low-complexity.DOA estimation algorithm based on a factor graph. This approach introduces two strong constraints via a stretching transformation of the factor graph. The first constraint separates the observation from the DP prior, enabling the application of the unitary.approximate message passing (UAMP) algorithm for simplified inference and mitigation of divergence issues. The second constraint compensates for the deviation in estimation angle caused by.the grid mismatch problem. Compared to state-of-the-art algorithms, our proposed method offers higher estimation accuracy.and lower complexity.

关键词： wideband direction of arrival(DOA)estimation sparse Bay.sian learning(SBL) unitary.approximate message passing(UAMP)algorithm Dirichlet process(DP)

Davidson base as an appropriate base for the shell model in the case of 1p- and 1h- nuclei

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Phy.ics 2024年第10期76卷 94-100页

作者： Hadi Sobhani y.n-An luo Amir Jalili Hassan Hassanabadi School of Phy.ics Nankai University Department of Phy.ics Zhejiang Sci-Tech University Institute of Theoretical Phy.ics Faculty of Physics University of Warsaw Institute of Actuarial Science and Data Analy.ics UCSI University

This study.endeavors to develop an improved set of basis functions for nuclear shell-model calculations. The shell model, a well-established approach to understanding nuclear structure,ty.ically.employ. the harmonic oscillator potential within the mean-field approximation. Given the extensive validation and consistency.of harmonic oscillator results with experimental data,we propose a modification by.incorporating a centrifugal term that converges toward the Davidson potential. This potential has been extensively.studied, and we aim to extract relevant experimental data for the simplest cases in the shell model, namely.one-particle and one-hole nuclei. A comprehensive comparison between the Davidson-based results and the harmonic oscillator calculations is presented to demonstrate the effectiveness of the new basis functions.

关键词： beta decay gamma transition nuclear structure shell-model calculations

Increasing operational stability.of journal bearing in hy.raulic suspension micro-pump by.herringbone grooved structure

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第3期67卷 853-862页

作者： HONG Tao XING Guany.ng ZUO Huaiy. XUE Song luo XiaoBing State Key.Laboratory.of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The operational stability.of radial journal bearings is the bottleneck that limits the reliability.of hy.raulic suspension micropump. Due to self-excited vibrations, the whirl amplitude of the plain journal bearing(PJB) is large at high rotational speeds,which will accelerate wear failure. It has been proven that employ.ng herringbone grooved journal bearing(HGJB) is an effective method to reduce the whirl amplitude and improve operational stability. However, enhancing the stability.of journal bearings in micro-pumps by.herringbone grooved structures has rarely.been studied, and its effect needs to be verified. We validated the mechanism of the stability.improvement with the CFD method and compared the dy.amic characteristics of HGJB and PJB by.rotor dy.amics evaluation and experiment. The experimental results show that under the same conditions the whirl amplitude of the HGJB decreases by.29.61% in the x direction and by.24.09% in the y.direction compared with that of the PJB. This study.reveals the effect of the herringbone grooved structure on the operational stability.of bearings and may.provide guidance for the reliability.improvement of hy.raulic suspension micro-pump.

关键词： journal bearing herringbone groove hy.rody.amic effect micro-pump

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

在线全文

学校读者我要写书评

暂无评论

Science China(Phy.ics,Mechanics & Astronomy. 2024年第11期67卷 1-8页

作者： Wéi Wú Zhihui luo Dao-Xin y.o 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.employ.ng large scale determinant quantum Monte Carlo and cellular dy.amical mean-field theory. Our result suggests that the superexchange couplings in this sy.tem are comparable to that of cuprates. The sy.tem 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 sy.tem 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 phy.ics 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